The study is divided into 2 phases, a Safety Lead-In phase and a randomized perioperative phase. In the Safety Lead-In Phase, the recommended combination dose (RCD) of vorasidenib will be determined. In the Randomized Perioperative Phase, the Lymphocytes infiltration in tumors will be evaluated following pre-surgical treatment with vorasidenib and pembrolizumab combination, compared to untreated control tumors. Prior to surgery, participants will be randomized to receive vorasidenib at the RCD in combination with pembrolizumab, or vorasidenib only, or no treatment (untreated control group). Following surgery, participants will have the option to receive treatment with vorasidenib in combination with pembrolizumab in 21-day cycles.~Study treatment will be administered until participant experiences unacceptable toxicity, disease progression, or other discontinuation criteria are met.
Vorasidenib in combination with pembrolizumab in participants with recurrent or progressive enhancing isocitrate dehydrogenase-1 (IDH-1) mutant astrocytomas.