Merck’s drug cuts endometrial cancer death risk by 32%

Merck and partner Kelun‑Biotech presented results from a global Phase III trial of the antibody‑drug conjugate sacituzumab tirumotecan, called sac‑TMT, at the 2026 European Society for Medical Oncology conference in Madrid. The study enrolled 776 patients with advanced or recurrent endometrial cancer who had already been treated with platinum chemotherapy and PD‑1 or PD‑L1 immunotherapy. The data showed a 32 % reduction in the risk of death compared with standard chemotherapy. Investigators said the findings could change how patients with this difficult disease are treated.

Survival Improvement

In the randomized TroFuse‑005 trial, median overall survival was 19.0 months for patients receiving sac‑TMT, versus 12.1 months for those on chemotherapy, giving a hazard ratio of 0.68 (95 % CI 0.55‑0.84). Median progression‑free survival was 7.2 months for sac‑TMT, versus 3.9 months for chemotherapy, with a hazard ratio of 0.59 (95 % CI 0.50‑0.70). The overall response rate was 35.1 % for sac‑TMT, compared with 17.3 % for chemotherapy.

Treatment‑related adverse events were reported in 97.1 % of patients on sac‑TMT and 89.6 % on chemotherapy. Grade 3 or higher events occurred in 54.4 % of the sac‑TMT group and 41.4 % of the chemotherapy group. The most common serious side effects were anemia (23.7 %) and neutropenia (20.1 %), while oral mucositis or stomatitis was seen in 9.9 %. Discontinuations due to toxicity were lower for sac‑TMT (3.1 %) than for chemotherapy (4.9 %).

The U.S. Food and Drug Administration has accepted a biologics license application for sac‑TMT in the indication studied in TroFuse‑005 and granted priority review. Merck plans to seek approval in the United States, Europe and other markets outside China. The drug is already approved in China. The company is running 18 global Phase III trials, 10 of them focused on women’s cancers, and believes the new therapy could become a cornerstone of advanced endometrial cancer treatment.