A Study of Carboplatin Plus Etoposide With or Without Atezolizumab in Participants With Untreated Extensive-Stage (ES) Small Cell Lung Cancer (SCLC)

Inclusion Criteria:

- Histologically or cytologically confirmed ES-SCLC (per the Veterans Administration
Lung Study Group [VALG] staging system)

- No prior systemic treatment for ES-SCLC

- Eastern Cooperative Oncology Group performance status of 0 or 1

- Measurable disease, as defined by RECIST v1.1

- Adequate hematologic and end organ function

- Treatment-free for at least 6 months since last chemo/radiotherapy, among those
treated (with curative intent) with prior chemo/radiotherapy for limited-stage SCLC

Exclusion Criteria:

- Active or untreated central nervous system (CNS) metastases as determined by computed
tomography (CT) or magnetic resonance imaging (MRI) evaluation

- Malignancies other than SCLC within 5 years prior to randomization, with the exception
of those with a negligible risk of metastasis or death treated with expected curative
outcome

- Pregnant or lactating women

- History of autoimmune disease

- History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced
pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening
chest CT scan. History of radiation pneumonitis in the radiation field (fibrosis) is
permitted.

- Positive test result for human immunodeficiency virus (HIV)

- Active hepatitis B or hepatitis C

- Severe infections at the time of randomization

- Significant cardiovascular disease

- Prior treatment with cluster of differentiation (CD) 137 agonists or immune checkpoint
blockade therapies, anti-programmed death-1 (PD-1), and anti-PD-L1 therapeutic
antibody

- History of severe (or known) hypersensitivity to chimeric or humanized antibodies or
fusion proteins or any component of atezolizumab formulation