Trial results for pembrolizumab (Keytruda) in ultramutated and hypermutated recurrent endometrial cancer were posted on ClinicalTrials.gov on 2025-06-11. The Phase 2 study demonstrated a median progression-free survival (PFS) of 27.4 months and a median overall survival (OS) of 71.5 months for participants.
Background
The study investigated pembrolizumab in patients with persistent, recurrent, or metastatic endometrial cancer characterized by an ultramutated or hypermutated (MMR gene-defective) phenotype, identified through next-generation sequencing and comprehensive genomic profiling.
Trial design
The Phase 2 study, NCT02899793, enrolled 25 participants with recurrent endometrial cancer. The trial's primary objectives were to assess the antitumor activity, measured by the proportion of objective response using RECIST 1.1 criteria, and to determine the nature and degree of toxicity of pembrolizumab as assessed by CTCAE in patients with persistent, recurrent, or metastatic endometrial carcinoma harboring an ultra-mutated or hyper-mutated (MMR gene-defective) phenotype.
Key results
The trial reported objective tumor response and safety outcomes for pembrolizumab. For the outcome "Frequency of Objective Tumor Response as Assessed by RECIST 1.1- Overall Response Rate (ORR)," participant counts were reported as 5, 9, 7, and 3. The median Duration of Progression-free Survival (PFS) was 27.4 months. The median Overall Survival (OS) was 71.5 months.
Regarding safety, the "Toxicity Grade of Adverse Events as Assessed by CTCAE v4" showed participant counts of 19, 6, 0, and 0. An analysis using the Fisher Exact method for subgroup difference in ORRs yielded a p-value of 0.024.
What this means
The reported median progression-free survival of 27.4 months and overall survival of 71.5 months suggest promising activity for pembrolizumab in this population of patients with ultramutated and hypermutated recurrent endometrial cancer. The observed objective tumor responses and the p-value of 0.024 for subgroup differences in ORRs indicate varying levels of antitumor activity within the study population. These results provide further insights into the potential role of pembrolizumab in this specific subset of endometrial cancer.
Source
The information for this article is based on trial results posted on ClinicalTrials.gov, a public database of clinical studies. The results for study NCT02899793, titled "Pembrolizumab in Ultramutated and Hypermutated Endometrial Cancer," were posted on 2025-06-11 on clinicaltrials.gov.