A Study of Ladiratuzumab Vedotin in Advanced Solid Tumors

This trial is designed to assess the antitumor activity, safety, and tolerability of LV alone and with pembrolizumab, for the treatment of solid tumors. Participants with the following advanced solid tumors will be enrolled: Cohort 1: small cell lung cancer (SCLC) Cohort 2: non-small cell lung cancer-squamous (NSCLC-squamous) Cohort 3: non-small cell lung cancer-nonsquamous (NSCLC-nonsquamous) Cohort 4: head and neck squamous cell carcinoma (HNSCC) Cohort 5: esophageal squamous cell carcinoma (esophageal-squamous) Cohort 6: gastric and gastroesophageal junction (GEJ) adenocarcinoma Cohort 7: castration-resistant prostate cancer (CRPC) Cohort 8: melanoma Participants will continue to receive study treatment until disease progression, unacceptable toxicity, investigator decision, consent withdrawal, study termination by the sponsor, pregnancy, or death, whichever comes first.