A Study to Evaluate DJI136, a DLL3-targeted CAR-T Therapy

Inclusion Criteria: * Phase I: Patients with ES-SCLC and disease progression after one or more chemotherapy regimens (that included a platinum-based doublet chemotherapy in combination with a PD-L1 inhibitor) according to the local SOC (2L+), unless the patient was ineligible to receive such therapies or was not a candidate for any available standard therapy, according to the investigator's judgement. Prior DLL3 (Delta-like ligand 3) targeted therapy is allowed. * Phase II: Patients with ES-SCLC who have received a platinum-based doublet chemotherapy in combination with a PD-L1 inhibitor according to local standard of care, unless the patient was ineligible to receive such therapies or was not a candidate for any available standard therapy, as determined by the investigator's judgment. Prior DLL-3 targeted therapy is not allowed. * Male or female patients must be ≥ 18 years of age. * Histologically or cytologically confirmed small cell lung cancer (SCLC). * At least one measurable lesion as defined by Response Evaluation Criteria in Solid Tumors (RECIST 1.1). * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Patients must have an archival tumor tissue available, collected within 6 months prior to screening. If an archival tumor sample, collected within 6 months prior to screening, is not available, patients must be willing to undergo a new tumor biopsy at screening; , however this specimen need not be collected prior to scheduling leukapheresis. If a new biopsy is not medically feasible, exceptions may be considered after documented discussion with the Novartis medical monitor. * Patient must be deemed suitable by the investigator to undergo the lymphodepletion (LD) regimen. * Patient must have an apheresis product of non-mobilized cells accepted for manufacturing. Exclusion Criteria: * Prior administration of a genetically modified cellular product, including prior DLL3-targeted CAR-T cell therapy. * Unstable or symptomatic central nervous system (CNS) metastases and/or carcinomatous meningitis. Stable brain metastases may participate provided they meet the specific criteria. * Uncontrolled seizure disorder. * Clinically significant active infections, including Hepatitis B/C and Human Immunodeficiency Virus (HIV). * Has a known additional malignancy that is progressing or requires active treatment, with specific exceptions as defined in the study protocol. * History of prior solid organ transplant or allogenic hematopoietic cell transplant * Other significant pulmonary, cardiac, hepatic, renal or neurologic disease, parameters for which are defined in the study protocol. * Pregnant or nursing women. Other protocol-defined inclusion/exclusion criteria may apply.