A Phase 1, Open-label Dose Escalation and Dose-Expansion Study Evaluating the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Preliminary Efficacy of D3L-001 Monotherapy in Subjects With HER2-Positive Advanced Solid Tumors.

Inclusion Criteria: * Subject must have documented HER2 positivity (determined by immunohistochemistry \[IHC\], in situ hybridization \[ISH\], Next Generation Sequencing \[NGS\] or other analysis techniques as appropriate). * Subject must have Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Subject must have left ventricular ejection fraction (LVEF) ≥50% by either echocardiography (ECHO) or multiple-gated acquisition (MUGA) within the screening period. * Subject must have adequate organ and marrow function within the screening period. Exclusion Criteria: * Subject…