Safety and Efficacy Findings From a Phase Ib/II Study of ASP-1929 Photoimmunotherapy With Pembrolizumab in Recurrent and/or Metastatic Head and Neck Squamous Cell Carcinoma

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 ther- apy). Primary objectives were safety/tolerability and objective response rate (ORR). Secondary objectives included overall sur- vival (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