MK-3475 - (KEYNOTE-048)

July 21, 2026: Alpha Tau Medical Ltd. (NASDAQ: DRTS, DRTSW) announced positive results from a single-center, prospective, open-label, single-arm study of Alpha DaRT plus pembrolizumab (Keytruda) in elderly patients with recurrent unresectable or metastatic head and neck squamous cell carcinoma (HNSCC) with PD-L1 CPS ≥1. Data are being presented as a podium presentation at the American Head and Neck Society (AHNS) 12th International Conference on Head and Neck Cancer (July 18–22, 2026; Boston).

Among nine evaluable patients (11 enrolled; two died before response assessment from causes described as unrelated), systemic ORR was 100% (4 complete responses, 5 partial responses; CR rate 44%) by RECIST v1.1. Median overall survival was 18.2 months and median progression-free survival was 5.4 months; four patients were alive at analysis. The release compares these outcomes to historical pembrolizumab monotherapy benchmarks from KEYNOTE-048 (ORR ~19%, OS 12.3 months, PFS ~3.2 months).

Safety: no Alpha DaRT-related serious adverse events; two Alpha DaRT-related AEs, both Grade 1. Recruitment is complete, and the trial met its Simon two-stage success criterion (>6 responses), allowing enrollment to stop early. The company states it is discussing with the U.S. FDA the possibility of a similar but larger U.S. study.