Merck Drug Meets Survival Goals in Endometrial Cancer Trial

Merck announced Monday that its investigational drug sacituzumab tirumotecan met its primary endpoints of overall survival and progression-free survival in patients with advanced or recurrent endometrial cancer.

The TroFuse-005 trial is the first global Phase 3 study to show a statistically significant survival improvement over chemotherapy in these patients, according to a Merck press release. It is also the first antibody-drug conjugate to achieve this result for endometrial cancer in this setting.

The trial enrolled 776 patients whose disease had worsened after platinum chemotherapy and immunotherapy. Patients were randomly assigned to receive sac-TMT every two weeks or a physician’s choice of chemotherapy, such as doxorubicin or paclitaxel. The patients knew which treatment they received.

Those given sac-TMT showed clinically meaningful improvement compared with physician’s choice treatment, the researchers found. The study also met response rate benchmarks and showed side effects similar to those seen in earlier trials of the drug.

Merck did not release specific numbers on survival benefit, response rates or side effect rates. The researchers plan to present the full Phase 3 data at an upcoming medical meeting.

Dr. Domenica Lorusso, the study’s global lead investigator and professor of obstetrics and gynecology at Humanitas University and Humanitas San Pio X in Milan, said the results indicate sac-TMT may address a critical unmet need for certain patients with advanced endometrial cancer.

"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," she said.

Dr. Brian Slomovitz, co-director of gynecologic oncology at Mount Sinai and an investigator on the trial, said the number of endometrial cancers and deaths from the disease are rising. In the United States, deaths from endometrial cancer now exceed those from ovarian cancer, making it the deadliest gynecologic malignancy.

"If the full data confirm this announcement, the key questions will be the magnitude of the survival benefit and the toxicity profile — those will define sac-TMT’s role," he said.