(Concerto) Study of BLU-451 in Advanced Cancers With EGFR Exon 20 Insertion Mutations

INCLUSION CRITERIA: All participants: * Documented EGFR mutation, based on Next-generation sequencing (NGS) testing of tumor or liquid biopsy analyzed in a local Clinical Laboratory Improvement Amendments (CLIA) (or International Organization for Standardization (ISO) 15189)-certified or equivalent laboratory are required. Redacted copies of laboratory results must be available for Sponsor review. * Able to provide a new or archived pretreatment formalin-fixed, paraffin-embedded (FFPE) tumor sample. For participants who received EGFR-targeted therapy subsequent to the most recent archived biopsy, all efforts should be made to obtain a new biopsy unless it is not safe or feasible to obtain one. * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. * Participants must be without seizures for at least 14 days prior to enrollment, and patients who receive treatment with anti-epileptic drugs must be on stable doses for at least 14 days prior to enrollment. * Adequate hematological, renal, and hepatic function: Participants in Phase 1 * Histologically or cytologically confirmed metastatic NSCLC (stage IVA and IVB per American Joint Committee on Cancer (AJCC) 8th edition) or other metastatic cancers except for primary CNS tumors (Part 1A or Part 2 only). * Must have evaluable or measurable disease per RECIST v1.1. * Progression on or after or intolerance to most recent systemic therapy. Participants in Phase 2 * Histologically or cytologically confirmed metastatic NSCLC (stage IVA and IVB per AJCC 8th edition). * Must have measurable disease by RECIST 1.1. EXCLUSION CRITERIA: * Have disease that is suitable for local therapy administered with curative intent. * Have tumor that harbors known driver alterations (including, but not limited to ROS, BRAF V600E, ALK, RET, HER2, MET, KRAS, NTRK1/2/3, EGFR C797X, or EGFR T790M mutation). These criteria are not applicable to Phase 1 Part 1B. * Have NSCLC with mixed cell histology or a tumor with known histologic transformation (NSCLC to SCLC, SCLC to NSCLC, or epithelial to mesenchymal transition). Other protocol-defined inclusion and exclusion criteria apply