INTRODUCTION: The objective of the Lung-MAP sub-study S1400A was to evaluate the response rate to durvalumab, an anti-programmed death-ligand 1 (PD-L1) antibody, in patients with squamous non-small-cell lung cancer (SqNSCLC). PATIENTS AND METHODS: Patients who progressed on at least 1 prior platinum-based chemotherapy were eligible. The study was designed as a phase II/III trial comparing durvalumab with docetaxel but was modified to a single-arm, phase II trial with the primary endpoint of objective response when immunotherapy became an approved treatment. RESULTS: A total of 116 patients were registered to this sub-study; 78 to durvalumab and 38 to docetaxel. Of the 78 patients, 9 were ineligible, and 1 was not evaluable for endpoints. Responses were achieved in 11 patients among the 68 eligible and evaluable patients on durvalumab (overall response rate, 16%; 95% confidence interval [CI], 7%-25%). The disease control rate was 54% (95% CI, 43%-66%), the median overall survival was 11.6 months (95% CI, 10.2-14.3 months), and the median progression-free survival was 2.9 months (95% CI, 2.0-4.0 months). PD-L1 data was available for 43 patients on durvalumab, with 14 (33%) patients who were PD-L1-positive (≥ 25%) and 2 responses (overall response rate, 14%; 95% CI, 0%-33%), the disease control rate was 57% (95% CI, 31%-83%), the median overall survival and progression-free survival were 10.7 months (95% CI, 9.2-14.3 months) and 2.3 months (95% CI, 1.4-4.2 months), respectively. Grade ≥ 3 treatment-related adverse events occurred in 22 (32%) patients on durvalumab, with 6 discontinuing owing to drug-related adverse events (9%; 95% CI, 2%-16%). CONCLUSIONS: Durvalumab shows single-agent activity and toxicities in this sub-group of patients that is comparable with other anti-programmed cell death protein 1/PD-L1 antibodies.