Safety and Preliminary Activity of BI115 in Advanced SCLC

Inclusion Criteria： 1. Participants must be able to understand and sign the written informed consent form for participation in this trial, including all evaluations and procedures specified in this protocol. 2. Male or female participants aged ≥18 years and ≤75 years. 3. Participants with histologically or cytologically confirmed advanced small cell lung cancer. 4. At least one measurable lesion according to RECIST V1.1 within 28 days prior to the first dose of IBI115. 5. Eastern Cooperative Oncology Group (ECOG) performance status score of 0-1. 6. Expected survival period ≥12 weeks. 7. Adequate bone marrow and organ function confirmed during the screening period. Exclusion Criteria： 1. Concurrent participation in another interventional clinical study, except for observational non-interventional studies or being in the survival follow-up phase of an interventional study. 2. Administration of a live vaccine within 4 weeks prior to the first dose of the study drug or a cancer vaccine within 3 months prior, or planning to receive any live vaccine during the study period. 3. Adverse reactions from prior anti-tumor therapy that have not resolved to CTCAE v6.0 Grade 0, Grade 1, or baseline levels by the time of the first dose of the study drug. 4. Known hypersensitivity or intolerance to IBI115, sintilimab, or any of their excipients.