US pharmaceutical company Merck & Co Inc (NYSE:MRK), known as MSD outside the US and Canada, announced on Wednesday that its Phase 3 KEYNOTE-C93 trial evaluating KEYTRUDA (pembrolizumab) met its primary endpoint of progression-free survival (PFS) in patients with mismatch repair deficient (dMMR) advanced or recurrent endometrial cancer.

The trial showed that KEYTRUDA monotherapy delivered a statistically significant and clinically meaningful improvement in PFS compared with platinum doublet chemotherapy, making it the first and only PD-1 inhibitor to achieve this result in a Phase 3 trial for these patients.

An interim analysis also showed a trend toward improved overall survival, although the data were not mature at the time of analysis. The study remains ongoing, with future evaluation planned for overall survival outcomes.

Merck stated that KEYTRUDA's safety profile in the trial was consistent with previous studies, with no new safety signals identified. Results will be presented at an upcoming medical meeting and shared with regulatory authorities.