Sarcoma & GIST

Research clinicians from the US and abroad participated in a scientific research roundtable this past September to establish the most important issues facing leiomyosarcoma (LMS) research and clinical trials. The workshop, expected to be an annual event, is a joint effort of the National Leiomyosarcoma Foundation (NLMSF) and Sarcoma Patients EuroNet (SPAEN).

The roundtable’s mission is to bring together sarcoma experts for a meeting dedicated to LMS, where participants discuss the present state of LMS and the continued challenges of diagnosis and treatment. Its goal is to develop working plans to close the gaps in LMS patient care and improve LMS patient-care protocols. They also advise the NLMSF on worthy and important research projects that deserve the foundation’s future funding efforts.

Plans for roundtable meetings in 2020 and 2021 are already underway. Between the annual meetings, workgroups continue to take steps toward addressing the issues identified by the roundtable. For more information on the roundtable and NLMSF, visit: https://nlmsf.org.

Research clinicians from the US and abroad participated in a scientific research roundtable this past September to establish the most important issues facing leiomyosarcoma (LMS) research and clinical trials. The workshop, expected to be an annual event, is a joint effort of the National Leiomyosarcoma Foundation (NLMSF) and Sarcoma Patients EuroNet (SPAEN).

The roundtable’s mission is to bring together sarcoma experts for a meeting dedicated to LMS, where participants discuss the present state of LMS and the continued challenges of diagnosis and treatment. Its goal is to develop working plans to close the gaps in LMS patient care and improve LMS patient-care protocols. They also advise the NLMSF on worthy and important research projects that deserve the foundation’s future funding efforts.

Plans for roundtable meetings in 2020 and 2021 are already underway. Between the annual meetings, workgroups continue to take steps toward addressing the issues identified by the roundtable. For more information on the roundtable and NLMSF, visit: https://nlmsf.org.

Research clinicians from the US and abroad participated in a scientific research roundtable this past September to establish the most important issues facing leiomyosarcoma (LMS) research and clinical trials. The workshop, expected to be an annual event, is a joint effort of the National Leiomyosarcoma Foundation (NLMSF) and Sarcoma Patients EuroNet (SPAEN).

The roundtable’s mission is to bring together sarcoma experts for a meeting dedicated to LMS, where participants discuss the present state of LMS and the continued challenges of diagnosis and treatment. Its goal is to develop working plans to close the gaps in LMS patient care and improve LMS patient-care protocols. They also advise the NLMSF on worthy and important research projects that deserve the foundation’s future funding efforts.

Plans for roundtable meetings in 2020 and 2021 are already underway. Between the annual meetings, workgroups continue to take steps toward addressing the issues identified by the roundtable. For more information on the roundtable and NLMSF, visit: https://nlmsf.org.

Investigators conducted a survey study of 214 patients with dermatofibrosarcoma protuberans (DFSP) or their family members using in part existing Facebook patient support groups (FBSG) to recruit respondents. They found the approach provides a “powerful” tool to collect relevant disease information from large numbers of patients with rare diseases.

A team of medical practitioners and patients developed the multiple-choice survey, and after testing the survey twice, posted a survey announcement on FBSGs for DFSP. The survey was live for 3 weeks in 2015. The investigators rapidly collected disease statistics, including information on recurrence, metastasis, surgical outcomes, diagnostic delay, and more, suggesting that FBSGs are useful medical research tools.

One hundred ninety-nine respondents were patients and 15 were family members. The respondents reported a median of 4 years to receive a correct diagnosis after noticing a lesion, ranging from less than 1 year to 42 years. About half the patients (52.3%) believed they received a misdiagnosis at some point, either from a dermatologist, primary care clinician, or another type of physician. Patients first noticed DFSP at a median age of 29.6 years. Many of their lesions appeared initially as flat plaques that eventually became protuberant. Because of this disconnect between the disease name and its clinical presentation, the investigators proposed the alternative term, dermatofibrosarcoma, often protuberant, be adopted. The investigators concluded that “FBSGs appear to be powerful tools to synergize effective and rapid research collaborations with large numbers of international patients with rare disease.” TSJ

Investigators conducted a survey study of 214 patients with dermatofibrosarcoma protuberans (DFSP) or their family members using in part existing Facebook patient support groups (FBSG) to recruit respondents. They found the approach provides a “powerful” tool to collect relevant disease information from large numbers of patients with rare diseases.

A team of medical practitioners and patients developed the multiple-choice survey, and after testing the survey twice, posted a survey announcement on FBSGs for DFSP. The survey was live for 3 weeks in 2015. The investigators rapidly collected disease statistics, including information on recurrence, metastasis, surgical outcomes, diagnostic delay, and more, suggesting that FBSGs are useful medical research tools.

One hundred ninety-nine respondents were patients and 15 were family members. The respondents reported a median of 4 years to receive a correct diagnosis after noticing a lesion, ranging from less than 1 year to 42 years. About half the patients (52.3%) believed they received a misdiagnosis at some point, either from a dermatologist, primary care clinician, or another type of physician. Patients first noticed DFSP at a median age of 29.6 years. Many of their lesions appeared initially as flat plaques that eventually became protuberant. Because of this disconnect between the disease name and its clinical presentation, the investigators proposed the alternative term, dermatofibrosarcoma, often protuberant, be adopted. The investigators concluded that “FBSGs appear to be powerful tools to synergize effective and rapid research collaborations with large numbers of international patients with rare disease.” TSJ

Investigators conducted a survey study of 214 patients with dermatofibrosarcoma protuberans (DFSP) or their family members using in part existing Facebook patient support groups (FBSG) to recruit respondents. They found the approach provides a “powerful” tool to collect relevant disease information from large numbers of patients with rare diseases.

A team of medical practitioners and patients developed the multiple-choice survey, and after testing the survey twice, posted a survey announcement on FBSGs for DFSP. The survey was live for 3 weeks in 2015. The investigators rapidly collected disease statistics, including information on recurrence, metastasis, surgical outcomes, diagnostic delay, and more, suggesting that FBSGs are useful medical research tools.

One hundred ninety-nine respondents were patients and 15 were family members. The respondents reported a median of 4 years to receive a correct diagnosis after noticing a lesion, ranging from less than 1 year to 42 years. About half the patients (52.3%) believed they received a misdiagnosis at some point, either from a dermatologist, primary care clinician, or another type of physician. Patients first noticed DFSP at a median age of 29.6 years. Many of their lesions appeared initially as flat plaques that eventually became protuberant. Because of this disconnect between the disease name and its clinical presentation, the investigators proposed the alternative term, dermatofibrosarcoma, often protuberant, be adopted. The investigators concluded that “FBSGs appear to be powerful tools to synergize effective and rapid research collaborations with large numbers of international patients with rare disease.” TSJ

Pexidartinib, the newly approved agent to treat patients with tenosynovial giant cell tumor (TGCT), received a category 1 recommendation from the National Comprehensive Cancer Network (NCCN) in the recent update of its Clinical Practice Guidelines in Oncology, Soft Tissue Sarcoma (Version 4.2019). A category 1 recommendation is based on a high level of evidence with uniform consensus that the intervention is appropriate.

The NCCN based its recommendation on the randomized, placebo-controlled phase 3 ENLIVEN study (NCT02371369) published in The Lancet (Tap WD, Gelderblom H, Palmerini E, et al. Lancet. 2019;394:478-487). The placebo-controlled portion of the study showed that patients treated with pexidartinib achieved a significantly higher overall response than patients in the placebo arm, 39% compared to none, respectively. The investigators identified mixed or cholestatic hepatotoxicity to be a risk of systemic therapy with the agent. Nevertheless, the “robust tumour response,” they wrote, “with improved patient symptoms and functional outcomes” establish pexidartinib as a potential treatment for TGCT in cases not amenable to improvement with surgery.

Pexidartinib, the newly approved agent to treat patients with tenosynovial giant cell tumor (TGCT), received a category 1 recommendation from the National Comprehensive Cancer Network (NCCN) in the recent update of its Clinical Practice Guidelines in Oncology, Soft Tissue Sarcoma (Version 4.2019). A category 1 recommendation is based on a high level of evidence with uniform consensus that the intervention is appropriate.

The NCCN based its recommendation on the randomized, placebo-controlled phase 3 ENLIVEN study (NCT02371369) published in The Lancet (Tap WD, Gelderblom H, Palmerini E, et al. Lancet. 2019;394:478-487). The placebo-controlled portion of the study showed that patients treated with pexidartinib achieved a significantly higher overall response than patients in the placebo arm, 39% compared to none, respectively. The investigators identified mixed or cholestatic hepatotoxicity to be a risk of systemic therapy with the agent. Nevertheless, the “robust tumour response,” they wrote, “with improved patient symptoms and functional outcomes” establish pexidartinib as a potential treatment for TGCT in cases not amenable to improvement with surgery.

Pexidartinib, the newly approved agent to treat patients with tenosynovial giant cell tumor (TGCT), received a category 1 recommendation from the National Comprehensive Cancer Network (NCCN) in the recent update of its Clinical Practice Guidelines in Oncology, Soft Tissue Sarcoma (Version 4.2019). A category 1 recommendation is based on a high level of evidence with uniform consensus that the intervention is appropriate.

The NCCN based its recommendation on the randomized, placebo-controlled phase 3 ENLIVEN study (NCT02371369) published in The Lancet (Tap WD, Gelderblom H, Palmerini E, et al. Lancet. 2019;394:478-487). The placebo-controlled portion of the study showed that patients treated with pexidartinib achieved a significantly higher overall response than patients in the placebo arm, 39% compared to none, respectively. The investigators identified mixed or cholestatic hepatotoxicity to be a risk of systemic therapy with the agent. Nevertheless, the “robust tumour response,” they wrote, “with improved patient symptoms and functional outcomes” establish pexidartinib as a potential treatment for TGCT in cases not amenable to improvement with surgery.

Angiosarcomas are malignant tumors of the vascular endothelium and are typically idiopathic. These tumors comprise 2% of all soft tissue sarcomas and have an estimated incidence of 2 per million.^1,2 Known causes of angiosarcoma include genetic syndromes—such as von Hippel- Lindau, Chuvash polycythemia, Bannayan- Riley-Ruvalcaba, Cowden, and hamartomatous polyposis syndromes— chronic lymphedema, and exposure to radiation.³ Vinyl chloride, arsenicals, and thorotrast are known to increase the incidence of liver angiosarcoma.⁴

Malignant transformation of hemangioma is rare. We describe metastatic angiosarcoma in a patient with a large, longterm treatment-resistant subcutaneous hemangioma, illustrating such a possibility. We review similar cases and discuss the value of determining pathogenesis in such patients.

Case Presentation and Summary

A 55-year-old female with a long-standing childhood hemangioma of the left lower extremity was referred to Ochsner Medical Center for tissue diagnosis of new pulmonary nodules. Her medical history included a 7 pack-year smoking history; she had quit 3 years prior. Her family history included a sister who died from breast cancer. The patient initially had a progressive, intermittently bleeding tumor in the left foot at age 7. She was diagnosed with hemangioma in her twenties. At that point, her tumor began to involve the posterior calf and femur, causing deformity. She had multiple surgical resections but reportedly all pathology demonstrated benign hemangioma. She received radiation for pain, a routine treatment at the time, but developed a focus of progression in the heel. Above-knee amputation was considered but could not be performed when hemangioma was discovered in the hip area. She was lost to follow-up between 2001 and 2015. Lower extremity magnetic resonance imaging in 2015 was stable with imaging prior to 2001. A repeat biopsy in 2016 demonstrated hemangioma. The patient then received radiation to a wider field, including the femur, with minimal response. She completed a course of steroids as well. Bevacizumab was started in 2017 and improved foot deformity. She also briefly trialed pazopanib for 4 weeks in 2018 in an attempt to switch to oral medications. Despite partial response, she discontinued both agents in July 2018 because of toxicity and the burden of recurrent infusions.

Four months later, she presented with 2 months of intermittent hemoptysis and 18 months of metallic odors. Additionally, she lost 25 pounds in 3 months, which she attributed to a diet plan. At this visit, her left lower extremity exhibited multiple subcutaneous tumors and nodules.

Computed tomography (CT) with contrast demonstrated innumerable pulmonary nodules, the largest measuring 2.2 cm in the right lower lobe superior segment. Positron emission tomography (PET)/CT revealed 2 nodules with mild hypermetabolic activity; the largest nodule had a maximum standardized uptake value of 2.7. Bronchoalveolar lavage studies showed intra-alveolar hemorrhage with hemosiderin-laden macrophages. No malignancy, granuloma, or dysplasia was found in transbronchial needle aspirate of the largest nodule. The patient had no lymphadenopathy.

At this hospital, surgical resection by video-assisted thoracoscopic surgery confirmed multifocal malignant epithelioid neoplasm suspicious for angiosarcoma. Multiple areas showed proliferation of atypical epithelioid-to-spindle cells. There were prominent associated hemosiderin-laden macrophages, fresh red blood cells, and dilated blood-filled spaces. Cells demonstrated hyperchromasia with irregular nuclear contours, prominent nucleoli, and mitoses  (FIGURE 1). Additionally, there were areas of focal organizing pneumonia. For atypical cells, staining was CD31-positive and CD34-negative. Staining was strongly positive for ERG. There was increased Ki-67 with retained INI expression and patchy weak reactivity for Fli-1.

Next-generation sequencing was performed. Specimen tumor content was 15%. Genomic findings included IDH1 p.R132C mutation, with variant allele frequency <10%. Testing was inconclusive for MSI and TMB mutations. PD-L1 assessment could not be performed. Unfortunately, the patient did not qualify for any clinical trials, as there were no matching alterations. This patient was lost to follow-up.

Discussion

Angiosarcoma accounts for 2% of soft tissue sarcomas.¹ Cutaneous angiosarcomas most commonly occur in the face and scalp of the elderly, or in sites of chronic lymphedema. Angiosarcoma also develops following radiation therapy.⁵ For breast cancers and tumors of the head and neck, irradiation has <1% risk of inducing secondary malignancy, including angiosarcoma.⁶

This patient had a new diagnosis of angiosarcoma in the setting of long-standing benign hemangioma with history of radiation treatment. Thus, it is unclear whether this angiosarcoma was primary, radiation-induced, or secondary to transformation from the preexisting vascular tumor. Post-irradiation sarcoma carries a less favorable prognosis compared to de novo sarcoma; however, reports conflict on whether this holds for angiosarcoma subtypes.⁶ Determining etiology may benefit patients for prognostication and possibly inform future selection of treatment modalities.

The mutational signature in radiation- associated sarcomas differs from that of sporadic sarcomas. First, radiation- associated sarcomas demonstrate more frequent small deletions and balanced translocations. TP53 mutations are found in up to 1/3 of radiation-associated sarcomas and are more often due to small deletions than in sporadic sarcomas.⁷ High-level MYC amplification occurs in 54%-100% of secondary angiosarcomas, compared to 0-7% in sporadic angiosarcomas. Co-amplification of FLT4 occurs in 11%-25% of secondary angiosarcomas.⁸ Additionally, transcriptome analysis revealed differential expression of a 135-gene signature compared to non-radiation- induced sarcomas.⁷ Although this patient was not specifically analyzed for such alterations, such tests may differentiate post-irradiation angiosarcoma from sporadic etiologies.

In this patient, the R132C IDH1 mutation was identified and may be the first reported case in angiosarcoma. Typically, this mutation occurs in chondrosarcoma, myeloid neoplasms, gliomas, and cholangiocarcinomas. It is also found in spindle cell hemangiomas but not in other vascular tumors.⁹ The clinical significance of this mutation is uncertain at this time.

There are approximately 36 reported cases of malignant disease arising in patients with less aggressive vascular tumors (TABLE 1). Of these, 25 of 36 involve angiosarcoma arising in patients with hemangioma. Four cases of angiosarcoma were reported in patients with hemangioendothelioma, 1 case of hemangioendothelioma in a patient with hemangioma, 1 case of Dabska tumor in a patient with hemangioma, and 1 case of angiosarcoma in a patient with Dabska tumor. Fifteen cases involved initial disease with adult onset and 21 involved initial disease with pediatric onset, suggesting even distribution. Malignant disease mostly occurred in adulthood, in 26 out of 33 cases. Latency to malignancy ranged from concurrent discovery to 54 years. Mean latency, excluding cases with concurrent discovery, was shorter with adult-onset initial disease, at 4.2 years, compared to 16 years among patients with onset of initial disease in childhood. Longer latency in the pediatric-onset population correlated with longer latent periods for radiation-induced angiosarcoma following benign disease, which is reported to average 23 years.¹⁰ Thirteen of 19 cases with pediatric onset disease had a history of radiotherapy, while 2 of 13 cases with adult onset disease did. Sixteen cases involved tumor in the bone and soft tissue, as in this patient. Notably, 4 of these cases involved long-standing hemangioma for 10 years or more, as in this patient, suggesting a possible correlation between long-standing vascular tumors and malignant transformation. Angiosarcoma arising in non-irradiated patients suggests that malignant transformation and de novo transformation may compete with radiation-induced mutation in tumorigenesis. Further, 8 cases involved angiosarcoma growing within another vascular tumor, demonstrating the possibility of malignant transformation. Dehner and Ishak described a histological model for quantifying such a risk; a validated model may be particularly useful in patients with long-standing hemangioma.¹¹

Etiology of tumorigenesis in cases of angiosarcoma arising in patients with a history of benign hemangioma may benefit prognostication and inform treatment selection in the future. Owing to long latent periods, radiation-associated angiosarcoma incidence may rise, as radiation therapy for benign hemangioma was recently routine. Future research may provide insight into disease progression and possibly predict the risk of angiosarcoma in patients with long-standing benign disease. TSJ

Angiosarcomas are malignant tumors of the vascular endothelium and are typically idiopathic. These tumors comprise 2% of all soft tissue sarcomas and have an estimated incidence of 2 per million.^1,2 Known causes of angiosarcoma include genetic syndromes—such as von Hippel- Lindau, Chuvash polycythemia, Bannayan- Riley-Ruvalcaba, Cowden, and hamartomatous polyposis syndromes— chronic lymphedema, and exposure to radiation.³ Vinyl chloride, arsenicals, and thorotrast are known to increase the incidence of liver angiosarcoma.⁴

Malignant transformation of hemangioma is rare. We describe metastatic angiosarcoma in a patient with a large, longterm treatment-resistant subcutaneous hemangioma, illustrating such a possibility. We review similar cases and discuss the value of determining pathogenesis in such patients.

Case Presentation and Summary

A 55-year-old female with a long-standing childhood hemangioma of the left lower extremity was referred to Ochsner Medical Center for tissue diagnosis of new pulmonary nodules. Her medical history included a 7 pack-year smoking history; she had quit 3 years prior. Her family history included a sister who died from breast cancer. The patient initially had a progressive, intermittently bleeding tumor in the left foot at age 7. She was diagnosed with hemangioma in her twenties. At that point, her tumor began to involve the posterior calf and femur, causing deformity. She had multiple surgical resections but reportedly all pathology demonstrated benign hemangioma. She received radiation for pain, a routine treatment at the time, but developed a focus of progression in the heel. Above-knee amputation was considered but could not be performed when hemangioma was discovered in the hip area. She was lost to follow-up between 2001 and 2015. Lower extremity magnetic resonance imaging in 2015 was stable with imaging prior to 2001. A repeat biopsy in 2016 demonstrated hemangioma. The patient then received radiation to a wider field, including the femur, with minimal response. She completed a course of steroids as well. Bevacizumab was started in 2017 and improved foot deformity. She also briefly trialed pazopanib for 4 weeks in 2018 in an attempt to switch to oral medications. Despite partial response, she discontinued both agents in July 2018 because of toxicity and the burden of recurrent infusions.

Four months later, she presented with 2 months of intermittent hemoptysis and 18 months of metallic odors. Additionally, she lost 25 pounds in 3 months, which she attributed to a diet plan. At this visit, her left lower extremity exhibited multiple subcutaneous tumors and nodules.

Computed tomography (CT) with contrast demonstrated innumerable pulmonary nodules, the largest measuring 2.2 cm in the right lower lobe superior segment. Positron emission tomography (PET)/CT revealed 2 nodules with mild hypermetabolic activity; the largest nodule had a maximum standardized uptake value of 2.7. Bronchoalveolar lavage studies showed intra-alveolar hemorrhage with hemosiderin-laden macrophages. No malignancy, granuloma, or dysplasia was found in transbronchial needle aspirate of the largest nodule. The patient had no lymphadenopathy.

At this hospital, surgical resection by video-assisted thoracoscopic surgery confirmed multifocal malignant epithelioid neoplasm suspicious for angiosarcoma. Multiple areas showed proliferation of atypical epithelioid-to-spindle cells. There were prominent associated hemosiderin-laden macrophages, fresh red blood cells, and dilated blood-filled spaces. Cells demonstrated hyperchromasia with irregular nuclear contours, prominent nucleoli, and mitoses  (FIGURE 1). Additionally, there were areas of focal organizing pneumonia. For atypical cells, staining was CD31-positive and CD34-negative. Staining was strongly positive for ERG. There was increased Ki-67 with retained INI expression and patchy weak reactivity for Fli-1.

Next-generation sequencing was performed. Specimen tumor content was 15%. Genomic findings included IDH1 p.R132C mutation, with variant allele frequency <10%. Testing was inconclusive for MSI and TMB mutations. PD-L1 assessment could not be performed. Unfortunately, the patient did not qualify for any clinical trials, as there were no matching alterations. This patient was lost to follow-up.

Discussion

Angiosarcoma accounts for 2% of soft tissue sarcomas.¹ Cutaneous angiosarcomas most commonly occur in the face and scalp of the elderly, or in sites of chronic lymphedema. Angiosarcoma also develops following radiation therapy.⁵ For breast cancers and tumors of the head and neck, irradiation has <1% risk of inducing secondary malignancy, including angiosarcoma.⁶

This patient had a new diagnosis of angiosarcoma in the setting of long-standing benign hemangioma with history of radiation treatment. Thus, it is unclear whether this angiosarcoma was primary, radiation-induced, or secondary to transformation from the preexisting vascular tumor. Post-irradiation sarcoma carries a less favorable prognosis compared to de novo sarcoma; however, reports conflict on whether this holds for angiosarcoma subtypes.⁶ Determining etiology may benefit patients for prognostication and possibly inform future selection of treatment modalities.

The mutational signature in radiation- associated sarcomas differs from that of sporadic sarcomas. First, radiation- associated sarcomas demonstrate more frequent small deletions and balanced translocations. TP53 mutations are found in up to 1/3 of radiation-associated sarcomas and are more often due to small deletions than in sporadic sarcomas.⁷ High-level MYC amplification occurs in 54%-100% of secondary angiosarcomas, compared to 0-7% in sporadic angiosarcomas. Co-amplification of FLT4 occurs in 11%-25% of secondary angiosarcomas.⁸ Additionally, transcriptome analysis revealed differential expression of a 135-gene signature compared to non-radiation- induced sarcomas.⁷ Although this patient was not specifically analyzed for such alterations, such tests may differentiate post-irradiation angiosarcoma from sporadic etiologies.

In this patient, the R132C IDH1 mutation was identified and may be the first reported case in angiosarcoma. Typically, this mutation occurs in chondrosarcoma, myeloid neoplasms, gliomas, and cholangiocarcinomas. It is also found in spindle cell hemangiomas but not in other vascular tumors.⁹ The clinical significance of this mutation is uncertain at this time.

There are approximately 36 reported cases of malignant disease arising in patients with less aggressive vascular tumors (TABLE 1). Of these, 25 of 36 involve angiosarcoma arising in patients with hemangioma. Four cases of angiosarcoma were reported in patients with hemangioendothelioma, 1 case of hemangioendothelioma in a patient with hemangioma, 1 case of Dabska tumor in a patient with hemangioma, and 1 case of angiosarcoma in a patient with Dabska tumor. Fifteen cases involved initial disease with adult onset and 21 involved initial disease with pediatric onset, suggesting even distribution. Malignant disease mostly occurred in adulthood, in 26 out of 33 cases. Latency to malignancy ranged from concurrent discovery to 54 years. Mean latency, excluding cases with concurrent discovery, was shorter with adult-onset initial disease, at 4.2 years, compared to 16 years among patients with onset of initial disease in childhood. Longer latency in the pediatric-onset population correlated with longer latent periods for radiation-induced angiosarcoma following benign disease, which is reported to average 23 years.¹⁰ Thirteen of 19 cases with pediatric onset disease had a history of radiotherapy, while 2 of 13 cases with adult onset disease did. Sixteen cases involved tumor in the bone and soft tissue, as in this patient. Notably, 4 of these cases involved long-standing hemangioma for 10 years or more, as in this patient, suggesting a possible correlation between long-standing vascular tumors and malignant transformation. Angiosarcoma arising in non-irradiated patients suggests that malignant transformation and de novo transformation may compete with radiation-induced mutation in tumorigenesis. Further, 8 cases involved angiosarcoma growing within another vascular tumor, demonstrating the possibility of malignant transformation. Dehner and Ishak described a histological model for quantifying such a risk; a validated model may be particularly useful in patients with long-standing hemangioma.¹¹

Etiology of tumorigenesis in cases of angiosarcoma arising in patients with a history of benign hemangioma may benefit prognostication and inform treatment selection in the future. Owing to long latent periods, radiation-associated angiosarcoma incidence may rise, as radiation therapy for benign hemangioma was recently routine. Future research may provide insight into disease progression and possibly predict the risk of angiosarcoma in patients with long-standing benign disease. TSJ

Angiosarcomas are malignant tumors of the vascular endothelium and are typically idiopathic. These tumors comprise 2% of all soft tissue sarcomas and have an estimated incidence of 2 per million.^1,2 Known causes of angiosarcoma include genetic syndromes—such as von Hippel- Lindau, Chuvash polycythemia, Bannayan- Riley-Ruvalcaba, Cowden, and hamartomatous polyposis syndromes— chronic lymphedema, and exposure to radiation.³ Vinyl chloride, arsenicals, and thorotrast are known to increase the incidence of liver angiosarcoma.⁴

Malignant transformation of hemangioma is rare. We describe metastatic angiosarcoma in a patient with a large, longterm treatment-resistant subcutaneous hemangioma, illustrating such a possibility. We review similar cases and discuss the value of determining pathogenesis in such patients.

