A Phase 1 Study of CPO301 in Adult Patients With Advanced or Metastatic Solid Tumors

The goal of this clinical trial is to test CPO301, a type of drug called an antibody drug conjugate in adult patients with advanced or metastatic solid tumors. The main questions it aims to answer are: * To assess the safety and tolerability of CPO301 at increasing doses and determine the dose to be used in the second part of the study (Part A) * To assess the safety and tolerability of CPO301 at the dose determined to be safe and tolerable in Part A in patients with Non-Small Cell Lung Cancer and potentially other tumor types (Part B) * To evaluate how quickly CPO301 is metabolized by the body (pharmacokinetics or PK) * To evaluate if antibodies to the study drug develop (immunogenicity) * To evaluate preliminary efficacy to the drug * To correlate preliminary efficacy with mutations in a biomarker called EGFR Participants will: * Provide written informed consent * Undergo screening tests to ensure they are eligible for study treatment * Attend all required study visits and receive CPO301 by intravenous injection every 3 weeks until the study doctor determines study treatment should be stopped, based on how well a participant is doing on treatment * Be followed for progression every 3 months for up to 2 years