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Three drug combinations represent next level for high-risk breast cancer
BRUSSELS – Now that dual combinations of targeted breast cancer drugs are standard treatment, researchers see up-front triple drug combinations as the next treatment frontier.
“Doublets are simply not enough,” Dejan Juric, MD, said at a breast cancer conference sponsored by the European Society of Medical Oncology. Triple-drug combinations offer the possibility of substantially-reduced rates of resistance development and the possibility of reducing dosages to improve tolerability.
One way to leverage the potential of a triple regimen is to target all three drugs at the same oncogenic pathway. “If we target a pathway with multiple drugs do we still need the maximally-tolerated dose of each? Clearly no,” said René Bernards, PhD, a professor at the Netherlands Cancer Institute in Amsterdam.
Dr. Bernards said he has as-yet unpublished evidence that individual-drug dosages can be cut when using a combination regimen that joins treatments targeted to the sequential signaling steps of Raf, MEK, and ERK in a key signaling cascade tied to the epidermal growth factor receptor (BBA Mol Cell Res. 2007 Aug;1773[8]:1263-84). “We now have drugs for all these [targets]. You can use 10% of the effective dose of each of these drugs and get complete inhibition of the pathway and not make cells resistant to these low-doses,” he declared.
Having drugs that work well together is critical, agreed Dr. Juric. “We need to keep searching for drugs where you can achieve nice inhibition by the triplet.” The goal is to “completely shut down a pathway,” he said. While “upfront combination is always superior to a sequential strategy, we hope that a new combination is not just more hits at the goal but a new quality.” The conventional concept of first-line, second-line, and third-line treatments is an “obstacle” to development of the most rational combinations.
A challenge when testing a triple regimen as first-line treatment is deciding which patients to target, as some hormone-receptor positive patients can do well on just an aromatase inhibitor.
“I don’t know which patients will do well on a single agent and who will need a combination,” said Dr. Juric. Given that uncertainty, his priorities are testing combination regimens that are both tolerable and cost effective. He also stressed the need to “better understand the tumor we are dealing with, using blood and biopsies, and use an adaptive approach” based on each tumor’s combination of characteristics.
As long as tolerability is possible, preclinical models suggest that the biggest impact from combination regimens comes in treatment naive patients. That would mean targeting patients with high-risk, estrogen–receptor positive breast cancer “where we know the risk continues for 20, 30 years and the long-term prognosis for relapse is very poor,” said Nicholas Turner, MD, a molecular oncologist at the Institute of Cancer Research and the Royal Marsden Hospital, both in London. “Perhaps a triple combination, if tolerable, would have the most potential to change the prognosis of these patients.”
Dr. Juric has been a consultant to Eisai, EMD, Novartis, and Serono. Dr. Bernards owns a portion of Agendia, a company that markets a breast cancer genetic test he codeveloped. Dr. Turner has received honoraria from Lilly, Novartis, Pfizer, and Roche.
[email protected]
On Twitter @mitchelzoler
BRUSSELS – Now that dual combinations of targeted breast cancer drugs are standard treatment, researchers see up-front triple drug combinations as the next treatment frontier.
“Doublets are simply not enough,” Dejan Juric, MD, said at a breast cancer conference sponsored by the European Society of Medical Oncology. Triple-drug combinations offer the possibility of substantially-reduced rates of resistance development and the possibility of reducing dosages to improve tolerability.
One way to leverage the potential of a triple regimen is to target all three drugs at the same oncogenic pathway. “If we target a pathway with multiple drugs do we still need the maximally-tolerated dose of each? Clearly no,” said René Bernards, PhD, a professor at the Netherlands Cancer Institute in Amsterdam.
Dr. Bernards said he has as-yet unpublished evidence that individual-drug dosages can be cut when using a combination regimen that joins treatments targeted to the sequential signaling steps of Raf, MEK, and ERK in a key signaling cascade tied to the epidermal growth factor receptor (BBA Mol Cell Res. 2007 Aug;1773[8]:1263-84). “We now have drugs for all these [targets]. You can use 10% of the effective dose of each of these drugs and get complete inhibition of the pathway and not make cells resistant to these low-doses,” he declared.
