Study of Atezolizumab Plus Carboplatin and Etoposide With or Without Tiragolumab in Participants With Untreated Extensive-Stage Small Cell Lung Cancer

The purpose of this multicenter study in China is to evaluate the safety and efficacy of tiragolumab plus atezolizumab and carboplatin and etoposide (CE) compared with placebo plus atezolizumab and CE in participants with untreated extensive-stage small cell lung cancer.

Inclusion Criteria: * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 * Histologically or cytologically confirmed Extensive-Stage Small Cell Lung Cancer (ES-SCLC) per the modified Veterans Administration Lung Study Group (VALG) staging system * No prior systemic treatment for ES-SCLC * For participants who have received prior chemoradiotherapy for limited-stage SCLC must have had treatment with curative intent and a treatment-free interval of at least 6 months between the last dose/cycle of chemotherapy, thoracic radiotherapy, or chemoradiotherapy and the diagnosis of ES-SCLC * Measurable diseases as defined by RECIST v1.1 * Submission of a pre-treatment tumor tissue sample * Adequate hematologic and end-organ function * Participants not receiving therapeutic anticoagulation with International Normalized Ratio (INR) and Activated Clotting Time (aPTT) \