This ongoing single-arm, open-label multicenter dose expansion cohort enrolled pts with R/M HNSCC with a tumor PD-L1 CPS≥1... The ORR in stage 1 was 44% (8 PRs, 4 SD) with a clinical benefit rate (CBR=PR+SD) of 67%; 7/12 (58%)...Stage 1 of this dose expansion cohort of BCA101+P shows encouraging anti-tumor activity with additive potential, particularly among HPV-neg pts; and the combination is well tolerated among this R/M HNSCC population.