Having drugs that work well together is critical, agreed Dr. Juric. “We need to keep searching for drugs where you can achieve nice inhibition by the triplet.” The goal is to “completely shut down a pathway,” he said. While “upfront combination is always superior to a sequential strategy, we hope that a new combination is not just more hits at the goal but a new quality.” The conventional concept of first-line, second-line, and third-line treatments is an “obstacle” to development of the most rational combinations.
A challenge when testing a triple regimen as first-line treatment is deciding which patients to target, as some hormone-receptor positive patients can do well on just an aromatase inhibitor.
“I don’t know which patients will do well on a single agent and who will need a combination,” said Dr. Juric. Given that uncertainty, his priorities are testing combination regimens that are both tolerable and cost effective. He also stressed the need to “better understand the tumor we are dealing with, using blood and biopsies, and use an adaptive approach” based on each tumor’s combination of characteristics.
As long as tolerability is possible, preclinical models suggest that the biggest impact from combination regimens comes in treatment naive patients. That would mean targeting patients with high-risk, estrogen–receptor positive breast cancer “where we know the risk continues for 20, 30 years and the long-term prognosis for relapse is very poor,” said Nicholas Turner, MD, a molecular oncologist at the Institute of Cancer Research and the Royal Marsden Hospital, both in London. “Perhaps a triple combination, if tolerable, would have the most potential to change the prognosis of these patients.”
Dr. Juric has been a consultant to Eisai, EMD, Novartis, and Serono. Dr. Bernards owns a portion of Agendia, a company that markets a breast cancer genetic test he codeveloped. Dr. Turner has received honoraria from Lilly, Novartis, Pfizer, and Roche.
[email protected]
On Twitter @mitchelzoler
BRUSSELS – Now that dual combinations of targeted breast cancer drugs are standard treatment, researchers see up-front triple drug combinations as the next treatment frontier.
“Doublets are simply not enough,” Dejan Juric, MD, said at a breast cancer conference sponsored by the European Society of Medical Oncology. Triple-drug combinations offer the possibility of substantially-reduced rates of resistance development and the possibility of reducing dosages to improve tolerability.
One way to leverage the potential of a triple regimen is to target all three drugs at the same oncogenic pathway. “If we target a pathway with multiple drugs do we still need the maximally-tolerated dose of each? Clearly no,” said René Bernards, PhD, a professor at the Netherlands Cancer Institute in Amsterdam.
Dr. Bernards said he has as-yet unpublished evidence that individual-drug dosages can be cut when using a combination regimen that joins treatments targeted to the sequential signaling steps of Raf, MEK, and ERK in a key signaling cascade tied to the epidermal growth factor receptor (BBA Mol Cell Res. 2007 Aug;1773[8]:1263-84). “We now have drugs for all these [targets]. You can use 10% of the effective dose of each of these drugs and get complete inhibition of the pathway and not make cells resistant to these low-doses,” he declared.
Having drugs that work well together is critical, agreed Dr. Juric. “We need to keep searching for drugs where you can achieve nice inhibition by the triplet.” The goal is to “completely shut down a pathway,” he said. While “upfront combination is always superior to a sequential strategy, we hope that a new combination is not just more hits at the goal but a new quality.” The conventional concept of first-line, second-line, and third-line treatments is an “obstacle” to development of the most rational combinations.
A challenge when testing a triple regimen as first-line treatment is deciding which patients to target, as some hormone-receptor positive patients can do well on just an aromatase inhibitor.
“I don’t know which patients will do well on a single agent and who will need a combination,” said Dr. Juric. Given that uncertainty, his priorities are testing combination regimens that are both tolerable and cost effective. He also stressed the need to “better understand the tumor we are dealing with, using blood and biopsies, and use an adaptive approach” based on each tumor’s combination of characteristics.
As long as tolerability is possible, preclinical models suggest that the biggest impact from combination regimens comes in treatment naive patients. That would mean targeting patients with high-risk, estrogen–receptor positive breast cancer “where we know the risk continues for 20, 30 years and the long-term prognosis for relapse is very poor,” said Nicholas Turner, MD, a molecular oncologist at the Institute of Cancer Research and the Royal Marsden Hospital, both in London. “Perhaps a triple combination, if tolerable, would have the most potential to change the prognosis of these patients.”
