659MO Pembrolizumab with or without chemotherapy for first-line treatment of recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC): 5-year results from KEYNOTE-048

Long-term follow-up (4 years) of the phase 3 KEYNOTE-048 (NCT02358031) study continued to demonstrate survival benefit with pembrolizumab monotherapy and pembrolizumab + chemotherapy vs EXTREME in first-line R/M HNSCC. Pembrolizumab showed significantly longer OS vs EXTREME in PD-L1 CPS ≥1. Given that pembrolizumab + chemotherapy or pembrolizumab for CPS ≥1 is standard of care for first-line R/M HNSCC in the United States, outcomes with extended follow-up are of interest. We present 5 years of follow-up in all patients (pts) from KEYNOTE-048.