Safety and Efficacy of BMS-986504 in Unresectable Malignant Peripheral Nerve Sheath Tumor

Inclusion Criteria: * Male or female participants ≥ 12 years of age at the time of screening. * Ability to understand and willingness to sign documentation of informed consent if ≥ 18 years of age or documentation of assent if 12-17 years of age. * Pathohistological verification of MPNST. * Measurable disease (size of primary tumor and metastatic lesions can be trended by CT or MRI scans). * Unresectable (locally advanced or metastatic) disease. * Confirmation of homozygous MTAP deletion by next generation sequencing * Recovery from the adverse effects of prior therapy at the time of enrollment to baseline or ≤ Grade 1 (excluding alopecia, peripheral neuropathy, and parameters superseded by other eligibility criteria \[eg, hematology parameters\]). Note: Participants with prior endocrine adverse effects are permitted to enroll if they are stably maintained on appropriate replacement therapy and are asymptomatic. * Recovery from the acute toxic effects (≤ grade 1 as defined by the National Cancer Institute Common Terminology Criteria for Adverse Events v5.0) of all prior chemotherapy prior to the entering study (exceptions: alopecia, anorexia, mass pain). * Normal marrow function and recovery of blood cell counts from any myelosuppressive chemotherapy prior to entering study: * Peripheral absolute neutrophil count (ANC) ≥ 1500/mcL (microliter). * Hemoglobin ≥ 9 g/dL (packed red blood cell transfusion is not allowed up to 14 days prior to starting BMS-986504 treatmen…