Case Presentation and Summary

A 55-year-old female with a long-standing childhood hemangioma of the left lower extremity was referred to Ochsner Medical Center for tissue diagnosis of new pulmonary nodules. Her medical history included a 7 pack-year smoking history; she had quit 3 years prior. Her family history included a sister who died from breast cancer. The patient initially had a progressive, intermittently bleeding tumor in the left foot at age 7. She was diagnosed with hemangioma in her twenties. At that point, her tumor began to involve the posterior calf and femur, causing deformity. She had multiple surgical resections but reportedly all pathology demonstrated benign hemangioma. She received radiation for pain, a routine treatment at the time, but developed a focus of progression in the heel. Above-knee amputation was considered but could not be performed when hemangioma was discovered in the hip area. She was lost to follow-up between 2001 and 2015. Lower extremity magnetic resonance imaging in 2015 was stable with imaging prior to 2001. A repeat biopsy in 2016 demonstrated hemangioma. The patient then received radiation to a wider field, including the femur, with minimal response. She completed a course of steroids as well. Bevacizumab was started in 2017 and improved foot deformity. She also briefly trialed pazopanib for 4 weeks in 2018 in an attempt to switch to oral medications. Despite partial response, she discontinued both agents in July 2018 because of toxicity and the burden of recurrent infusions.

Four months later, she presented with 2 months of intermittent hemoptysis and 18 months of metallic odors. Additionally, she lost 25 pounds in 3 months, which she attributed to a diet plan. At this visit, her left lower extremity exhibited multiple subcutaneous tumors and nodules.

Computed tomography (CT) with contrast demonstrated innumerable pulmonary nodules, the largest measuring 2.2 cm in the right lower lobe superior segment. Positron emission tomography (PET)/CT revealed 2 nodules with mild hypermetabolic activity; the largest nodule had a maximum standardized uptake value of 2.7. Bronchoalveolar lavage studies showed intra-alveolar hemorrhage with hemosiderin-laden macrophages. No malignancy, granuloma, or dysplasia was found in transbronchial needle aspirate of the largest nodule. The patient had no lymphadenopathy.

At this hospital, surgical resection by video-assisted thoracoscopic surgery confirmed multifocal malignant epithelioid neoplasm suspicious for angiosarcoma. Multiple areas showed proliferation of atypical epithelioid-to-spindle cells. There were prominent associated hemosiderin-laden macrophages, fresh red blood cells, and dilated blood-filled spaces. Cells demonstrated hyperchromasia with irregular nuclear contours, prominent nucleoli, and mitoses  (FIGURE 1). Additionally, there were areas of focal organizing pneumonia. For atypical cells, staining was CD31-positive and CD34-negative. Staining was strongly positive for ERG. There was increased Ki-67 with retained INI expression and patchy weak reactivity for Fli-1.

Next-generation sequencing was performed. Specimen tumor content was 15%. Genomic findings included IDH1 p.R132C mutation, with variant allele frequency <10%. Testing was inconclusive for MSI and TMB mutations. PD-L1 assessment could not be performed. Unfortunately, the patient did not qualify for any clinical trials, as there were no matching alterations. This patient was lost to follow-up.

Discussion

Angiosarcoma accounts for 2% of soft tissue sarcomas.¹ Cutaneous angiosarcomas most commonly occur in the face and scalp of the elderly, or in sites of chronic lymphedema. Angiosarcoma also develops following radiation therapy.⁵ For breast cancers and tumors of the head and neck, irradiation has <1% risk of inducing secondary malignancy, including angiosarcoma.⁶

This patient had a new diagnosis of angiosarcoma in the setting of long-standing benign hemangioma with history of radiation treatment. Thus, it is unclear whether this angiosarcoma was primary, radiation-induced, or secondary to transformation from the preexisting vascular tumor. Post-irradiation sarcoma carries a less favorable prognosis compared to de novo sarcoma; however, reports conflict on whether this holds for angiosarcoma subtypes.⁶ Determining etiology may benefit patients for prognostication and possibly inform future selection of treatment modalities.

The mutational signature in radiation- associated sarcomas differs from that of sporadic sarcomas. First, radiation- associated sarcomas demonstrate more frequent small deletions and balanced translocations. TP53 mutations are found in up to 1/3 of radiation-associated sarcomas and are more often due to small deletions than in sporadic sarcomas.⁷ High-level MYC amplification occurs in 54%-100% of secondary angiosarcomas, compared to 0-7% in sporadic angiosarcomas. Co-amplification of FLT4 occurs in 11%-25% of secondary angiosarcomas.⁸ Additionally, transcriptome analysis revealed differential expression of a 135-gene signature compared to non-radiation- induced sarcomas.⁷ Although this patient was not specifically analyzed for such alterations, such tests may differentiate post-irradiation angiosarcoma from sporadic etiologies.

In this patient, the R132C IDH1 mutation was identified and may be the first reported case in angiosarcoma. Typically, this mutation occurs in chondrosarcoma, myeloid neoplasms, gliomas, and cholangiocarcinomas. It is also found in spindle cell hemangiomas but not in other vascular tumors.⁹ The clinical significance of this mutation is uncertain at this time.

There are approximately 36 reported cases of malignant disease arising in patients with less aggressive vascular tumors (TABLE 1). Of these, 25 of 36 involve angiosarcoma arising in patients with hemangioma. Four cases of angiosarcoma were reported in patients with hemangioendothelioma, 1 case of hemangioendothelioma in a patient with hemangioma, 1 case of Dabska tumor in a patient with hemangioma, and 1 case of angiosarcoma in a patient with Dabska tumor. Fifteen cases involved initial disease with adult onset and 21 involved initial disease with pediatric onset, suggesting even distribution. Malignant disease mostly occurred in adulthood, in 26 out of 33 cases. Latency to malignancy ranged from concurrent discovery to 54 years. Mean latency, excluding cases with concurrent discovery, was shorter with adult-onset initial disease, at 4.2 years, compared to 16 years among patients with onset of initial disease in childhood. Longer latency in the pediatric-onset population correlated with longer latent periods for radiation-induced angiosarcoma following benign disease, which is reported to average 23 years.¹⁰ Thirteen of 19 cases with pediatric onset disease had a history of radiotherapy, while 2 of 13 cases with adult onset disease did. Sixteen cases involved tumor in the bone and soft tissue, as in this patient. Notably, 4 of these cases involved long-standing hemangioma for 10 years or more, as in this patient, suggesting a possible correlation between long-standing vascular tumors and malignant transformation. Angiosarcoma arising in non-irradiated patients suggests that malignant transformation and de novo transformation may compete with radiation-induced mutation in tumorigenesis. Further, 8 cases involved angiosarcoma growing within another vascular tumor, demonstrating the possibility of malignant transformation. Dehner and Ishak described a histological model for quantifying such a risk; a validated model may be particularly useful in patients with long-standing hemangioma.¹¹

Etiology of tumorigenesis in cases of angiosarcoma arising in patients with a history of benign hemangioma may benefit prognostication and inform treatment selection in the future. Owing to long latent periods, radiation-associated angiosarcoma incidence may rise, as radiation therapy for benign hemangioma was recently routine. Future research may provide insight into disease progression and possibly predict the risk of angiosarcoma in patients with long-standing benign disease. TSJ

The previous issue of The Sarcoma Journal focused on findings from numerous clinical trials in sarcomas of various histologies presented at ASCO’s annual meeting. This issue features a study on enrollment issues that surround clinical trials in sarcoma and sheds light on patient perceptions on clinical trial enrollment.

Clinical trials and their investigators are frequently impacted by enrollment issues, such as the limited number of eligible patients and the wide variations in time it can take to reach complete enrollment. For example, the phase 3 ANNOUNCE trial of olaratumab in soft tissue sarcoma completed its accrual of 509 patients in a record 10 months, while the trial of temozolomide by the European Pediatric Soft Tissue Sarcoma Study Group took 6 years to enroll 120 patients. Recruitment difficulties may even hamper the investigators’ and sponsors’ ability to bring a trial to a meaningful conclusion.

An interesting finding from the study published in this issue is the correlation between knowledge about trials and the positive attitude towards participating in them. People who had participated in clinical trials had higher levels of knowledge and developed more favorable attitudes towards clinical trials. One of the goals of the Sarcoma Foundation of America (curesarcoma.org) is to increase awareness of the numbers and types of ongoing clinical trials in sarcoma, benefitting patients and investigators alike. The SFA operates the Clinical Trial Navigating Service, which offers patients, caregivers, and health care professionals up-to-date information about sarcoma clinical trials throughout the United States and Canada. The service, provided in collaboration with EmergingMed, helps patients search for clinical trial options that match their specific diagnosis and treatment history.

The paper published in this issue suggests that, through patient education and careful trial design, sarcoma could become a paradigm for trial enrollment in other therapeutic areas. Together—as physicians, investigators, patients, trial sponsors, and anyone interested in curing sarcoma—we may be able to accomplish this. It’s certainly worth a try.

William D. Tap, MD
Editor-in-Chief

The previous issue of The Sarcoma Journal focused on findings from numerous clinical trials in sarcomas of various histologies presented at ASCO’s annual meeting. This issue features a study on enrollment issues that surround clinical trials in sarcoma and sheds light on patient perceptions on clinical trial enrollment.

Clinical trials and their investigators are frequently impacted by enrollment issues, such as the limited number of eligible patients and the wide variations in time it can take to reach complete enrollment. For example, the phase 3 ANNOUNCE trial of olaratumab in soft tissue sarcoma completed its accrual of 509 patients in a record 10 months, while the trial of temozolomide by the European Pediatric Soft Tissue Sarcoma Study Group took 6 years to enroll 120 patients. Recruitment difficulties may even hamper the investigators’ and sponsors’ ability to bring a trial to a meaningful conclusion.

An interesting finding from the study published in this issue is the correlation between knowledge about trials and the positive attitude towards participating in them. People who had participated in clinical trials had higher levels of knowledge and developed more favorable attitudes towards clinical trials. One of the goals of the Sarcoma Foundation of America (curesarcoma.org) is to increase awareness of the numbers and types of ongoing clinical trials in sarcoma, benefitting patients and investigators alike. The SFA operates the Clinical Trial Navigating Service, which offers patients, caregivers, and health care professionals up-to-date information about sarcoma clinical trials throughout the United States and Canada. The service, provided in collaboration with EmergingMed, helps patients search for clinical trial options that match their specific diagnosis and treatment history.

The paper published in this issue suggests that, through patient education and careful trial design, sarcoma could become a paradigm for trial enrollment in other therapeutic areas. Together—as physicians, investigators, patients, trial sponsors, and anyone interested in curing sarcoma—we may be able to accomplish this. It’s certainly worth a try.

William D. Tap, MD
Editor-in-Chief

The previous issue of The Sarcoma Journal focused on findings from numerous clinical trials in sarcomas of various histologies presented at ASCO’s annual meeting. This issue features a study on enrollment issues that surround clinical trials in sarcoma and sheds light on patient perceptions on clinical trial enrollment.

Clinical trials and their investigators are frequently impacted by enrollment issues, such as the limited number of eligible patients and the wide variations in time it can take to reach complete enrollment. For example, the phase 3 ANNOUNCE trial of olaratumab in soft tissue sarcoma completed its accrual of 509 patients in a record 10 months, while the trial of temozolomide by the European Pediatric Soft Tissue Sarcoma Study Group took 6 years to enroll 120 patients. Recruitment difficulties may even hamper the investigators’ and sponsors’ ability to bring a trial to a meaningful conclusion.

An interesting finding from the study published in this issue is the correlation between knowledge about trials and the positive attitude towards participating in them. People who had participated in clinical trials had higher levels of knowledge and developed more favorable attitudes towards clinical trials. One of the goals of the Sarcoma Foundation of America (curesarcoma.org) is to increase awareness of the numbers and types of ongoing clinical trials in sarcoma, benefitting patients and investigators alike. The SFA operates the Clinical Trial Navigating Service, which offers patients, caregivers, and health care professionals up-to-date information about sarcoma clinical trials throughout the United States and Canada. The service, provided in collaboration with EmergingMed, helps patients search for clinical trial options that match their specific diagnosis and treatment history.

The paper published in this issue suggests that, through patient education and careful trial design, sarcoma could become a paradigm for trial enrollment in other therapeutic areas. Together—as physicians, investigators, patients, trial sponsors, and anyone interested in curing sarcoma—we may be able to accomplish this. It’s certainly worth a try.

William D. Tap, MD
Editor-in-Chief

Introduction

The development of new cancer therapies relies on the successful development and completion of clinical trials. While clinical trials have led to significant improvements in cancer treatment, the success is dependent upon patient enrollment and participation. Unfortunately, fewer than 5% of adult patients enroll in trials.^1-3 This represents a significant barrier to the development and approval of new cancer treatments. Reasons for low accrual into trials are multifactorial, but include structural barriers (eg, clinic access), clinical barriers (eg, eligibility criteria), and physician and patient attitudes towards trial enrollment.^4,5 One study at the University of California Davis Cancer Center reported 49% of patients declined participation despite meeting eligibility criteria,^3,6 suggesting that psychosocial barriers such as knowledge of trials and attitudes towards clinical research are a major impediment to accrual.^7-9

Bone and soft tissue sarcoma represent a heterogeneous group of tumors of mesenchymal origin that are an important cause of morbidity and mortality. Local disease is often treated with a multidisciplinary approach including surgery, radiation, and systemic therapy. Metastatic disease is predominantly treated palliatively with systemic therapy.¹⁰ Given its rarity and heterogeneity, trial accrual is of particular importance in sarcoma and often requires multiple sites to enroll adequate numbers of patients. While sarcoma represents <1% of adult malignancies overall, it constitutes ~15% of malignancies in the adolescent and young adult (AYA) population (15- 39 years old).^11,12 Sarcoma represents a patient population in which low trial accrual has been correlated with lack of progress in cancer-related outcomes in both the adult and AYA populations.¹³ The reasons for low accrual rates among patients with sarcoma are poorly understood.

Sarcomas represent a molecularly and biologically heterogeneous group of malignancies with over 100 different subtypes.¹² As a result, there has been significant interest in performing molecular profiling, or genetic sequencing, to identify “targetable” mutations. Targetable mutations refer to a specific genetic change identified within the tumor molecular profile for which there is a specific drug that may demonstrate activity against a particular tumor. Given the widespread utilization of this technology in sarcoma, identifying and understanding patient perceptions with regard to molecular profiling is critically important in this disease.¹⁴

In this study, we use a cross-sectional design to describe patient perceptions of trial enrollment among patients with bone and soft tissue sarcoma through validated measures, including attitudes towards clinical trials, knowledge of clinical trials, and perceived ability (ie, self-efficacy) to carry out actions involved in making an informed decision about clinical trial participation, receptivity to learning more about clinical trials, and willingness to participate in clinical trials.6 In addition, we describe this patient cohort’s perceptions of molecular profiling, as current and future trials are increasingly driven by molecular or other biomarkers.

Methods

This was a cross-sectional electronic survey study of patients with bone and soft tissue sarcoma treated at Northwestern Medicine (NM) over a 5-year period. NM Enterprise Data Warehouse (NMEDW) is a single, comprehensive, and integrated repository of all clinical and research data sources within NM. The study was approved by the Northwestern University Institutional Review Board.

Survey

The investigators designed a self-administered, online survey, which was built using Research Electronic Data Capture (REDCap). The survey consisted of three sections that were answered using skip logic—a custom path through the survey that varied based on patients’ answers: (1) Patient demographic information and trial perceptions (answered by all patients); (2) Thoughts about molecular profiling (answered by patients who answered “yes” to the question, “Have you heard about molecular profiling of tumors?”); and (3) Considerations to undergo molecular profiling (answered by patients who answered “yes” to the question, “Have you undergone profiling of your cancer?”).

Thoughts about molecular profiling of tumors were assessed using nine items (TABLE 1). Of these, items assessing potential benefit or harm of molecular profiling were assessed using a 7-step Likert scale. Items assessing maximal benefit or harm of therapy, importance of quality vs length of life, and concern about the cost of molecular testing were assessed using a 5-step Likert scale. The study team developed and piloted these questions because there is no validated survey assessing these domains.

Considerations to undergo molecular profiling were assessed using 17 items. Items were in response to the question, “To what extent did you consider the following issues or concerns at the time you decided to get molecular testing of your cancer?” Responses were assessed using a 5-point Likert scale.

Data Collection

Patients 18 years and older evaluated at NM between November 20, 2012, and November 20, 2017, with a diagnosis of sarcoma were identified by query of the NMEDW by ICD-10 codes (C40, C41.9, C44.99, C45-49, C55, C71.9, D48, D49.9, and M12.20) or equivalent ICD-9 codes. Patients were subsequently excluded if they did not have a diagnosis of bone or soft tissue sarcoma, no e-mail address listed, had died, or had not been evaluated at an NM clinic in the previous 5 years. Patients with a diagnosis of gastrointestinal stromal tumor and Kaposi’s sarcoma were also excluded.

A personalized contact e-mail was sent to patients containing an explanation of the survey and an internet link to the electronic survey through REDCap from January 2018 to March 2018. If patients did not respond to the survey, two follow-up reminder e-mails were sent 2 and 4 days following the initial survey. The link was protected so that each patient could complete the survey only once. Responses were collected through the REDCap platform. Patients read and signed an electronic consent form prior to completing the survey.

Upon completion of the survey, patients were offered a $50 VISA gift card as compensation, with an option to donate their compensation to the Robert H. Lurie Comprehensive Cancer Center Sarcoma Research Fund.

Over the described survey period, open clinical trials for patients with bone and soft tissue sarcoma available at NM were evaluated. The number of patients screened and accrued to each trial were recorded.

Statistical analysis

Responses were separated from the personal data for complete anonymization. Descriptive statistical analysis was performed for demographics and disease variables and were summarized using frequencies and percentages. Median and range were used for age. Correlations between continuous variables were analyzed using Spearman correlations. Scores were compared between subgroups using the Mann-Whitney test. Descriptive statistics for knowledge, attitude, and ability scores include means and 95% confidence intervals. Correlations were interpreted as small (r=0.10), medium (r=0.30), or large (r=0.50).15 Statistical significance was indicated when P<0.05.

Results

Patients

Seven hundred fifty patients were eligible to participate in the survey and received the initial and two follow-up e-mails. Twenty e-mailed surveys bounced back. Three hundred nine patients opened the initial e-mail and 283 patients (37.7% of total and 91.6% of opened) completed at least a portion of the survey, with 182 patients completing the entire survey (FIGURE 1). Data for analysis were used from patients who completed at least a portion of the survey.

Baseline characteristics of patients who responded can be seen in TABLE 2. Patients had a median age of 56, the majority were female (59.4%), white (88.2%), and most had college or university graduate degrees or higher educational level (69.0%). Patients had various different histological subtypes, with the most common being liposarcoma (16.5%) and leiomyosarcoma (16.0%). Slightly more than a quarter (26.8%) of patients had metastatic disease, and 84.2% had never been enrolled in a clinical trial. Previous treatments included surgery (91.1%), radiation (53.2%), and chemotherapy (51.6%). Prior to completing the survey, 85.4% reported being receptive to a cancer clinical trial, while 60.7% of patients reported willingness to participate in a clinical trial.

Knowledge, attitudes, and perceived ability

A statistically significant correlation was observed between greater knowledge of trials and more positive attitudes towards trials (P<0.001; r=0.5, FIGURE 2A). In relating patient attitudes with perceived ability, again a significant correlation was seen (P<0.001; r=0.4, FIGURE 2B). In contrast, knowledge had a weak correlation with perceived ability (P=0.024; r=0.2, FIGURE 2C). There was no difference regarding patient knowledge, attitudes, or perceived ability by age, gender, race, or income.

Knowledge, attitudes, perceived ability, and clinical trial enrollment

Thirty patients reported clinical trial experience (either previously or currently enrolled in trials) and 160 patients were never enrolled. Of the 30 patients with trial experience, 7 reported being currently enrolled, while 23 reported previous enrollment. Of these patients, 16 had metastatic disease, while 12 had non-metastatic disease, and 2 were unsure whether or not they had metastatic disease.

Patients with previous clinical trial exposure (currently or previously enrolled in clinical trials) demonstrated significantly greater trial knowledge, with a mean knowledge score of 9.3 (CI 8.5-10.0) compared with 7.7 (CI 7.3-8.1) among patients without trial exposure (P=0.002; FIGURE 3A). Similarly, patients with trial experience also had statistically significant more positive attitudes towards trials as compared with patients with no trial experience, with a mean attitude score of 3.8 (CI 3.6-4.0) and 3.5 (CI 3.4-3.6), respectively (P=0.001; FIGURE 3B). While numerically patients with trial experience have greater perceived ability compared with patients with no trial experience, with a mean score of 4.4 (CI 4.2-4.6) and 4.2 (CI 4.1-4.3), respectively, this difference did not reach statistical significance (FIGURE 3C).

Knowledge, attitudes, perceived ability, and disease stage

An analysis was performed comparing patients with metastatic vs non-metastatic disease. It was observed that patients with metastatic disease had similar knowledge of trials compared with non-metastatic patients, with a mean knowledge score of 8.4 (CI 7.7- 9.1) and 7.9 (CI 7.5-8.4), respectively, (P=0.3; FIGURE 4A). In contrast, patients with metastatic disease had more positive attitudes compared with non-metastatic patients, with a mean score of 3.7 (CI 3.5-3.8) and 3.5 (CI 3.4-3.6), respectively, which was statistically significant (P=0.03; FIGURE 4B). There was no difference in perceived ability in metastatic vs non-metastatic patients (FIGURE 4C).

Thoughts about molecular profiling

Of the total number of patients, 46 patients had heard of molecular profiling and were presented with questions regarding their thoughts (TABLE 3). Approximately two-thirds (65.2%) thought there would be a 50% or greater likelihood of finding a targetable result in their tumor molecular profile. A majority (71.7%) of patients thought that a new experimental therapy chosen based on a patient’s tumor molecular profile would have at least a 50% chance of controlling the cancer. Somewhat less than a third (30.4%) of patients thought that total cure is the maximal benefit a patient could experience as a result of a treatment on a clinical trial using a drug chosen based on molecular tests. About half (52.2%) of patients agreed with the statement, “I am concerned about the cost of the test to molecularly profile my cancer.”

Considerations to undergo molecular profiling

Eighteen patients had undergone molecular profiling of their tumor. These patients were posed the question, “To what extent did you consider the following issues or concerns at the time you decided to get molecular testing of your cancer?” (TABLE 4). A majority (83.3%) of patients stated that wanting to live as long as possible was important, and 72.2% of patients stated that quality of life was important. A majority (83.3%) of patients stated that hope for a cure was an extremely or quite a bit important consideration. Helping future cancer patients was extremely or quite a bit important for 77.8% of patients, while wanting to be a part of research was not at all or of little importance in 50.0% of patients.

Clinical trials at NM

Twenty-four clinical trials were available at NM between the years 2012 and 2017 for patients with bone and soft tissue sarcoma. Of these trials, 3 of 24 were for non-metastatic patients, while the remaining 21 were open only to metastatic patients. The median number of patients screened per trial was 11 (range 0-66) and the median number of patients accrued per trial was 9 (range 0-58). Of the 24 trials, 17 were not subtype specific (13 included soft tissue sarcoma alone while 4 included both bone and soft tissue sarcoma). The remaining 7 trials were sarcoma subtype specific (eg, angiosarcoma, liposarcoma, etc). Trials available at NM during this period are included in TABLE 5. There were 318 patients screened and 262 patients accrued to sarcoma trials over this time period, with a screen failure rate of 17.6% overall.

Discussion

Our study sought to describe perceptions of clinical trial enrollment among patients with bone and soft tissue sarcoma in order to elucidate and overcome barriers to enrollment, which to the best of our knowledge had not been previously described. Using previously validated patient- reported outcomes in the literature,⁶ our data reveal a correlation between knowledge of trials and more positive attitudes towards trials. This underscores the importance of awareness and educational strategies in this cancer population as a whole. Interventions should focus on patient perceptions that contribute to lack of participation, such as fear of side effects, loss of control (eg, idea of placebo or randomization), logistical challenges (eg, additional time or convenient location), and cost.^3,5,7,16,17 For example, patients concerned about randomization should be educated on equipoise and other ethical considerations in trial design.⁵ Previous research has suggested that a multimedia psychoeducational intervention was effective in improving attitudes toward trials.⁶ Educating patients on the essential role of trials in oncology care, as demonstrated by the vast number of new drug approvals in recent years, is an essential strategy to improve attitudes, and subsequently leads to higher patient accrual rates. 

In our study, both knowledge and at titudes were increased in patients with previous trial exposure. This suggests that either patients with greater knowledge and more positive attitudes are more likely to enroll in trials, or that patients with direct trial exposure are more knowledgeable and develop more positive attitudes. Our patient population was overall receptive to learning more about clinical trials (85.4%) and willing to participate (65.8%). At the same time, our study demonstrated low to medium correlations between attitudes and perceived ability to take steps towards making an informed decision to enroll in a trial (r=0.4), which may partially be explained by the absence of a tangible trial opportunity. While we did not assess specifically whether patients in our study were offered a trial, there was a substantial trial menu at NM with limited screen failures and decent trial accrual over the time frame of our study. This underscores the importance not only of patient-focused strategies to increase educational and attitudinal resources, but also a need to focus on research-site optimization that includes opening of multiple trials in various settings, systematic pre-screening of patients, and eligibility criteria that are inclusive and rational.⁵

The patient population with metastatic disease demonstrated more positive attitudes towards enrolling in clinical trials. This cohort accrued well to clinical trials, with 21 of 24 trials enrolling specifically patients with metastatic disease. Of the patients who responded to our survey, patients with previous trial exposure were enriched for patients with metastatic disease (53.3% metastatic among previous trial exposure versus 26.8% metastatic overall). These observations are likely reflective of the need for novel therapies in this disease setting. At the same time, approximately 25% of patients with localized soft tissue sarcoma will develop distant metastatic disease after successful treatment of their primary tumor, which increases to 40% to 50% in larger and higher-grade tumors.¹⁸ Three of 24 trials were open for patients with non-metastatic disease, of which one managed to accrue patients. Patients with non-metastatic disease had more negative attitudes towards trial enrollment. These disproportionate findings suggest a need for interventions to increase patient awareness and attitudes towards trial enrollment among this patient population and the importance of research-site optimization for trial opportunities across disease states.

