Overview

This is a randomized, open-label study of Serplulimab plus chemotherapy (Carboplatin-Etoposide) in comparison with Atezolizumab plus chemotherapy in previously untreated US patients with ES-SCLC.

Subjects in this study will be randomized to arm A or B at 1:1 ratio as follows:

• Arm A (Serplulimab): Serplulimab + chemotherapy (carboplatin-etoposide)
• Arm B (control): Atezolizumab + chemotherapy (carboplatin-etoposide)

Eligibility

Inclusion Criteria:

Voluntary participation in clinical studies.

Male or female aged ≥ 18 years at the time of signing the ICF.

        Histologically or cytologically diagnosed with ES-SCLC (according to the Veterans
        Administration Lung Study Group staging system).
        No prior systemic therapy for ES-SCLC.
        At least one measurable lesion as assessed according to RECIST 1.1 within 4 weeks prior to
        randomization.
        Major organs are functioning well.
        Every effort should be made to provide tumor tissues for the determination of PD-L1
        expression.
        An ECOG PS score of 0 or 1.
        An expected survival ≥ 12 weeks.
        Subjects with prior denosumab use that can and agree to switch to bisphosphonate therapy
        for bone metastases starting prior to randomization and throughout treatment.
        Participant must keep contraception.
        Exclusion Criteria:
        Histologically or cytologically confirmed mixed SCLC.
        Known history of severe allergy to any monoclonal antibody.
        Known hypersensitivity to carboplatin or etoposide.
        Patients with myocardial infarction within half a year before the first dose of the study
        drug, poorly controlled arrhythmia.
        Pregnant or breastfeeding females.
        Patients with a known history of psychotropic drug abuse or drug addiction.
        Patients who have other factors that could lead to the early termination of this study
        based on the investigator's judgment.