Safety, Preliminary Effectiveness of BNT327, an Investigational Therapy for Patients With Small-cell Lung Cancer in Combination With Chemotherapy

Inclusion Criteria (applicable to all participants unless otherwise specified): * Cohort 1 only: Have histologically or cytologically confirmed ES-SCLC (using the American Joint Committee on Cancer \[AJCC\]) tumor node metastasis \[TNM\] staging system combined with Veterans Administration Lung Study Group two-stage classification scheme). For AJCC TNM staging system: AJCC 8th edition stage IV (T any, N any, M1a/b/c), or T3\~4 for multiple lung nodules or tumor/nodule volume that cannot be encompassed in a tolerable radiotherapy plan. * Cohort 1 only: Participants who have not received systemic therapy for ES-SCLC for various reasons including potential intolerance of the standard-of-care per the patient's treating physician's judgment. However, participants with prior chemoradiotherapy for Limited-Stage Small-Cell Lung Cancer (LS-SCLC) must have been treated with curative intent and had a treatment-free interval of at least 6 months since the last systemic anticancer treatment including chemotherapy, radiotherapy, or chemoradiotherapy before the diagnosis of ES-SCLC to be eligible. * Cohort 2 and Cohort 3 only: Participants with SCLC who have disease progression/relapse after first-line platinum-based chemotherapy with or without immunotherapy, or after first-line platinum-based chemotherapy and one second-line of chemotherapy (not the same chemotherapy agent in the specific arm to be enrolled to) with time to progression ≥3 months during second-line treatment. * Have given…