Pembrolizumab plus epacadostat in patients with recurrent/metastatic head and neck squamous cell carcinoma (KEYNOTE-669/ECHO-304): a phase 3, randomized, open-label study por Byoung Chul Cho, Irene Braña, Beatriz Cirauqui, Sercan Aksoy, Felix Couture, Ruey-Long Hong, Wilson H. Miller, Manuel Chaves-Conde, Margarida Teixeira, Lance Leopold, Mihaela Munteanu, Joy Yang Ge, Ramona F. Swaby, Brett G. M. Hughes