KEYTRUDA Shows Strong Results in Endometrial Cancer Study
Merck, known as MSD outside the United States and Canada, has announced positive results from its Phase 3 KEYNOTE-C93 clinical trial evaluating KEYTRUDA (pembrolizumab) as a first-line treatment for certain patients with advanced or recurrent endometrial cancer. The study met its main goal by showing that KEYTRUDA significantly delayed disease progression compared with standard chemotherapy.
The trial included patients with mismatch repair deficient (dMMR) advanced or recurrent endometrial cancer who had not previously received systemic chemotherapy or whose cancer returned more than six months after completing earlier adjuvant treatment.
According to Merck, KEYTRUDA is the first and only PD-1 inhibitor to demonstrate a statistically significant and clinically meaningful improvement in progression-free survival (PFS) as a single treatment compared with platinum-based doublet chemotherapy in a Phase 3 trial for this group of patients.
Progression-free survival measures how long patients live without their cancer getting worse. Improving this outcome is considered an important goal in cancer treatment because it can help patients maintain a better quality of life and delay the need for additional therapies.
The study also evaluated overall survival (OS), another major endpoint. At a planned interim analysis conducted by an independent Data Monitoring Committee, researchers observed a positive trend toward improved overall survival among patients receiving KEYTRUDA. However, the survival data are not yet mature enough to determine whether the difference is statistically significant. The trial is continuing, and a final analysis of overall survival will be completed after more patient follow-up.
In addition to meeting its primary endpoint, the trial showed encouraging results for several other measures of treatment effectiveness. Patients receiving KEYTRUDA experienced clinically meaningful overall response rates, along with improved complete response rates and longer duration of response, indicating that many patients responded well to treatment and maintained those responses over time.
The safety profile of KEYTRUDA in the study was consistent with what has been observed in previous clinical trials. Merck reported that no new safety concerns were identified during the trial.
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 principal investigator, said the findings represent an important milestone.
He noted that this is the first Phase 3 study of a PD-1 inhibitor to demonstrate better progression-free survival than platinum-based chemotherapy when used alone as an initial treatment. According to Dr. Slomovitz, the results suggest that KEYTRUDA could offer patients a chemotherapy-free treatment option in the frontline setting.
Dr. Gursel Aktan, Vice President of Global Clinical Development at Merck Research Laboratories, said the results further strengthen KEYTRUDA’s role in treating endometrial cancer, a disease whose incidence continues to increase. He thanked the patients and investigators who participated in the study and said the company looks forward to sharing the complete findings with the medical community and regulatory agencies.
Merck plans to present the full study results at an upcoming medical conference and submit the data to health authorities for review.
KEYTRUDA already has several approved uses in the United States for endometrial cancer. It is approved in combination with chemotherapy for certain patients with advanced or recurrent disease, in combination with LENVIMA (lenvatinib) for specific patients whose tumors are mismatch repair proficient (pMMR), and as a single treatment for patients with advanced MSI-H or dMMR endometrial cancer whose disease has progressed after earlier therapy.
The company is also continuing to expand its research in endometrial cancer through additional clinical trials. These include studies evaluating sacituzumab tirumotecan (sac-TMT), an investigational antibody-drug conjugate being developed with Kelun-Biotech, in both previously treated patients and earlier stages of the disease.
If confirmed by future analyses and regulatory review, the KEYNOTE-C93 findings could provide a new chemotherapy-free first-line treatment option for patients with dMMR advanced or recurrent endometrial cancer, offering another important advance in the growing use of immunotherapy for gynecologic cancers.