Merck drug cuts death risk by a third in advanced endometrial cancer

The antibody-drug conjugate sacituzumab tirumotecan, from Merck and China’s Kelun-Biotech, lowered the risk of cancer progression by 41% and death by 32% compared with standard chemotherapy in a randomized Phase 3 trial of advanced or recurrent endometrial cancer, according to results presented Monday at the European Society for Medical Oncology congress and published simultaneously in The Lancet. The trial, TroFuse-005/ENGOT-en23/GOG-3095, enrolled 776 women whose disease had progressed after initial chemotherapy and pembrolizumab (Keytruda); 386 were randomly assigned to sac-TMT and 390 to chemotherapy alone.

Among these patients, those in the sac-TMT group had a 41% lower risk of cancer progression and a 32% lower risk of death than those in the standard chemotherapy group. A response, such as tumor shrinkage, was seen in 35.1% of women treated with sac-TMT versus 17.3% of those treated with chemotherapy alone. The most common adverse events in the sac-TMT arm were low blood counts such as anemia and neutropenia, mouth inflammation, and dry or itchy eyes; investigators described these as manageable.

Sacituzumab tirumotecan binds to Trop-2, a protein found in large amounts on endometrial cancer cells, and delivers a cell-killing chemical.

The trial recruited patients at over 200 centers in 29 countries spanning Europe, Asia, and North America; most participants were followed for at least one year after randomization. Bhavana Pothuri, the study’s principal investigator and a professor at NYU Grossman School of Medicine, said the results “establish this drug as a new standard treatment in recurrent endometrial cancer”. She said the results point to potential benefit in other cancers that overexpress Trop-2, such as lung, breast, ovarian, and intestinal tumors.

The findings apply to women who had already received chemotherapy and pembrolizumab and whose endometrial cancer had advanced or recurred; the trial does not show benefit in earlier lines of treatment. Uterine cancer deaths in the U.S. now exceed 14,000 a year, with about 68,000 new cases expected in 2026, according to study co-investigator Michelle Lightfoot. Merck has 18 global Phase 3 trials of sac-TMT under way, 10 of them in women’s cancers, to seek approvals in the U.S., Europe, and elsewhere outside China. The drug is already approved in China and is important to Merck’s effort to replace revenue that Keytruda will lose after its 2028 patent expiration.

Update, November 2, 2026

Medical News Today reported on Monday that the U.S. Food and Drug Administration has accepted the Biologics License Application for sacituzumab tirumotecan for priority review. "Based on these data, the U.S. FDA has accepted the Biologics License Application for priority review," study author Domenica Lorusso told the publication. Lorusso made the statement in an article about the Phase 3 TroFuse-005 trial.