Encouraging clinical activity with observed deepening of responses in 35 evaluable first line head and neck patients treated with HB-200 plus pembrolizumab In a subset of 17 evaluable patients with PD-L1 combined positive score (CPS) of 20 or higher, the Company's selected registrational pivotal trial population, data showed confirmed ORR of 53%, CR rate of 18%, and DCR of 82% Preliminary progression-free survival (PFS) was 16.3 months and preliminary overall survival (OS) rate was 88% at 9 months for the C ...