ELVN-002 in HER2 Mutant Non-Small Cell Lung Cancer

Inclusion Criteria: Phase 1a Monotherapy Dose Escalation and Exploration: * Pathologically documented advanced stage solid tumor * Progressed following all standard treatment or not appropriate for standard treatment * HER2 mutation, HER2 amplification or HER2 positive based on local testing Phase 1b Monotherapy * Pathologically documented unresectable and/or metastatic non-squamous NSCLC * HER2 mutation identified by tissue (fresh or archival) or ctDNA. Local testing for up to 20 patients the remainder centrally confirmed. * Measurable disease * No known epidermal growth factor receptor (EGFR), ROS1, anaplastic lymphoma kinase (ALK), or BRAF V600E mutation * Progressed after receiving at least 1 prior systemic therapy including a platinum-based chemotherapy with or without immunotherapy, or not appropriate for standard treatment. * No prior HER2 tyrosine kinase inhibitor. Prior HER2 directed antibodies or anti-body drug conjugates are allowed * No limit on prior number of therapies Phase 1a Combination with T-DXd * Pathologically documented advanced stage NSCLC * Progressed after receiving at least 1 prior systemic therapy. * HER2 mutation based on local/historical testing of tissue or circulating tumor DNA * No known EGFR, ROS1, ALK, or BRAF V600E mutation * No prior T-DXd * No clinically severe pulmonary compromise * No limit on prior number of therapies Phase 1a Combination Breast Cancer * Documented HER2 positive (Immunohistochemical \[IHC\] 3+ or IHC2+/in situ h…