Merck Announces TroFuse-005 Trial for Sac-TMT Met Primary Endpoints of OS and PFS in Advanced or Recurrent Endometrial Cancer

RAHWAY, N.J.--May 18, 2026 EDT-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the pivotal Phase 3 TroFuse-005 trial evaluating sacituzumab tirumotecan (sac-TMT), an investigational TROP2-directed antibody-drug conjugate (ADC) being developed in collaboration with Kelun-Biotech, met its primary endpoints of overall survival (OS) and progression-free survival (PFS) in certain patients with advanced or recurrent endometrial cancer. TroFuse-005 is the first global Phase 3 trial to demonstrate statistically significant improvement in both OS and PFS compared to chemotherapy for these patients and the first and only ADC to do so for patients with endometrial cancer in this setting.

At a pre-specified interim analysis, sac-TMT demonstrated a statistically significant and clinically meaningful improvement in OS and PFS compared to treatment of physician’s choice (TPC, consisting of doxorubicin or paclitaxel) for patients with endometrial cancer who have previously received platinum-based chemotherapy and anti-PD-1/L1 immunotherapy either together or separately. The study also reached its key secondary endpoint of objective response rate. These data will be presented at an upcoming medical meeting and discussed with regulatory authorities worldwide.
The safety profile was consistent with what has been observed in previously reported studies of sac-TMT; no new safety signals were observed.

“These results show sac-TMT may be able to address a critical unmet need for certain patients with advanced endometrial cancer, one of the only cancers increasing in both incidence and mortality worldwide,” said Dr. Domenica Lorusso, the study’s global lead investigator, lead investigator for ENGOT and professor of Obstetrics and Gynecology at Humanitas University and Humanitas San Pio X, Milan. “Despite recent advances, patients whose disease progresses following treatment with platinum and immunotherapy are urgently in need of new options, and these findings show for the first time that a TROP2 ADC may be an effective option in this setting.”

“The scale and ambition of our expansive TroFuse program reflects our deep commitment to advancing one of the industry’s leading ADC pipelines to make a difference for more people facing cancer and builds on our legacy of leadership in gynecologic cancer research,” said Dr. Dean Y. Li, president, Merck Research Laboratories. “These findings reinforce our belief that sac-TMT, with its proprietary bifunctional linker designed with the intent to maximize payload delivery to tumors while minimizing impact on healthy cells in the body, has the potential to become a cornerstone in the treatment of certain patients with advanced endometrial cancer. We thank the patients and investigators for participating in our studies as well as our collaborators at Kelun-Biotech for helping us advance this important treatment.”

TroFuse-005 also marks the first positive Phase 3 results from Merck’s TroFuse clinical development program for sac-TMT. The program currently consists of 17 ongoing global Phase 3 trials across multiple tumor types, the broadest range of disease and treatment settings compared to any TROP2-directed ADC to date, including 10 Phase 3 trials in women’s cancers. The program is evaluating sac-TMT across a diverse range of tumor types, including endometrial, bladder, breast, cervical, gastric, non-small cell lung and ovarian cancers, and it spans early-to-late-stage disease as both monotherapy and in combination with immunotherapies. This includes the ongoing TroFuse-033 trial in first line mismatch repair proficient endometrial cancer.