Clinical Research Directory

Inclusion Criteria: * Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, 2 * Histological diagnosis including but not limited to one of the following advanced solid tumors: * Part A * Extended stage small cell lung cancer (ES-SCLC) * High-grade neuroendocrine neoplasms (NENs) * G3 neuroendocrine tumor (NET) and neuroendocrine carcinoma (NEC, pulmonary and extrapulmonary) * Non-squamous non-small cell lung cancer (NSCLC) * Colorectal cancer * Part B * Cohort B1: ES-SCLC * Cohort B2: Non-squamous NSCLC * Other Part B cohorts: Cohort-specific disease indication may include those listed under Part A above * Participants must have disease that is considered to be incurable and meet the appropriate criteria below: * Part A: * ES-SCLC: Participants must have received, or be ineligible to receive, prior platinum-based chemotherapy and a programmed cell death-1/programmed death-ligand 1 (PD-\[L\]1) monoclonal antibody. * Other tumor types, with Medical Monitor approval: Participants must have received, or be ineligible to receive, available SOC treatments, or have no satisfactory SOC treatment options available. * Part B: * Cohort B1 (ES-SCLC): * Participants must have received, or be ineligible to receive, prior platinum-based chemotherapy and a PD-\[L\]1 monoclonal antibody. * Cohort B2 (non-sq NSCLC): * Participants must have previously received, or be ineligible to receive, platinum-based chemotherapy and a PD-\[L\]1 monoclonal antibody. Participants with a known actionable biomarker(s) must have been treated with at least one prior appropriate available targeted therapy. * Other Part B cohorts: Criteria will be specified based on the disease indications selected. * Participants must have measurable disease as per RECIST v1.1 * Participants must have adequate organ function. Exclusion Criteria: * Previously treated with an ADC with a DNA topoisomerase inhibitor (TOP1) payload * Note: Participants with non-squamous NSCLC who have received up to one prior ADC with a TOP1 inhibitor payload are eligible. Participants with other tumor types previously treated with an ADC with a TOP1 inhibitor payload may be eligible if approved by the Medical Monitor. * History of an anaphylactic reaction to TOP1 inhibitors or TOP1-inhibiting ADCs. * Known active central nervous system (CNS) metastases and/or carcinomatous meningitis * Known history of another primary malignancy, unless the participant has undergone potentially curative therapy with no evidence of recurrence and/or negligible risk of metastatic disease and death and consulted with the Medical Monitor.