FDA Accepts Pembrolizumab Application as Single Agent for Subgroup of Patients With Advanced Endometrial Carcinoma

Officials with the FDA have accepted a new supplemental Biologics License Application for pembrolizumab (Keytruda, Merck) as a single agent for the treatment of patients with advanced endometrial carcinoma that is microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR), whose disease has progressed following prior systemic therapy and who are not candidates for curative surgery or radiation.

Endometrial carcinoma begins in the endometrium and is the most common type of uterine cancer. An estimated 417,000 new cases were diagnosed with more than 97,000 deaths resulted from the disease in 2020, according to a Merck press release. The number of people diagnosed with this cancer is expected to rise and it is estimated that approximately 30% of endometrial carcinomas are MSI-H or dMMR.

The application is based on overall response data from cohorts D and K of the KEYNOTE-158 trial. The full findings will be presented at the European Society for Medical Oncology Congress 2021 and the FDA has set a Prescription Drug User Fee Act date for March 28, 2022.

“The FDA’s acceptance of our application adds to our momentum of advancing new treatment options to address the most challenging cancers facing women,” said Scot Ebbinghaus, MD, vice president of clinical research at Merck Research Laboratories, in the press release.

KEYNOTE-158 is an ongoing global, open-label, non-randomized, multi-cohort, multi-center, phase 2 clinical trial evaluating pembrolizumab in patients with multiple types of advanced solid tumors that have progressed on standard of care treatments. Cohort K included 79 patients with MSI-H endometrial carcinoma and cohort D included 11 patients with MSI-H endometrial carcinoma.

With these cohorts, a total of 90 pooled patients received pembrolizumab monotherapy as 200 mg fixed dose every 3 weeks. The primary endpoint was overall response rate as evaluated by independent central review and secondary endpoints include progression-free survival, overall survival, duration of response, and safety.

“Keytruda monotherapy is already playing a role for the treatment of certain patients with advanced endometrial carcinoma through the tumor-agnostic MSI-H indication which received accelerated approval four years ago,” Ebbinghaus said in the press release. “We look forward to sharing the latest results from KEYNOTE-158, including updated data for Keytruda in certain types of MSI-H/dMMR advanced endometrial carcinoma, at the ESMO Congress in September.”

Pembrolizumab is currently approved for the treatment of adult and pediatric patients with unresectable or metastatic MSI-H or dMMR solid tumors that have progressed following prior treatment and who have no satisfactory alternative treatment options. This indication was approved under FDA accelerated approval based on tumor response rate and durability of response.

Pembrolizumab was also granted accelerated approval in September 2019 and received full approval in July 2021 for the treatment of patients with advanced endometrial carcinoma that is not MSI-H or dMMR, who have disease progression following prior systemic therapy, and who are not candidates for curative surgery or radiation. This approval is in combination with Lenvatinib (Lenvima, Eisai).

Earlier this week, pembrolizumab was approved in combination with lenvatinib for the first-line treatment of adult patients with advanced renal cell carcinoma.

REFERENCE

FDA Accepts Application for Merck’s Keytruda (pembrolizumab) as Single Agent for Certain Patients With MSI-H/dMMR Advanced Endometrial Carcinoma. News release. Merck; August 10, 2021. Accessed August 11, 2021. https://www.merck.com/news/fda-accepts-application-for-mercks-keytruda-pembrolizumab-as-single-agent-for-certain-patients-with-msi-h-dmmr-advanced-endometrial-carcinoma/