A Phase 1/1b Study of IAM1363 in HER2 Cancers

This is a Phase 1/1b open-label, multi-center study, designed to evaluate IAM1363 in participants with advanced cancers that harbor HER2 alterations. This study consists of the following 4 parts: * Part 1 (Monotherapy Dose Escalation) * Part 2 (Dose Optimization) * Part 3 (Dose Expansion) * Part 4 (Combination Cohorts) Part 1 will enroll participants with a confirmed, relapsed/refractory malignancy with documented diagnosis of HER2 alterations including participants with brain metastases. Once a provisional maximum tolerated dose (MTD)/recommended Phase 2 dose (RP2D) has been determined, Part 2 will enroll additional cohorts to optimize dose selection and to further evaluate the safety and preliminary efficacy of IAM1363. Following completion of Dose Optimization, Part 3 will be opened to enroll tumor-specific cohorts utilizing a Simon 2-Stage Minimax Design to evaluate IAM1363 at the selected dose(s). Part 4 will enroll 4 cohorts of participants who will receive IAM1363 in combination with other anti-cancer agents.