Background: EAGLE is a phase 3 study evaluating efficacy of D (anti-PD-L1 mAb) monotherapy and D+T (anti-CTLA-4 mAb) vs standard of care (SOC) in pts with R/M HNSCC who progressed following platinum-based therapy (NCT02369874). Methods: Pts were randomized 1:1:1 to D 10 mg/kg IV every 2 weeks (Q2W), D+T (D 20 mg/kg IV Q4W + T 1 mg/kg IV Q4W for 4 doses, then D 10 mg/kg IV Q2W), or SOC (investigator’s choice: cetuximab, taxane, methotrexate, or fluoropyrimidine-based regimen). The primary endpoint was overall survival (OS) with dual primary objectives of D+T vs SOC and D vs SOC. Additional endpoints included objective response rate (ORR), duration of response (DoR), and adverse events (AEs). Results: 240 pts were randomized to D, 247 to D+T and 249 to SOC. An imbalance for Eastern Cooperative Oncology Group performance status (ECOG PS) was seen in favor of the SOC arm (D, PS 0 = 26%, PS 1 = 74%; D+T, PS 0 = 26%, PS 1 = 74%; SOC, PS 0 = 32%, PS 1 = 68%). The risk of death was not statistically significantly different for D compared with SOC (HR: 0.88; 95% CI: 0.72–1.08; P = 0.20) or D+T vs SOC (HR: 1.04; 95% CI: 0.85–1.26; P = 0.76). Efficacy data are provided in the table. Treatment-related AEs Grade ≥3 were reported in 10.1% of pts (regardless of causality Grade ≥3 AEs were 41.4%) in the D arm, 16.3% (51.2%) for D+T, and 24.2% (44.2%) for SOC. Following treatment, 2% of pts in D, 5% in D+T and 15% in SOC received immunotherapy. Conclusions: D and D+T did not demonstrate a statistically significant improvement in OS compared to standard chemotherapy in pts with R/M HNSCC. Median OS and ORR of D arm were similar to other studies with checkpoint inhibitors. The SOC arm outperformed what has been seen for SOC arms in previous studies; subsequent immunotherapy may have confounded the OS analyses. The safety profile for D and D + T in R/M HNSCC is consistent with previous trials. Clinical trial information: NCT02369874