1047PDPembrolizumab for recurrent head and neck squamous cell carcinoma (HNSCC): Post hoc analyses of treatment options from the phase III KEYNOTE-040 trial. (23rd October 2018) - Le Tourneau, C; Cohen, E E W; Harrington, K J; Dinis, J; Licitra, L; Ahn, M -J; Soria, A; Machiels, J-P; Mach, N; Mehra, R; Burtness, B; Zhang, P; et al.