AMG 757 and AMG 404 in Subjects With Small Cell Lung Cancer (SCLC)

Inclusion Criteria:

* Participant has provided informed consent/assent prior to initiation of any study specific activities/procedures
* Age greater than or equal to 18 years old at the same time of signing the informed consent
* Participants with histologically or cytologically confirmed Small Cell Lung Cancer (SCLC) who progressed or recurred following at least 1 platinum-based regimen
* Eastern Cooperative Oncology Group (ECOG) 0 to 1
* Participants with treated brain metastases are eligible provided they meet defined criteria
* Adequate organ function as defined in protocol

Exclusion Criteria:

* History of other malignancy within the past 2 years with exceptions
* Major surgery within 28 days of first dose of tarlatamab
* Untreated or symptomatic brain metastases and leptomeningeal disease
* Prior anti-cancer therapy, including anti-PD1 or anti-PDL1 antibody therapy: at least 28 days must have elapsed between any prior anti-cancer therapy and the first planned dose of tarlatamab

Exceptions:

* Participants who received prior chemotherapy must have completed at least 14 days before the first dose of tarlatamab and all treatment-related toxicity resolved to grade ≤ 1.
* Participants who received prior palliative radiotherapy must have completed at least 7 days before the first dose of tarlatamab

  * Participants who received prior tarlatamab therapy or prior delta-like ligand 3 (DLL3) x cluster of differentiation 3 (CD3) bispecific therapy are not eligible
  * Participants who experienced recurrent grade 2 pneumonitis or severe or life-threatening immune-mediated adverse events or infusion-related reactions including those that lead to permanent discontinuation while on treatment with immuno-oncology agents
  * History of any immune-related colitis. Infectious colitis is allowed if evidence of adequate treatment and clinical recovery exists and at least 3 months interval observed since diagnosis of colitis
  * Participants with evidence of interstitial lung disease or active, non-infectious pneumonitis
  * 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
  * History of solid organ transplantation
  * History of hypophysitis or pituitary dysfunction
  * Active autoimmune disease that has required systemic treatment (except replacement therapy) within the past 2 years or any other diseases requiring immunosuppressive therapy while on study. Participants with Type I diabetes, vitiligo, psoriasis, hypo- or hyper-thyroid disease not requiring immunosuppressive treatment are permitted