Rigel Pharma announces publication of final 5-year data on Rezlidhia (olutasidenib) in patients with R/R mIDH1 AML in the Journal of Hematology & Oncology

Rigel Pharmaceuticals Inc. announced a peer-reviewed publication in the Journal of Hematology & Oncology of the final five-year data from the pivotal cohort of the Phase II registrational trial evaluating Rezlidhia  (olutasidenib) for the treatment of patients with relapsed or refractory (R/R) mutant isocitrate dehydrogenase-1 (mIDH1) acute myeloid leukemia (AML). Rezlidhia  is a potent, selective, oral, small-molecule inhibitor of mIDH1 that is approved for the treatment of R/R mIDH1 AML.

The publication reports the final follow-up analysis of the registrational Phase II trial, with an additional two years of efficacy and safety data. These five-year data further support the durable responses and manageable safety profile observed with olutasidenib in patients with R/R mIDH1 AML, including those R/R to prior venetoclax. The safety profile remained consistent with what was previously reported, with no new safety signals identified.

Additional key points from the paper include:

•iFor the overall population, the five-year safety profile of olutasidenib remained consistent, with no new safety signals identified compared to the three-year analysis, and no new cases of differentiation syndrome reported.

• • Of 147 efficacy evaluable patients, complete remission (CR) or CR with partial hematologic recovery (CRh) was achieved in 35%. The median duration of CR/CRh was 25.3 months. Overall response rate (ORR) was 48%, with median duration of 15.5 months. Median overall survival (OS) was 11.5 months.
• •Transfusion independence (for ≥56 days) from red blood cells was achieved in 34 patients (39%) who were dependent at baseline and for platelets was achieved in 28 patients (41%) who were dependent at baseline.
• •Among the 71 patients who achieved an overall response, 66% of patients achieved a response within 2 months, 24% required 2 to 4 months to respond and 10% required at least 4.6 (up to 10.2) months of therapy to achieve a response. Median OS was 32.7 months.
• •Patients with one to two prior regimens had a higher CR/CRh rate (41%), ORR (54%), and longer median OS (13 months) compared to those with ≥3 prior regimens (CR/CRh: 24%; ORR: 39%; median  OS: 8.9 months).
• •In the 12 patients that were R/R to prior venetoclax, 33% achieved a CR/CRh; median duration of CR/CRh was not reached (3 patients ongoing at 22.6, 36.9 and 50.6 months), and median OS was 16.2 months.
• The publication, titled “Olutasidenib for Mutated IDH1 Acute Myeloid Leukemia: Final Five-Year Results From the Phase 2 Pivotal Cohort,” was published online

“This long-term final analysis of olutasidenib reinforces the potential for olutasidenib in mIDH1 AML,” said Dr. Lisa Rojkjaer, Rigel’s chief medical officer. “The data to date demonstrates clinical benefit across a range of patients and underscores the importance of maintaining therapy for at least 6 months in the absence of toxicity or disease progression to optimize the ability to achieve a response.”.

“Since its launch, olutasidenib has become an important treatment option for patients with relapsed or refractory mIDH1 AML due to its clinical activity and durable responses, including patients previously treated with venetoclax who have particularly poor outcomes,” said Dr. Jorge E. Cortes, Phase II trial investigator and Director, Georgia Cancer Center, Cecil F. Whitaker Jr., GRA Eminent Scholar Chair in Cancer. “These incremental data support earlier findings and provide additional insights that further enhance the opportunity for olutasidenib to positively impact the outcome of patients with mIDH1 AML.”

See- Cortes J, Curti A, Fenaux PJ et al. Olutasidenib for mutated IDH1 acute myeloid leukemia: final five-year results from the phase 2 pivotal cohort. J Hematol Oncol  2025 Nov 14;18(1):102 doi: 10.1186/s13045-025-01751-w.