A Phase 1/2 Study of GEN1286 in Patients With Advanced Solid Tumors

The purpose of this trial is to evaluate the safety, tolerability, pharmacokinetics (PK), anti-tumor activity and immunogenic potential of GEN1286 in participants with advanced solid tumors. This trial consists of 2 parts: * Part A: Dose escalation and dose level expansion * Part B: Tumor-specific expansion with dose optimization

Key Inclusion Criteria: * Participants must be ≥ 18 years of age at the time of informed consent; have measurable disease according to RECIST 1.1; Eastern Cooperative Oncology Group (ECOG) performance status (PS) score of 0 or 1; adequate organ, bone marrow, liver, coagulation, and renal function; and be willing to provide a pretreatment tumor specimen. * All participants must have pathologically confirmed diagnosis of advanced solid tumor. * Participants must have metastatic or unresectable locally advanced, recurrent disease not amenable to further local therapy and must have previously received therapies known to confer clinical benefit (unless ineligible to receive, refused to receive, or therapy is unavailable in the region). Key Exclusion Criteria: \- Prior treatment with topoisomerase 1-based antibody-drug conjugate (ADC) therapy. Note: Other protocol-defined inclusion and exclusion criteria may apply.