Dr. Juric has been a consultant to Eisai, EMD, Novartis, and Serono. Dr. Bernards owns a portion of Agendia, a company that markets a breast cancer genetic test he codeveloped. Dr. Turner has received honoraria from Lilly, Novartis, Pfizer, and Roche.
[email protected]
On Twitter @mitchelzoler
EXPERT ANALYSIS FROM IMPAKT 2017
Two new biomarkers show breast cancer validity
BRUSSELS – A pair of breast cancer biomarkers look promising for making better prognosis assessments of selected patients, but acceptance of both into practice will need further documentation of their clinical utility, declared a senior breast cancer oncologist who served as discussant for the studies.
One of the markers is high intratumor heterogeneity of estrogen receptor density, a flag of poor prognosis when heterogeneity is high. The second marker is the phosphorylated signal transducer and activator of transcription (pSTAT) 3, which appeared to link with good prognosis in estrogen receptor–positive breast cancer.
The data on intratumor estrogen-receptor heterogeneity came from specimens collected from the low-risk breast cancer patients enrolled in the Stockholm Adjuvant Tamoxifen trial during 1976-1990 (Acta Oncol. 2007 July 8;46[2]:133-45). Enrolled patients had lymph node–negative disease and primary tumors smaller than 30 mm. During the trial, researchers preserved formalin-fixed tumor specimens in paraffin from 778 patients, which formed the basis for the current study, explained Linda S. Lindström, PhD, a cancer epidemiologist at the Karolinska Institute in Stockholm. Slides from the specimens were restained for their estrogen receptor content in 2014 and assessed by two independent breast cancer pathologists. They scored the heterogeneity of estrogen receptor distribution as high, medium, or low, and Dr. Lindström and her associates calculated a hazard ratio for 25-year patient survival when they compared 593 specimens with high or low receptor heterogeneity. They adjusted the hazard ratios for several baseline variables including age, year of breast cancer diagnosis, HER2 status, Ki67 status, tumor grade, tumor size, randomization to tamoxifen or placebo treatment, and other factors.
“Routine clinical assessment of intratumor heterogeneity of estrogen receptor may identify patients at high long-term risk for fatal breast cancer that may potentially change clinical management, especially for patients with luminal A subtype tumors,” Dr. Lindström said.“I’d like to see the C statistic; will the prognostic model improve significantly with this added?” Dr. Linn wondered. “We need at least two more independent validations.”
The second biomarker study used two separate analyses of pSTAT3 expression. The first involved specimens collected from 3,074 patients with luminal breast cancer. Analysis of pSTAT3 gene signature expression showed that, the higher the expression levels were, associated with better relapse-free survival during follow-up out to as long as 8 years, reported Amir Sonnenblick, MD, an oncologist at the Sharret Institute of Oncology of Hadassah-Hebrew University Medical Center in Jerusalem.
Univariate analysis showed that binary pSTAT3 expression (positive or negative) significantly correlated with 10-year overall survival, with a hazard ratio of 0.66 (P = .04) for patients with positive expression, compared with those with no pSTAT3 expression, Dr. Sonnenblick said.
“pSTAT3 is associated with improved outcome in estrogen receptor–positive breast cancer. Future trials should take pSTAT3 status into account,” he concluded.
Dr. Linn cautioned that pSTAT3 expression should not be used to identify patients who can forgo chemotherapy, as the gene signature expression analysis showed that, even among patients with high pSTAT3 expression, long-term survival was still less than 90%.
Dr. Lindström and Dr. Sonnenblick had no disclosures. Dr. Linn has been an adviser to AstraZeneca, Cergentis, IBM Health, Novartis, Pfizer, Phillips Health, Roche, and Sanofi.
[email protected]
On Twitter @mitchelzoler
BRUSSELS – A pair of breast cancer biomarkers look promising for making better prognosis assessments of selected patients, but acceptance of both into practice will need further documentation of their clinical utility, declared a senior breast cancer oncologist who served as discussant for the studies.
One of the markers is high intratumor heterogeneity of estrogen receptor density, a flag of poor prognosis when heterogeneity is high. The second marker is the phosphorylated signal transducer and activator of transcription (pSTAT) 3, which appeared to link with good prognosis in estrogen receptor–positive breast cancer.