Molecular profiling of tumors and biomarker identification has become a critical component of further characterizing cancer subtypes. In our study, a majority (65.2%) thought there would be a 50% or greater likelihood of finding a targetable result in their molecular profile. Molecular data on 5,749 bone and soft tissue sarcomas suggested that 9.5% of tumors demonstrate a “targetable result,” defined as a new molecular finding for which there is an FDA-approved drug for malignancies other than sarcoma (eg, BRAF V600E, Her2, etc.),¹⁹ suggesting an overestimation in our patient cohort of the likelihood of benefit of molecular profiling. These results highlight that the growing use of molecular profiling has increased the need for educational and supportive resources to help patients understand the utility of molecular profiling and aid in shared decision-making surrounding the results.

At the same time, the importance of identifying a targetable mutation in patients with sarcoma cannot be understated. As a recent example of this paradigm, tumors that harbor fusions with the neurotrophic receptor tyrosine kinase 1, 2, or 3 (NTRK1, 2, and 3) have a high response rate (~75%) to drugs that target these fusions, such as larotrectinib and entrectinib.¹³ Molecular profiling and identification of predictive biomarkers in small patient subsets has led to great challenges in trial design and research-site optimization. Novel designs that incorporate molecular profiling,²⁰ such as the Lung- MAP trial²¹ and NCI’s Molecular Analysis for Therapy Choice (MATCH) trial,²² are emerging to identify new therapies for small patient subsets. As a rare and increasingly heterogeneous cancer, sarcoma represents a paradigm to provide insight into optimizing patient perceptions and research enterprises to maximize clinical trial enrollment. 

Some limitations of our study include a homogeneous and selected patient population that was predominantly Caucasian and highly educated. Therefore, these findings should not be extrapolated to other populations with barriers to trial accrual, such as lower socioeconomic or minority populations. The low response rate and failure of some to complete the survey may have introduced some bias. Additionally, our data include self-reported outcomes, which could have affected our results. Finally, the limited number of patients who had undergone or heard of molecular profiling limited our ability to draw definitive conclusions, and should be assessed in larger patient cohorts.

While our paper addresses a unique population—the sarcoma patient—similar themes and issues pertain to all oncology patients. A recent review was published in the American Society of Clinical Oncology Educational Book²³ looking at methods to overcome barriers to clinical trial enrollment. Their paper clearly illustrates mechanisms to assist with overcoming financial burdens associated with cancer clinical trials, overcoming barriers as they relate to patient and clinician difficulty in coping with the uncertainty inherent in clinical trial participation, and highlight the role of a patient navigator in clinical trial participation.

Conclusions

Interventions aimed at increasing awareness, knowledge, and attitudes towards clinical trials among sarcoma patients may lead to increased trial enrollment and greater progress in cancer treatment in this population. In addition to patient- focused interventions, thoughtful and strategic clinical trial designs that allow for the development of biomarker- driven therapeutics, while at the same time optimizing patient accrual rates, should be developed. Evaluation of barriers to clinical trial enrollment and molecular profiling of tumors among bone and soft tissue sarcoma patients at an academic center can serve as a paradigm to overcome barriers to enrollment in the era of an increasingly heterogeneous cancer population. TSJ

Introduction

The development of new cancer therapies relies on the successful development and completion of clinical trials. While clinical trials have led to significant improvements in cancer treatment, the success is dependent upon patient enrollment and participation. Unfortunately, fewer than 5% of adult patients enroll in trials.^1-3 This represents a significant barrier to the development and approval of new cancer treatments. Reasons for low accrual into trials are multifactorial, but include structural barriers (eg, clinic access), clinical barriers (eg, eligibility criteria), and physician and patient attitudes towards trial enrollment.^4,5 One study at the University of California Davis Cancer Center reported 49% of patients declined participation despite meeting eligibility criteria,^3,6 suggesting that psychosocial barriers such as knowledge of trials and attitudes towards clinical research are a major impediment to accrual.^7-9

Bone and soft tissue sarcoma represent a heterogeneous group of tumors of mesenchymal origin that are an important cause of morbidity and mortality. Local disease is often treated with a multidisciplinary approach including surgery, radiation, and systemic therapy. Metastatic disease is predominantly treated palliatively with systemic therapy.¹⁰ Given its rarity and heterogeneity, trial accrual is of particular importance in sarcoma and often requires multiple sites to enroll adequate numbers of patients. While sarcoma represents <1% of adult malignancies overall, it constitutes ~15% of malignancies in the adolescent and young adult (AYA) population (15- 39 years old).^11,12 Sarcoma represents a patient population in which low trial accrual has been correlated with lack of progress in cancer-related outcomes in both the adult and AYA populations.¹³ The reasons for low accrual rates among patients with sarcoma are poorly understood.

Sarcomas represent a molecularly and biologically heterogeneous group of malignancies with over 100 different subtypes.¹² As a result, there has been significant interest in performing molecular profiling, or genetic sequencing, to identify “targetable” mutations. Targetable mutations refer to a specific genetic change identified within the tumor molecular profile for which there is a specific drug that may demonstrate activity against a particular tumor. Given the widespread utilization of this technology in sarcoma, identifying and understanding patient perceptions with regard to molecular profiling is critically important in this disease.¹⁴

In this study, we use a cross-sectional design to describe patient perceptions of trial enrollment among patients with bone and soft tissue sarcoma through validated measures, including attitudes towards clinical trials, knowledge of clinical trials, and perceived ability (ie, self-efficacy) to carry out actions involved in making an informed decision about clinical trial participation, receptivity to learning more about clinical trials, and willingness to participate in clinical trials.6 In addition, we describe this patient cohort’s perceptions of molecular profiling, as current and future trials are increasingly driven by molecular or other biomarkers.

Methods

This was a cross-sectional electronic survey study of patients with bone and soft tissue sarcoma treated at Northwestern Medicine (NM) over a 5-year period. NM Enterprise Data Warehouse (NMEDW) is a single, comprehensive, and integrated repository of all clinical and research data sources within NM. The study was approved by the Northwestern University Institutional Review Board.

Survey

The investigators designed a self-administered, online survey, which was built using Research Electronic Data Capture (REDCap). The survey consisted of three sections that were answered using skip logic—a custom path through the survey that varied based on patients’ answers: (1) Patient demographic information and trial perceptions (answered by all patients); (2) Thoughts about molecular profiling (answered by patients who answered “yes” to the question, “Have you heard about molecular profiling of tumors?”); and (3) Considerations to undergo molecular profiling (answered by patients who answered “yes” to the question, “Have you undergone profiling of your cancer?”).

Thoughts about molecular profiling of tumors were assessed using nine items (TABLE 1). Of these, items assessing potential benefit or harm of molecular profiling were assessed using a 7-step Likert scale. Items assessing maximal benefit or harm of therapy, importance of quality vs length of life, and concern about the cost of molecular testing were assessed using a 5-step Likert scale. The study team developed and piloted these questions because there is no validated survey assessing these domains.

Considerations to undergo molecular profiling were assessed using 17 items. Items were in response to the question, “To what extent did you consider the following issues or concerns at the time you decided to get molecular testing of your cancer?” Responses were assessed using a 5-point Likert scale.

Data Collection

Patients 18 years and older evaluated at NM between November 20, 2012, and November 20, 2017, with a diagnosis of sarcoma were identified by query of the NMEDW by ICD-10 codes (C40, C41.9, C44.99, C45-49, C55, C71.9, D48, D49.9, and M12.20) or equivalent ICD-9 codes. Patients were subsequently excluded if they did not have a diagnosis of bone or soft tissue sarcoma, no e-mail address listed, had died, or had not been evaluated at an NM clinic in the previous 5 years. Patients with a diagnosis of gastrointestinal stromal tumor and Kaposi’s sarcoma were also excluded.

A personalized contact e-mail was sent to patients containing an explanation of the survey and an internet link to the electronic survey through REDCap from January 2018 to March 2018. If patients did not respond to the survey, two follow-up reminder e-mails were sent 2 and 4 days following the initial survey. The link was protected so that each patient could complete the survey only once. Responses were collected through the REDCap platform. Patients read and signed an electronic consent form prior to completing the survey.

Upon completion of the survey, patients were offered a $50 VISA gift card as compensation, with an option to donate their compensation to the Robert H. Lurie Comprehensive Cancer Center Sarcoma Research Fund.

Over the described survey period, open clinical trials for patients with bone and soft tissue sarcoma available at NM were evaluated. The number of patients screened and accrued to each trial were recorded.

Statistical analysis

Responses were separated from the personal data for complete anonymization. Descriptive statistical analysis was performed for demographics and disease variables and were summarized using frequencies and percentages. Median and range were used for age. Correlations between continuous variables were analyzed using Spearman correlations. Scores were compared between subgroups using the Mann-Whitney test. Descriptive statistics for knowledge, attitude, and ability scores include means and 95% confidence intervals. Correlations were interpreted as small (r=0.10), medium (r=0.30), or large (r=0.50).15 Statistical significance was indicated when P<0.05.

Results

Patients

Seven hundred fifty patients were eligible to participate in the survey and received the initial and two follow-up e-mails. Twenty e-mailed surveys bounced back. Three hundred nine patients opened the initial e-mail and 283 patients (37.7% of total and 91.6% of opened) completed at least a portion of the survey, with 182 patients completing the entire survey (FIGURE 1). Data for analysis were used from patients who completed at least a portion of the survey.

Baseline characteristics of patients who responded can be seen in TABLE 2. Patients had a median age of 56, the majority were female (59.4%), white (88.2%), and most had college or university graduate degrees or higher educational level (69.0%). Patients had various different histological subtypes, with the most common being liposarcoma (16.5%) and leiomyosarcoma (16.0%). Slightly more than a quarter (26.8%) of patients had metastatic disease, and 84.2% had never been enrolled in a clinical trial. Previous treatments included surgery (91.1%), radiation (53.2%), and chemotherapy (51.6%). Prior to completing the survey, 85.4% reported being receptive to a cancer clinical trial, while 60.7% of patients reported willingness to participate in a clinical trial.

Knowledge, attitudes, and perceived ability

A statistically significant correlation was observed between greater knowledge of trials and more positive attitudes towards trials (P<0.001; r=0.5, FIGURE 2A). In relating patient attitudes with perceived ability, again a significant correlation was seen (P<0.001; r=0.4, FIGURE 2B). In contrast, knowledge had a weak correlation with perceived ability (P=0.024; r=0.2, FIGURE 2C). There was no difference regarding patient knowledge, attitudes, or perceived ability by age, gender, race, or income.

Knowledge, attitudes, perceived ability, and clinical trial enrollment

Thirty patients reported clinical trial experience (either previously or currently enrolled in trials) and 160 patients were never enrolled. Of the 30 patients with trial experience, 7 reported being currently enrolled, while 23 reported previous enrollment. Of these patients, 16 had metastatic disease, while 12 had non-metastatic disease, and 2 were unsure whether or not they had metastatic disease.

Patients with previous clinical trial exposure (currently or previously enrolled in clinical trials) demonstrated significantly greater trial knowledge, with a mean knowledge score of 9.3 (CI 8.5-10.0) compared with 7.7 (CI 7.3-8.1) among patients without trial exposure (P=0.002; FIGURE 3A). Similarly, patients with trial experience also had statistically significant more positive attitudes towards trials as compared with patients with no trial experience, with a mean attitude score of 3.8 (CI 3.6-4.0) and 3.5 (CI 3.4-3.6), respectively (P=0.001; FIGURE 3B). While numerically patients with trial experience have greater perceived ability compared with patients with no trial experience, with a mean score of 4.4 (CI 4.2-4.6) and 4.2 (CI 4.1-4.3), respectively, this difference did not reach statistical significance (FIGURE 3C).

Knowledge, attitudes, perceived ability, and disease stage

An analysis was performed comparing patients with metastatic vs non-metastatic disease. It was observed that patients with metastatic disease had similar knowledge of trials compared with non-metastatic patients, with a mean knowledge score of 8.4 (CI 7.7- 9.1) and 7.9 (CI 7.5-8.4), respectively, (P=0.3; FIGURE 4A). In contrast, patients with metastatic disease had more positive attitudes compared with non-metastatic patients, with a mean score of 3.7 (CI 3.5-3.8) and 3.5 (CI 3.4-3.6), respectively, which was statistically significant (P=0.03; FIGURE 4B). There was no difference in perceived ability in metastatic vs non-metastatic patients (FIGURE 4C).

Thoughts about molecular profiling

Of the total number of patients, 46 patients had heard of molecular profiling and were presented with questions regarding their thoughts (TABLE 3). Approximately two-thirds (65.2%) thought there would be a 50% or greater likelihood of finding a targetable result in their tumor molecular profile. A majority (71.7%) of patients thought that a new experimental therapy chosen based on a patient’s tumor molecular profile would have at least a 50% chance of controlling the cancer. Somewhat less than a third (30.4%) of patients thought that total cure is the maximal benefit a patient could experience as a result of a treatment on a clinical trial using a drug chosen based on molecular tests. About half (52.2%) of patients agreed with the statement, “I am concerned about the cost of the test to molecularly profile my cancer.”

Considerations to undergo molecular profiling

Eighteen patients had undergone molecular profiling of their tumor. These patients were posed the question, “To what extent did you consider the following issues or concerns at the time you decided to get molecular testing of your cancer?” (TABLE 4). A majority (83.3%) of patients stated that wanting to live as long as possible was important, and 72.2% of patients stated that quality of life was important. A majority (83.3%) of patients stated that hope for a cure was an extremely or quite a bit important consideration. Helping future cancer patients was extremely or quite a bit important for 77.8% of patients, while wanting to be a part of research was not at all or of little importance in 50.0% of patients.

Clinical trials at NM

Twenty-four clinical trials were available at NM between the years 2012 and 2017 for patients with bone and soft tissue sarcoma. Of these trials, 3 of 24 were for non-metastatic patients, while the remaining 21 were open only to metastatic patients. The median number of patients screened per trial was 11 (range 0-66) and the median number of patients accrued per trial was 9 (range 0-58). Of the 24 trials, 17 were not subtype specific (13 included soft tissue sarcoma alone while 4 included both bone and soft tissue sarcoma). The remaining 7 trials were sarcoma subtype specific (eg, angiosarcoma, liposarcoma, etc). Trials available at NM during this period are included in TABLE 5. There were 318 patients screened and 262 patients accrued to sarcoma trials over this time period, with a screen failure rate of 17.6% overall.

Discussion

Our study sought to describe perceptions of clinical trial enrollment among patients with bone and soft tissue sarcoma in order to elucidate and overcome barriers to enrollment, which to the best of our knowledge had not been previously described. Using previously validated patient- reported outcomes in the literature,⁶ our data reveal a correlation between knowledge of trials and more positive attitudes towards trials. This underscores the importance of awareness and educational strategies in this cancer population as a whole. Interventions should focus on patient perceptions that contribute to lack of participation, such as fear of side effects, loss of control (eg, idea of placebo or randomization), logistical challenges (eg, additional time or convenient location), and cost.^3,5,7,16,17 For example, patients concerned about randomization should be educated on equipoise and other ethical considerations in trial design.⁵ Previous research has suggested that a multimedia psychoeducational intervention was effective in improving attitudes toward trials.⁶ Educating patients on the essential role of trials in oncology care, as demonstrated by the vast number of new drug approvals in recent years, is an essential strategy to improve attitudes, and subsequently leads to higher patient accrual rates. 

In our study, both knowledge and at titudes were increased in patients with previous trial exposure. This suggests that either patients with greater knowledge and more positive attitudes are more likely to enroll in trials, or that patients with direct trial exposure are more knowledgeable and develop more positive attitudes. Our patient population was overall receptive to learning more about clinical trials (85.4%) and willing to participate (65.8%). At the same time, our study demonstrated low to medium correlations between attitudes and perceived ability to take steps towards making an informed decision to enroll in a trial (r=0.4), which may partially be explained by the absence of a tangible trial opportunity. While we did not assess specifically whether patients in our study were offered a trial, there was a substantial trial menu at NM with limited screen failures and decent trial accrual over the time frame of our study. This underscores the importance not only of patient-focused strategies to increase educational and attitudinal resources, but also a need to focus on research-site optimization that includes opening of multiple trials in various settings, systematic pre-screening of patients, and eligibility criteria that are inclusive and rational.⁵

The patient population with metastatic disease demonstrated more positive attitudes towards enrolling in clinical trials. This cohort accrued well to clinical trials, with 21 of 24 trials enrolling specifically patients with metastatic disease. Of the patients who responded to our survey, patients with previous trial exposure were enriched for patients with metastatic disease (53.3% metastatic among previous trial exposure versus 26.8% metastatic overall). These observations are likely reflective of the need for novel therapies in this disease setting. At the same time, approximately 25% of patients with localized soft tissue sarcoma will develop distant metastatic disease after successful treatment of their primary tumor, which increases to 40% to 50% in larger and higher-grade tumors.¹⁸ Three of 24 trials were open for patients with non-metastatic disease, of which one managed to accrue patients. Patients with non-metastatic disease had more negative attitudes towards trial enrollment. These disproportionate findings suggest a need for interventions to increase patient awareness and attitudes towards trial enrollment among this patient population and the importance of research-site optimization for trial opportunities across disease states.

Molecular profiling of tumors and biomarker identification has become a critical component of further characterizing cancer subtypes. In our study, a majority (65.2%) thought there would be a 50% or greater likelihood of finding a targetable result in their molecular profile. Molecular data on 5,749 bone and soft tissue sarcomas suggested that 9.5% of tumors demonstrate a “targetable result,” defined as a new molecular finding for which there is an FDA-approved drug for malignancies other than sarcoma (eg, BRAF V600E, Her2, etc.),¹⁹ suggesting an overestimation in our patient cohort of the likelihood of benefit of molecular profiling. These results highlight that the growing use of molecular profiling has increased the need for educational and supportive resources to help patients understand the utility of molecular profiling and aid in shared decision-making surrounding the results.

At the same time, the importance of identifying a targetable mutation in patients with sarcoma cannot be understated. As a recent example of this paradigm, tumors that harbor fusions with the neurotrophic receptor tyrosine kinase 1, 2, or 3 (NTRK1, 2, and 3) have a high response rate (~75%) to drugs that target these fusions, such as larotrectinib and entrectinib.¹³ Molecular profiling and identification of predictive biomarkers in small patient subsets has led to great challenges in trial design and research-site optimization. Novel designs that incorporate molecular profiling,²⁰ such as the Lung- MAP trial²¹ and NCI’s Molecular Analysis for Therapy Choice (MATCH) trial,²² are emerging to identify new therapies for small patient subsets. As a rare and increasingly heterogeneous cancer, sarcoma represents a paradigm to provide insight into optimizing patient perceptions and research enterprises to maximize clinical trial enrollment. 

Some limitations of our study include a homogeneous and selected patient population that was predominantly Caucasian and highly educated. Therefore, these findings should not be extrapolated to other populations with barriers to trial accrual, such as lower socioeconomic or minority populations. The low response rate and failure of some to complete the survey may have introduced some bias. Additionally, our data include self-reported outcomes, which could have affected our results. Finally, the limited number of patients who had undergone or heard of molecular profiling limited our ability to draw definitive conclusions, and should be assessed in larger patient cohorts.

While our paper addresses a unique population—the sarcoma patient—similar themes and issues pertain to all oncology patients. A recent review was published in the American Society of Clinical Oncology Educational Book²³ looking at methods to overcome barriers to clinical trial enrollment. Their paper clearly illustrates mechanisms to assist with overcoming financial burdens associated with cancer clinical trials, overcoming barriers as they relate to patient and clinician difficulty in coping with the uncertainty inherent in clinical trial participation, and highlight the role of a patient navigator in clinical trial participation.

Conclusions

Interventions aimed at increasing awareness, knowledge, and attitudes towards clinical trials among sarcoma patients may lead to increased trial enrollment and greater progress in cancer treatment in this population. In addition to patient- focused interventions, thoughtful and strategic clinical trial designs that allow for the development of biomarker- driven therapeutics, while at the same time optimizing patient accrual rates, should be developed. Evaluation of barriers to clinical trial enrollment and molecular profiling of tumors among bone and soft tissue sarcoma patients at an academic center can serve as a paradigm to overcome barriers to enrollment in the era of an increasingly heterogeneous cancer population. TSJ

Introduction

The development of new cancer therapies relies on the successful development and completion of clinical trials. While clinical trials have led to significant improvements in cancer treatment, the success is dependent upon patient enrollment and participation. Unfortunately, fewer than 5% of adult patients enroll in trials.^1-3 This represents a significant barrier to the development and approval of new cancer treatments. Reasons for low accrual into trials are multifactorial, but include structural barriers (eg, clinic access), clinical barriers (eg, eligibility criteria), and physician and patient attitudes towards trial enrollment.^4,5 One study at the University of California Davis Cancer Center reported 49% of patients declined participation despite meeting eligibility criteria,^3,6 suggesting that psychosocial barriers such as knowledge of trials and attitudes towards clinical research are a major impediment to accrual.^7-9

Bone and soft tissue sarcoma represent a heterogeneous group of tumors of mesenchymal origin that are an important cause of morbidity and mortality. Local disease is often treated with a multidisciplinary approach including surgery, radiation, and systemic therapy. Metastatic disease is predominantly treated palliatively with systemic therapy.¹⁰ Given its rarity and heterogeneity, trial accrual is of particular importance in sarcoma and often requires multiple sites to enroll adequate numbers of patients. While sarcoma represents <1% of adult malignancies overall, it constitutes ~15% of malignancies in the adolescent and young adult (AYA) population (15- 39 years old).^11,12 Sarcoma represents a patient population in which low trial accrual has been correlated with lack of progress in cancer-related outcomes in both the adult and AYA populations.¹³ The reasons for low accrual rates among patients with sarcoma are poorly understood.

Sarcomas represent a molecularly and biologically heterogeneous group of malignancies with over 100 different subtypes.¹² As a result, there has been significant interest in performing molecular profiling, or genetic sequencing, to identify “targetable” mutations. Targetable mutations refer to a specific genetic change identified within the tumor molecular profile for which there is a specific drug that may demonstrate activity against a particular tumor. Given the widespread utilization of this technology in sarcoma, identifying and understanding patient perceptions with regard to molecular profiling is critically important in this disease.¹⁴

In this study, we use a cross-sectional design to describe patient perceptions of trial enrollment among patients with bone and soft tissue sarcoma through validated measures, including attitudes towards clinical trials, knowledge of clinical trials, and perceived ability (ie, self-efficacy) to carry out actions involved in making an informed decision about clinical trial participation, receptivity to learning more about clinical trials, and willingness to participate in clinical trials.6 In addition, we describe this patient cohort’s perceptions of molecular profiling, as current and future trials are increasingly driven by molecular or other biomarkers.

Methods

This was a cross-sectional electronic survey study of patients with bone and soft tissue sarcoma treated at Northwestern Medicine (NM) over a 5-year period. NM Enterprise Data Warehouse (NMEDW) is a single, comprehensive, and integrated repository of all clinical and research data sources within NM. The study was approved by the Northwestern University Institutional Review Board.

Survey

The investigators designed a self-administered, online survey, which was built using Research Electronic Data Capture (REDCap). The survey consisted of three sections that were answered using skip logic—a custom path through the survey that varied based on patients’ answers: (1) Patient demographic information and trial perceptions (answered by all patients); (2) Thoughts about molecular profiling (answered by patients who answered “yes” to the question, “Have you heard about molecular profiling of tumors?”); and (3) Considerations to undergo molecular profiling (answered by patients who answered “yes” to the question, “Have you undergone profiling of your cancer?”).

Thoughts about molecular profiling of tumors were assessed using nine items (TABLE 1). Of these, items assessing potential benefit or harm of molecular profiling were assessed using a 7-step Likert scale. Items assessing maximal benefit or harm of therapy, importance of quality vs length of life, and concern about the cost of molecular testing were assessed using a 5-step Likert scale. The study team developed and piloted these questions because there is no validated survey assessing these domains.

Considerations to undergo molecular profiling were assessed using 17 items. Items were in response to the question, “To what extent did you consider the following issues or concerns at the time you decided to get molecular testing of your cancer?” Responses were assessed using a 5-point Likert scale.

Data Collection

Patients 18 years and older evaluated at NM between November 20, 2012, and November 20, 2017, with a diagnosis of sarcoma were identified by query of the NMEDW by ICD-10 codes (C40, C41.9, C44.99, C45-49, C55, C71.9, D48, D49.9, and M12.20) or equivalent ICD-9 codes. Patients were subsequently excluded if they did not have a diagnosis of bone or soft tissue sarcoma, no e-mail address listed, had died, or had not been evaluated at an NM clinic in the previous 5 years. Patients with a diagnosis of gastrointestinal stromal tumor and Kaposi’s sarcoma were also excluded.

A personalized contact e-mail was sent to patients containing an explanation of the survey and an internet link to the electronic survey through REDCap from January 2018 to March 2018. If patients did not respond to the survey, two follow-up reminder e-mails were sent 2 and 4 days following the initial survey. The link was protected so that each patient could complete the survey only once. Responses were collected through the REDCap platform. Patients read and signed an electronic consent form prior to completing the survey.

Upon completion of the survey, patients were offered a $50 VISA gift card as compensation, with an option to donate their compensation to the Robert H. Lurie Comprehensive Cancer Center Sarcoma Research Fund.

Over the described survey period, open clinical trials for patients with bone and soft tissue sarcoma available at NM were evaluated. The number of patients screened and accrued to each trial were recorded.

