Thorne, Amy Haseley

ABSTRACT Background ASP‐1929 photoimmunotherapy—cetuximab conjugated to IRDye 700DX and red light (690 nm) for localized drug activation—results in rapid, selective cell killing. Methods This phase Ib/II open‐label study evaluated ASP‐1929 photoimmunotherapy plus pembrolizumab in patients with recurrent/metastatic HNSCC (≥ 1 accessible lesion, PD‐L1 combined positive score ≥ 1, ineligible for standard locoregional therapy). Primary objectives were safety/tolerability and objective response rate (ORR). Secondary objectives included overall survival (OS) and progression‐free survival (PFS). Results Eighteen patients (median age 63 years, 74% male) comprised the photoimmunotherapy‐evaluable population. The confirmed ORR was 27.8% (95% CI 9.7–53.5); four of five responders had complete responses (95% CI, 6.4–47.6). Median OS was 25.6 months (95% CI, 14.6–not evaluable); median PFS was 2.9 months (95% CI, 1.4–14.6). The most common serious adverse reactions were dysphagia and tongue edema (each n = 2; 10.5%). Conclusions ASP‐1929 photoimmunotherapy plus pembrolizumab was generally tolerable, with promising efficacy in patients with recurrent/metastatic HNSCC.