Safety and Efficacy Study of Safusidenib in Participants With IDH1-Mutant Glioma Who Discontinued Vorasidenib Treatment Due to Progressive Disease

Key Inclusion Criteria: * Histologically confirmed Grade 2 or 3 IDH-mutant astrocytoma or IDH-mutant and 1p19q co-deleted oligodendroglioma, according to WHO CNS 2021 criteria * IDH1 mutation (e.g., R132H/C/G/S/L) based on immunohistochemistry (IHC) (R132H only), PCR, or next generation sequencing (NGS). * Have had at least 1 prior surgery for glioma (biopsy, sub-total resection, or gross total resection). * Measurable disease per modified RANO 2.0 confirmed by BICR during Screening. * Previously treated with vorasidenib and experienced radiographic disease progression during treatment and are not in need of immediate chemotherapy or radiotherapy in the opinion of the Investigator. Disease progression must be confirmed by BICR using modified RANO 2.0. * Adequate hematologic and organ function * Expected survival of ≥12 months Key Exclusion Criteria: * Any prior anticancer therapy other than surgery (biopsy, sub-total, or gross total resection) and vorasidenib for treatment of glioma. * Discontinued vorasidenib for toxicity or any reason other than radiographic disease progression * Prior treatment with anti-angiogenic agents such as Avastin (bevacizumab) or investigational agents for glioma. * Brainstem or spinal cord involvement either as primary location, site of multifocal involvement, or by significant tumor extension. * Significant functional or neurocognitive deficits, including uncontrolled seizures * Evidence of leptomeningeal disease. * Use of therapeutic doses of steroids for signs/symptoms of glioma. Participants taking physiologic doses (defined as equivalent of \<1.5 mg of dexamethasone equivalent) for medical conditions not related to glioma will be permitted.