A Phase I Study to Evaluate the Safety,Tolerability, Pharmacokinetics, and Efficacy of YL211 in Patients With Advanced Solid Tumors

This is a multicenter, open-label, Phase 1 study. The study will enroll subjects with advanced solid tumors. It consists of three parts. Part 1 is dose-escalation part. In part 1, the safety and tolerability of YL211 in patients with selected advanced solid tumors will be evaluated and the MTD and RED will be determined. Part 2 is backfill enrollment part. We will further estimate the safety and efficacy of YL211 in patients with selected adcance tumor to select the RED(s) of YL211. Part 3 is dose-expansion part. In this part, we will further evaluate the safety and efficacy of YL211 at the MTD/RED(s) in patients with selected advanced solid tumors YL211 will be administered intravenously (IV) until criteria of treatment discontinuation are met.

Inclusion Criteria: 1. Informed of the trial before the start of the trial and voluntarily sign their name and date on the ICF. 2. Aged ≥18 years. 3. Be able and willing to comply with protocol visits and procedures. 4. History of an advanced solid tumors who failed currently available standard therapies and are not amenable to surgical resection, or for whom no available standard therapy or no other approved therapeutic options that have demonstrated clinical benefit. 5. Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1. 6. Adequate organ and bone marrow function. 7. Have at least 1 extracranial measurable tumor lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Exclusion Criteria: 1. Inadequate washout period for prior anticancer treatment before the first dose of study drug. 2. Uncontrolled or clinically significant cardiovascular and cerebrovascular diseases. 3. Clinically significant concomitant pulmonary disease. 4. Uncontrolled infection that requires systemic therapy within 2 weeks before the first dose. 5. Unresolved toxicities from previous anticancer therapy. 6. A history of severe hypersensitivity reactions to the drug substances, inactive ingredients in the drug product, or other monoclonal antibodies.