Vorasidenib in Combination With Temozolomide (TMZ) in IDH-mutant Glioma

The objective of this study is to determine the safety and tolerability of vorasidenib in combination with temozolomide (TMZ) and to establish the recommended combination dose (RCD) of vorasidenib. The study will begin as a Phase Ib study to determine the RCD and then will transition to a Phase II study to assess the clinical efficacy of vorasidenib at the RCD in combination with TMZ. During the treatment period participants will have study visits on day 1 and 22 of each cycle, with additional visits occurring during the first cycle of the Phase 1b study. Approximately 30 days after treatment has ended, a safety follow-up visit will occur and then participants will be followed for survival every 3 months. Study visits may include questionnaires, blood tests, ECG, vital signs, and a physical examination.