Alpha Tau Medical Ltd. (Nasdaq: DRTS, DRTSW) announced clinical study results showing a 100% objective response rate among nine evaluable elderly patients with locally advanced or metastatic head and neck squamous cell carcinoma (HNSCC) treated with its Alpha DaRT device in combination with pembrolizumab (Keytruda).

The results were presented at the American Head and Neck Society 12th International Conference on Head and Neck Cancer in Boston, Massachusetts, held July 18-22, 2026.

Among the nine evaluable patients, the combination produced four complete responses and five partial responses. Median overall survival was 18.2 months and median progression-free survival was 5.4 months. For comparison, pembrolizumab monotherapy in a similar population in the KEYNOTE-048 trial produced an objective response rate of approximately 19%, a median overall survival of 12.3 months, and median progression-free survival of approximately 3.2 months. Direct comparisons between unrelated clinical studies should be made with caution due to differences in study designs and patient populations.

The single-center, prospective, open-label study enrolled 11 patients with a mean age of 72 years. Two patients died before response evaluation could be completed. The trial used a Simon two-stage adaptive design and was permitted to stop for success once more than six patients responded, a threshold that was met.

No Alpha DaRT-related serious adverse events were observed. Only two Alpha DaRT-related adverse events were reported, both Grade 1 in severity.

The study was conducted at Hadassah University Medical Center in Jerusalem, Israel. Alpha Tau stated it is in ongoing discussions with the U.S. Food and Drug Administration regarding a potential larger study in the United States.

Alpha Tau, founded in 2016, is an Israeli oncology company developing Alpha DaRT, a device that delivers alpha radiation into solid tumors via intratumoral radium-224 impregnated sources.