Lynch-like MSI-H Endometrial Cancer Exhibits Superior Outcomes with Pembrolizumab

In this phase 2 trial of recurrent platinum-resistant MSI-H/dMMR endometrial cancer patients fully sequenced via whole exome and FoundationOne, the Lynch-like subgroup achieved a 100% objective response rate compared to 44% in MLH1-methylated cases. They also showed significantly improved progression-free and overall survival over nearly 97 person-years of follow-up.

These findings highlight the prognostic importance of distinguishing between Lynch-like and methylated MSI-H endometrial cancers, suggesting that patient stratification may optimize immunotherapy benefits with pembrolizumab in future studies.