Statistical analysis

Responses were separated from the personal data for complete anonymization. Descriptive statistical analysis was performed for demographics and disease variables and were summarized using frequencies and percentages. Median and range were used for age. Correlations between continuous variables were analyzed using Spearman correlations. Scores were compared between subgroups using the Mann-Whitney test. Descriptive statistics for knowledge, attitude, and ability scores include means and 95% confidence intervals. Correlations were interpreted as small (r=0.10), medium (r=0.30), or large (r=0.50).15 Statistical significance was indicated when P<0.05.

Results

Patients

Seven hundred fifty patients were eligible to participate in the survey and received the initial and two follow-up e-mails. Twenty e-mailed surveys bounced back. Three hundred nine patients opened the initial e-mail and 283 patients (37.7% of total and 91.6% of opened) completed at least a portion of the survey, with 182 patients completing the entire survey (FIGURE 1). Data for analysis were used from patients who completed at least a portion of the survey.

Baseline characteristics of patients who responded can be seen in TABLE 2. Patients had a median age of 56, the majority were female (59.4%), white (88.2%), and most had college or university graduate degrees or higher educational level (69.0%). Patients had various different histological subtypes, with the most common being liposarcoma (16.5%) and leiomyosarcoma (16.0%). Slightly more than a quarter (26.8%) of patients had metastatic disease, and 84.2% had never been enrolled in a clinical trial. Previous treatments included surgery (91.1%), radiation (53.2%), and chemotherapy (51.6%). Prior to completing the survey, 85.4% reported being receptive to a cancer clinical trial, while 60.7% of patients reported willingness to participate in a clinical trial.

Knowledge, attitudes, and perceived ability

A statistically significant correlation was observed between greater knowledge of trials and more positive attitudes towards trials (P<0.001; r=0.5, FIGURE 2A). In relating patient attitudes with perceived ability, again a significant correlation was seen (P<0.001; r=0.4, FIGURE 2B). In contrast, knowledge had a weak correlation with perceived ability (P=0.024; r=0.2, FIGURE 2C). There was no difference regarding patient knowledge, attitudes, or perceived ability by age, gender, race, or income.

Knowledge, attitudes, perceived ability, and clinical trial enrollment

Thirty patients reported clinical trial experience (either previously or currently enrolled in trials) and 160 patients were never enrolled. Of the 30 patients with trial experience, 7 reported being currently enrolled, while 23 reported previous enrollment. Of these patients, 16 had metastatic disease, while 12 had non-metastatic disease, and 2 were unsure whether or not they had metastatic disease.

Patients with previous clinical trial exposure (currently or previously enrolled in clinical trials) demonstrated significantly greater trial knowledge, with a mean knowledge score of 9.3 (CI 8.5-10.0) compared with 7.7 (CI 7.3-8.1) among patients without trial exposure (P=0.002; FIGURE 3A). Similarly, patients with trial experience also had statistically significant more positive attitudes towards trials as compared with patients with no trial experience, with a mean attitude score of 3.8 (CI 3.6-4.0) and 3.5 (CI 3.4-3.6), respectively (P=0.001; FIGURE 3B). While numerically patients with trial experience have greater perceived ability compared with patients with no trial experience, with a mean score of 4.4 (CI 4.2-4.6) and 4.2 (CI 4.1-4.3), respectively, this difference did not reach statistical significance (FIGURE 3C).

Knowledge, attitudes, perceived ability, and disease stage

An analysis was performed comparing patients with metastatic vs non-metastatic disease. It was observed that patients with metastatic disease had similar knowledge of trials compared with non-metastatic patients, with a mean knowledge score of 8.4 (CI 7.7- 9.1) and 7.9 (CI 7.5-8.4), respectively, (P=0.3; FIGURE 4A). In contrast, patients with metastatic disease had more positive attitudes compared with non-metastatic patients, with a mean score of 3.7 (CI 3.5-3.8) and 3.5 (CI 3.4-3.6), respectively, which was statistically significant (P=0.03; FIGURE 4B). There was no difference in perceived ability in metastatic vs non-metastatic patients (FIGURE 4C).

Thoughts about molecular profiling

Of the total number of patients, 46 patients had heard of molecular profiling and were presented with questions regarding their thoughts (TABLE 3). Approximately two-thirds (65.2%) thought there would be a 50% or greater likelihood of finding a targetable result in their tumor molecular profile. A majority (71.7%) of patients thought that a new experimental therapy chosen based on a patient’s tumor molecular profile would have at least a 50% chance of controlling the cancer. Somewhat less than a third (30.4%) of patients thought that total cure is the maximal benefit a patient could experience as a result of a treatment on a clinical trial using a drug chosen based on molecular tests. About half (52.2%) of patients agreed with the statement, “I am concerned about the cost of the test to molecularly profile my cancer.”

Considerations to undergo molecular profiling

Eighteen patients had undergone molecular profiling of their tumor. These patients were posed the question, “To what extent did you consider the following issues or concerns at the time you decided to get molecular testing of your cancer?” (TABLE 4). A majority (83.3%) of patients stated that wanting to live as long as possible was important, and 72.2% of patients stated that quality of life was important. A majority (83.3%) of patients stated that hope for a cure was an extremely or quite a bit important consideration. Helping future cancer patients was extremely or quite a bit important for 77.8% of patients, while wanting to be a part of research was not at all or of little importance in 50.0% of patients.

Clinical trials at NM

Twenty-four clinical trials were available at NM between the years 2012 and 2017 for patients with bone and soft tissue sarcoma. Of these trials, 3 of 24 were for non-metastatic patients, while the remaining 21 were open only to metastatic patients. The median number of patients screened per trial was 11 (range 0-66) and the median number of patients accrued per trial was 9 (range 0-58). Of the 24 trials, 17 were not subtype specific (13 included soft tissue sarcoma alone while 4 included both bone and soft tissue sarcoma). The remaining 7 trials were sarcoma subtype specific (eg, angiosarcoma, liposarcoma, etc). Trials available at NM during this period are included in TABLE 5. There were 318 patients screened and 262 patients accrued to sarcoma trials over this time period, with a screen failure rate of 17.6% overall.

Discussion

Our study sought to describe perceptions of clinical trial enrollment among patients with bone and soft tissue sarcoma in order to elucidate and overcome barriers to enrollment, which to the best of our knowledge had not been previously described. Using previously validated patient- reported outcomes in the literature,⁶ our data reveal a correlation between knowledge of trials and more positive attitudes towards trials. This underscores the importance of awareness and educational strategies in this cancer population as a whole. Interventions should focus on patient perceptions that contribute to lack of participation, such as fear of side effects, loss of control (eg, idea of placebo or randomization), logistical challenges (eg, additional time or convenient location), and cost.^3,5,7,16,17 For example, patients concerned about randomization should be educated on equipoise and other ethical considerations in trial design.⁵ Previous research has suggested that a multimedia psychoeducational intervention was effective in improving attitudes toward trials.⁶ Educating patients on the essential role of trials in oncology care, as demonstrated by the vast number of new drug approvals in recent years, is an essential strategy to improve attitudes, and subsequently leads to higher patient accrual rates. 

In our study, both knowledge and at titudes were increased in patients with previous trial exposure. This suggests that either patients with greater knowledge and more positive attitudes are more likely to enroll in trials, or that patients with direct trial exposure are more knowledgeable and develop more positive attitudes. Our patient population was overall receptive to learning more about clinical trials (85.4%) and willing to participate (65.8%). At the same time, our study demonstrated low to medium correlations between attitudes and perceived ability to take steps towards making an informed decision to enroll in a trial (r=0.4), which may partially be explained by the absence of a tangible trial opportunity. While we did not assess specifically whether patients in our study were offered a trial, there was a substantial trial menu at NM with limited screen failures and decent trial accrual over the time frame of our study. This underscores the importance not only of patient-focused strategies to increase educational and attitudinal resources, but also a need to focus on research-site optimization that includes opening of multiple trials in various settings, systematic pre-screening of patients, and eligibility criteria that are inclusive and rational.⁵

The patient population with metastatic disease demonstrated more positive attitudes towards enrolling in clinical trials. This cohort accrued well to clinical trials, with 21 of 24 trials enrolling specifically patients with metastatic disease. Of the patients who responded to our survey, patients with previous trial exposure were enriched for patients with metastatic disease (53.3% metastatic among previous trial exposure versus 26.8% metastatic overall). These observations are likely reflective of the need for novel therapies in this disease setting. At the same time, approximately 25% of patients with localized soft tissue sarcoma will develop distant metastatic disease after successful treatment of their primary tumor, which increases to 40% to 50% in larger and higher-grade tumors.¹⁸ Three of 24 trials were open for patients with non-metastatic disease, of which one managed to accrue patients. Patients with non-metastatic disease had more negative attitudes towards trial enrollment. These disproportionate findings suggest a need for interventions to increase patient awareness and attitudes towards trial enrollment among this patient population and the importance of research-site optimization for trial opportunities across disease states.

Molecular profiling of tumors and biomarker identification has become a critical component of further characterizing cancer subtypes. In our study, a majority (65.2%) thought there would be a 50% or greater likelihood of finding a targetable result in their molecular profile. Molecular data on 5,749 bone and soft tissue sarcomas suggested that 9.5% of tumors demonstrate a “targetable result,” defined as a new molecular finding for which there is an FDA-approved drug for malignancies other than sarcoma (eg, BRAF V600E, Her2, etc.),¹⁹ suggesting an overestimation in our patient cohort of the likelihood of benefit of molecular profiling. These results highlight that the growing use of molecular profiling has increased the need for educational and supportive resources to help patients understand the utility of molecular profiling and aid in shared decision-making surrounding the results.

At the same time, the importance of identifying a targetable mutation in patients with sarcoma cannot be understated. As a recent example of this paradigm, tumors that harbor fusions with the neurotrophic receptor tyrosine kinase 1, 2, or 3 (NTRK1, 2, and 3) have a high response rate (~75%) to drugs that target these fusions, such as larotrectinib and entrectinib.¹³ Molecular profiling and identification of predictive biomarkers in small patient subsets has led to great challenges in trial design and research-site optimization. Novel designs that incorporate molecular profiling,²⁰ such as the Lung- MAP trial²¹ and NCI’s Molecular Analysis for Therapy Choice (MATCH) trial,²² are emerging to identify new therapies for small patient subsets. As a rare and increasingly heterogeneous cancer, sarcoma represents a paradigm to provide insight into optimizing patient perceptions and research enterprises to maximize clinical trial enrollment. 

Some limitations of our study include a homogeneous and selected patient population that was predominantly Caucasian and highly educated. Therefore, these findings should not be extrapolated to other populations with barriers to trial accrual, such as lower socioeconomic or minority populations. The low response rate and failure of some to complete the survey may have introduced some bias. Additionally, our data include self-reported outcomes, which could have affected our results. Finally, the limited number of patients who had undergone or heard of molecular profiling limited our ability to draw definitive conclusions, and should be assessed in larger patient cohorts.

While our paper addresses a unique population—the sarcoma patient—similar themes and issues pertain to all oncology patients. A recent review was published in the American Society of Clinical Oncology Educational Book²³ looking at methods to overcome barriers to clinical trial enrollment. Their paper clearly illustrates mechanisms to assist with overcoming financial burdens associated with cancer clinical trials, overcoming barriers as they relate to patient and clinician difficulty in coping with the uncertainty inherent in clinical trial participation, and highlight the role of a patient navigator in clinical trial participation.

Conclusions

Interventions aimed at increasing awareness, knowledge, and attitudes towards clinical trials among sarcoma patients may lead to increased trial enrollment and greater progress in cancer treatment in this population. In addition to patient- focused interventions, thoughtful and strategic clinical trial designs that allow for the development of biomarker- driven therapeutics, while at the same time optimizing patient accrual rates, should be developed. Evaluation of barriers to clinical trial enrollment and molecular profiling of tumors among bone and soft tissue sarcoma patients at an academic center can serve as a paradigm to overcome barriers to enrollment in the era of an increasingly heterogeneous cancer population. TSJ

The good news: AYA survival improvement was at least as large as in younger children and older adults comparing deaths in two time periods, 1988-2000 and 2001-2014, in a California Cancer Registry.

The bad news: There was no statistically significant difference in survival between time periods for patients with bone and soft tissue sarcoma.

The good news: AYA survival improvement was at least as large as in younger children and older adults comparing deaths in two time periods, 1988-2000 and 2001-2014, in a California Cancer Registry.

The bad news: There was no statistically significant difference in survival between time periods for patients with bone and soft tissue sarcoma.

The good news: AYA survival improvement was at least as large as in younger children and older adults comparing deaths in two time periods, 1988-2000 and 2001-2014, in a California Cancer Registry.

The bad news: There was no statistically significant difference in survival between time periods for patients with bone and soft tissue sarcoma.

Behind Olaratumab's Phase 3 Disappointment

ANNOUNCE, the phase 3 trial designed to confirm the clinical benefit of olaratumab in patients with advanced soft tissue sarcoma (STS), failed to meet its primary endpoint of overall survival (OS) in all STS histologies and the leiomyosarcoma population. The previous phase 1b/2 signal-finding study of olaratumab had achieved an unprecedented improvement in OS, and the US Food and Drug Administration (FDA) awarded olaratumab accelerated approval in October 2016. By December 2018, olaratumab received additional accelerated, conditional, and full approvals in more than 40 countries worldwide. William D. Tap, MD, chief of the Sarcoma Medical Oncology Service at Memorial Sloan Kettering Cancer Center in New York, presented the phase 3 results and provided some explanations for the findings during the plenary session at ASCO.

ANNOUNCE (NCT02451943), which was designed and enrolled prior to olaratumab receiving accelerated approval, opened in September 2015 and completed accrual 10 months later in July 2016. Investigators randomized and treated 509 patients with advanced STS not amenable to curative therapy, 258 patients in the olaratumab-doxorubicin arm and 251 in the placebo-doxorubicin arm. Most patients (46%) had leiomyosarcoma, followed by liposarcoma (18%), pleomorphic sarcoma (13%), and 24% of the patient population had 26 unique histologies. Three-quarters of the patients had no prior systemic therapy.

Results

As of the data cutoff on December 5, 2018, there were no survival differences in the intention-to-treat population, in the total STS population nor in the leiomyosarcoma subpopulation, with olaratumab-doxorubicin compared to placebo-doxorubicin. For the total STS population, median OS with olaratumab- doxorubicin was 20.4 months and with placebo-doxorubicin 19.7 months. “This is the highest survival rate described to date in any phase 3 sarcoma study,” Dr. Tap said. “It is of particular interest as ANNOUNCE did not mandate treatment in the first line.” In the leiomyosarcoma population, median OS was 21.6 months with olaratumab and 21.9 months with placebo. The secondary endpoints of progression-free survival (PFS), overall response rate, and disease control rate did not favor olaratumab either.

Investigators are examining the relationship between PDGFRα expression and OS in ANNOUNCE. PDGFRα-positive tumors tended to do worse with olaratumab than PDGFRα-negative tumors. The investigators noticed a 6-month difference in OS between these populations favoring PDGFRα-negative tumors. Additional biomarker analyses are ongoing.

A large and concerted effort is underway, Dr. Tap said, to understand the results of the ANNOUNCE study alone and in context with the phase 1b/2 study. “There are no noted discrepancies in study conduct or data integrity which could explain these findings or the differences between the two studies.”

Possible explanations

The designs of the phase 1b/2 and phase 3 studies had some important differences. The phase 1b/2 study was a small, open-label, US-centric study (10 sites) that did not include a placebo or subtype- specified analyses. Its primary endpoint was PFS, it did not have a loading dose of olaratumab, and it specified the timing of dexrazoxane administration after 300 mg/m2 of doxorubicin.

ANNOUNCE, on the other hand, was a large (n=509), international (110 study sites), double-blind, placebo-controlled trial that had outcomes evaluated in STS and leiomyosarcoma. Its primary endpoint was OS, it had a loading dose of olaratumab of 20 mg/kg, and there was no restriction as to the timing of dexrazoxane administration.

Dr. Tap pointed out that in ANNOUNCE it was difficult to predict or control for factors that may have had an unanticipated influence on outcomes, such as albumin levels as a surrogate for disease burden and behavior of PDGFRα status. It is possible, he said, that olaratumab has no activity in STS and that the phase 1b/2 results were due to, among other things, the small sample size, numerous represented histologies with disparate clinical behavior, and the effect of subtype-specific therapies on overall survival, given subsequently or even by chance. On the other hand, it is also possible, he said, that olaratumab has some activity in STS, with outcomes being affected by the heterogeneity of the study populations, differences in trial design, and the performance of the ANNOUNCE control arm. Whatever the case, he said, accelerated approval allowed patients to have access to a potentially life-prolonging drug with little added toxicity.

Discussion

In the expert discussion following the presentation, Jaap Verweij, MD, PhD, of Erasmus University Medical Center in Rotterdam, The Netherlands, congratulated the investigators for performing the study at an unprecedented pace. He commented that lumping STS subtypes together is problematic, as different histological subtypes behave as though they are different diseases. Small numbers of each tumor subtype and subtypes with slow tumor growth can impact trial outcomes. In the phase 1b/2 and phase 3 trials, 26 different subtypes were represented in each study. Dr. Verweij pointed out this could have made a big difference in the phase 1b/2 study, in which there were only 66 patients in each arm.

It is striking to note, he said, that without exception, phase 2 randomized studies in STS involving doxorubicin consistently overestimated and wrongly predicted PFS in the subsequent phase 3 studies. And the situation is similar for OS. The results of the ANNOUNCE study are no exception, he added. “Taken together, these studies indicate that phase 2 studies in soft tissue sarcomas, certainly those involving additions of drugs to doxorubicin, even if randomized, should be interpreted with great caution,” he said.

SOURCE: Tap WD, et al. J Clin Oncol 37, 2019 (suppl; abstr LBA3)

The study was sponsored by Eli Lilly and Company.

Dr. Tap reported research funding from Lilly and Dr. Verweij had nothing to report related to this study. Abstract coauthors disclosed numerous financial relationships, including consulting/advisory roles and/or research funding from Lilly, and several were employed by Lilly.

Addition of Temozolomide May Improve Outcomes in RMS

Investigators from the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) found that the addition of temozolomide (T) to vincristine and irinotecan (VI) may improve outcomes in adults and children with relapsed or refractory rhabdomyosarcoma (RMS). Principal investigator of the study, Anne Sophie Defachelles, MD, pediatric oncologist at the Centre Oscar Lambret in Lille, France, presented the results on behalf of the EpSSG.

The international, randomized (1:1), open-label, phase 2 trial (VIT-0910; NCT01355445) was conducted at 37 centers in 5 countries. Patients ages 6 months to 50 years with RMS were eligible. They could not have had prior irinotecan or temozolomide. A 2015 protocol amendment limited enrollment to patients at relapse and increased the enrollment goal by 40 patients. After the 2015 amendment, patients with refractory disease were no longer eligible.

From January 2012 to April 2018, investigators enrolled 120 patients, 60 on each arm. Two patients in the VI arm were not treated. Patients were a median age of 10.5 years in the VI arm and 12 years in the VIT arm, 92% (VI) and 87% (VIT) had relapsed disease, 8% (VI) and 13% (VIT) had refractory disease, and 55% (VI) and 68% (VIT) had metastatic disease at study entry.

Results

Patients achieved an OR rate of 44% (VIT) and 31% (VI) for the whole population, one-sided P value <.0001. The adjusted odds ratio for the whole population was 0.50, P=.09. PFS was 4.7 months (VIT) and 3.2 months (VI), “a nearly significant reduction in the risk of progression,” Dr. Defachelles noted. Median OS was 15.0 months (VIT) and 10.3 months (VI), which amounted to “a large and significant reduction in the risk of death,” she said. The adjusted hazard ratio was 0.55, P=.006.

Adverse events of grade 3 or higher were more frequent in the VIT arm, with hematologic toxicity the most frequent (81% for VIT, 59% for VI), followed by gastrointestinal adverse events. “VIT was significantly more toxic than VI,” Dr. Defachelles observed, “but the toxicity was manageable.”

“VIT is now the standard treatment in Europe for relapsed rhabdomyosarcoma and will be the control arm in the multiarm, multistage RMS study for relapsed patients,” she said.

SOURCE: Defachelles AS, et al. J Clin Oncol 37, 2019 (suppl; abstr 10000)

The study was sponsored by Centre Oscar Lambret and SFCE (Société Française de Lutte contre les Cancers et Lucémies de l’Enfant et de l’Adolescent) served as collaborator.

Drs. Defachelles and Wagner had no relationships to disclose. A few coauthors had advisory/consulting or speaker roles for various commercial interests, including two for Merck (temozolomide).

Pazopanib Increases Pathologic Necrosis Rates in STS

Pazopanib added to a regimen of preoperative chemoradiation in non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) significantly increased the rate of near-complete pathologic response in both children and adults with intermediate or high-risk disease. Pazopanib, a multitargeted receptor tyrosine kinase inhibitor, works in multiple signaling pathways involved in tumorigenesis— VEGFR-1, -2, -3, PDGFRα/β, and c-kit. A phase 3 study demonstrated significant improvement in progression-free survival (PFS) in advanced STS patients and was the basis for its approval in the US and elsewhere for treatment of this patient population. Preclinical data suggest synergy between pazopanib and cytotoxic chemotherapy, forming the rationale for the current trial with neoadjuvant pazopanib added to chemoradiation.

According to the investigators, the trial (ARST1321) is the first ever collaborative study codeveloped, written, and conducted by pediatric (Children’s Oncology Group) and adult (NRG Oncology) cancer cooperative groups (NCT02180867). Aaron R. Weiss, MD, of the Maine Medical Center in Portland and study cochair, presented the data for the chemotherapy arms at ASCO. The primary objectives of the study were to determine the feasibility of preoperative chemoradiation with or without pazopanib and to compare the rates of complete pathologic response in patients receiving radiation or chemoradiation with or without pazopanib. Pathologic necrosis rates of 90% or better have been found to be predictive of outcome in STS.

Results

As of the June 30, 2018, cutoff, 81 patients were enrolled on the chemotherapy arms: 42 in the pazopanib plus chemoradiation arm and 39 in the chemoradiation-only arm. Sixty-one percent of all patients were 18 years or older, and the median age was 20.3 years. Most patients (73%) did not have metastatic disease, and the major histologies represented were synovial sarcoma (49%) and undifferentiated pleomorphic sarcoma (25%).

At week 13, patients in the pazopanib arm showed significant improvement, with 14 (58%) of those evaluated having pathologic necrosis of at least 90%, compared with 4 (22%) in the chemoradiation-only arm (P=.02). The study was closed to further accrual.

Eighteen patients were not evaluable for pathologic response and 21 were pending pathologic evaluation at week 13. Radiographic response rates were not statistically significant on either arm. No complete responses (CR) were achieved in the pazopanib arm, but 14 patients (52%) achieved a partial response (PR) and 12 (44%) had stable disease (SD). In the chemoradiation-only arm, 2 patients (8%) achieved a CR, 12 (50%) a PR, and 8 (33%) SD. Fifteen patients in each arm were not evaluated for radiographic response.

The pazopanib arm experienced more febrile neutropenia and myelotoxicity during induction and continuation phases than the chemoradiation-only arm. In general, investigators indicated pazopanib combined with chemoradiation was well tolerated and no unexpected toxicities arose during the trial.

In the post-presentation discussion, Dr. Raphael E. Pollock, MD, PhD, of The Ohio State University, called it a tremendous challenge to interdigitate primary local therapies in systemic approaches, particularly in the neoadjuvant context. He pointed out that in an earlier study, a 95% to 100% necrosis level was needed to achieve a significant positive impact on outcomes and perhaps a subsequent prospective trial could determine the best level. He questioned whether the availability of only 60% of patient responses could affect the conclusions and whether the high number of toxicities (73.8% grade 3/4 with pazopanib) might be too high to consider the treatment for most patients, given the intensity of the regimen.

SOURCE: Weiss AR, et al. J Clin Oncol 37, 2019 (suppl; abstr 11002)

The study was sponsored by the National Cancer Institute.

Drs. Weiss and Pollock had no relationships with commercial interests to disclose. A few investigators disclosed advisory, consulting, or research roles with pharmaceutical companies, including one who received institutional research funding from Novartis (pazopanib).

Gemcitabine Plus Pazopanib a Potential Alternative in STS

In a phase 2 study of gemcitabine with pazopanib (G+P) or gemcitabine with docetaxel (G+D), investigators concluded the combination with pazopanib can be considered an alternative to that with docetaxel in select patients with advanced soft tissue sarcoma (STS). They reported similar progression-free survival (PFS) and rate of toxicity for the two regimens. Neeta Somaiah, MD, of the University of Texas MD Anderson Cancer Center in Houston, presented the findings of the investigator-initiated effort (NCT01593748) at ASCO.

The investigators enrolled 90 patients, 45 in each arm. Patients were a mean age of 56 years, and there was no difference in age or gender distribution between the arms. Patients with leiomyosarcoma (31% overall) or prior pelvic radiation (11% overall) were similar between the arms. The overall response rate using RECIST 1.1 criteria was partial response (PR) in 8 of 44 evaluable patients (18%) in the G+D arm and 5 of 43 evaluable patients (12%) in the G+P arm. Stable disease (SD) was observed in 21 patients (48%) in the G+D arm and 24 patients (56%) in the G+P arm. This amounted to a clinical benefit rate (PR + SD) of 66% and 68% for the G+D and G+P arms, respectively (Fisher’s exact test, P>.99). The median PFS was 4.1 months on both arms and the difference in median overall survival— 15.9 months in the G+D arm and 12.4 months in the G+P arm—was not statistically significant.

Adverse events (AEs) of grade 3 or higher occurred in 19.9% of patients on G+D and 20.6% on G+P. Serious AEs occurred in 33% (G+D) and 22% (G+P). Dose reductions were necessary in 80% of patients on G+P and doses were held in 93%. Dr. Somaiah explained that this may have been because the starting dose of gemcitabine and pazopanib (1000 mg/m² of gemcitabine on days 1 and 8 and 800 mg of pazopanib) was “probably higher than what we should have started at.” The rate of doses held was also higher in the pazopanib arm (93%) compared with the docetaxel arm (58%). This was likely because pazopanib was a daily dosing, so if there was a toxicity it was more likely to be held than docetaxel, she observed. Grade 3 or higher toxicities occurring in 5% or more of patients in either arm consisted generally of cytopenias and fatigue. The G+P arm experienced a high amount of neutropenia, most likely because this arm did not receive granulocyte-colony stimulating factor (GCSF) support, as opposed to the G+D arm.

