Participants with relapsed rather than refractory AML, as well as females, were more likely to get a durable response from the oral IDH1 inhibitor olutasidenib (Rezlidhia), according to a new analysis of pivotal trial data.
The drug was evaluated in a phase II registrational study in IDH1-mutated relapsed/refractory AML or myelodysplastic syndromes (NCT02719574). In the study, the complete remission (CR)/CR with partial hematologic recovery (CRh) rate was 35%, with a median CR/CRh duration of 25.9 months, supporting US approval in 2022.
In an analysis presented at ASCO 2026, Justin Watts, MD, of the University of Miami and colleagues explored what baseline factors, including sex, disease stage and molecular characteristics, were associated with longer-term responders who did not go on to receive a transplant.
Out of 147 evaluable patients in the registrational study, 51 had achieved CR/CRh, of which 26 responded for more than 12 months and did not get a transplant.
Researchers found that disease status at the time of enrollment (relapsed vs refractory) and sex (female) were associated with the likelihood of maintaining a benefit for more than 12 months in multivariable analyses (OR, 0.19 and OR, 0.21, respectively).
They did not find differences in the likelihood to get a >12 month benefit based on the type of IDH1 variant, the presence of non-IDH1 mutations (eg, DNMT3A, NPM1), age, number of prior therapies or dependence on transfusions at baseline.
The longest response in the cohort of patients with Cr/CRh for more than 12 months without going on to transplant was 54 months, researchers reported.
Reference
Watts J, Jonas B, Pigneux A, et al. Association of acute myeloid leukemia (AML) patient, disease, and molecular characteristics with a long-term (LT) response to olutasidenib. Abstract #6523. Presented at the 2026 ASCO Annual Meeting; May 29-June 2, 2026; Chicago.
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