Defining a response
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Single-agent therapy with decitabine elicited favorable responses in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) who had cytogenetic abnormalities associated with an unfavorable risk profile, a study showed.

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The current study raises the important question of the definition of a response. Complete remission conventionally entails bone marrow with less than 5% blasts and normalization of blood counts; absent these, remission is considered incomplete. After various confounding factors are taken into account, a complete response with cytotoxic therapy is associated with longer remissions and longer survival than is complete remission with incomplete count recovery.

The authors of this paper considered a response to be blast clearance to less than 5%, but complete remission was seen in only 4 of the 21 patients with TP53 mutations who fulfilled this criterion. The mutant allele burden was also similar in patients who had a response, regardless of blood count recovery.

In contrast, measurable residual disease is considerably more frequent in patients with complete remission with incomplete count recovery than in patients with complete remission who have received cytotoxic therapy, indicating that more data are needed on subsequent clinical outcomes according to whether clearance of blasts is accompanied by count recovery in patients with AML and TP53 mutations who have received decitabine.

AML “targeted-therapy” trials typically involve one drug, and this policy is called into question by the diverse molecular architecture (and brief remissions) observed in this trial. The trial by Welch et al. points to inevitable, rational replacement of large trials in which homogeneous therapy is administered for a heterogeneous disease by smaller, subgroup-specific trials.

The article also suggests questions that are likely to complicate this future.

Dr. Elihu Estey is with the division of hematology, University of Washington Medical Center, and the clinical research division, Fred Hutchinson Cancer Research Center, Seattle. He had no disclosures. These remarks were taken from an editorial accompanying Dr. Welch’s paper (N Engl J Med. 2016;375:2023-36).

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The current study raises the important question of the definition of a response. Complete remission conventionally entails bone marrow with less than 5% blasts and normalization of blood counts; absent these, remission is considered incomplete. After various confounding factors are taken into account, a complete response with cytotoxic therapy is associated with longer remissions and longer survival than is complete remission with incomplete count recovery.

The authors of this paper considered a response to be blast clearance to less than 5%, but complete remission was seen in only 4 of the 21 patients with TP53 mutations who fulfilled this criterion. The mutant allele burden was also similar in patients who had a response, regardless of blood count recovery.

In contrast, measurable residual disease is considerably more frequent in patients with complete remission with incomplete count recovery than in patients with complete remission who have received cytotoxic therapy, indicating that more data are needed on subsequent clinical outcomes according to whether clearance of blasts is accompanied by count recovery in patients with AML and TP53 mutations who have received decitabine.

AML “targeted-therapy” trials typically involve one drug, and this policy is called into question by the diverse molecular architecture (and brief remissions) observed in this trial. The trial by Welch et al. points to inevitable, rational replacement of large trials in which homogeneous therapy is administered for a heterogeneous disease by smaller, subgroup-specific trials.

The article also suggests questions that are likely to complicate this future.

Dr. Elihu Estey is with the division of hematology, University of Washington Medical Center, and the clinical research division, Fred Hutchinson Cancer Research Center, Seattle. He had no disclosures. These remarks were taken from an editorial accompanying Dr. Welch’s paper (N Engl J Med. 2016;375:2023-36).

Body

 

The current study raises the important question of the definition of a response. Complete remission conventionally entails bone marrow with less than 5% blasts and normalization of blood counts; absent these, remission is considered incomplete. After various confounding factors are taken into account, a complete response with cytotoxic therapy is associated with longer remissions and longer survival than is complete remission with incomplete count recovery.

The authors of this paper considered a response to be blast clearance to less than 5%, but complete remission was seen in only 4 of the 21 patients with TP53 mutations who fulfilled this criterion. The mutant allele burden was also similar in patients who had a response, regardless of blood count recovery.

In contrast, measurable residual disease is considerably more frequent in patients with complete remission with incomplete count recovery than in patients with complete remission who have received cytotoxic therapy, indicating that more data are needed on subsequent clinical outcomes according to whether clearance of blasts is accompanied by count recovery in patients with AML and TP53 mutations who have received decitabine.

AML “targeted-therapy” trials typically involve one drug, and this policy is called into question by the diverse molecular architecture (and brief remissions) observed in this trial. The trial by Welch et al. points to inevitable, rational replacement of large trials in which homogeneous therapy is administered for a heterogeneous disease by smaller, subgroup-specific trials.

The article also suggests questions that are likely to complicate this future.

Dr. Elihu Estey is with the division of hematology, University of Washington Medical Center, and the clinical research division, Fred Hutchinson Cancer Research Center, Seattle. He had no disclosures. These remarks were taken from an editorial accompanying Dr. Welch’s paper (N Engl J Med. 2016;375:2023-36).

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Defining a response
Defining a response

 

Single-agent therapy with decitabine elicited favorable responses in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) who had cytogenetic abnormalities associated with an unfavorable risk profile, a study showed.

 

Single-agent therapy with decitabine elicited favorable responses in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) who had cytogenetic abnormalities associated with an unfavorable risk profile, a study showed.

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Key clinical point: Decitabine induced short-term clinical remissions in patients with AML who had TP53 mutations and tended to be highly resistant to treatment.

Major finding: Of 116 patients, 53 (46%) experienced bone marrow blast clearance (less than 5% blasts), and response rates were higher among those with an unfavorable cytogenetic risk profile.

Data source: A prospective single-center clinical trial that evaluated single-agent decitabine in 84 adult patients with AML or MDS, with an extension cohort.

Disclosures: The study was supported by the Specialized Program of Research Excellence in AML of the National Cancer Institute and the Genomics of AML Program Project. Dr. Welch had no disclosures, and several of his coauthors reported relationships with industry.