Dr. Somaiah pointed out that the 12% response rate for the G+P combination is similar to what has been previously presented and higher than single-agent gemcitabine or pazopanib, but not higher than the G+D combination. The PFS of 4.1 months was less than anticipated, she added, but it was similar on both arms. The investigators believe the G+P combination warrants further exploration.

SOURCE: Somaiah N, et al. J Clin Oncol 37, 2019 (suppl; abstr 11008)

The study was sponsored by the Medical University of South Carolina, with Novartis as collaborator.

Dr. Somaiah disclosed Advisory Board roles for Blueprint, Deciphera, and Bayer. Abstract coauthors disclosed advisory/consulting roles or research funding from various commercial interests, including Novartis (pazopanib) and Pfizer (gemcitabine).

rEECur Trial Finding Optimal Chemotherapy Regimen for Ewing Sarcoma

Interim results of the first and largest randomized trial in patients with refractory or recurrent Ewing sarcoma (ES), the rEECur trial, are guiding the way to finding the optimal chemotherapy regimen to treat the disease. Until now, there has been little prospective evidence and no randomized data to guide treatment choices in relapsed or refractory patients, and hence no real standard of care, according to the presentation at ASCO. Several molecularly targeted therapies are emerging, and they require a standardized chemotherapy backbone against which they can be tested.

Results

Two hundred twenty patients 4 years or older and younger than 50 years with recurrent or refractory histologically confirmed ES of bone or soft tissue were randomized to receive GD (n=72) or TC, IT, or IFOS (n=148). Sixty-two GD patients and 123 TC/IT/IFOS patients were included in the primary outcome analysis. Patients were predominantly male (70%), with a median age of 19 years (range, 4 to 49). About two-thirds (67.3%) were post-pubertal. Most patients (85%) were primary refractory or experienced their first disease recurrence, and 89% had measurable disease.

Investigators assessed the primary outcome of objective response after 4 cycles of therapy and found 11% of patients treated with GD responded compared to 24% in the other 3 arms combined. When they subjected the data to Bayesian analysis, there was a 25% chance that the response rate in the GD arm was better than the response in Arm A, a 2% chance that it was better than Arm B, and a 3% chance that it was better than Arm C. Because this study was still blinded at the time of the presentation, investigators didn’t know which regimen constituted which arm. The probability that response favored GD, however, was low.

The investigators observed no surprising safety findings. Eighty-five percent of all patients experienced at least 1 adverse event. Most frequent grade 3‐5 events consisted of pneumonitis (50%, 60%), neutropenic fever (17%, 25%), and diarrhea (0, 12%) in GD and the combined 3 arms, respectively. Grade 3 events in the GD arm were lower than in the other 3 arms combined. There was 1 toxic death attributed to neutropenic sepsis in 1 of the 3 blinded arms.

Median progression-free survival (PFS) for all patients was approximately 5 months. Bayesian analysis suggested there was a low probability that GD was more effective than the other 3 arms: a 22% chance that GD was better than Arm A, a 3% chance that it was better than Arm B, and a 7% chance that it was better than Arm C. Bayesian analysis also suggested there was a probability that OS favored GD. Because the trial directs only the first 4 or 6 cycles of treatment and the patients receive more treatment after trial-directed therapy, investigators were not fully able to interpret this.

Data suggested GD is a less effective regimen than the other 3 regimens both by objective response rate and PFS, so GD has been dropped from the study. Investigators already had more than 75 evaluable patients in each of the 3 arms for the second interim analysis to take place. In a discussion following the presentation, Jayesh Desai, FRACP, of Peter MacCallum Cancer Centre in Melbourne, Australia, called this study a potentially practice-changing trial at this early stage, noting that the GD combination will be de-prioritized in practice based on these results.

SOURCE: McCabe MG, et al. J Clin Oncol 37, 2019 (suppl; abstr 11007)

The rEECur trial is sponsored by the University of Birmingham (UK) and received funding from the European Union’s Seventh Framework Programme under a grant agreement.

Dr. McCabe disclosed no conflicts of interest. Other authors disclosed consulting, advisory roles, or research funding from numerous pharmaceutical companies, including Lilly (gemcitabine) and Pfizer (irinotecan). Dr. Desai disclosed a consulting/advisory role and institutional research funding from Lilly.

Abemaciclib Meets Primary Endpoint in Phase 2 Trial of DDLS

The newer and more potent CDK4 inhibitor, abemaciclib, met its primary endpoint in the investigator-initiated, single-center, single-arm, phase 2 trial in patients with advanced progressive dedifferentiated liposarcoma (DDLS). Twenty-two patients (76%) achieved progression-free survival (PFS) at 12 weeks for a median PFS of 30 weeks. A subset of patients experienced prolonged clinical benefit, remaining on study with stable disease for over 900 days. The study (NCT02846987) was conducted at Memorial Sloan Kettering Cancer Center (MSKCC) in New York and Mark A. Dickson, MD, presented the results at ASCO.

Results

Thirty patients, 29 evaluable, with metastatic or recurrent DDLS were enrolled and treated with abemaciclib 200 mg orally twice daily between August 2016 and October 2018. Data cutoff for the presentation was the first week of May 2019. Patients were a median of 62 years, 60% were male, and half had no prior systemic treatment. Prior systemic treatments for those previously treated included doxorubicin, olaratumab, gemcitabine, docetaxel, ifosfamide, eribulin, and trabectedin. For 87%, the primary tumor was in their abdomen or retroperitoneum.

Toxicity was as expected with this class of agent, according to the investigators. The most common grades 2 and 3 toxicities, respectively, possibly related to the study drug, occurring in more than 1 patient included anemia (70%, 37%), thrombocytopenia (13%, 13%), neutropenia (43%, 17%), and lymphocyte count decreased (23%, 23%). Very few of these adverse events were grade 4—none for anemia, and 3% each for thrombocytopenia, neutropenia, and lymphocyte count decreased. Diarrhea of grades 2 and 3 occurred in 27% and 7% of patients, respectively, and was managed well with loperamide.

In addition to reaching the primary endpoint of 15 patients or more achieving PFS at 12 weeks, 1 patient had a confirmed partial response (PR) and another an unconfirmed PR. At data cutoff, 11 patients remained on study with stable disease or PR. The investigators conducted correlative studies that indicated all patients had CDK4 and MDM2 amplification with no loss of retinoblastoma tumor suppressor. They observed an inverse correlation between CDK4 amplification and PFS—the higher the level of CDK4 amplification, the shorter the PFS. They also found additional genomic alterations, including JUN, GLI1, ARID1A, TERT, and ATRX. TERT amplification was also associated with shorter PFS. Based on these findings, the investigators believe a phase 3 study of abemaciclib in DDLS is warranted.

Winette van der Graaf, MD, PhD, of the Netherlands Cancer Institute in Amsterdam, in the discussion following the presentation, concurred that it is certainly time for a multicenter phase 3 study of CDK4 inhibitors in DDLS, and a strong international collaboration is key to conducting such studies, particularly in rare cancers. On a critical note, Dr. van der Graaf expressed concern that no patient-reported outcomes were measured after 120 patients, including those in previous studies, were treated on palbociclib and abemaciclib. Given that the toxicities of the CDK4 inhibitors are quite different, she recommended including patient-reported outcomes in future studies using validated health-related quality-of-life instruments.

SOURCE: Dickson MA, et al. J Clin Oncol 37, 2019 (suppl; abstr 11004)

The study was sponsored by Memorial Sloan Kettering Cancer Center, with the study collaborator, Eli Lilly and Company.

Dr. Dickson disclosed research funding from Lilly, the company that provided the study drug. Dr. van der Graaf had no relevant relationships to disclose. Abstract coauthors had consulting/advisory roles or research funding from various companies, including Lilly.

nab-Sirolimus Provides Benefits in Advanced Malignant PEComa

In a prospective phase 2 study of nab-sirolimus in advanced malignant perivascular epithelioid cell tumor (PEComa), the mTOR inhibitor achieved an objective response rate (ORR) of 42% with an acceptable safety profile, despite using relatively high doses of nab-sirolimus compared to other mTOR inhibitors. Activation of the mTOR pathway is common in PEComa, and earlier case reports had indicated substantial clinical benefit with mTOR inhibitor treatment. nab-Sirolimus (ABI-009) is a novel intravenous mTOR inhibitor consisting of nanoparticles of albumin-bound sirolimus. It has significantly higher anti-tumor activity than oral mTOR inhibitors and greater mTOR target suppression at an equal dose. Andrew J. Wagner, MD, PhD, of the Dana-Farber Cancer Institute in Boston, presented the findings of AMPECT (NCT02494570)—Advanced Malignant PEComa Trial—at ASCO.

Results

The drug was well tolerated, with toxicities similar to those of oral mTOR inhibitors. Treatment-related adverse events (TRAEs) occurring in 25% or more of patients were mostly grade 1 or 2 toxicities. Hematologic TRAEs included anemia (47%) and thrombocytopenia (32%) of any grade. Nonhematologic events of any grade included stomatitis/ mucositis (74%), dermatitis/rash (65%), fatigue (59%), nausea (47%), and diarrhea (38%), among others. A few grade 3 events occurred on study, most notably stomatitis/mucositis (18%). Severe adverse events (SAEs) were also uncommon, occurring in 7 of 34 patients (21%). Pneumonitis is common in orally administered mTOR inhibitors; 6 patients (18%) treated with nab-sirolimus had grade 1 or 2 pneumonitis.

Of the 31 evaluable patients, 13 (42%) had an objective response, all of which were partial responses (PR). Eleven (35%) had stable disease and 7 (23%) had progressive disease. The disease control rate, consisting of PR and stable disease, was 77%. The median duration of response had not been reached as of the data cutoff on May 10, 2019. At that time, it was 6.2 months (range, 1.5 to 27.7+). The median time to response was 1.4 months and the median progression-free survival (PFS) was 8.4 months. The PFS rate at 6 months was 61%. Three patients had received treatment for over a year and another 3 patients for more than 2 years.

Correlation with biomarkers

Of the 25 patients who had tissue suitable for next-generation sequencing, 9 had TSC2 mutations, 5 had TSC1 mutations, and 11 had neither mutation. Strikingly, 9 of 9 patients with TSC2 mutations developed a PR, while only 1 with a TSC1 mutation responded. One patient with no TSC1/2 mutation also responded and 2 patients with unknown mutational status responded. The investigators also analyzed pS6 status by immunohistochemistry—pS6 is a marker of mTOR hyperactivity. Twenty- five patient samples were available for analysis. Eight of 8 patients who were negative for pS6 staining did not have a response, while 10 of 17 (59%) who were pS6-positive had a PR.

In the discussion that followed, Winette van der Graaf, MD, of the Netherlands Cancer Institute in Amsterdam, noted that this study showed that biomarkers can be used for patient selection, although TSC2 mutations are not uniquely linked with response. She indicated a comparator with sirolimus would have been of great interest.

SOURCE: Wagner AJ, et al. J Clin Oncol 37, 2019 (suppl; abstr 11005).

The study was sponsored by Aadi Bioscience, Inc., and funded in part by a grant from the FDA Office of Orphan Products Development (OOPD).

Disclosures relevant to this presentation include contininstitutional research funding from Aadi Bioscience for Dr. Wagner and a few other abstract coauthors. Several coauthors are employed by Aadi Bioscience and have stock or other ownership interests. Dr. van der Graaf had nothing to disclose.

Cabozantinib Achieves Disease Control in GIST

The phase 2 EORTC 1317 trial, known as CaboGIST (NCT02216578), met its primary endpoint of progression-free survival (PFS) at 12 weeks in patients with metastatic gastrointestinal stromal tumor (GIST) treated with the tyrosine kinase inhibitor (TKI) cabozantinib. Twenty-four (58.5%) of the 41 patients in the primary study population, and 30 (60%) of the entire 50-patient population, were progression-free at 12 weeks. The study needed 21 patients to be progression- free for cabozantinib to warrant further exploration in GIST patients.

This investigator-initiated study had as its primary objective assessment of the safety and activity of cabozantinib in patients with metastatic GIST who had progressed on imatinib and sunitinib. The patients could not have been exposed to other KIT- or PDGFR-directed TKIs, such as regorafenib. Secondary objectives included the assessment of cabozantinib in different mutational subtypes of GIST. Patients received cabozantinib tablets once daily until they experienced no further clinical benefit or became intolerant to the drug or chose to discontinue therapy. Fifty patients started treatment between February 2017 and August 2018. All were evaluable for the primary endpoint, and one-third of patients contininstitutional cabozantinib treatment as of the database cutoff in January 2019.

Results

Patients were a median age of 63 years. Virtually all patients (92%) had prior surgery and only 8% had prior radiotherapy. The daily cabozantinib dose was a median 47.2 mg and duration of treatment was a median 20.4 weeks. No patient discontinued treatment due to toxicity, but 88% discontinued due to disease progression.

Safety signals were the same as for other indications in which cabozantinib is used. Almost all patients (94%) had at least 1 treatment-related adverse event of grades 1‐4, including diarrhea (74%), palmar-plantar erythrodysesthesia (58%), fatigue (46%), and hypertension (46%), which are typical of treatment with cabozantinib. Hematologic toxicities in this trial were clinically irrelevant, according to the investigators, consisting of small numbers of grades 2‐3 anemia, lymphopenia, white blood cell count abnormality, and neutropenia. Biochemical abnormalities included grades 3 and 4 hypophosphatemia, increased grades 3 and 4 gamma-glutamyl transferase, grade 3 hyponatremia, and grade 3 hypokalemia, in 8% or more of patients.

Overall survival was a median 14.4 months, with 16 patients still on treatment at the time of data cutoff. Twenty- four patients were progression-free at week 12, satisfying the study decision rule for clinical benefit. Median duration of PFS was 6.0 months. Seven patients (14%) achieved a confirmed partial response (PR) and 33 (66%) achieved stable disease (SD). Nine patients had progressive disease as their best response, 3 of whom had some clinical benefit. Forty patients (80%) experienced a clinical benefit of disease control (PR + SD).

An analysis of the relationship of genotype, duration, and RECIST response showed objective responses in patients with primary exon 11 mutations, with exon 9 mutations, and with exon 17 mutations, and in 2 patients without any known mutational information at the time of the presentation. Patients with stable disease were spread across all mutational subsets in the trial. The investigators suggested the definitive role of MET and AXL inhibition in GIST be assessed further in future clinical trials.

SOURCE: Schöffski P, et al. J Clin Oncol 37, 2019 (suppl; abstr 11006).

The study was sponsored by the European Organization for Research and Treatment of Cancer (EORTC).

Presenting author, Patrick Schöffski, MD, of KU Leuven and Leuven Cancer Institute in Belgium, disclosed institutional relationships with multiple pharmaceutical companies for consulting and research funding, including research funding from Exelixis, the developer of cabozantinib. No other abstract coauthor disclosed a relationship with Exelixis.

Larotectinib Effective in TRK Fusion Cancers

Pediatric patients with tropomyosin receptor kinase (TRK) fusions involving NTRK1, NTRK2, and NTRK3 genes had a high response rate with durable responses and a favorable safety profile when treated with larotrectinib, according to a presentation at ASCO. In this pediatric subset of children and adolescents from the SCOUT and NAVIGATE studies, the overall response rate (ORR) was 94%, with a 35% complete response (CR), 59% partial response (PR), and 6% stable disease as of the data cutoff at the end of July 2018.

Investigators enrolled 38 children and adolescents younger than 18 years from the SCOUT (NCT02637687) and NAVIGATE (NCT02576431) studies of larotrectinib who had non-central nervous system (CNS) TRK fusion cancers. Not all patients had the recommended phase 2 dose, Dr. van Tilburg pointed out, but most did. Hence, 29 of the 38 patients received the 100 mg/m² twice-daily, phase 2 dose until progression, withdrawal, or unacceptable toxicity.

Patients were young, with a median age of 2.3 years (range, 0.1 to 14.0 years). Almost two-thirds (61%) had prior surgery, 11% had prior radiotherapy, and 68% had prior systemic therapy. For 12 patients, larotrectinib was their first systemic therapy. The predominant tumor types were infantile fibrosarcoma (47%) and other soft tissue sarcoma (42%). And 47% of patients had NTRK3 fusions with ETV6, most of which were infantile fibrosarcoma.

Efficacy

Thirty-four patients were evaluable, and 32 had a reduction in tumor size, for an ORR of 94%, CR of 35%, and PR of 59%. Two patients with infantile fibrosarcoma had pathologic CRs—after treatment, no fibroid tissue in the tumors could be found. Median time to response was 1.8 months, median duration of treatment was 10.24 months, and 33 of 38 patients (87%) remained on treatment or underwent surgery with curative intent. As of the data cutoff of July 30, 2018, the secondary endpoints were not yet reached. However, 84% of responders were estimated to have a response duration of a year or more, and progression-free and overall survival looked very promising, according to Dr. van Tilburg.

Adverse events were primarily grades 1 and 2. The grades 3 and 4 treatment-related adverse events were quite few and consisted of increased alanine aminotransferase, decreased neutrophil count, and nausea. Longer follow-up of the patient safety profile is required, particularly since NTRK has multiple roles in neurodevelopment. The investigators recommended that routine testing for NTRK gene fusions in pediatric patients with cancer be conducted in appropriate clinical contexts.

In a discussion after the presentation, Daniel Alexander Morgenstern, MB BChir, PhD, of Great Ormond Street Hospital, London, UK, said that in many ways, the NTRK inhibitors have become the new poster child for precision oncology in pediatrics because of “these really spectacular results” with larotrectinib [and entrectinib]. One of the questions he raised regarding larotrectinib was the issue of CNS penetration, since patients with CNS cancer were not enrolled in the trial and preclinical data suggest limited CNS penetration for larotrectinib.

SOURCE: van Tilburg CM, et al. J Clin Oncol 37, 2019 (suppl; abstr 10010).

The studies were funded by Loxo Oncology, Inc., and Bayer AG.

Disclosures relevant to this presentation include consulting or advisory roles for Bayer for Drs. van Tilburg and Morgenstern. A few coauthors also had consulting/advisory roles or research funding from various companies, including Loxo and Bayer.

Behind Olaratumab's Phase 3 Disappointment

ANNOUNCE, the phase 3 trial designed to confirm the clinical benefit of olaratumab in patients with advanced soft tissue sarcoma (STS), failed to meet its primary endpoint of overall survival (OS) in all STS histologies and the leiomyosarcoma population. The previous phase 1b/2 signal-finding study of olaratumab had achieved an unprecedented improvement in OS, and the US Food and Drug Administration (FDA) awarded olaratumab accelerated approval in October 2016. By December 2018, olaratumab received additional accelerated, conditional, and full approvals in more than 40 countries worldwide. William D. Tap, MD, chief of the Sarcoma Medical Oncology Service at Memorial Sloan Kettering Cancer Center in New York, presented the phase 3 results and provided some explanations for the findings during the plenary session at ASCO.

ANNOUNCE (NCT02451943), which was designed and enrolled prior to olaratumab receiving accelerated approval, opened in September 2015 and completed accrual 10 months later in July 2016. Investigators randomized and treated 509 patients with advanced STS not amenable to curative therapy, 258 patients in the olaratumab-doxorubicin arm and 251 in the placebo-doxorubicin arm. Most patients (46%) had leiomyosarcoma, followed by liposarcoma (18%), pleomorphic sarcoma (13%), and 24% of the patient population had 26 unique histologies. Three-quarters of the patients had no prior systemic therapy.

Results

As of the data cutoff on December 5, 2018, there were no survival differences in the intention-to-treat population, in the total STS population nor in the leiomyosarcoma subpopulation, with olaratumab-doxorubicin compared to placebo-doxorubicin. For the total STS population, median OS with olaratumab- doxorubicin was 20.4 months and with placebo-doxorubicin 19.7 months. “This is the highest survival rate described to date in any phase 3 sarcoma study,” Dr. Tap said. “It is of particular interest as ANNOUNCE did not mandate treatment in the first line.” In the leiomyosarcoma population, median OS was 21.6 months with olaratumab and 21.9 months with placebo. The secondary endpoints of progression-free survival (PFS), overall response rate, and disease control rate did not favor olaratumab either.

Investigators are examining the relationship between PDGFRα expression and OS in ANNOUNCE. PDGFRα-positive tumors tended to do worse with olaratumab than PDGFRα-negative tumors. The investigators noticed a 6-month difference in OS between these populations favoring PDGFRα-negative tumors. Additional biomarker analyses are ongoing.

A large and concerted effort is underway, Dr. Tap said, to understand the results of the ANNOUNCE study alone and in context with the phase 1b/2 study. “There are no noted discrepancies in study conduct or data integrity which could explain these findings or the differences between the two studies.”

Possible explanations

The designs of the phase 1b/2 and phase 3 studies had some important differences. The phase 1b/2 study was a small, open-label, US-centric study (10 sites) that did not include a placebo or subtype- specified analyses. Its primary endpoint was PFS, it did not have a loading dose of olaratumab, and it specified the timing of dexrazoxane administration after 300 mg/m2 of doxorubicin.

ANNOUNCE, on the other hand, was a large (n=509), international (110 study sites), double-blind, placebo-controlled trial that had outcomes evaluated in STS and leiomyosarcoma. Its primary endpoint was OS, it had a loading dose of olaratumab of 20 mg/kg, and there was no restriction as to the timing of dexrazoxane administration.

Dr. Tap pointed out that in ANNOUNCE it was difficult to predict or control for factors that may have had an unanticipated influence on outcomes, such as albumin levels as a surrogate for disease burden and behavior of PDGFRα status. It is possible, he said, that olaratumab has no activity in STS and that the phase 1b/2 results were due to, among other things, the small sample size, numerous represented histologies with disparate clinical behavior, and the effect of subtype-specific therapies on overall survival, given subsequently or even by chance. On the other hand, it is also possible, he said, that olaratumab has some activity in STS, with outcomes being affected by the heterogeneity of the study populations, differences in trial design, and the performance of the ANNOUNCE control arm. Whatever the case, he said, accelerated approval allowed patients to have access to a potentially life-prolonging drug with little added toxicity.

Discussion

In the expert discussion following the presentation, Jaap Verweij, MD, PhD, of Erasmus University Medical Center in Rotterdam, The Netherlands, congratulated the investigators for performing the study at an unprecedented pace. He commented that lumping STS subtypes together is problematic, as different histological subtypes behave as though they are different diseases. Small numbers of each tumor subtype and subtypes with slow tumor growth can impact trial outcomes. In the phase 1b/2 and phase 3 trials, 26 different subtypes were represented in each study. Dr. Verweij pointed out this could have made a big difference in the phase 1b/2 study, in which there were only 66 patients in each arm.

It is striking to note, he said, that without exception, phase 2 randomized studies in STS involving doxorubicin consistently overestimated and wrongly predicted PFS in the subsequent phase 3 studies. And the situation is similar for OS. The results of the ANNOUNCE study are no exception, he added. “Taken together, these studies indicate that phase 2 studies in soft tissue sarcomas, certainly those involving additions of drugs to doxorubicin, even if randomized, should be interpreted with great caution,” he said.

SOURCE: Tap WD, et al. J Clin Oncol 37, 2019 (suppl; abstr LBA3)

The study was sponsored by Eli Lilly and Company.

Dr. Tap reported research funding from Lilly and Dr. Verweij had nothing to report related to this study. Abstract coauthors disclosed numerous financial relationships, including consulting/advisory roles and/or research funding from Lilly, and several were employed by Lilly.

Addition of Temozolomide May Improve Outcomes in RMS

Investigators from the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) found that the addition of temozolomide (T) to vincristine and irinotecan (VI) may improve outcomes in adults and children with relapsed or refractory rhabdomyosarcoma (RMS). Principal investigator of the study, Anne Sophie Defachelles, MD, pediatric oncologist at the Centre Oscar Lambret in Lille, France, presented the results on behalf of the EpSSG.

The international, randomized (1:1), open-label, phase 2 trial (VIT-0910; NCT01355445) was conducted at 37 centers in 5 countries. Patients ages 6 months to 50 years with RMS were eligible. They could not have had prior irinotecan or temozolomide. A 2015 protocol amendment limited enrollment to patients at relapse and increased the enrollment goal by 40 patients. After the 2015 amendment, patients with refractory disease were no longer eligible.

From January 2012 to April 2018, investigators enrolled 120 patients, 60 on each arm. Two patients in the VI arm were not treated. Patients were a median age of 10.5 years in the VI arm and 12 years in the VIT arm, 92% (VI) and 87% (VIT) had relapsed disease, 8% (VI) and 13% (VIT) had refractory disease, and 55% (VI) and 68% (VIT) had metastatic disease at study entry.

Results

Patients achieved an OR rate of 44% (VIT) and 31% (VI) for the whole population, one-sided P value <.0001. The adjusted odds ratio for the whole population was 0.50, P=.09. PFS was 4.7 months (VIT) and 3.2 months (VI), “a nearly significant reduction in the risk of progression,” Dr. Defachelles noted. Median OS was 15.0 months (VIT) and 10.3 months (VI), which amounted to “a large and significant reduction in the risk of death,” she said. The adjusted hazard ratio was 0.55, P=.006.

Adverse events of grade 3 or higher were more frequent in the VIT arm, with hematologic toxicity the most frequent (81% for VIT, 59% for VI), followed by gastrointestinal adverse events. “VIT was significantly more toxic than VI,” Dr. Defachelles observed, “but the toxicity was manageable.”

“VIT is now the standard treatment in Europe for relapsed rhabdomyosarcoma and will be the control arm in the multiarm, multistage RMS study for relapsed patients,” she said.

SOURCE: Defachelles AS, et al. J Clin Oncol 37, 2019 (suppl; abstr 10000)

The study was sponsored by Centre Oscar Lambret and SFCE (Société Française de Lutte contre les Cancers et Lucémies de l’Enfant et de l’Adolescent) served as collaborator.

