Nivolumab (Nivo) vs Investigator's Choice (IC) for Platinum-Refractory (PR) Recurrent or Metastatic (R/M) Squamous Cell Carcinoma of the Head and Neck (SCCHN; CheckMate 141): Outcomes in First-line (1L) R/M Patients (Pts) and Updated Safety and Efficacy

6019Background: In CheckMate 141, a randomized, phase 3 trial, nivo demonstrated superior overall survival (OS) and better tolerability in patients (pts) with PR R/M SCCHN compared with IC. Pts with SCCHN progressing within 6 mos of platinum in the primary treatment setting have dismal prognosis. We report outcomes in pts who were PR in the primary or adjuvant setting, and updated results in the overall population. Methods: Pts (N = 361) with PR R/M SCCHN were randomized 2:1 to nivo 3 mg/kg every 2 weeks or weekly IC (methotrexate, docetaxel, or cetuximab). Primary endpoint was OS estimated by Kaplan-Meier method. Cox proportional hazards models were used to estimate hazard ratios (HRs) and confidence intervals (CIs). Additional endpoints include objective response rate (ORR) and safety. Outcomes were analyzed overall and post hoc in pts who were PR in the primary/adjuvant setting and received nivo/IC as 1L R/M therapy. Results: Characteristics of the 78 (21.6%) pts who received nivo (n = 52) or IC (n = 2...