US pharmaceutical company Merck & Co Inc (NYSE:MRK), known as MSD outside the US and Canada, announced on Wednesday that Health Canada has approved KEYTRUDA (pembrolizumab) in combination with carboplatin and paclitaxel, followed by KEYTRUDA as monotherapy, for adult patients with primary advanced or recurrent endometrial carcinoma.

This approval is based on results from the Phase 3 KEYNOTE-868/NRG-GY018 trial, which demonstrated significant improvements in progression-free survival (PFS) for both deficient mismatch repair (dMMR) and proficient mismatch repair (pMMR) patient populations.

In the trial, pembrolizumab plus carboplatin and paclitaxel reduced the risk of disease progression or death by 43% in the pMMR group and by 66% in the dMMR group compared to placebo with chemotherapy. Median PFS for pMMR patients was 13.1 months versus 8.7 months in the placebo group, while median PFS was not reached for dMMR patients treated with pembrolizumab, compared to 8.3 months in the placebo group.

Endometrial carcinoma, which begins in the endometrium, accounts for 95% of uterine cancer cases and is the fourth most common cancer among women in Canada, with 8,600 cases and 1,600 deaths estimated in 2024.

The KEYNOTE-868/NRG-GY018 trial randomised 810 patients with advanced stage or recurrent endometrial cancer to receive either pembrolizumab or placebo in combination with standard chemotherapy, followed by maintenance therapy. Secondary endpoints included overall survival, objective response rate, duration of response and safety.