Adjuvant Chemotherapy and Immunotherapy for Completely Resected Small Cell Lung Cancer

Inclusion Criteria: * Age ≥ 18 years. * Body weight \>30 kg. * Must have a life expectancy of at least 12 weeks. * Must have histologically or cytologically confirmed diagnosis of pathologic T1-T2 N0-1 M0 small-cell lung cancer per the American Joint Committee on Cancer staging system, 8th edition. * Have completely resected (wedge resection, segmentectomy, lobectomy, sleeve lobectomy, bilobectomy, or pneumonectomy) small-cell lung cancer within 78 days of enrollment. * Complete mediastinal lymph node dissection (MLND) or systematic mediastinal lymph node sampling is required. * No prior systemic therapies, for small cell lung cancer. * Post-operative radiation for the resected small cell lung cancer is acceptable per treating physician in the setting of N1 disease, but no other prior radiation for small cell lung cancer. * ECOG performance status 0-1. Exclusion Criteria: * Patients who are receiving any other investigational agents. * Concurrent enrollment in another clinical study involving investigational treatment directed to treatment of patients with small cell lung cancer. * Prior treatment with durvalumab. * History of another primary malignancy except for: * Malignancy treated with curative intent and with no known active disease ≥2 years before the first dose of IP and of low potential risk for recurrence. * Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease. * Superficial bladder cancer without active disease after treatment. * Low grade prostate cancer without indication for active treatment. * Adequately treated carcinoma in situ without evidence of disease. * Patients with a history of cerebrovascular accident including transient ischemic attack (TIA), pulmonary embolism or insufficiently treated deep venous thrombosis (DVT) within the past 3 months. * Patients with hemoptysis in excess of 2.5 mL within 2 weeks prior to the first dose of study medication. * Patients requiring concomitant therapy with phenytoin, phenobarbital, or carbamazepine.