The data on intratumor estrogen-receptor heterogeneity came from specimens collected from the low-risk breast cancer patients enrolled in the Stockholm Adjuvant Tamoxifen trial during 1976-1990 (Acta Oncol. 2007 July 8;46[2]:133-45). Enrolled patients had lymph node–negative disease and primary tumors smaller than 30 mm. During the trial, researchers preserved formalin-fixed tumor specimens in paraffin from 778 patients, which formed the basis for the current study, explained Linda S. Lindström, PhD, a cancer epidemiologist at the Karolinska Institute in Stockholm. Slides from the specimens were restained for their estrogen receptor content in 2014 and assessed by two independent breast cancer pathologists. They scored the heterogeneity of estrogen receptor distribution as high, medium, or low, and Dr. Lindström and her associates calculated a hazard ratio for 25-year patient survival when they compared 593 specimens with high or low receptor heterogeneity. They adjusted the hazard ratios for several baseline variables including age, year of breast cancer diagnosis, HER2 status, Ki67 status, tumor grade, tumor size, randomization to tamoxifen or placebo treatment, and other factors.
“Routine clinical assessment of intratumor heterogeneity of estrogen receptor may identify patients at high long-term risk for fatal breast cancer that may potentially change clinical management, especially for patients with luminal A subtype tumors,” Dr. Lindström said.“I’d like to see the C statistic; will the prognostic model improve significantly with this added?” Dr. Linn wondered. “We need at least two more independent validations.”
The second biomarker study used two separate analyses of pSTAT3 expression. The first involved specimens collected from 3,074 patients with luminal breast cancer. Analysis of pSTAT3 gene signature expression showed that, the higher the expression levels were, associated with better relapse-free survival during follow-up out to as long as 8 years, reported Amir Sonnenblick, MD, an oncologist at the Sharret Institute of Oncology of Hadassah-Hebrew University Medical Center in Jerusalem.
Univariate analysis showed that binary pSTAT3 expression (positive or negative) significantly correlated with 10-year overall survival, with a hazard ratio of 0.66 (P = .04) for patients with positive expression, compared with those with no pSTAT3 expression, Dr. Sonnenblick said.
“pSTAT3 is associated with improved outcome in estrogen receptor–positive breast cancer. Future trials should take pSTAT3 status into account,” he concluded.
Dr. Linn cautioned that pSTAT3 expression should not be used to identify patients who can forgo chemotherapy, as the gene signature expression analysis showed that, even among patients with high pSTAT3 expression, long-term survival was still less than 90%.
Dr. Lindström and Dr. Sonnenblick had no disclosures. Dr. Linn has been an adviser to AstraZeneca, Cergentis, IBM Health, Novartis, Pfizer, Phillips Health, Roche, and Sanofi.
[email protected]
On Twitter @mitchelzoler
BRUSSELS – A pair of breast cancer biomarkers look promising for making better prognosis assessments of selected patients, but acceptance of both into practice will need further documentation of their clinical utility, declared a senior breast cancer oncologist who served as discussant for the studies.
One of the markers is high intratumor heterogeneity of estrogen receptor density, a flag of poor prognosis when heterogeneity is high. The second marker is the phosphorylated signal transducer and activator of transcription (pSTAT) 3, which appeared to link with good prognosis in estrogen receptor–positive breast cancer.
The data on intratumor estrogen-receptor heterogeneity came from specimens collected from the low-risk breast cancer patients enrolled in the Stockholm Adjuvant Tamoxifen trial during 1976-1990 (Acta Oncol. 2007 July 8;46[2]:133-45). Enrolled patients had lymph node–negative disease and primary tumors smaller than 30 mm. During the trial, researchers preserved formalin-fixed tumor specimens in paraffin from 778 patients, which formed the basis for the current study, explained Linda S. Lindström, PhD, a cancer epidemiologist at the Karolinska Institute in Stockholm. Slides from the specimens were restained for their estrogen receptor content in 2014 and assessed by two independent breast cancer pathologists. They scored the heterogeneity of estrogen receptor distribution as high, medium, or low, and Dr. Lindström and her associates calculated a hazard ratio for 25-year patient survival when they compared 593 specimens with high or low receptor heterogeneity. They adjusted the hazard ratios for several baseline variables including age, year of breast cancer diagnosis, HER2 status, Ki67 status, tumor grade, tumor size, randomization to tamoxifen or placebo treatment, and other factors.
