Study of Low-Dose Radiotherapy (LDRT) Concurrent Cisplatin/Carboplatin Plus Etoposide With Atezolizumab for Patients With Extensive-Stage Small Cell Lung Cancer

Prior treatment

• Significant cardiovascular disease within 3 months prior to initiation of study treatment, unstable arrhythmia, or unstable angina

Other illness

• History of leptomeningeal disease
• Active or history of autoimmune disease or immune deficiency
• History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, or idiopathic pneumonitis, or evidence of active pneumonitis on screening chest computed tomography (CT) scan
• Active tuberculosis
• History of malignancy other than small cell lung cancer (SCLC) within 5 years prior to initiation of study treatment, with the exception of the cancer under investigation in this study and malignancies with a negligible risk of metastasis or death

Other

• Symptomatic, untreated, or actively progressing central nervous system (CNS) metastases
• Uncontrolled tumor-related pain
• Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures
• Uncontrolled or symptomatic hypercalcemia

• Histologically or cytologically confirmed ES-SCLC
• No prior treatment for ES-SCLC
• Measurable disease, as defined by RECIST v1.1. Previously irradiated lesions can be considered as measurable disease only if progressive disease has been unequivocally documented at that site since radiation.
• ECOG performance status of 0 or 1
• Life expectancy \>= 3 months
• Adequate hematologic and end-organ function
• For participants receiving therapeutic anticoagulation: stable anticoagulant regimen
• Negative human immunodeficiency virus (HIV) test at screening
• Negative hepatitis B surface antigen (HBsAg) test at screening
• Positive hepatitis B surface antibody (HBsAb) test at screening, or negative HBsAb at screening accompanied by either of the following: Negative total hepatitis B core antibody (HBcAb), or positive total HBcAb test followed by a negative hepatitis B virus (HBV) DNA test. The HBV DNA test must be performed for participants who have a negative HBsAg test, a negative HBsAb test, and a positive total HBcAb test.
• Negative hepatitis C virus (HCV) antibody test at screening, or positive HCV antibody test followed by a negative HCV RNA test at screening. The HCV RNA test must be performed for participants who have a positive HCV antibody test.
• For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraception
• For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use a condom, and agreement to refrain from donating sperm