Rahway, N.J. — Merck announced that Keytruda significantly improved progression-free survival compared with chemotherapy in certain patients with advanced or recurrent endometrial cancer in a Phase 3 clinical trial.
The KEYNOTE-C93 study evaluated Keytruda as a monotherapy in patients whose tumors were mismatch repair deficient, or dMMR, and who had not previously received systemic chemotherapy or whose cancer returned more than six months after completing adjuvant therapy.
Merck said Keytruda became the first PD-1 inhibitor to demonstrate a statistically significant and clinically meaningful progression-free survival benefit as a monotherapy compared with platinum-based doublet chemotherapy in this patient population in a Phase 3 trial.
At a prespecified interim analysis conducted by an independent Data Monitoring Committee, Keytruda also showed a trend toward improved overall survival, the trial’s other primary endpoint. However, the overall survival data were not mature, and the study will continue until a future analysis.
The analysis also showed clinically meaningful overall and complete response rates, as well as duration of response, according to the company.
The safety profile of Keytruda was consistent with findings from previously reported studies, and no new safety signals were identified. Merck plans to present the results at an upcoming medical meeting and share them with regulatory authorities.
“This is the first Phase 3 trial of a PD-1 inhibitor to show improved PFS compared to platinum doublet chemotherapy when given as monotherapy in the frontline setting for these patients, potentially providing a chemo-free option,” said Dr. Brian Slomovitz, Director of Gynecologic Oncology and Deputy Director of the Braman Comprehensive Cancer Center at Mount Sinai Medical Center in Miami Beach, Florida, and the study’s overall Principal Investigator.
“These findings build upon the well-established role of KEYTRUDA in endometrial cancer, one of the few cancers with rising incidence rates,” said Dr. Gursel Aktan, Vice President, Global Clinical Development, Merck Research Laboratories. “We are committed to helping women facing this disease by advancing potential treatment options. We thank the patients and investigators for their important contributions to this study and look forward to sharing these results with the medical community.”
KEYNOTE-C93 enrolled 299 patients who were randomly assigned to receive either 400 milligrams of Keytruda intravenously every six weeks for up to 18 cycles or a combination of paclitaxel and carboplatin every three weeks for six cycles.
The trial’s dual primary endpoints are progression-free survival, assessed through blinded independent central review, and overall survival. Overall response rate is a key secondary endpoint.
In the U.S., Keytruda is approved for three uses in certain patients with endometrial cancer, including in combination with carboplatin and paclitaxel for primary advanced or recurrent disease.
It is also approved in combination with Lenvima for certain patients whose tumors are mismatch repair proficient or not microsatellite instability-high and as a monotherapy for previously treated advanced endometrial cancer that is microsatellite instability-high or dMMR.
Merck is also evaluating Keytruda and sacituzumab tirumotecan, an investigational TROP2-directed antibody-drug conjugate being developed with Kelun-Biotech, in additional endometrial cancer studies.