“Routine clinical assessment of intratumor heterogeneity of estrogen receptor may identify patients at high long-term risk for fatal breast cancer that may potentially change clinical management, especially for patients with luminal A subtype tumors,” Dr. Lindström said.“I’d like to see the C statistic; will the prognostic model improve significantly with this added?” Dr. Linn wondered. “We need at least two more independent validations.”
The second biomarker study used two separate analyses of pSTAT3 expression. The first involved specimens collected from 3,074 patients with luminal breast cancer. Analysis of pSTAT3 gene signature expression showed that, the higher the expression levels were, associated with better relapse-free survival during follow-up out to as long as 8 years, reported Amir Sonnenblick, MD, an oncologist at the Sharret Institute of Oncology of Hadassah-Hebrew University Medical Center in Jerusalem.
Univariate analysis showed that binary pSTAT3 expression (positive or negative) significantly correlated with 10-year overall survival, with a hazard ratio of 0.66 (P = .04) for patients with positive expression, compared with those with no pSTAT3 expression, Dr. Sonnenblick said.
“pSTAT3 is associated with improved outcome in estrogen receptor–positive breast cancer. Future trials should take pSTAT3 status into account,” he concluded.
Dr. Linn cautioned that pSTAT3 expression should not be used to identify patients who can forgo chemotherapy, as the gene signature expression analysis showed that, even among patients with high pSTAT3 expression, long-term survival was still less than 90%.
Dr. Lindström and Dr. Sonnenblick had no disclosures. Dr. Linn has been an adviser to AstraZeneca, Cergentis, IBM Health, Novartis, Pfizer, Phillips Health, Roche, and Sanofi.
[email protected]
On Twitter @mitchelzoler
AT IMPAKT 2017 BREAST CANCER CONFERENCE
Key clinical point:
Major finding: High estrogen-receptor heterogeneity linked with worse outcomes; pSTAT3 expression linked with better outcomes.
Data source: A total of 593 patients enrolled in the Stockholm Adjuvant Tamoxifen trial, and 610 patients enrolled in the Breast International Group 2-98 trial.
Disclosures: Dr. Lindström and Dr. Sonnenblick had no disclosures. Dr. Linn has been an advisor to AstraZeneca, Cergentis, IBM Health, Novartis, Pfizer, Phillips Health, Roche, and Sanofi.
Biomarkers come up empty for ribociclib targeting
BRUSSELS – The inability of researchers to find a biomarker that could flag a subgroup of breast cancer patients with increased responsiveness to ribociclib plus an aromatase inhibitor was “somewhat disappointing,” Philippe Bedard, MD, said at a breast cancer conference sponsored by the European Society for Medical Oncology.
Many patients who are candidates for this combination treatment, approved by the Food and Drug Administration in March 2017 for postmenopausal women with advanced breast cancer that is hormone receptor positive and HER2 negative, could also do just as well on an aromatase inhibitor alone, said Dr. Bedard, of the Princess Margaret Cancer Centre in Toronto.
“The only validated marker for response to a cyclin-dependent kinase 4/6 inhibitor [such as ribociclib] is hormone receptor positivity. The bottom line is that you can’t target to a more specific subgroup with a biomarker,” Dr. Bedard said in an interview.
The researchers who ran the study collected tumor specimens at baseline from all participants, and Fabrice André, MD reported results from analyses run for seven different biomarkers. The analysis looked at protein levels for three biomarkers – Rb, Ki67, and p16 – in 479, 463, and 405 patients respectively; messenger RNA levels for CCND1, CDKN2A, and ESR1 in 386 patients; and DNA mutational status for the PIKC3A gene in 573 patients. In all seven cases, responsiveness to ribociclib was roughly similar regardless of protein or RNA expression levels or the type of PIKC3A (wild or mutated) the tumor carried, reported Dr. André of the Gustave Roussy Cancer Institute in Villejuif, France. Additional biomarker studies on the MONALEESA-2 specimens are ongoing, he said.
