Study Evaluating Safety, Tolerability and Pharmacokinetics (PK) of Tarlatamab in Adults With Small Cell Lung Cancer (SCLC)

Inclusion Criteria:

1. Participant has provided informed consent prior to initiation of any study-specific activities/procedures
2. Age greater than or equal to 18 years old at the time of signing the informed consent
3. Histologically or cytologically confirmed SCLC. For parts A, C, D, E, F, and G: relapsed/refractory small cell lung cancer (R/R SCLC) who progressed or recurred following platinum-based regimen
4. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2
5. Participants with treated brain metastases are eligible provided they meet defined criteria
6. Adequate organ function as defined in protocol

Exclusion Criteria:

1. History of other malignancy within the past 2 years prior to first dose of tarlatamab with exceptions
2. Major surgery within 28 days of first dose tarlatamab
3. Untreated (includes new lesions or progression in previously treated lesions) or symptomatic brain metastases and leptomeningeal disease (regardless of symptomatic or not).
4. Prior anti-cancer therapy: at least 28 days must have elapsed between any prior anti-cancer therapy and first dose of tarlatamab with the following exceptions: participants who received conventional chemotherapy are eligible if at least 14 days have elapsed and if all treatment-related toxicity has been resolved to Grade less than or equal to 1; and prior palliative radiotherapy must have been completed at least 7 days before the first dose of tarlatamab
5. Participants who experienced severe, life-threatening or recurrent (Grade 2 or higher) immune-mediated AEs or infusion-related reactions including those that lead to permanent discontinuation while on treatment with immune-oncology agents
6. Has evidence of interstitial lung disease or active, non-infectious pneumonitis
7. Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of tarlatamab
8. Part C only: history of solid organ transplantation or active autoimmune disease that has required systemic treatment within the past 2 years
9. Participant with symptoms and/or clinical signs and/or radiographic signs that indicate an acute and/or uncontrolled active systemic infection within 7 days prior to the first dose of investigational product administration