KENILWORTH (NJ) (dpa-AFX) - Merck & Co., Inc. (MRK) announced positive results from the Phase 3 KEYNOTE-C93 trial, evaluating KEYTRUDA (pembrolizumab), Merck's anti-PD-1 therapy, as monotherapy for the treatment of patients with mismatch repair deficient (dMMR) advanced or recurrent endometrial cancer who had not previously received systemic chemotherapy or who experienced recurrence after receiving prior adjuvant therapy.
According to the company, KEYTRUDA monotherapy demonstrated a statistically significant and clinically meaningful improvement in the primary endpoint of progression-free survival (PFS), reducing the risk of disease progression or death by 43% compared with platinum-doublet chemotherapy.
After a median follow-up of 36.7 months, median PFS was 38.2 months versus 8.4 months for chemotherapy, while the estimated 36-month PFS rates were 52.8% and 30.0%, respectively.
In addition to the PFS benefit, KEYTRUDA demonstrated a favourable trend toward improved overall survival (OS), the trial's other primary endpoint, compared with platinum-doublet chemotherapy, although the result did not reach statistical significance. (HR=0.77; 95% CI, 0.52-1.15; p=0.1000).
Median OS was not reached in either arm, while the 36-month OS rates were 70.7% for KEYTRUDA and 62.0% for chemotherapy. The study is continuing, and additional OS data will be collected as follow-up progresses.
For safety, Grade 3 or higher treatment-related adverse events (TRAEs) occurred in 18.1% of patients treated with KEYTRUDA (n=149), compared with 50.7% of patients who received chemotherapy (n=144). The most common Grade 3 or higher TRAE was anaemia, reported in 2.0% of patients in the KEYTRUDA arm versus 18.1% in the chemotherapy arm.
'After years of platinum-based chemotherapy serving as the frontline standard, these findings could help provide an additional treatment option beyond carboplatin plus paclitaxel in combination with KEYTRUDA for these patients,' said Dr Brian Slomovitz, the study's overall principal investigator.
The results will be presented today during a Presidential Symposium at the European Society for Medical Oncology (ESMO) Congress 2026.
MRK has traded between $82.01 and $156.92 over the last year. The stock closed Monday's trade at $ 140.61, down 3.21%,
In the overnight market, MRK is up 0.29% at $141.02.
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