• Have a histopathological diagnosis (fresh or banked tumor biopsy sample collected within the last 3 years) consistent with locally advanced or metastatic conventional chondrosarcoma Grades 1, 2, or 3 and not eligible for curative resection.

• Have at least one BICR-confirmed measurable lesion as defined by RECIST v1.1. Participants who have received prior radiation therapy are eligible provided measurable disease falls outside of the treatment field or within the field and has shown ≥20% growth in size since post-treatment assessment.

• Have received 0 or 1 prior systemic treatment regimen in the advanced/metastatic setting for chondrosarcoma.

• Have radiographic progression/recurrence of disease according to RECIST v1.1 defined as:

‣ Radiographic progression of disease (local and/or distant) documented by 2 imaging assessments performed no more than 6 months (±2 weeks) apart within 12 months before randomization.

‣ OR

⁃ Any recurrence of disease (local and/or distant) after complete surgical resection and documented by imaging within 6 months (±2 weeks) before randomization.

• Have documented IDH1 gene-mutated disease (from a fresh tumor biopsy or the most recent banked tumor tissue available that was sourced from either a primary or metastatic tumor lesion) based on central laboratory testing (R132C/L/G/H/S mutation variants tested)

• Have recovered from any clinically relevant sequelae and toxic effects of any prior surgery, radiotherapy, or other therapy intended for the treatment of cancer.