Drs. Defachelles and Wagner had no relationships to disclose. A few coauthors had advisory/consulting or speaker roles for various commercial interests, including two for Merck (temozolomide).

Pazopanib Increases Pathologic Necrosis Rates in STS

Pazopanib added to a regimen of preoperative chemoradiation in non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) significantly increased the rate of near-complete pathologic response in both children and adults with intermediate or high-risk disease. Pazopanib, a multitargeted receptor tyrosine kinase inhibitor, works in multiple signaling pathways involved in tumorigenesis— VEGFR-1, -2, -3, PDGFRα/β, and c-kit. A phase 3 study demonstrated significant improvement in progression-free survival (PFS) in advanced STS patients and was the basis for its approval in the US and elsewhere for treatment of this patient population. Preclinical data suggest synergy between pazopanib and cytotoxic chemotherapy, forming the rationale for the current trial with neoadjuvant pazopanib added to chemoradiation.

According to the investigators, the trial (ARST1321) is the first ever collaborative study codeveloped, written, and conducted by pediatric (Children’s Oncology Group) and adult (NRG Oncology) cancer cooperative groups (NCT02180867). Aaron R. Weiss, MD, of the Maine Medical Center in Portland and study cochair, presented the data for the chemotherapy arms at ASCO. The primary objectives of the study were to determine the feasibility of preoperative chemoradiation with or without pazopanib and to compare the rates of complete pathologic response in patients receiving radiation or chemoradiation with or without pazopanib. Pathologic necrosis rates of 90% or better have been found to be predictive of outcome in STS.

Results

As of the June 30, 2018, cutoff, 81 patients were enrolled on the chemotherapy arms: 42 in the pazopanib plus chemoradiation arm and 39 in the chemoradiation-only arm. Sixty-one percent of all patients were 18 years or older, and the median age was 20.3 years. Most patients (73%) did not have metastatic disease, and the major histologies represented were synovial sarcoma (49%) and undifferentiated pleomorphic sarcoma (25%).

At week 13, patients in the pazopanib arm showed significant improvement, with 14 (58%) of those evaluated having pathologic necrosis of at least 90%, compared with 4 (22%) in the chemoradiation-only arm (P=.02). The study was closed to further accrual.

Eighteen patients were not evaluable for pathologic response and 21 were pending pathologic evaluation at week 13. Radiographic response rates were not statistically significant on either arm. No complete responses (CR) were achieved in the pazopanib arm, but 14 patients (52%) achieved a partial response (PR) and 12 (44%) had stable disease (SD). In the chemoradiation-only arm, 2 patients (8%) achieved a CR, 12 (50%) a PR, and 8 (33%) SD. Fifteen patients in each arm were not evaluated for radiographic response.

The pazopanib arm experienced more febrile neutropenia and myelotoxicity during induction and continuation phases than the chemoradiation-only arm. In general, investigators indicated pazopanib combined with chemoradiation was well tolerated and no unexpected toxicities arose during the trial.

In the post-presentation discussion, Dr. Raphael E. Pollock, MD, PhD, of The Ohio State University, called it a tremendous challenge to interdigitate primary local therapies in systemic approaches, particularly in the neoadjuvant context. He pointed out that in an earlier study, a 95% to 100% necrosis level was needed to achieve a significant positive impact on outcomes and perhaps a subsequent prospective trial could determine the best level. He questioned whether the availability of only 60% of patient responses could affect the conclusions and whether the high number of toxicities (73.8% grade 3/4 with pazopanib) might be too high to consider the treatment for most patients, given the intensity of the regimen.

SOURCE: Weiss AR, et al. J Clin Oncol 37, 2019 (suppl; abstr 11002)

The study was sponsored by the National Cancer Institute.

Drs. Weiss and Pollock had no relationships with commercial interests to disclose. A few investigators disclosed advisory, consulting, or research roles with pharmaceutical companies, including one who received institutional research funding from Novartis (pazopanib).

Gemcitabine Plus Pazopanib a Potential Alternative in STS

In a phase 2 study of gemcitabine with pazopanib (G+P) or gemcitabine with docetaxel (G+D), investigators concluded the combination with pazopanib can be considered an alternative to that with docetaxel in select patients with advanced soft tissue sarcoma (STS). They reported similar progression-free survival (PFS) and rate of toxicity for the two regimens. Neeta Somaiah, MD, of the University of Texas MD Anderson Cancer Center in Houston, presented the findings of the investigator-initiated effort (NCT01593748) at ASCO.

The investigators enrolled 90 patients, 45 in each arm. Patients were a mean age of 56 years, and there was no difference in age or gender distribution between the arms. Patients with leiomyosarcoma (31% overall) or prior pelvic radiation (11% overall) were similar between the arms. The overall response rate using RECIST 1.1 criteria was partial response (PR) in 8 of 44 evaluable patients (18%) in the G+D arm and 5 of 43 evaluable patients (12%) in the G+P arm. Stable disease (SD) was observed in 21 patients (48%) in the G+D arm and 24 patients (56%) in the G+P arm. This amounted to a clinical benefit rate (PR + SD) of 66% and 68% for the G+D and G+P arms, respectively (Fisher’s exact test, P>.99). The median PFS was 4.1 months on both arms and the difference in median overall survival— 15.9 months in the G+D arm and 12.4 months in the G+P arm—was not statistically significant.

Adverse events (AEs) of grade 3 or higher occurred in 19.9% of patients on G+D and 20.6% on G+P. Serious AEs occurred in 33% (G+D) and 22% (G+P). Dose reductions were necessary in 80% of patients on G+P and doses were held in 93%. Dr. Somaiah explained that this may have been because the starting dose of gemcitabine and pazopanib (1000 mg/m² of gemcitabine on days 1 and 8 and 800 mg of pazopanib) was “probably higher than what we should have started at.” The rate of doses held was also higher in the pazopanib arm (93%) compared with the docetaxel arm (58%). This was likely because pazopanib was a daily dosing, so if there was a toxicity it was more likely to be held than docetaxel, she observed. Grade 3 or higher toxicities occurring in 5% or more of patients in either arm consisted generally of cytopenias and fatigue. The G+P arm experienced a high amount of neutropenia, most likely because this arm did not receive granulocyte-colony stimulating factor (GCSF) support, as opposed to the G+D arm.

Dr. Somaiah pointed out that the 12% response rate for the G+P combination is similar to what has been previously presented and higher than single-agent gemcitabine or pazopanib, but not higher than the G+D combination. The PFS of 4.1 months was less than anticipated, she added, but it was similar on both arms. The investigators believe the G+P combination warrants further exploration.

SOURCE: Somaiah N, et al. J Clin Oncol 37, 2019 (suppl; abstr 11008)

The study was sponsored by the Medical University of South Carolina, with Novartis as collaborator.

Dr. Somaiah disclosed Advisory Board roles for Blueprint, Deciphera, and Bayer. Abstract coauthors disclosed advisory/consulting roles or research funding from various commercial interests, including Novartis (pazopanib) and Pfizer (gemcitabine).

rEECur Trial Finding Optimal Chemotherapy Regimen for Ewing Sarcoma

Interim results of the first and largest randomized trial in patients with refractory or recurrent Ewing sarcoma (ES), the rEECur trial, are guiding the way to finding the optimal chemotherapy regimen to treat the disease. Until now, there has been little prospective evidence and no randomized data to guide treatment choices in relapsed or refractory patients, and hence no real standard of care, according to the presentation at ASCO. Several molecularly targeted therapies are emerging, and they require a standardized chemotherapy backbone against which they can be tested.

Results

Two hundred twenty patients 4 years or older and younger than 50 years with recurrent or refractory histologically confirmed ES of bone or soft tissue were randomized to receive GD (n=72) or TC, IT, or IFOS (n=148). Sixty-two GD patients and 123 TC/IT/IFOS patients were included in the primary outcome analysis. Patients were predominantly male (70%), with a median age of 19 years (range, 4 to 49). About two-thirds (67.3%) were post-pubertal. Most patients (85%) were primary refractory or experienced their first disease recurrence, and 89% had measurable disease.

Investigators assessed the primary outcome of objective response after 4 cycles of therapy and found 11% of patients treated with GD responded compared to 24% in the other 3 arms combined. When they subjected the data to Bayesian analysis, there was a 25% chance that the response rate in the GD arm was better than the response in Arm A, a 2% chance that it was better than Arm B, and a 3% chance that it was better than Arm C. Because this study was still blinded at the time of the presentation, investigators didn’t know which regimen constituted which arm. The probability that response favored GD, however, was low.

The investigators observed no surprising safety findings. Eighty-five percent of all patients experienced at least 1 adverse event. Most frequent grade 3‐5 events consisted of pneumonitis (50%, 60%), neutropenic fever (17%, 25%), and diarrhea (0, 12%) in GD and the combined 3 arms, respectively. Grade 3 events in the GD arm were lower than in the other 3 arms combined. There was 1 toxic death attributed to neutropenic sepsis in 1 of the 3 blinded arms.

Median progression-free survival (PFS) for all patients was approximately 5 months. Bayesian analysis suggested there was a low probability that GD was more effective than the other 3 arms: a 22% chance that GD was better than Arm A, a 3% chance that it was better than Arm B, and a 7% chance that it was better than Arm C. Bayesian analysis also suggested there was a probability that OS favored GD. Because the trial directs only the first 4 or 6 cycles of treatment and the patients receive more treatment after trial-directed therapy, investigators were not fully able to interpret this.

Data suggested GD is a less effective regimen than the other 3 regimens both by objective response rate and PFS, so GD has been dropped from the study. Investigators already had more than 75 evaluable patients in each of the 3 arms for the second interim analysis to take place. In a discussion following the presentation, Jayesh Desai, FRACP, of Peter MacCallum Cancer Centre in Melbourne, Australia, called this study a potentially practice-changing trial at this early stage, noting that the GD combination will be de-prioritized in practice based on these results.

SOURCE: McCabe MG, et al. J Clin Oncol 37, 2019 (suppl; abstr 11007)

The rEECur trial is sponsored by the University of Birmingham (UK) and received funding from the European Union’s Seventh Framework Programme under a grant agreement.

Dr. McCabe disclosed no conflicts of interest. Other authors disclosed consulting, advisory roles, or research funding from numerous pharmaceutical companies, including Lilly (gemcitabine) and Pfizer (irinotecan). Dr. Desai disclosed a consulting/advisory role and institutional research funding from Lilly.

Abemaciclib Meets Primary Endpoint in Phase 2 Trial of DDLS

The newer and more potent CDK4 inhibitor, abemaciclib, met its primary endpoint in the investigator-initiated, single-center, single-arm, phase 2 trial in patients with advanced progressive dedifferentiated liposarcoma (DDLS). Twenty-two patients (76%) achieved progression-free survival (PFS) at 12 weeks for a median PFS of 30 weeks. A subset of patients experienced prolonged clinical benefit, remaining on study with stable disease for over 900 days. The study (NCT02846987) was conducted at Memorial Sloan Kettering Cancer Center (MSKCC) in New York and Mark A. Dickson, MD, presented the results at ASCO.

Results

Thirty patients, 29 evaluable, with metastatic or recurrent DDLS were enrolled and treated with abemaciclib 200 mg orally twice daily between August 2016 and October 2018. Data cutoff for the presentation was the first week of May 2019. Patients were a median of 62 years, 60% were male, and half had no prior systemic treatment. Prior systemic treatments for those previously treated included doxorubicin, olaratumab, gemcitabine, docetaxel, ifosfamide, eribulin, and trabectedin. For 87%, the primary tumor was in their abdomen or retroperitoneum.

Toxicity was as expected with this class of agent, according to the investigators. The most common grades 2 and 3 toxicities, respectively, possibly related to the study drug, occurring in more than 1 patient included anemia (70%, 37%), thrombocytopenia (13%, 13%), neutropenia (43%, 17%), and lymphocyte count decreased (23%, 23%). Very few of these adverse events were grade 4—none for anemia, and 3% each for thrombocytopenia, neutropenia, and lymphocyte count decreased. Diarrhea of grades 2 and 3 occurred in 27% and 7% of patients, respectively, and was managed well with loperamide.

In addition to reaching the primary endpoint of 15 patients or more achieving PFS at 12 weeks, 1 patient had a confirmed partial response (PR) and another an unconfirmed PR. At data cutoff, 11 patients remained on study with stable disease or PR. The investigators conducted correlative studies that indicated all patients had CDK4 and MDM2 amplification with no loss of retinoblastoma tumor suppressor. They observed an inverse correlation between CDK4 amplification and PFS—the higher the level of CDK4 amplification, the shorter the PFS. They also found additional genomic alterations, including JUN, GLI1, ARID1A, TERT, and ATRX. TERT amplification was also associated with shorter PFS. Based on these findings, the investigators believe a phase 3 study of abemaciclib in DDLS is warranted.

Winette van der Graaf, MD, PhD, of the Netherlands Cancer Institute in Amsterdam, in the discussion following the presentation, concurred that it is certainly time for a multicenter phase 3 study of CDK4 inhibitors in DDLS, and a strong international collaboration is key to conducting such studies, particularly in rare cancers. On a critical note, Dr. van der Graaf expressed concern that no patient-reported outcomes were measured after 120 patients, including those in previous studies, were treated on palbociclib and abemaciclib. Given that the toxicities of the CDK4 inhibitors are quite different, she recommended including patient-reported outcomes in future studies using validated health-related quality-of-life instruments.

SOURCE: Dickson MA, et al. J Clin Oncol 37, 2019 (suppl; abstr 11004)

The study was sponsored by Memorial Sloan Kettering Cancer Center, with the study collaborator, Eli Lilly and Company.

Dr. Dickson disclosed research funding from Lilly, the company that provided the study drug. Dr. van der Graaf had no relevant relationships to disclose. Abstract coauthors had consulting/advisory roles or research funding from various companies, including Lilly.

nab-Sirolimus Provides Benefits in Advanced Malignant PEComa

In a prospective phase 2 study of nab-sirolimus in advanced malignant perivascular epithelioid cell tumor (PEComa), the mTOR inhibitor achieved an objective response rate (ORR) of 42% with an acceptable safety profile, despite using relatively high doses of nab-sirolimus compared to other mTOR inhibitors. Activation of the mTOR pathway is common in PEComa, and earlier case reports had indicated substantial clinical benefit with mTOR inhibitor treatment. nab-Sirolimus (ABI-009) is a novel intravenous mTOR inhibitor consisting of nanoparticles of albumin-bound sirolimus. It has significantly higher anti-tumor activity than oral mTOR inhibitors and greater mTOR target suppression at an equal dose. Andrew J. Wagner, MD, PhD, of the Dana-Farber Cancer Institute in Boston, presented the findings of AMPECT (NCT02494570)—Advanced Malignant PEComa Trial—at ASCO.

Results

The drug was well tolerated, with toxicities similar to those of oral mTOR inhibitors. Treatment-related adverse events (TRAEs) occurring in 25% or more of patients were mostly grade 1 or 2 toxicities. Hematologic TRAEs included anemia (47%) and thrombocytopenia (32%) of any grade. Nonhematologic events of any grade included stomatitis/ mucositis (74%), dermatitis/rash (65%), fatigue (59%), nausea (47%), and diarrhea (38%), among others. A few grade 3 events occurred on study, most notably stomatitis/mucositis (18%). Severe adverse events (SAEs) were also uncommon, occurring in 7 of 34 patients (21%). Pneumonitis is common in orally administered mTOR inhibitors; 6 patients (18%) treated with nab-sirolimus had grade 1 or 2 pneumonitis.

Of the 31 evaluable patients, 13 (42%) had an objective response, all of which were partial responses (PR). Eleven (35%) had stable disease and 7 (23%) had progressive disease. The disease control rate, consisting of PR and stable disease, was 77%. The median duration of response had not been reached as of the data cutoff on May 10, 2019. At that time, it was 6.2 months (range, 1.5 to 27.7+). The median time to response was 1.4 months and the median progression-free survival (PFS) was 8.4 months. The PFS rate at 6 months was 61%. Three patients had received treatment for over a year and another 3 patients for more than 2 years.

Correlation with biomarkers

Of the 25 patients who had tissue suitable for next-generation sequencing, 9 had TSC2 mutations, 5 had TSC1 mutations, and 11 had neither mutation. Strikingly, 9 of 9 patients with TSC2 mutations developed a PR, while only 1 with a TSC1 mutation responded. One patient with no TSC1/2 mutation also responded and 2 patients with unknown mutational status responded. The investigators also analyzed pS6 status by immunohistochemistry—pS6 is a marker of mTOR hyperactivity. Twenty- five patient samples were available for analysis. Eight of 8 patients who were negative for pS6 staining did not have a response, while 10 of 17 (59%) who were pS6-positive had a PR.

In the discussion that followed, Winette van der Graaf, MD, of the Netherlands Cancer Institute in Amsterdam, noted that this study showed that biomarkers can be used for patient selection, although TSC2 mutations are not uniquely linked with response. She indicated a comparator with sirolimus would have been of great interest.

SOURCE: Wagner AJ, et al. J Clin Oncol 37, 2019 (suppl; abstr 11005).

The study was sponsored by Aadi Bioscience, Inc., and funded in part by a grant from the FDA Office of Orphan Products Development (OOPD).

Disclosures relevant to this presentation include contininstitutional research funding from Aadi Bioscience for Dr. Wagner and a few other abstract coauthors. Several coauthors are employed by Aadi Bioscience and have stock or other ownership interests. Dr. van der Graaf had nothing to disclose.

Cabozantinib Achieves Disease Control in GIST

The phase 2 EORTC 1317 trial, known as CaboGIST (NCT02216578), met its primary endpoint of progression-free survival (PFS) at 12 weeks in patients with metastatic gastrointestinal stromal tumor (GIST) treated with the tyrosine kinase inhibitor (TKI) cabozantinib. Twenty-four (58.5%) of the 41 patients in the primary study population, and 30 (60%) of the entire 50-patient population, were progression-free at 12 weeks. The study needed 21 patients to be progression- free for cabozantinib to warrant further exploration in GIST patients.

This investigator-initiated study had as its primary objective assessment of the safety and activity of cabozantinib in patients with metastatic GIST who had progressed on imatinib and sunitinib. The patients could not have been exposed to other KIT- or PDGFR-directed TKIs, such as regorafenib. Secondary objectives included the assessment of cabozantinib in different mutational subtypes of GIST. Patients received cabozantinib tablets once daily until they experienced no further clinical benefit or became intolerant to the drug or chose to discontinue therapy. Fifty patients started treatment between February 2017 and August 2018. All were evaluable for the primary endpoint, and one-third of patients contininstitutional cabozantinib treatment as of the database cutoff in January 2019.

Results

Patients were a median age of 63 years. Virtually all patients (92%) had prior surgery and only 8% had prior radiotherapy. The daily cabozantinib dose was a median 47.2 mg and duration of treatment was a median 20.4 weeks. No patient discontinued treatment due to toxicity, but 88% discontinued due to disease progression.

Safety signals were the same as for other indications in which cabozantinib is used. Almost all patients (94%) had at least 1 treatment-related adverse event of grades 1‐4, including diarrhea (74%), palmar-plantar erythrodysesthesia (58%), fatigue (46%), and hypertension (46%), which are typical of treatment with cabozantinib. Hematologic toxicities in this trial were clinically irrelevant, according to the investigators, consisting of small numbers of grades 2‐3 anemia, lymphopenia, white blood cell count abnormality, and neutropenia. Biochemical abnormalities included grades 3 and 4 hypophosphatemia, increased grades 3 and 4 gamma-glutamyl transferase, grade 3 hyponatremia, and grade 3 hypokalemia, in 8% or more of patients.

Overall survival was a median 14.4 months, with 16 patients still on treatment at the time of data cutoff. Twenty- four patients were progression-free at week 12, satisfying the study decision rule for clinical benefit. Median duration of PFS was 6.0 months. Seven patients (14%) achieved a confirmed partial response (PR) and 33 (66%) achieved stable disease (SD). Nine patients had progressive disease as their best response, 3 of whom had some clinical benefit. Forty patients (80%) experienced a clinical benefit of disease control (PR + SD).

An analysis of the relationship of genotype, duration, and RECIST response showed objective responses in patients with primary exon 11 mutations, with exon 9 mutations, and with exon 17 mutations, and in 2 patients without any known mutational information at the time of the presentation. Patients with stable disease were spread across all mutational subsets in the trial. The investigators suggested the definitive role of MET and AXL inhibition in GIST be assessed further in future clinical trials.

SOURCE: Schöffski P, et al. J Clin Oncol 37, 2019 (suppl; abstr 11006).

The study was sponsored by the European Organization for Research and Treatment of Cancer (EORTC).

Presenting author, Patrick Schöffski, MD, of KU Leuven and Leuven Cancer Institute in Belgium, disclosed institutional relationships with multiple pharmaceutical companies for consulting and research funding, including research funding from Exelixis, the developer of cabozantinib. No other abstract coauthor disclosed a relationship with Exelixis.

Larotectinib Effective in TRK Fusion Cancers

Pediatric patients with tropomyosin receptor kinase (TRK) fusions involving NTRK1, NTRK2, and NTRK3 genes had a high response rate with durable responses and a favorable safety profile when treated with larotrectinib, according to a presentation at ASCO. In this pediatric subset of children and adolescents from the SCOUT and NAVIGATE studies, the overall response rate (ORR) was 94%, with a 35% complete response (CR), 59% partial response (PR), and 6% stable disease as of the data cutoff at the end of July 2018.

Investigators enrolled 38 children and adolescents younger than 18 years from the SCOUT (NCT02637687) and NAVIGATE (NCT02576431) studies of larotrectinib who had non-central nervous system (CNS) TRK fusion cancers. Not all patients had the recommended phase 2 dose, Dr. van Tilburg pointed out, but most did. Hence, 29 of the 38 patients received the 100 mg/m² twice-daily, phase 2 dose until progression, withdrawal, or unacceptable toxicity.

Patients were young, with a median age of 2.3 years (range, 0.1 to 14.0 years). Almost two-thirds (61%) had prior surgery, 11% had prior radiotherapy, and 68% had prior systemic therapy. For 12 patients, larotrectinib was their first systemic therapy. The predominant tumor types were infantile fibrosarcoma (47%) and other soft tissue sarcoma (42%). And 47% of patients had NTRK3 fusions with ETV6, most of which were infantile fibrosarcoma.

Efficacy

Thirty-four patients were evaluable, and 32 had a reduction in tumor size, for an ORR of 94%, CR of 35%, and PR of 59%. Two patients with infantile fibrosarcoma had pathologic CRs—after treatment, no fibroid tissue in the tumors could be found. Median time to response was 1.8 months, median duration of treatment was 10.24 months, and 33 of 38 patients (87%) remained on treatment or underwent surgery with curative intent. As of the data cutoff of July 30, 2018, the secondary endpoints were not yet reached. However, 84% of responders were estimated to have a response duration of a year or more, and progression-free and overall survival looked very promising, according to Dr. van Tilburg.

Adverse events were primarily grades 1 and 2. The grades 3 and 4 treatment-related adverse events were quite few and consisted of increased alanine aminotransferase, decreased neutrophil count, and nausea. Longer follow-up of the patient safety profile is required, particularly since NTRK has multiple roles in neurodevelopment. The investigators recommended that routine testing for NTRK gene fusions in pediatric patients with cancer be conducted in appropriate clinical contexts.

In a discussion after the presentation, Daniel Alexander Morgenstern, MB BChir, PhD, of Great Ormond Street Hospital, London, UK, said that in many ways, the NTRK inhibitors have become the new poster child for precision oncology in pediatrics because of “these really spectacular results” with larotrectinib [and entrectinib]. One of the questions he raised regarding larotrectinib was the issue of CNS penetration, since patients with CNS cancer were not enrolled in the trial and preclinical data suggest limited CNS penetration for larotrectinib.

SOURCE: van Tilburg CM, et al. J Clin Oncol 37, 2019 (suppl; abstr 10010).

The studies were funded by Loxo Oncology, Inc., and Bayer AG.

Disclosures relevant to this presentation include consulting or advisory roles for Bayer for Drs. van Tilburg and Morgenstern. A few coauthors also had consulting/advisory roles or research funding from various companies, including Loxo and Bayer.

Behind Olaratumab's Phase 3 Disappointment

ANNOUNCE, the phase 3 trial designed to confirm the clinical benefit of olaratumab in patients with advanced soft tissue sarcoma (STS), failed to meet its primary endpoint of overall survival (OS) in all STS histologies and the leiomyosarcoma population. The previous phase 1b/2 signal-finding study of olaratumab had achieved an unprecedented improvement in OS, and the US Food and Drug Administration (FDA) awarded olaratumab accelerated approval in October 2016. By December 2018, olaratumab received additional accelerated, conditional, and full approvals in more than 40 countries worldwide. William D. Tap, MD, chief of the Sarcoma Medical Oncology Service at Memorial Sloan Kettering Cancer Center in New York, presented the phase 3 results and provided some explanations for the findings during the plenary session at ASCO.

ANNOUNCE (NCT02451943), which was designed and enrolled prior to olaratumab receiving accelerated approval, opened in September 2015 and completed accrual 10 months later in July 2016. Investigators randomized and treated 509 patients with advanced STS not amenable to curative therapy, 258 patients in the olaratumab-doxorubicin arm and 251 in the placebo-doxorubicin arm. Most patients (46%) had leiomyosarcoma, followed by liposarcoma (18%), pleomorphic sarcoma (13%), and 24% of the patient population had 26 unique histologies. Three-quarters of the patients had no prior systemic therapy.

Results

As of the data cutoff on December 5, 2018, there were no survival differences in the intention-to-treat population, in the total STS population nor in the leiomyosarcoma subpopulation, with olaratumab-doxorubicin compared to placebo-doxorubicin. For the total STS population, median OS with olaratumab- doxorubicin was 20.4 months and with placebo-doxorubicin 19.7 months. “This is the highest survival rate described to date in any phase 3 sarcoma study,” Dr. Tap said. “It is of particular interest as ANNOUNCE did not mandate treatment in the first line.” In the leiomyosarcoma population, median OS was 21.6 months with olaratumab and 21.9 months with placebo. The secondary endpoints of progression-free survival (PFS), overall response rate, and disease control rate did not favor olaratumab either.

