BACKGROUND: Nivolumab was the first immune checkpoint inhibitor approved for previously treated advanced non-small cell lung cancer (NSCLC). Before its introduction in the market, nivolumab was made available to NSCLC patients through an expanded access program (EAP). Here we present the Italian cohort of patients with non-squamous NSCLC enrolled in a worldwide nivolumab EAP, with subgroup analyses involving elderly patients, patients with central nervous system (CNS) metastases and patients receiving nivolumab beyond progression. METHODS: Pretreated patients with advanced non-squamous NSCLC received nivolumab at 3Â mg/kg every 2 weeks up to 24 months. Efficacy data (investigator-assessed tumour response, progression date and survival) and safety data were collected. FINDINGS: 1588 patients were treated across 153 Italian centres. Overall response rate and disease control rate were 18% and 44%, respectively; median overall survival (OS) was 11.3 months (95% CI: 10.2-12.4). Elderly patients (â‰¥70 nÂ =Â 522; â‰¥75 nÂ =Â 232) achieved outcomes similar to the global study population; patients with CNS metastases (nÂ =Â 409) had an OS of 8.6 months (95% CI: 6.4-10.8), and a 1-year OS rate of 43%. Nivolumab was administered beyond progression to 276 patients (26%), 57 of whom achieved subsequent disease control; the median OS of patients receiving nivolumab beyond progression was 16.2 months (95% CI: 14.0-18.4), while 1-year OS rate was 62%. INTERPRETATION: To date, this is the largest clinical experience with nivolumab in a real-world setting. Our data support its use in clinical practice for pretreated non-squamous NSCLC, including patients with older age or CNS metastases.