Merck (NYSE: MRK) announced that its experimental cancer drug sacituzumab tirumotecan met primary endpoints for overall survival and progression-free survival in a phase 3 trial for patients with advanced or recurrent endometrial cancer.

The TroFuse-005 trial evaluated the TROP2-directed antibody-drug conjugate in 776 patients whose disease progressed after platinum-based chemotherapy and anti-PD-1/L1 immunotherapy. At a pre-specified interim analysis, sacituzumab tirumotecan showed statistically significant improvement compared to physician's choice chemotherapy consisting of doxorubicin or paclitaxel.

The study also met its key secondary endpoint of objective response rate. The safety profile remained consistent with previous studies of the drug, with no new safety signals observed, according to the company's press release.

Sacituzumab tirumotecan is being developed in collaboration with Kelun-Biotech. Under their agreement, Kelun-Biotech granted Merck exclusive rights to develop, manufacture and commercialize the drug outside of Greater China.

The trial represents the first positive phase 3 results from Merck's TroFuse clinical development program for sacituzumab tirumotecan. The program includes 17 ongoing global phase 3 trials across multiple tumor types, with 10 trials focused on women's cancers.

Endometrial cancer is estimated to affect approximately 68,270 patients in the U.S. in 2026, with about 14,450 deaths expected from the disease. The cancer begins in the inner lining of the uterus and represents more than 90% of uterine body cancers.

Merck plans to present the trial data at an upcoming medical meeting and discuss the results with regulatory authorities worldwide.