Merck & Co. reported that patients with previously treated advanced or recurrent endometrial cancer had median overall survival of 19 months on its experimental drug, versus 12.1 months on chemotherapy.
The randomized, open-label TroFuse-005 trial enrolled 776 patients who had received platinum-based chemotherapy and anti-PD-1 or anti-PD-L1 immunotherapy, either together or separately. Participants received sacituzumab tirumotecan or chemotherapy with doxorubicin or paclitaxel, chosen by their physician. Median follow-up was 14 months.
Merck reported a 32% lower hazard of death with sacituzumab tirumotecan, with a hazard ratio of 0.68 and a 95% confidence interval of 0.55 to 0.84. Median progression-free survival was 7.2 months with the drug and 3.9 months with chemotherapy; the company reported a 41% lower hazard of progression or death. The objective response rates were 35.1% and 17.3%, respectively, while median response duration was 11.1 months and 6.9 months.
The findings concern patients whose cancer was already advanced or had returned. They do not establish whether the drug prevents a first recurrence after treatment for earlier-stage disease.
Treatment-related adverse events classified as Grade 3 or higher occurred in 54.4% of patients receiving the drug and 41.4% of those receiving chemotherapy, Merck said. The company listed anemia, neutropenia and oral mucositis or stomatitis among the most common severe events in the drug group. Treatment-related deaths were reported in three patients in each group.
Sacituzumab tirumotecan is an antibody-drug conjugate designed to target TROP2, a protein found in abundance on endometrial cancer cells, and deliver a cancer-killing compound to tumors. Merck funded the trial and is developing the drug with Kelun-Biotech.
Bhavana Pothuri, the study’s principal investigator and a gynecologic oncologist, said clinical guidelines should be reassessed to account for the drug. Merck and NYU Langone said the results were presented Monday, Oct. 26, at the European Society for Medical Oncology Congress and published online in The Lancet.
The U.S. Food and Drug Administration accepted Merck’s Biologics License Application for priority review, the company said, and set June 15, 2027, as the target action date. The drug remains investigational.
