Keytruda alone beats chemotherapy in advanced endometrial cancer trial
Editorial illustration — Press Pass USAImmunotherapy alone beat chemotherapy as a first treatment for women with advanced or recurrent mismatch repair deficient endometrial cancer, according to phase 3 results presented Monday at the European Society for Medical Oncology Congress in Madrid and published simultaneously in The Lancet.
The KEYNOTE-C93 trial enrolled 299 patients and compared Merck's pembrolizumab (Keytruda) alone against carboplatin and paclitaxel chemotherapy. Median progression-free survival was 38.2 months with pembrolizumab versus 8.4 months with chemotherapy, a 43% reduction in the risk of progression or death (hazard ratio 0.57). At three years, 52.8% of patients on pembrolizumab remained progression-free, compared with 30.0% on chemotherapy.
Overall survival showed a favorable but not yet statistically significant trend for pembrolizumab (hazard ratio 0.77), with three-year survival rates of 70.7% versus 62.0%; follow-up continues. Severe treatment-related side effects were also less common with immunotherapy alone, occurring in 18.1% of patients versus 50.7% on chemotherapy, and patients reported better quality of life.
The trial was led by Dr. Brian Slomovitz of Mount Sinai Medical Center. An invited discussant at the congress noted that chemotherapy plus immunotherapy still offers a better cancer outcome than immunotherapy alone, but at the cost of higher toxicity — leaving pembrolizumab alone as a chemotherapy-free option for patients who prioritize tolerability and quality of life. Pembrolizumab alone remains investigational for this use and is not an approved first-line treatment.
Sources: Merck (Oct 26, 2026); Mount Sinai Medical Center (Oct 26, 2026); The Lancet (2026); ESMO Congress 2026, presentation LBA12.
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