The main objective of the study is to compare the efficacy of tarlatamab in combination with durvalumab, carboplatin and etoposide to the combination of durvalumab, carboplatin and etoposide on prolonging overall survival (OS).

Inclusion Criteria:

• Participant has provided informed consent before initiation of any study-specific activities/procedures.
• Age ≥ 18 years or ≥ legal age within the country if it is older than 18 years.
• Histologically or cytologically documented ES-SCLC (American Joint Committee on Cancer, 2017, Stage IV SCLC [T any, N any, M1 a/b/c]), or T3 to T4 due to multiple lung nodules that are too extensive or have tumor/nodal volume that is too large to be encompassed in a tolerable radiation plan.
• Measurable disease as defined per RECIST 1.1.
• Suitable to receive carboplatin, etoposide and durvalumab regimen as first-line treatment per investigator clinical assessment.
• Minimum life expectancy ≥ 12 weeks.

Exclusion Criteria:

• Participants can have no history of other malignancy in the last 2 years.
• Any symptomatic central nervous system (CNS) metastases, or leptomeningeal disease.
• They will have no history of severe or life-threatening events to immune-mediated therapy.
• History of arterial thrombosis (eg, stroke or transient ischemic attack) within 6 months prior to first dose of study treatment.
• They will have no active autoimmune or inflammatory disorders.
• Presence of active human immunodeficiency virus (HIV) or active Hepatitis (B/C) infection.
• Evidence or interstitial lung disease (ILD) or active, non-infectious pneumonitis.
• History of solid organ transplant.
• They will not have had a myocardial infarction and/or symptomatic congestive heart failure (New York Heart Association > class II) within 6 months prior to first dose of study treatment.

De-identified individual patient data for variables necessary to address the specific research question in an approved data sharing request.

Data sharing requests relating to this study will be considered beginning 18 months after the study has ended and either 1) the product and indication have been granted marketing authorization in both the US and Europe or 2) clinical development for the product and/or indication discontinues and the data will not be submitted to regulatory authorities. There is no end date for eligibility to submit a data sharing request for this study.

Qualified researchers may submit a request containing the research objectives, the Amgen product(s) and Amgen study/studies in scope, endpoints/outcomes of interest, statistical analysis plan, data requirements, publication plan, and qualifications of the researcher(s). In general, Amgen does not grant external requests for individual patient data for the purpose of re-evaluating safety and efficacy issues already addressed in the product labelling. Requests are reviewed by a committee of internal advisors. If not approved, a Data Sharing Independent Review Panel will arbitrate and make the final decision. Upon approval, information necessary to address the research question will be provided under the terms of a data sharing agreement. This may include anonymized individual patient data and/or available supporting documents, containing fragments of analysis code where provided in analysis specifications. Further details are available at the URL below.