Investigators are examining the relationship between PDGFRα expression and OS in ANNOUNCE. PDGFRα-positive tumors tended to do worse with olaratumab than PDGFRα-negative tumors. The investigators noticed a 6-month difference in OS between these populations favoring PDGFRα-negative tumors. Additional biomarker analyses are ongoing.

A large and concerted effort is underway, Dr. Tap said, to understand the results of the ANNOUNCE study alone and in context with the phase 1b/2 study. “There are no noted discrepancies in study conduct or data integrity which could explain these findings or the differences between the two studies.”

Possible explanations

The designs of the phase 1b/2 and phase 3 studies had some important differences. The phase 1b/2 study was a small, open-label, US-centric study (10 sites) that did not include a placebo or subtype- specified analyses. Its primary endpoint was PFS, it did not have a loading dose of olaratumab, and it specified the timing of dexrazoxane administration after 300 mg/m2 of doxorubicin.

ANNOUNCE, on the other hand, was a large (n=509), international (110 study sites), double-blind, placebo-controlled trial that had outcomes evaluated in STS and leiomyosarcoma. Its primary endpoint was OS, it had a loading dose of olaratumab of 20 mg/kg, and there was no restriction as to the timing of dexrazoxane administration.

Dr. Tap pointed out that in ANNOUNCE it was difficult to predict or control for factors that may have had an unanticipated influence on outcomes, such as albumin levels as a surrogate for disease burden and behavior of PDGFRα status. It is possible, he said, that olaratumab has no activity in STS and that the phase 1b/2 results were due to, among other things, the small sample size, numerous represented histologies with disparate clinical behavior, and the effect of subtype-specific therapies on overall survival, given subsequently or even by chance. On the other hand, it is also possible, he said, that olaratumab has some activity in STS, with outcomes being affected by the heterogeneity of the study populations, differences in trial design, and the performance of the ANNOUNCE control arm. Whatever the case, he said, accelerated approval allowed patients to have access to a potentially life-prolonging drug with little added toxicity.

Discussion

In the expert discussion following the presentation, Jaap Verweij, MD, PhD, of Erasmus University Medical Center in Rotterdam, The Netherlands, congratulated the investigators for performing the study at an unprecedented pace. He commented that lumping STS subtypes together is problematic, as different histological subtypes behave as though they are different diseases. Small numbers of each tumor subtype and subtypes with slow tumor growth can impact trial outcomes. In the phase 1b/2 and phase 3 trials, 26 different subtypes were represented in each study. Dr. Verweij pointed out this could have made a big difference in the phase 1b/2 study, in which there were only 66 patients in each arm.

It is striking to note, he said, that without exception, phase 2 randomized studies in STS involving doxorubicin consistently overestimated and wrongly predicted PFS in the subsequent phase 3 studies. And the situation is similar for OS. The results of the ANNOUNCE study are no exception, he added. “Taken together, these studies indicate that phase 2 studies in soft tissue sarcomas, certainly those involving additions of drugs to doxorubicin, even if randomized, should be interpreted with great caution,” he said.

SOURCE: Tap WD, et al. J Clin Oncol 37, 2019 (suppl; abstr LBA3)

The study was sponsored by Eli Lilly and Company.

Dr. Tap reported research funding from Lilly and Dr. Verweij had nothing to report related to this study. Abstract coauthors disclosed numerous financial relationships, including consulting/advisory roles and/or research funding from Lilly, and several were employed by Lilly.

Addition of Temozolomide May Improve Outcomes in RMS

Investigators from the European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) found that the addition of temozolomide (T) to vincristine and irinotecan (VI) may improve outcomes in adults and children with relapsed or refractory rhabdomyosarcoma (RMS). Principal investigator of the study, Anne Sophie Defachelles, MD, pediatric oncologist at the Centre Oscar Lambret in Lille, France, presented the results on behalf of the EpSSG.

The international, randomized (1:1), open-label, phase 2 trial (VIT-0910; NCT01355445) was conducted at 37 centers in 5 countries. Patients ages 6 months to 50 years with RMS were eligible. They could not have had prior irinotecan or temozolomide. A 2015 protocol amendment limited enrollment to patients at relapse and increased the enrollment goal by 40 patients. After the 2015 amendment, patients with refractory disease were no longer eligible.

From January 2012 to April 2018, investigators enrolled 120 patients, 60 on each arm. Two patients in the VI arm were not treated. Patients were a median age of 10.5 years in the VI arm and 12 years in the VIT arm, 92% (VI) and 87% (VIT) had relapsed disease, 8% (VI) and 13% (VIT) had refractory disease, and 55% (VI) and 68% (VIT) had metastatic disease at study entry.

Results

Patients achieved an OR rate of 44% (VIT) and 31% (VI) for the whole population, one-sided P value <.0001. The adjusted odds ratio for the whole population was 0.50, P=.09. PFS was 4.7 months (VIT) and 3.2 months (VI), “a nearly significant reduction in the risk of progression,” Dr. Defachelles noted. Median OS was 15.0 months (VIT) and 10.3 months (VI), which amounted to “a large and significant reduction in the risk of death,” she said. The adjusted hazard ratio was 0.55, P=.006.

Adverse events of grade 3 or higher were more frequent in the VIT arm, with hematologic toxicity the most frequent (81% for VIT, 59% for VI), followed by gastrointestinal adverse events. “VIT was significantly more toxic than VI,” Dr. Defachelles observed, “but the toxicity was manageable.”

“VIT is now the standard treatment in Europe for relapsed rhabdomyosarcoma and will be the control arm in the multiarm, multistage RMS study for relapsed patients,” she said.

SOURCE: Defachelles AS, et al. J Clin Oncol 37, 2019 (suppl; abstr 10000)

The study was sponsored by Centre Oscar Lambret and SFCE (Société Française de Lutte contre les Cancers et Lucémies de l’Enfant et de l’Adolescent) served as collaborator.

Drs. Defachelles and Wagner had no relationships to disclose. A few coauthors had advisory/consulting or speaker roles for various commercial interests, including two for Merck (temozolomide).

Pazopanib Increases Pathologic Necrosis Rates in STS

Pazopanib added to a regimen of preoperative chemoradiation in non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) significantly increased the rate of near-complete pathologic response in both children and adults with intermediate or high-risk disease. Pazopanib, a multitargeted receptor tyrosine kinase inhibitor, works in multiple signaling pathways involved in tumorigenesis— VEGFR-1, -2, -3, PDGFRα/β, and c-kit. A phase 3 study demonstrated significant improvement in progression-free survival (PFS) in advanced STS patients and was the basis for its approval in the US and elsewhere for treatment of this patient population. Preclinical data suggest synergy between pazopanib and cytotoxic chemotherapy, forming the rationale for the current trial with neoadjuvant pazopanib added to chemoradiation.

According to the investigators, the trial (ARST1321) is the first ever collaborative study codeveloped, written, and conducted by pediatric (Children’s Oncology Group) and adult (NRG Oncology) cancer cooperative groups (NCT02180867). Aaron R. Weiss, MD, of the Maine Medical Center in Portland and study cochair, presented the data for the chemotherapy arms at ASCO. The primary objectives of the study were to determine the feasibility of preoperative chemoradiation with or without pazopanib and to compare the rates of complete pathologic response in patients receiving radiation or chemoradiation with or without pazopanib. Pathologic necrosis rates of 90% or better have been found to be predictive of outcome in STS.

Results

As of the June 30, 2018, cutoff, 81 patients were enrolled on the chemotherapy arms: 42 in the pazopanib plus chemoradiation arm and 39 in the chemoradiation-only arm. Sixty-one percent of all patients were 18 years or older, and the median age was 20.3 years. Most patients (73%) did not have metastatic disease, and the major histologies represented were synovial sarcoma (49%) and undifferentiated pleomorphic sarcoma (25%).

At week 13, patients in the pazopanib arm showed significant improvement, with 14 (58%) of those evaluated having pathologic necrosis of at least 90%, compared with 4 (22%) in the chemoradiation-only arm (P=.02). The study was closed to further accrual.

Eighteen patients were not evaluable for pathologic response and 21 were pending pathologic evaluation at week 13. Radiographic response rates were not statistically significant on either arm. No complete responses (CR) were achieved in the pazopanib arm, but 14 patients (52%) achieved a partial response (PR) and 12 (44%) had stable disease (SD). In the chemoradiation-only arm, 2 patients (8%) achieved a CR, 12 (50%) a PR, and 8 (33%) SD. Fifteen patients in each arm were not evaluated for radiographic response.

The pazopanib arm experienced more febrile neutropenia and myelotoxicity during induction and continuation phases than the chemoradiation-only arm. In general, investigators indicated pazopanib combined with chemoradiation was well tolerated and no unexpected toxicities arose during the trial.

In the post-presentation discussion, Dr. Raphael E. Pollock, MD, PhD, of The Ohio State University, called it a tremendous challenge to interdigitate primary local therapies in systemic approaches, particularly in the neoadjuvant context. He pointed out that in an earlier study, a 95% to 100% necrosis level was needed to achieve a significant positive impact on outcomes and perhaps a subsequent prospective trial could determine the best level. He questioned whether the availability of only 60% of patient responses could affect the conclusions and whether the high number of toxicities (73.8% grade 3/4 with pazopanib) might be too high to consider the treatment for most patients, given the intensity of the regimen.

SOURCE: Weiss AR, et al. J Clin Oncol 37, 2019 (suppl; abstr 11002)

The study was sponsored by the National Cancer Institute.

Drs. Weiss and Pollock had no relationships with commercial interests to disclose. A few investigators disclosed advisory, consulting, or research roles with pharmaceutical companies, including one who received institutional research funding from Novartis (pazopanib).

Gemcitabine Plus Pazopanib a Potential Alternative in STS

In a phase 2 study of gemcitabine with pazopanib (G+P) or gemcitabine with docetaxel (G+D), investigators concluded the combination with pazopanib can be considered an alternative to that with docetaxel in select patients with advanced soft tissue sarcoma (STS). They reported similar progression-free survival (PFS) and rate of toxicity for the two regimens. Neeta Somaiah, MD, of the University of Texas MD Anderson Cancer Center in Houston, presented the findings of the investigator-initiated effort (NCT01593748) at ASCO.

The investigators enrolled 90 patients, 45 in each arm. Patients were a mean age of 56 years, and there was no difference in age or gender distribution between the arms. Patients with leiomyosarcoma (31% overall) or prior pelvic radiation (11% overall) were similar between the arms. The overall response rate using RECIST 1.1 criteria was partial response (PR) in 8 of 44 evaluable patients (18%) in the G+D arm and 5 of 43 evaluable patients (12%) in the G+P arm. Stable disease (SD) was observed in 21 patients (48%) in the G+D arm and 24 patients (56%) in the G+P arm. This amounted to a clinical benefit rate (PR + SD) of 66% and 68% for the G+D and G+P arms, respectively (Fisher’s exact test, P>.99). The median PFS was 4.1 months on both arms and the difference in median overall survival— 15.9 months in the G+D arm and 12.4 months in the G+P arm—was not statistically significant.

Adverse events (AEs) of grade 3 or higher occurred in 19.9% of patients on G+D and 20.6% on G+P. Serious AEs occurred in 33% (G+D) and 22% (G+P). Dose reductions were necessary in 80% of patients on G+P and doses were held in 93%. Dr. Somaiah explained that this may have been because the starting dose of gemcitabine and pazopanib (1000 mg/m² of gemcitabine on days 1 and 8 and 800 mg of pazopanib) was “probably higher than what we should have started at.” The rate of doses held was also higher in the pazopanib arm (93%) compared with the docetaxel arm (58%). This was likely because pazopanib was a daily dosing, so if there was a toxicity it was more likely to be held than docetaxel, she observed. Grade 3 or higher toxicities occurring in 5% or more of patients in either arm consisted generally of cytopenias and fatigue. The G+P arm experienced a high amount of neutropenia, most likely because this arm did not receive granulocyte-colony stimulating factor (GCSF) support, as opposed to the G+D arm.

Dr. Somaiah pointed out that the 12% response rate for the G+P combination is similar to what has been previously presented and higher than single-agent gemcitabine or pazopanib, but not higher than the G+D combination. The PFS of 4.1 months was less than anticipated, she added, but it was similar on both arms. The investigators believe the G+P combination warrants further exploration.

SOURCE: Somaiah N, et al. J Clin Oncol 37, 2019 (suppl; abstr 11008)

The study was sponsored by the Medical University of South Carolina, with Novartis as collaborator.

Dr. Somaiah disclosed Advisory Board roles for Blueprint, Deciphera, and Bayer. Abstract coauthors disclosed advisory/consulting roles or research funding from various commercial interests, including Novartis (pazopanib) and Pfizer (gemcitabine).

rEECur Trial Finding Optimal Chemotherapy Regimen for Ewing Sarcoma

Interim results of the first and largest randomized trial in patients with refractory or recurrent Ewing sarcoma (ES), the rEECur trial, are guiding the way to finding the optimal chemotherapy regimen to treat the disease. Until now, there has been little prospective evidence and no randomized data to guide treatment choices in relapsed or refractory patients, and hence no real standard of care, according to the presentation at ASCO. Several molecularly targeted therapies are emerging, and they require a standardized chemotherapy backbone against which they can be tested.

Results

Two hundred twenty patients 4 years or older and younger than 50 years with recurrent or refractory histologically confirmed ES of bone or soft tissue were randomized to receive GD (n=72) or TC, IT, or IFOS (n=148). Sixty-two GD patients and 123 TC/IT/IFOS patients were included in the primary outcome analysis. Patients were predominantly male (70%), with a median age of 19 years (range, 4 to 49). About two-thirds (67.3%) were post-pubertal. Most patients (85%) were primary refractory or experienced their first disease recurrence, and 89% had measurable disease.

Investigators assessed the primary outcome of objective response after 4 cycles of therapy and found 11% of patients treated with GD responded compared to 24% in the other 3 arms combined. When they subjected the data to Bayesian analysis, there was a 25% chance that the response rate in the GD arm was better than the response in Arm A, a 2% chance that it was better than Arm B, and a 3% chance that it was better than Arm C. Because this study was still blinded at the time of the presentation, investigators didn’t know which regimen constituted which arm. The probability that response favored GD, however, was low.

The investigators observed no surprising safety findings. Eighty-five percent of all patients experienced at least 1 adverse event. Most frequent grade 3‐5 events consisted of pneumonitis (50%, 60%), neutropenic fever (17%, 25%), and diarrhea (0, 12%) in GD and the combined 3 arms, respectively. Grade 3 events in the GD arm were lower than in the other 3 arms combined. There was 1 toxic death attributed to neutropenic sepsis in 1 of the 3 blinded arms.

Median progression-free survival (PFS) for all patients was approximately 5 months. Bayesian analysis suggested there was a low probability that GD was more effective than the other 3 arms: a 22% chance that GD was better than Arm A, a 3% chance that it was better than Arm B, and a 7% chance that it was better than Arm C. Bayesian analysis also suggested there was a probability that OS favored GD. Because the trial directs only the first 4 or 6 cycles of treatment and the patients receive more treatment after trial-directed therapy, investigators were not fully able to interpret this.

Data suggested GD is a less effective regimen than the other 3 regimens both by objective response rate and PFS, so GD has been dropped from the study. Investigators already had more than 75 evaluable patients in each of the 3 arms for the second interim analysis to take place. In a discussion following the presentation, Jayesh Desai, FRACP, of Peter MacCallum Cancer Centre in Melbourne, Australia, called this study a potentially practice-changing trial at this early stage, noting that the GD combination will be de-prioritized in practice based on these results.

SOURCE: McCabe MG, et al. J Clin Oncol 37, 2019 (suppl; abstr 11007)

The rEECur trial is sponsored by the University of Birmingham (UK) and received funding from the European Union’s Seventh Framework Programme under a grant agreement.

Dr. McCabe disclosed no conflicts of interest. Other authors disclosed consulting, advisory roles, or research funding from numerous pharmaceutical companies, including Lilly (gemcitabine) and Pfizer (irinotecan). Dr. Desai disclosed a consulting/advisory role and institutional research funding from Lilly.

Abemaciclib Meets Primary Endpoint in Phase 2 Trial of DDLS

The newer and more potent CDK4 inhibitor, abemaciclib, met its primary endpoint in the investigator-initiated, single-center, single-arm, phase 2 trial in patients with advanced progressive dedifferentiated liposarcoma (DDLS). Twenty-two patients (76%) achieved progression-free survival (PFS) at 12 weeks for a median PFS of 30 weeks. A subset of patients experienced prolonged clinical benefit, remaining on study with stable disease for over 900 days. The study (NCT02846987) was conducted at Memorial Sloan Kettering Cancer Center (MSKCC) in New York and Mark A. Dickson, MD, presented the results at ASCO.

Results

Thirty patients, 29 evaluable, with metastatic or recurrent DDLS were enrolled and treated with abemaciclib 200 mg orally twice daily between August 2016 and October 2018. Data cutoff for the presentation was the first week of May 2019. Patients were a median of 62 years, 60% were male, and half had no prior systemic treatment. Prior systemic treatments for those previously treated included doxorubicin, olaratumab, gemcitabine, docetaxel, ifosfamide, eribulin, and trabectedin. For 87%, the primary tumor was in their abdomen or retroperitoneum.

Toxicity was as expected with this class of agent, according to the investigators. The most common grades 2 and 3 toxicities, respectively, possibly related to the study drug, occurring in more than 1 patient included anemia (70%, 37%), thrombocytopenia (13%, 13%), neutropenia (43%, 17%), and lymphocyte count decreased (23%, 23%). Very few of these adverse events were grade 4—none for anemia, and 3% each for thrombocytopenia, neutropenia, and lymphocyte count decreased. Diarrhea of grades 2 and 3 occurred in 27% and 7% of patients, respectively, and was managed well with loperamide.

In addition to reaching the primary endpoint of 15 patients or more achieving PFS at 12 weeks, 1 patient had a confirmed partial response (PR) and another an unconfirmed PR. At data cutoff, 11 patients remained on study with stable disease or PR. The investigators conducted correlative studies that indicated all patients had CDK4 and MDM2 amplification with no loss of retinoblastoma tumor suppressor. They observed an inverse correlation between CDK4 amplification and PFS—the higher the level of CDK4 amplification, the shorter the PFS. They also found additional genomic alterations, including JUN, GLI1, ARID1A, TERT, and ATRX. TERT amplification was also associated with shorter PFS. Based on these findings, the investigators believe a phase 3 study of abemaciclib in DDLS is warranted.

Winette van der Graaf, MD, PhD, of the Netherlands Cancer Institute in Amsterdam, in the discussion following the presentation, concurred that it is certainly time for a multicenter phase 3 study of CDK4 inhibitors in DDLS, and a strong international collaboration is key to conducting such studies, particularly in rare cancers. On a critical note, Dr. van der Graaf expressed concern that no patient-reported outcomes were measured after 120 patients, including those in previous studies, were treated on palbociclib and abemaciclib. Given that the toxicities of the CDK4 inhibitors are quite different, she recommended including patient-reported outcomes in future studies using validated health-related quality-of-life instruments.

SOURCE: Dickson MA, et al. J Clin Oncol 37, 2019 (suppl; abstr 11004)

The study was sponsored by Memorial Sloan Kettering Cancer Center, with the study collaborator, Eli Lilly and Company.

Dr. Dickson disclosed research funding from Lilly, the company that provided the study drug. Dr. van der Graaf had no relevant relationships to disclose. Abstract coauthors had consulting/advisory roles or research funding from various companies, including Lilly.

nab-Sirolimus Provides Benefits in Advanced Malignant PEComa

In a prospective phase 2 study of nab-sirolimus in advanced malignant perivascular epithelioid cell tumor (PEComa), the mTOR inhibitor achieved an objective response rate (ORR) of 42% with an acceptable safety profile, despite using relatively high doses of nab-sirolimus compared to other mTOR inhibitors. Activation of the mTOR pathway is common in PEComa, and earlier case reports had indicated substantial clinical benefit with mTOR inhibitor treatment. nab-Sirolimus (ABI-009) is a novel intravenous mTOR inhibitor consisting of nanoparticles of albumin-bound sirolimus. It has significantly higher anti-tumor activity than oral mTOR inhibitors and greater mTOR target suppression at an equal dose. Andrew J. Wagner, MD, PhD, of the Dana-Farber Cancer Institute in Boston, presented the findings of AMPECT (NCT02494570)—Advanced Malignant PEComa Trial—at ASCO.

Results

The drug was well tolerated, with toxicities similar to those of oral mTOR inhibitors. Treatment-related adverse events (TRAEs) occurring in 25% or more of patients were mostly grade 1 or 2 toxicities. Hematologic TRAEs included anemia (47%) and thrombocytopenia (32%) of any grade. Nonhematologic events of any grade included stomatitis/ mucositis (74%), dermatitis/rash (65%), fatigue (59%), nausea (47%), and diarrhea (38%), among others. A few grade 3 events occurred on study, most notably stomatitis/mucositis (18%). Severe adverse events (SAEs) were also uncommon, occurring in 7 of 34 patients (21%). Pneumonitis is common in orally administered mTOR inhibitors; 6 patients (18%) treated with nab-sirolimus had grade 1 or 2 pneumonitis.

Of the 31 evaluable patients, 13 (42%) had an objective response, all of which were partial responses (PR). Eleven (35%) had stable disease and 7 (23%) had progressive disease. The disease control rate, consisting of PR and stable disease, was 77%. The median duration of response had not been reached as of the data cutoff on May 10, 2019. At that time, it was 6.2 months (range, 1.5 to 27.7+). The median time to response was 1.4 months and the median progression-free survival (PFS) was 8.4 months. The PFS rate at 6 months was 61%. Three patients had received treatment for over a year and another 3 patients for more than 2 years.

Correlation with biomarkers

Of the 25 patients who had tissue suitable for next-generation sequencing, 9 had TSC2 mutations, 5 had TSC1 mutations, and 11 had neither mutation. Strikingly, 9 of 9 patients with TSC2 mutations developed a PR, while only 1 with a TSC1 mutation responded. One patient with no TSC1/2 mutation also responded and 2 patients with unknown mutational status responded. The investigators also analyzed pS6 status by immunohistochemistry—pS6 is a marker of mTOR hyperactivity. Twenty- five patient samples were available for analysis. Eight of 8 patients who were negative for pS6 staining did not have a response, while 10 of 17 (59%) who were pS6-positive had a PR.

In the discussion that followed, Winette van der Graaf, MD, of the Netherlands Cancer Institute in Amsterdam, noted that this study showed that biomarkers can be used for patient selection, although TSC2 mutations are not uniquely linked with response. She indicated a comparator with sirolimus would have been of great interest.

SOURCE: Wagner AJ, et al. J Clin Oncol 37, 2019 (suppl; abstr 11005).

The study was sponsored by Aadi Bioscience, Inc., and funded in part by a grant from the FDA Office of Orphan Products Development (OOPD).

Disclosures relevant to this presentation include contininstitutional research funding from Aadi Bioscience for Dr. Wagner and a few other abstract coauthors. Several coauthors are employed by Aadi Bioscience and have stock or other ownership interests. Dr. van der Graaf had nothing to disclose.

Cabozantinib Achieves Disease Control in GIST

The phase 2 EORTC 1317 trial, known as CaboGIST (NCT02216578), met its primary endpoint of progression-free survival (PFS) at 12 weeks in patients with metastatic gastrointestinal stromal tumor (GIST) treated with the tyrosine kinase inhibitor (TKI) cabozantinib. Twenty-four (58.5%) of the 41 patients in the primary study population, and 30 (60%) of the entire 50-patient population, were progression-free at 12 weeks. The study needed 21 patients to be progression- free for cabozantinib to warrant further exploration in GIST patients.

This investigator-initiated study had as its primary objective assessment of the safety and activity of cabozantinib in patients with metastatic GIST who had progressed on imatinib and sunitinib. The patients could not have been exposed to other KIT- or PDGFR-directed TKIs, such as regorafenib. Secondary objectives included the assessment of cabozantinib in different mutational subtypes of GIST. Patients received cabozantinib tablets once daily until they experienced no further clinical benefit or became intolerant to the drug or chose to discontinue therapy. Fifty patients started treatment between February 2017 and August 2018. All were evaluable for the primary endpoint, and one-third of patients contininstitutional cabozantinib treatment as of the database cutoff in January 2019.

Results

Patients were a median age of 63 years. Virtually all patients (92%) had prior surgery and only 8% had prior radiotherapy. The daily cabozantinib dose was a median 47.2 mg and duration of treatment was a median 20.4 weeks. No patient discontinued treatment due to toxicity, but 88% discontinued due to disease progression.

Safety signals were the same as for other indications in which cabozantinib is used. Almost all patients (94%) had at least 1 treatment-related adverse event of grades 1‐4, including diarrhea (74%), palmar-plantar erythrodysesthesia (58%), fatigue (46%), and hypertension (46%), which are typical of treatment with cabozantinib. Hematologic toxicities in this trial were clinically irrelevant, according to the investigators, consisting of small numbers of grades 2‐3 anemia, lymphopenia, white blood cell count abnormality, and neutropenia. Biochemical abnormalities included grades 3 and 4 hypophosphatemia, increased grades 3 and 4 gamma-glutamyl transferase, grade 3 hyponatremia, and grade 3 hypokalemia, in 8% or more of patients.

Overall survival was a median 14.4 months, with 16 patients still on treatment at the time of data cutoff. Twenty- four patients were progression-free at week 12, satisfying the study decision rule for clinical benefit. Median duration of PFS was 6.0 months. Seven patients (14%) achieved a confirmed partial response (PR) and 33 (66%) achieved stable disease (SD). Nine patients had progressive disease as their best response, 3 of whom had some clinical benefit. Forty patients (80%) experienced a clinical benefit of disease control (PR + SD).

An analysis of the relationship of genotype, duration, and RECIST response showed objective responses in patients with primary exon 11 mutations, with exon 9 mutations, and with exon 17 mutations, and in 2 patients without any known mutational information at the time of the presentation. Patients with stable disease were spread across all mutational subsets in the trial. The investigators suggested the definitive role of MET and AXL inhibition in GIST be assessed further in future clinical trials.

