BL-M14D1 Plus Atezolizumab vs Standard of Care in First-Line Extensive-Stage Small Cell Lung Cancer (BrenDeLL-Lung01)

Inclusion Criteria:

• Histologically or cytologically confirmed first-line (1L), extensive-stage (ES)small cell lung cancer (SCLC)

• Must be eligible to receive a platinum-based chemotherapy regimen in combinationwith an anti-PD-L1 inhibitor.

• At least one measurable lesion based on RECIST v1.1 per investigator assessment.

• An Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 to 1.

• Adequate organ function

Exclusion Criteria:

• Received any kind of platinum or etoposide treatment for limited stage (LS) SCLCwithin 6 months prior to enrollment.

• Participants who have received prior topoisomerase inhibitor-based ADC therapy.

• Participants with history of severe heart disease

• Participants with active autoimmune diseases and inflammatory diseases,

• Participants with other prior or concurrent malignancies except for basal cellcarcinoma of the skin, squamous cell carcinoma of the skin and/or carcinoma in situafter adequate resection, or other malignancy treated with curative intent with adisease-free interval of at least 3 years

• Other protocol-defined inclusion/exclusion criteria apply.