Background: Avelumab, a human anti–PD-L1 IgG1 monoclonal antibody, is an approved treatment for metastatic Merkel cell carcinoma in various countries and platinum-treated advanced urothelial carcinoma in the US. In phase 1b studies, avelumab has shown antitumor activity and acceptable safety in patients with advanced NSCLC. Here, we report long-term data for avelumab in patients (pts) with platinum-treated NSCLC. Methods: In a phase 1b cohort of JAVELIN Solid Tumor (NCT01772004), pts with stage IIIB–IV NSCLC unselected for PD-L1 status, with progression after platinum doublet therapy, received avelumab 10 mg/kg Q2W as second-line (2L) or later treatment until confirmed progression, unacceptable toxicity, or withdrawal. PD-L1 expression was assessed using PD-L1 IHC 73-10 assay. Time-to-event endpoints were estimated using Kaplan-Meier methods. Results: 184 pts received avelumab. At data cutoff on Feb 15, 2017, median follow-up was 33.9 months (range, 31.0-40.7) and 9 pts (4.9%) remained on treatment. 58 pts (31.5%) had received ≥2 prior lines of therapy for advanced disease. The objective response rate (ORR) was 14.1% (95% CI, 9.4-20.0), including complete response in 1.1%, and median duration of response was 17.5 months (95% CI, 6.9-21.4). Progression-free survival (PFS) rates at 6 months and 1 yr (95% CI) were 24.2% (18.1-30.8) and 16.5% (11.3-22.5). Overall survival (OS) rates at 1 and 2 yrs (95% CI) were 42.5% (35.1-49.7) and 25.0% (18.7-31.8). In evaluable pts with PD-L1+ (n = 122) and PD-L1− (n = 20) tumors ( > 1% tumor cell cutoff), ORR (95% CI) was 16.4% (12.1-21.5) vs 10.0% (2.7-24.5), the 1-yr PFS rate was 19.1% (12.3-27.0) vs 5.0% (0.3-20.5), median OS was 11.1 (8.4-17.3) vs 4.6 (2.8-12.5) months, and the 2-yr OS rate was 30.0% (21.7-38.7) vs 17.1% (4.4-37.0), respectively. Safety findings were consistent with earlier analyses; 14.7% had a grade ≥3 treatment-related adverse event, most commonly ( > 1%) infusion-related reaction (2.2%), lipase increase (1.6%), and pneumonitis (1.1%), and no treatment-related deaths occurred. Conclusions: Avelumab as 2L or later therapy is associated with durable responses and long-term OS in pts with platinum-treated advanced NSCLC. Clinical trial information: NCT01772004