SOURCE: Schöffski P, et al. J Clin Oncol 37, 2019 (suppl; abstr 11006).

The study was sponsored by the European Organization for Research and Treatment of Cancer (EORTC).

Presenting author, Patrick Schöffski, MD, of KU Leuven and Leuven Cancer Institute in Belgium, disclosed institutional relationships with multiple pharmaceutical companies for consulting and research funding, including research funding from Exelixis, the developer of cabozantinib. No other abstract coauthor disclosed a relationship with Exelixis.

Larotectinib Effective in TRK Fusion Cancers

Pediatric patients with tropomyosin receptor kinase (TRK) fusions involving NTRK1, NTRK2, and NTRK3 genes had a high response rate with durable responses and a favorable safety profile when treated with larotrectinib, according to a presentation at ASCO. In this pediatric subset of children and adolescents from the SCOUT and NAVIGATE studies, the overall response rate (ORR) was 94%, with a 35% complete response (CR), 59% partial response (PR), and 6% stable disease as of the data cutoff at the end of July 2018.

Investigators enrolled 38 children and adolescents younger than 18 years from the SCOUT (NCT02637687) and NAVIGATE (NCT02576431) studies of larotrectinib who had non-central nervous system (CNS) TRK fusion cancers. Not all patients had the recommended phase 2 dose, Dr. van Tilburg pointed out, but most did. Hence, 29 of the 38 patients received the 100 mg/m² twice-daily, phase 2 dose until progression, withdrawal, or unacceptable toxicity.

Patients were young, with a median age of 2.3 years (range, 0.1 to 14.0 years). Almost two-thirds (61%) had prior surgery, 11% had prior radiotherapy, and 68% had prior systemic therapy. For 12 patients, larotrectinib was their first systemic therapy. The predominant tumor types were infantile fibrosarcoma (47%) and other soft tissue sarcoma (42%). And 47% of patients had NTRK3 fusions with ETV6, most of which were infantile fibrosarcoma.

Efficacy

Thirty-four patients were evaluable, and 32 had a reduction in tumor size, for an ORR of 94%, CR of 35%, and PR of 59%. Two patients with infantile fibrosarcoma had pathologic CRs—after treatment, no fibroid tissue in the tumors could be found. Median time to response was 1.8 months, median duration of treatment was 10.24 months, and 33 of 38 patients (87%) remained on treatment or underwent surgery with curative intent. As of the data cutoff of July 30, 2018, the secondary endpoints were not yet reached. However, 84% of responders were estimated to have a response duration of a year or more, and progression-free and overall survival looked very promising, according to Dr. van Tilburg.

Adverse events were primarily grades 1 and 2. The grades 3 and 4 treatment-related adverse events were quite few and consisted of increased alanine aminotransferase, decreased neutrophil count, and nausea. Longer follow-up of the patient safety profile is required, particularly since NTRK has multiple roles in neurodevelopment. The investigators recommended that routine testing for NTRK gene fusions in pediatric patients with cancer be conducted in appropriate clinical contexts.

In a discussion after the presentation, Daniel Alexander Morgenstern, MB BChir, PhD, of Great Ormond Street Hospital, London, UK, said that in many ways, the NTRK inhibitors have become the new poster child for precision oncology in pediatrics because of “these really spectacular results” with larotrectinib [and entrectinib]. One of the questions he raised regarding larotrectinib was the issue of CNS penetration, since patients with CNS cancer were not enrolled in the trial and preclinical data suggest limited CNS penetration for larotrectinib.

SOURCE: van Tilburg CM, et al. J Clin Oncol 37, 2019 (suppl; abstr 10010).

The studies were funded by Loxo Oncology, Inc., and Bayer AG.

Disclosures relevant to this presentation include consulting or advisory roles for Bayer for Drs. van Tilburg and Morgenstern. A few coauthors also had consulting/advisory roles or research funding from various companies, including Loxo and Bayer.

Since its inception, the Sarcoma Foundation of America (SFA) has awarded research grants for the best, most promising research to cure sarcoma. This year SFA awarded $750,000 in research funds to 15 scientists as part of its 2019 SFA Research Grant program. The grants, worth $50,000 each, explore numerous sarcoma subtypes, multiple strategies, and different approaches to find effective treatments for many forms of the disease. Research projects are listed below alphabetically by investigator last name. More details are available on the SFA’s grant pages, available at https://www.curesarcoma.org/grant

Since its inception, the Sarcoma Foundation of America (SFA) has awarded research grants for the best, most promising research to cure sarcoma. This year SFA awarded $750,000 in research funds to 15 scientists as part of its 2019 SFA Research Grant program. The grants, worth $50,000 each, explore numerous sarcoma subtypes, multiple strategies, and different approaches to find effective treatments for many forms of the disease. Research projects are listed below alphabetically by investigator last name. More details are available on the SFA’s grant pages, available at https://www.curesarcoma.org/grant

Since its inception, the Sarcoma Foundation of America (SFA) has awarded research grants for the best, most promising research to cure sarcoma. This year SFA awarded $750,000 in research funds to 15 scientists as part of its 2019 SFA Research Grant program. The grants, worth $50,000 each, explore numerous sarcoma subtypes, multiple strategies, and different approaches to find effective treatments for many forms of the disease. Research projects are listed below alphabetically by investigator last name. More details are available on the SFA’s grant pages, available at https://www.curesarcoma.org/grant

Spindle cell sarcomas are part of a rare, heterogeneous family of connective tissue tumors. These tumors are primarily treated with surgery and have a high risk of recurrence and distant metastasis with elevated mortality rates.¹ Other than the evidence for first-line therapy with doxorubicin in advanced soft tissue sarcoma, little evidence exists to point to an optimal second-line therapy. This is due to the diversity of soft tissue sarcomas, which encompass approximately 70 different histologic subtypes that can each respond differently to treatment.² As such, newer strategies, including immunotherapy and targeted molecular drugs, are being developed.

Quiescent in most adult tissues, the Hedgehog signaling pathway, when inappropriately activated, has been implicated in the development of multiple types of cancers, including basal cell, breast, prostate, hepatocellular, pancreatic, and brain cancer.³ The Hedgehog signaling pathway is an important regulator of cell growth and differentiation in early development, but when inappropriately activated can lead to cell proliferation and increased angiogenic factors, decreased apoptosis, and breakdown of tight junctions promoting cancer growth and metastasis.⁴ Recent data reveal that the Hedgehog pathway plays a specific role in activation of satellite cells, proliferation of myoblasts, and differentiation of skeletal muscle.⁵ Activation of this embryonic pathway has been implicated in embryonal rhabdoymyosarcoma, osteosarcoma, and chondrosarcoma.^5-7

This pathway has recently been recognized as a therapeutic target, with the development of vismodegib, a targeted Hedgehog pathway inhibitor. This novel agent is in active use for treatment of advanced basal cell carcinoma and is currently undergoing trials for various other malignancies. Recently, a phase 2a basket study, called MyPathway, evaluated the use of targeted therapies in 35 different advanced refractory solid tumors harboring specific molecular alterations. Out of 21 patients with mutations in the Hedgehog pathway, 3 had a partial response to vismodegib—one had an unknown primary tumor, another a squamous skin cancer, and the third a salivary gland cancer.⁸ Vismodegib (GDC-0449) was also evaluated in a phase 2 multicenter clinical trial in patients with progressive advanced chondrosarcoma.7 Although the study did not meet its primary endpoint, the proportion of patients with non-progressive disease was 25.6% at 6 months. Investigators observed that the benefit occurred in the subset of patients with overexpression of the Hedgehog ligand. Genomic studies for mutations in SMO and PTCH genes were available for only 28 and 26 patients, respectively, of the 45 patients enrolled on the trial. While there were no mutations identified, expression data revealed that overexpression of the Hedgehog ligand was present in 65% of cases tested (13 out of 20 patients). In patients with stable disease at 6 months, all had overexpression of the Hedgehog ligand.⁷ These studies point to the potential use of vismodegib in both bone and soft tissue sarcomas, and more specifically, to the importance of genomic testing in these cases.

Case Presentation and Summary

This report describes the novel use of vismodegib, an oral Hedgehog signaling pathway inhibitor, in the treatment of a patient with metastatic soft tissue sarcoma.

An 18-year-old female with no particular previous illnesses was initially diagnosed with superficial soft tissue sarcoma overlying the right hip in 2013. Due to the complexity of pathology, a second opinion was requested and revealed atypical cellular spindle and epithelioid cells, morphologically and immunohistochemically suggestive of spindle cell sarcoma, not otherwise specified. She underwent negative-margin resection in January 2014. Her course was complicated by two recurrences in the right inguinal lymph nodes in July 2014 and July 2015. She was treated with lymph node dissection in 2014, followed by numerous right lymph node dissections and adjuvant radiation in 2015.

A routine computerized tomography (CT) scan of the thorax-abdomen and pelvis in August 2016 revealed recurrence of disease, with multiple lung nodules as well as metastases in the retroperitoneum. She received 6 cycles of gemcitabine and docetaxel with stability of disease. The patient was then started on a PI3K inhibitor as part of a clinical trial, as genotypic analysis of the tumor revealed an activating mutation of the PI3K gene. The patient’s course was complicated by acute obstructive renal failure requiring a double J stent for right-sided hydronephrosis.

Repeat imaging revealed disease progression, and the patient was then switched to liposomal doxorubicin alone for 4 months and then in combination with olaratumab. She received the combined treatment for a total of 3 months, which was then stopped when she was found to have new peritoneal implants and worsening ascites. At this time, tissue was sent for FoundationOne® next generation sequencing (NGS)-based genomic testing, and the patient received one dose of nivolumab.

In January 2018, 2 days after receiving her first dose of nivolumab, the patient required admission for worsening abdominal pain secondary to progression of her disease (FIGURE 1). She was found to have acute kidney injury on top of chronic kidney disease due to hydronephrosis requiring a left-sided double J stent. She also had transaminitis resulting from a common bile duct stricture treated with a biliary stent and worsening ascites requiring regular paracentesis. This was all in the context of new or growing metastatic implants.

At this time, the result of the FoundationOne genomic testing revealed PTCH1 loss of exons 1-24 and CDKN2A/B loss. Mutation of tumor suppressor gene PTCH1 leads to Hedgehog pathway activation and therefore the patient was started on vismodegib on January 22, 2018. She was discharged from the hospital in stable condition a day later, on January 23.

The patient’s clinical status subsequently improved, with significant reduction in her chronic abdominal pain and very minimal side effects. Clinically, the patient’s acute kidney injury resolved (from a creatinine of 272 μmol/L at discharge to 85 μmol/L after a week of treatment) and her liver enzymes normalized (from an alkaline phosphatase of 301 U/L to 83 U/L, and alanine transaminase of 111 U/L to 38 U/L). CT scan of her chest and abdomen, which was performed 1 month post treatment, revealed stability of disease with absence of ascites (FIGURE 2). The patient continued to have a good response to treatment for 6 months, with no recurrence of pain or ascites.

Six months later, in July 2018, the patient developed increasing pain and a CT scan revealed worsening of abdominopelvic carcinomatosis. In this context, vismodegib was discontinued on July 17. In the next 5 months, she went on to receive carboplatin and paclitaxel, gemcitabine, and nivolumab consecutively with no response. She was admitted to hospital on December 30 for a pain crisis. She passed away on January 9, 2019, from fecal peritonitis.

Discussion

To the best of our knowledge, this is the first patient with metastatic sarcoma to receive vismodegib, a Hedgehog signaling pathway inhibitor. She achieved an excellent clinical response with progression- free disease for approximately 6 months after starting treatment.

There is no current standard second- line treatment for metastatic soft tissue sarcoma. The choice of systemic therapy is histology-driven and therefore treatment is individualized for each patient. The future of oncology is heading towards an even more personalized approach with molecular profiling. Our case report highlights the relevance of genomic testing and targeted therapies, especially in cases of diverse clinical and biological disease behavior.

Molecular targeting is even more necessary in patients with advanced cancer who have failed multiple lines of treatment. As in our study, these patients can obtain a significant response with meaningful improvement in their quality of life. Future research is currently focusing on identifying new molecular targets in patients with advanced refractory cancers. Further studies will need to be done to determine whether these molecular targeting agents, such as vismodegib, lead to significant outcome changes in these patients.

Spindle cell sarcomas are part of a rare, heterogeneous family of connective tissue tumors. These tumors are primarily treated with surgery and have a high risk of recurrence and distant metastasis with elevated mortality rates.¹ Other than the evidence for first-line therapy with doxorubicin in advanced soft tissue sarcoma, little evidence exists to point to an optimal second-line therapy. This is due to the diversity of soft tissue sarcomas, which encompass approximately 70 different histologic subtypes that can each respond differently to treatment.² As such, newer strategies, including immunotherapy and targeted molecular drugs, are being developed.

Quiescent in most adult tissues, the Hedgehog signaling pathway, when inappropriately activated, has been implicated in the development of multiple types of cancers, including basal cell, breast, prostate, hepatocellular, pancreatic, and brain cancer.³ The Hedgehog signaling pathway is an important regulator of cell growth and differentiation in early development, but when inappropriately activated can lead to cell proliferation and increased angiogenic factors, decreased apoptosis, and breakdown of tight junctions promoting cancer growth and metastasis.⁴ Recent data reveal that the Hedgehog pathway plays a specific role in activation of satellite cells, proliferation of myoblasts, and differentiation of skeletal muscle.⁵ Activation of this embryonic pathway has been implicated in embryonal rhabdoymyosarcoma, osteosarcoma, and chondrosarcoma.^5-7

This pathway has recently been recognized as a therapeutic target, with the development of vismodegib, a targeted Hedgehog pathway inhibitor. This novel agent is in active use for treatment of advanced basal cell carcinoma and is currently undergoing trials for various other malignancies. Recently, a phase 2a basket study, called MyPathway, evaluated the use of targeted therapies in 35 different advanced refractory solid tumors harboring specific molecular alterations. Out of 21 patients with mutations in the Hedgehog pathway, 3 had a partial response to vismodegib—one had an unknown primary tumor, another a squamous skin cancer, and the third a salivary gland cancer.⁸ Vismodegib (GDC-0449) was also evaluated in a phase 2 multicenter clinical trial in patients with progressive advanced chondrosarcoma.7 Although the study did not meet its primary endpoint, the proportion of patients with non-progressive disease was 25.6% at 6 months. Investigators observed that the benefit occurred in the subset of patients with overexpression of the Hedgehog ligand. Genomic studies for mutations in SMO and PTCH genes were available for only 28 and 26 patients, respectively, of the 45 patients enrolled on the trial. While there were no mutations identified, expression data revealed that overexpression of the Hedgehog ligand was present in 65% of cases tested (13 out of 20 patients). In patients with stable disease at 6 months, all had overexpression of the Hedgehog ligand.⁷ These studies point to the potential use of vismodegib in both bone and soft tissue sarcomas, and more specifically, to the importance of genomic testing in these cases.

Case Presentation and Summary

This report describes the novel use of vismodegib, an oral Hedgehog signaling pathway inhibitor, in the treatment of a patient with metastatic soft tissue sarcoma.

An 18-year-old female with no particular previous illnesses was initially diagnosed with superficial soft tissue sarcoma overlying the right hip in 2013. Due to the complexity of pathology, a second opinion was requested and revealed atypical cellular spindle and epithelioid cells, morphologically and immunohistochemically suggestive of spindle cell sarcoma, not otherwise specified. She underwent negative-margin resection in January 2014. Her course was complicated by two recurrences in the right inguinal lymph nodes in July 2014 and July 2015. She was treated with lymph node dissection in 2014, followed by numerous right lymph node dissections and adjuvant radiation in 2015.

A routine computerized tomography (CT) scan of the thorax-abdomen and pelvis in August 2016 revealed recurrence of disease, with multiple lung nodules as well as metastases in the retroperitoneum. She received 6 cycles of gemcitabine and docetaxel with stability of disease. The patient was then started on a PI3K inhibitor as part of a clinical trial, as genotypic analysis of the tumor revealed an activating mutation of the PI3K gene. The patient’s course was complicated by acute obstructive renal failure requiring a double J stent for right-sided hydronephrosis.

Repeat imaging revealed disease progression, and the patient was then switched to liposomal doxorubicin alone for 4 months and then in combination with olaratumab. She received the combined treatment for a total of 3 months, which was then stopped when she was found to have new peritoneal implants and worsening ascites. At this time, tissue was sent for FoundationOne® next generation sequencing (NGS)-based genomic testing, and the patient received one dose of nivolumab.

In January 2018, 2 days after receiving her first dose of nivolumab, the patient required admission for worsening abdominal pain secondary to progression of her disease (FIGURE 1). She was found to have acute kidney injury on top of chronic kidney disease due to hydronephrosis requiring a left-sided double J stent. She also had transaminitis resulting from a common bile duct stricture treated with a biliary stent and worsening ascites requiring regular paracentesis. This was all in the context of new or growing metastatic implants.

At this time, the result of the FoundationOne genomic testing revealed PTCH1 loss of exons 1-24 and CDKN2A/B loss. Mutation of tumor suppressor gene PTCH1 leads to Hedgehog pathway activation and therefore the patient was started on vismodegib on January 22, 2018. She was discharged from the hospital in stable condition a day later, on January 23.

The patient’s clinical status subsequently improved, with significant reduction in her chronic abdominal pain and very minimal side effects. Clinically, the patient’s acute kidney injury resolved (from a creatinine of 272 μmol/L at discharge to 85 μmol/L after a week of treatment) and her liver enzymes normalized (from an alkaline phosphatase of 301 U/L to 83 U/L, and alanine transaminase of 111 U/L to 38 U/L). CT scan of her chest and abdomen, which was performed 1 month post treatment, revealed stability of disease with absence of ascites (FIGURE 2). The patient continued to have a good response to treatment for 6 months, with no recurrence of pain or ascites.

Six months later, in July 2018, the patient developed increasing pain and a CT scan revealed worsening of abdominopelvic carcinomatosis. In this context, vismodegib was discontinued on July 17. In the next 5 months, she went on to receive carboplatin and paclitaxel, gemcitabine, and nivolumab consecutively with no response. She was admitted to hospital on December 30 for a pain crisis. She passed away on January 9, 2019, from fecal peritonitis.

Discussion

To the best of our knowledge, this is the first patient with metastatic sarcoma to receive vismodegib, a Hedgehog signaling pathway inhibitor. She achieved an excellent clinical response with progression- free disease for approximately 6 months after starting treatment.

There is no current standard second- line treatment for metastatic soft tissue sarcoma. The choice of systemic therapy is histology-driven and therefore treatment is individualized for each patient. The future of oncology is heading towards an even more personalized approach with molecular profiling. Our case report highlights the relevance of genomic testing and targeted therapies, especially in cases of diverse clinical and biological disease behavior.

Molecular targeting is even more necessary in patients with advanced cancer who have failed multiple lines of treatment. As in our study, these patients can obtain a significant response with meaningful improvement in their quality of life. Future research is currently focusing on identifying new molecular targets in patients with advanced refractory cancers. Further studies will need to be done to determine whether these molecular targeting agents, such as vismodegib, lead to significant outcome changes in these patients.

Spindle cell sarcomas are part of a rare, heterogeneous family of connective tissue tumors. These tumors are primarily treated with surgery and have a high risk of recurrence and distant metastasis with elevated mortality rates.¹ Other than the evidence for first-line therapy with doxorubicin in advanced soft tissue sarcoma, little evidence exists to point to an optimal second-line therapy. This is due to the diversity of soft tissue sarcomas, which encompass approximately 70 different histologic subtypes that can each respond differently to treatment.² As such, newer strategies, including immunotherapy and targeted molecular drugs, are being developed.

Quiescent in most adult tissues, the Hedgehog signaling pathway, when inappropriately activated, has been implicated in the development of multiple types of cancers, including basal cell, breast, prostate, hepatocellular, pancreatic, and brain cancer.³ The Hedgehog signaling pathway is an important regulator of cell growth and differentiation in early development, but when inappropriately activated can lead to cell proliferation and increased angiogenic factors, decreased apoptosis, and breakdown of tight junctions promoting cancer growth and metastasis.⁴ Recent data reveal that the Hedgehog pathway plays a specific role in activation of satellite cells, proliferation of myoblasts, and differentiation of skeletal muscle.⁵ Activation of this embryonic pathway has been implicated in embryonal rhabdoymyosarcoma, osteosarcoma, and chondrosarcoma.^5-7

This pathway has recently been recognized as a therapeutic target, with the development of vismodegib, a targeted Hedgehog pathway inhibitor. This novel agent is in active use for treatment of advanced basal cell carcinoma and is currently undergoing trials for various other malignancies. Recently, a phase 2a basket study, called MyPathway, evaluated the use of targeted therapies in 35 different advanced refractory solid tumors harboring specific molecular alterations. Out of 21 patients with mutations in the Hedgehog pathway, 3 had a partial response to vismodegib—one had an unknown primary tumor, another a squamous skin cancer, and the third a salivary gland cancer.⁸ Vismodegib (GDC-0449) was also evaluated in a phase 2 multicenter clinical trial in patients with progressive advanced chondrosarcoma.7 Although the study did not meet its primary endpoint, the proportion of patients with non-progressive disease was 25.6% at 6 months. Investigators observed that the benefit occurred in the subset of patients with overexpression of the Hedgehog ligand. Genomic studies for mutations in SMO and PTCH genes were available for only 28 and 26 patients, respectively, of the 45 patients enrolled on the trial. While there were no mutations identified, expression data revealed that overexpression of the Hedgehog ligand was present in 65% of cases tested (13 out of 20 patients). In patients with stable disease at 6 months, all had overexpression of the Hedgehog ligand.⁷ These studies point to the potential use of vismodegib in both bone and soft tissue sarcomas, and more specifically, to the importance of genomic testing in these cases.

Case Presentation and Summary

This report describes the novel use of vismodegib, an oral Hedgehog signaling pathway inhibitor, in the treatment of a patient with metastatic soft tissue sarcoma.

An 18-year-old female with no particular previous illnesses was initially diagnosed with superficial soft tissue sarcoma overlying the right hip in 2013. Due to the complexity of pathology, a second opinion was requested and revealed atypical cellular spindle and epithelioid cells, morphologically and immunohistochemically suggestive of spindle cell sarcoma, not otherwise specified. She underwent negative-margin resection in January 2014. Her course was complicated by two recurrences in the right inguinal lymph nodes in July 2014 and July 2015. She was treated with lymph node dissection in 2014, followed by numerous right lymph node dissections and adjuvant radiation in 2015.

A routine computerized tomography (CT) scan of the thorax-abdomen and pelvis in August 2016 revealed recurrence of disease, with multiple lung nodules as well as metastases in the retroperitoneum. She received 6 cycles of gemcitabine and docetaxel with stability of disease. The patient was then started on a PI3K inhibitor as part of a clinical trial, as genotypic analysis of the tumor revealed an activating mutation of the PI3K gene. The patient’s course was complicated by acute obstructive renal failure requiring a double J stent for right-sided hydronephrosis.

Repeat imaging revealed disease progression, and the patient was then switched to liposomal doxorubicin alone for 4 months and then in combination with olaratumab. She received the combined treatment for a total of 3 months, which was then stopped when she was found to have new peritoneal implants and worsening ascites. At this time, tissue was sent for FoundationOne® next generation sequencing (NGS)-based genomic testing, and the patient received one dose of nivolumab.

In January 2018, 2 days after receiving her first dose of nivolumab, the patient required admission for worsening abdominal pain secondary to progression of her disease (FIGURE 1). She was found to have acute kidney injury on top of chronic kidney disease due to hydronephrosis requiring a left-sided double J stent. She also had transaminitis resulting from a common bile duct stricture treated with a biliary stent and worsening ascites requiring regular paracentesis. This was all in the context of new or growing metastatic implants.

At this time, the result of the FoundationOne genomic testing revealed PTCH1 loss of exons 1-24 and CDKN2A/B loss. Mutation of tumor suppressor gene PTCH1 leads to Hedgehog pathway activation and therefore the patient was started on vismodegib on January 22, 2018. She was discharged from the hospital in stable condition a day later, on January 23.

The patient’s clinical status subsequently improved, with significant reduction in her chronic abdominal pain and very minimal side effects. Clinically, the patient’s acute kidney injury resolved (from a creatinine of 272 μmol/L at discharge to 85 μmol/L after a week of treatment) and her liver enzymes normalized (from an alkaline phosphatase of 301 U/L to 83 U/L, and alanine transaminase of 111 U/L to 38 U/L). CT scan of her chest and abdomen, which was performed 1 month post treatment, revealed stability of disease with absence of ascites (FIGURE 2). The patient continued to have a good response to treatment for 6 months, with no recurrence of pain or ascites.

Six months later, in July 2018, the patient developed increasing pain and a CT scan revealed worsening of abdominopelvic carcinomatosis. In this context, vismodegib was discontinued on July 17. In the next 5 months, she went on to receive carboplatin and paclitaxel, gemcitabine, and nivolumab consecutively with no response. She was admitted to hospital on December 30 for a pain crisis. She passed away on January 9, 2019, from fecal peritonitis.

Discussion

To the best of our knowledge, this is the first patient with metastatic sarcoma to receive vismodegib, a Hedgehog signaling pathway inhibitor. She achieved an excellent clinical response with progression- free disease for approximately 6 months after starting treatment.

There is no current standard second- line treatment for metastatic soft tissue sarcoma. The choice of systemic therapy is histology-driven and therefore treatment is individualized for each patient. The future of oncology is heading towards an even more personalized approach with molecular profiling. Our case report highlights the relevance of genomic testing and targeted therapies, especially in cases of diverse clinical and biological disease behavior.

Molecular targeting is even more necessary in patients with advanced cancer who have failed multiple lines of treatment. As in our study, these patients can obtain a significant response with meaningful improvement in their quality of life. Future research is currently focusing on identifying new molecular targets in patients with advanced refractory cancers. Further studies will need to be done to determine whether these molecular targeting agents, such as vismodegib, lead to significant outcome changes in these patients.