Rigel Pharma scores FDA approval for leukemia, kicking off showdown with Servier in IDH1
When Rigel Pharma bought olutasidenib from Forma Therapeutics, it acquired a drug that already secured a PDUFA date at the FDA — for February 2023. But regulators are ready to give their OK sooner than that.
The FDA has approved the IDH1 inhibitor as a treatment for adult patients with relapsed or refractory acute myeloid leukemia who have a susceptible IDH-1 (isocitrate dehydrogenase-1) mutation as detected by an FDA-greenlit test. Rigel will market it as Rezlidhia.
The OK puts Rigel in direct competition with Servier, which bought Agios’ Tibsovo — the first approved drug in the IDH1 class — and several other IDH-targeting programs as Agios offloaded its cancer pipeline.
Rigel touted a composite complete remission (CR) and complete remission with partial hematological recovery (CRh) rate of 35% — with a median duration of 25.9 months.
While Forma first developed Rezlidhia, it had long deemed the drug a non-core program. Rigel paid $2 million in cash to snag full rights, and promised Forma another $17.5 million soon upon meeting regulatory, approval and first commercial sales milestones. The rest of the $235 million deal is tied to future development and commercial work.