Study CA2450001 is a randomized, double-blind, 2 arm, multicenter Phase 3 trial to compare the efficacy and safety of BMS-986489 in combination with chemotherapy (induction) followed by BMS-986489 maintenance vs atezolizumab in combination with chemotherapy (induction) followed by atezolizumab maintenance as 1L therapy in participants with ES-SCLC.

A. BMS-986489 in combination with carboplatin plus etoposide Q3W (induction) followed by BMS-986489 maintenance Q4W (Arm A)
B. Atezolizumab in combination with carboplatin plus etoposide Q3W (induction) followed by atezolizumab as maintenance Q4W (Arm B).

Overall Survival (OS= time from randomization until death from any cause)

a. Must have a diagnosis of Extensive-Stage Small Cell Lung Cancer (ES-SCLC). This is a type of lung cancer that has spread widely in the body.
b. Must be healthy enough to do normal activities with little or no help. This is based on the ECOG performance scale, which is a way to measure how well a
person can perform daily activities. (ECOG PS of 0 or 1)
c. Must have at least one tumor that can be measured using special imaging techniques like a CT scan or MRI. The tumor must be located in a place other than
the brain and nervous system.
Imaging CT-scan (area thorax & abdomen) preferably with contrast performed within 28 days prior to randomization can be used for screening.
d. Participants with CNS metastases are eligible if CNS metastases are asymptomatic and do not require immediate treatment, or have been treated and
participants have neurologically returned to baseline (except for residual signs or symptoms related to the CNS treatment). In addition, participants must
have been either off corticosteroids, or on a stable or decreasing dose of ≤ 10 mg daily prednisone (or equivalent) for a least 2 weeks prior to randomization.
Imaging performed within 28 days prior to randomization must document radiographic stability of CNS lesions and be performed after completion of any
CNS-directed therapy.

a. Patients who have a different type of cancer than Extensive-Stage Small Cell Lung Cancer (ES-SCLC) cannot participate. This is a specific type of lung cancer that has spread widely in the body.
b. Patients who are not in the age range specified for the study cannot participate. The study is open to certain age groups only.
c. Patients who are part of a vulnerable population, which means they might need special protection or care, cannot participate.
d. Patients who are not eligible for the specific treatment plan being tested in the study cannot participate.