The Evaluation of PC14586 in Patients With Advanced Solid Tumors Harboring a TP53 Y220C Mutation (PYNNACLE)

Inclusion Criteria: * At least 18 years of age or 12 to 17 years of age after Safety Review Committee approval. * Locally advanced or metastatic solid malignancy with a TP53 Y220C mutation * Eastern Cooperative Oncology Group (ECOG) status of 0 or 1 * Previously treated with one or more lines of anticancer therapy and progressive disease * Adequate organ function * Measurable disease per RECIST v1.1 (Phase 2) Additional Criteria for Inclusion in Phase 1b (rezatapopt) + pembrolizumab combination) * Anti-PD-1/PD-L1 naive or must have progressed on treatment * Measurable disease Exclusion Criteria: * Anti-cancer therapy within 21 days (or 5 half-lives) of receiving the study drug * Radiotherapy within 14 days of receiving the study drug * Primary CNS tumor * History of leptomeningeal disease or spinal cord compression * Brain metastases, unless neurologically stable and do not require steroids to treat associated neurological symptoms * Stroke or transient ischemic attack within 6 months prior to screening * Heart conditions such as unstable angina within 6 months prior to screening, uncontrolled hypertension, a heart attack within 6 months prior to screening, congestive heart failure, prolongation of QT interval, or other rhythm abnormalities * Strong CYP3A4 inducers and strong CYP2C9 inhibitors/inducers within 14 days of first dose of rezatapopt * History of gastrointestinal (GI) disease that may interfere with absorption of study drug or patients unable to take oral medi…