A Study of YL201 in Combination With Serplulimab in Participants With Treatment-naïve Extensive-stage Small Cell Lung Cancer

Prior treatment

• History of immune-related adverse events (irAEs) of CTCAE Grade ≥3 during prior immunotherapy, or unresolved adverse events from previous antitumor therapy.
• Major surgery (excluding diagnostic procedures) or severe trauma within 4 weeks prior to randomization or planned major surgery during the study period.
• History of interstitial lung disease (ILD) /pneumonitis requiring steroid treatment, or current diagnosis of ILD/pneumonitis, or concurrent pulmonary disease leading to clinically severe impairment of respiratory function.
• Active autoimmune or inflammatory diseases within 2 years prior to randomization.
• Severe infection within 4 weeks prior to randomization, or active infection requiring intravenous anti-infective therapy within 2 weeks or oral anti-infective therapy within 1 week prior to randomization.
• History of other primary malignancies within 5 years prior to randomization.
• Known hypersensitivity to any component of the investigational product.

Other illness

• History of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation.
• Presence of severe and uncontrolled cardiovascular or cerebrovascular disease.
• Known active tuberculosis or active syphilis infection.
• History of immunodeficiency or positive for human immunodeficiency virus (HIV) antibodies test.
• Active hepatitis B virus (HBV) or hepatitis C virus (HCV) infection. Participants with inactive HBV infection must receive antiviral therapy throughout the study.
• Any condition that, in the opinion of the investigator, would make the participant unsuitable for study participation.

Other

• Any histological types of transformed SCLC or combined SCLC.
• Presence of active brain metastases, brainstem metastases, or leptomeningeal metastases.
• Females who are pregnant or breastfeeding, or who plan to become pregnant or breastfeed during the study period.

• Voluntarily sign the written informed consent form and comply with the protocol requirements
• Age ≥18 years.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• Histologically or cytologically confirmed extensive-stage small cell lung cancer (ES-SCLC).
• No prior systemic treatment for ES-SCLC.
• At least one extracranial measurable lesion according to RECIST v1.1.
• Adequate organ function.
• Life expectancy ≥3 months.