Olutasidenib (FT-2102) in patients with relapsed or refractory IDH1-mutant glioma: a multicenter, open-label, phase 1b/2 trial.

Abstract

Olutasidenib (FT2102) is a highly potent, orally bioavailable, brain-penetrant and selective inhibitor of mutant isocitrate dehydrogenase 1 (IDH1). The aim of the study was to determine the safety and clinical activity of olutasidenib in patients with relapsed/refractory gliomas harboring an IDH1 R132X mutation. This was an open-label, multicenter, non-randomized, phase 1b/2 clinical trial. Eligible patients (≥18 years) had histologically confirmed IDH1 R132Xmutated glioma that relapsed or progressed on or following standard therapy and had measurable disease. Patients received olutasidenib, 150 mg orally twice daily (BID) in continuous 28-day cycles. The primary endpoints were dose-limiting toxicities (DLTs) (cycle 1) and safety in phase 1 and objective response rate using the Modified Response Assessment in Neuro-Oncology criteria in phase 2. Twenty-six patients were enrolled and followed for a median 15.1 months (7.3‒19.4). No DLTs were observed in the single-agent glioma cohort and the pharmacokinetic relationship supported olutasidenib 150 mg BID as the recommended phase 2 dose. In the response-evaluable population, disease control rate (objective response plus stable disease) was 48%. Two (8%) patients demonstrated a best response of partial response and eight (32%) had stable disease for at least 4 months. Grade 3‒4 adverse events (≥10%) included alanine aminotransferase increased and aspartate aminotransferase increased (three [12%], each). Olutasidenib 150 mg BID was well tolerated in patients with relapsed/refractory gliomas harboring an IDH1 R132X mutation and demonstrated preliminary evidence of clinical activity in this heavily pretreated population.