A Trial for the Treatment of Advanced Large-Cell Neuroendocrine Cancer of the Lung

Inclusion Criteria: (main criteria) 1. Patient has provided written informed consent and is able to consent 2. Patients with pulmonary large-cell neuroendocrine carcinoma (LCNEC) defined by local histology and immunohistochemistry; patients with mixed histology are eligible if LCNEC is the predominant histology, i.e. ≥50% 3. Patients with locally advanced or metastatic disease without curative treatment options 4. All patients must have received one, but not more than one, cycle of platinum/etoposide chemotherapy with or without immune checkpoint inhibitor (standard-of-care; SoC). Other than that, patients must be previously untreated with systemic therapy. 5. Measurable disease according to RECIST v1.11 Exclusion Criteria: (main criteria) 1. Symptomatic brain metastases (Patients with asymptomatic brain metastases are allowed provided they are clinically stable, receiving no or a stable dose of anticonvulsants without steroid treatment for at least 3 weeks.) 2. Known leptomeningeal disease 3. Any prior systemic treatment for metastatic disease, except for one cycle of SoC as described under inclusion criteria 4. Previous treatment with obrixtamig or any anti-DLL3 compound including T-cell engagers and antibody-drug conjugates