In December 2022, the FDA approved Rezlidhia (olutasidenib; from Forma Therapeutics), a new oral IDH1 inhibitor, for adults with relapsed (coming back) or refractory (not responding to therapy) acute myeloid leukemia (AML) and a susceptible IDH1 mutation, as detected by an FDA-approved test, which was approved on the same day.
This approval was based on an open-label, single-arm, multicenter clinical trial that included 147 patients with relapsed or refractory AML and an IDH1 mutation. Patients received Rezlidhia twice daily until disease progression, unacceptable side effects, or having a transplant. The average duration of treatment with Rezlidhia was 4.7 months, and 16 patients had a transplant after receiving this new medication.
Overall, 32% of the patients had complete remission with Rezlidhia and 2.7% of the patients had complete remission with partial hematologic recovery. The average duration of complete remission or complete remission with hematologic recovery was 25.9 months.
Of the 86 patients who were receiving red blood cell and/or platelet transfusions before the start of the study, 29 patients no longer needed transfusions during any 56 days after starting treatment. Of the 61 patients who did not need transfusions at the beginning of the study, 39 patients remained transfusion-free during any 56 days after starting treatment with Rezlidhia.
The most common side effects reported with Rezlidhia were nausea, fatigue/malaise, arthralgia, constipation, leukocytosis, dyspnea, fever, rash, mucositis, diarrhea, and transaminitis. Rezlidhia is associated with serious risk for differentiation syndrome, which can be fatal.
