CLINICAL TRIAL / NCT07046923

Inclusion Criteria: * Have one of the following advanced or metastatic solid tumor cancers: * Non-small cell lung cancer (NSCLC) * Small cell lung cancer (SCLC) * Endometrial cancer * Triple negative breast cancer (TNBC) (characterized by HR-negative disease and HER2-negative expression according to American Society of Clinical Oncology (ASCO) - College of American Pathologists guidelines). * Received all standard therapies for which the individual was deemed to be an appropriate candidate by the treating investigator; OR the individual is refusing the remaining most appropriate standard of care treatment; OR there is no standard therapy available for the disease. * Eastern Cooperative Oncology Group (ECOG) performance status of ≤1. * For dose optimization/dose and expansion cohorts (Cohort A2, Cohort B): Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Exclusion Criteria: * Prior treatment with a protein tyrosine kinase 7 (PTK7) antibody-drug conjugate (ADC) with a topoisomerase I inhibitor as payload (prior therapy with a PTK7 ADC with a non-topoisomerase I inhibitor payload OR non-PTK7 ADC with any payload is permitted). * Any serious unresolved toxicities from prior therapy. * Individual with known or suspected history of uncontrolled central nervous system (CNS) metastases. * Individual with active uncontrolled systemic bacterial, viral, fungal, or parasitic infection. * Significant cardiovascular disease. * Prolongation of QT interval corrected for heart rate using Fridericia's formula (QTcF) > 470 milliseconds (ms) * History of pneumonitis/interstitial lung disease. * Individuals who are pregnant, breastfeeding, or plan to breastfeed during the trial or within 30 days of the last dose of trial intervention.