[email protected]
On Twitter @mitchelzoler
Correction, 5/6/17: An earlier version of this article misstated the citation.
BRUSSELS – The inability of researchers to find a biomarker that could flag a subgroup of breast cancer patients with increased responsiveness to ribociclib plus an aromatase inhibitor was “somewhat disappointing,” Philippe Bedard, MD, said at a breast cancer conference sponsored by the European Society for Medical Oncology.
Many patients who are candidates for this combination treatment, approved by the Food and Drug Administration in March 2017 for postmenopausal women with advanced breast cancer that is hormone receptor positive and HER2 negative, could also do just as well on an aromatase inhibitor alone, said Dr. Bedard, of the Princess Margaret Cancer Centre in Toronto.
“The only validated marker for response to a cyclin-dependent kinase 4/6 inhibitor [such as ribociclib] is hormone receptor positivity. The bottom line is that you can’t target to a more specific subgroup with a biomarker,” Dr. Bedard said in an interview.
The researchers who ran the study collected tumor specimens at baseline from all participants, and Fabrice André, MD reported results from analyses run for seven different biomarkers. The analysis looked at protein levels for three biomarkers – Rb, Ki67, and p16 – in 479, 463, and 405 patients respectively; messenger RNA levels for CCND1, CDKN2A, and ESR1 in 386 patients; and DNA mutational status for the PIKC3A gene in 573 patients. In all seven cases, responsiveness to ribociclib was roughly similar regardless of protein or RNA expression levels or the type of PIKC3A (wild or mutated) the tumor carried, reported Dr. André of the Gustave Roussy Cancer Institute in Villejuif, France. Additional biomarker studies on the MONALEESA-2 specimens are ongoing, he said.
[email protected]
On Twitter @mitchelzoler
Correction, 5/6/17: An earlier version of this article misstated the citation.
BRUSSELS – The inability of researchers to find a biomarker that could flag a subgroup of breast cancer patients with increased responsiveness to ribociclib plus an aromatase inhibitor was “somewhat disappointing,” Philippe Bedard, MD, said at a breast cancer conference sponsored by the European Society for Medical Oncology.
Many patients who are candidates for this combination treatment, approved by the Food and Drug Administration in March 2017 for postmenopausal women with advanced breast cancer that is hormone receptor positive and HER2 negative, could also do just as well on an aromatase inhibitor alone, said Dr. Bedard, of the Princess Margaret Cancer Centre in Toronto.
“The only validated marker for response to a cyclin-dependent kinase 4/6 inhibitor [such as ribociclib] is hormone receptor positivity. The bottom line is that you can’t target to a more specific subgroup with a biomarker,” Dr. Bedard said in an interview.
The researchers who ran the study collected tumor specimens at baseline from all participants, and Fabrice André, MD reported results from analyses run for seven different biomarkers. The analysis looked at protein levels for three biomarkers – Rb, Ki67, and p16 – in 479, 463, and 405 patients respectively; messenger RNA levels for CCND1, CDKN2A, and ESR1 in 386 patients; and DNA mutational status for the PIKC3A gene in 573 patients. In all seven cases, responsiveness to ribociclib was roughly similar regardless of protein or RNA expression levels or the type of PIKC3A (wild or mutated) the tumor carried, reported Dr. André of the Gustave Roussy Cancer Institute in Villejuif, France. Additional biomarker studies on the MONALEESA-2 specimens are ongoing, he said.
[email protected]
On Twitter @mitchelzoler
Correction, 5/6/17: An earlier version of this article misstated the citation.
EXPERT ANALYSIS FROM IMPAKT 2017 BREAST CANCER CONFERENCE
Key clinical point:
Major finding: Hazard ratio benefits from ribociclib plus letrozole, compared with letrozole alone, were similar regardless of the levels of seven biomarkers.
Data source: Exploratory analysis of tumor specimens collected from 668 patients with breast cancer enrolled in the MONALEESA-2 study.
Disclosures: MONALEESA-2 was sponsored by Novartis, the company that markets ribociclib (Kisqali). Dr. Bedard has received honoraria from Novartis, Pfizer, Roche, and Sanofi, and he has received research funding from Novartis and several other companies. Dr. André has received research funding from Novartis, AstraZeneca, Lilly, and Pfizer.