A Study to Evaluate the Safety, Pharmacokinetics, and Activity of Enzelkitug as a Single Agent and in Combination With Checkpoint Inhibitor in Participants With Locally Advanced or Metastatic Solid Tumors

This is a first-in-human study to evaluate the safety, tolerability, pharmacokinetics (PK), and anti-tumor activity of enzelkitug when administered as a single agent and in combination with atezolizumab or pembrolizumab in adult participants with locally advanced or metastatic solid tumors, including non small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), melanoma, triple-negative breast cancer (TNBC), esophageal cancer, gastric cancer, cervical cancer, colorectal cancer (CRC), urothelial carcinoma (UC), clear cell renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC). Participants will be enrolled in 2 stages: dose escalation and dose expansion.

Inclusion Criteria: * Life expectancy of at least 12 weeks * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Measurable disease according to Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1) * Histologically confirmed locally advanced, recurrent, or metastatic incurable solid tumor malignancy * Tumor specimen availability Exclusion Criteria: * Pregnant or breastfeeding or intention of becoming pregnant during the study or within 4 months after the final dose of enzelkitug, or 4 months after the final dose of pembrolizumab, or 5 months after the final dose of atezolizumab * Any anti-cancer therapy, whether investigational or approved, including chemotherapy, hormonal therapy, and/or radiotherapy, within 3 weeks prior to initiation of study treatment * Active hepatitis B (HBV) or hepatitis C (HCV) or tuberculosis * Positive test for human immunodeficiency virus (HIV) infection * Acute or chronic active Epstein-Barr virus (EBV) infection at screening * Administration of a live, attenuated vaccine (e.g., FluMist) within 4 weeks before first enzelkitug infusion * Symptomatic, untreated, or actively progressing central nervous system (CNS) metastases * Active or history of autoimmune disease * Prior allogeneic stem cell or organ transplantation