Overview
- The phase 3 STAMP (EA6174) trial enrolled 293 patients after surgery between 2018 and 2023, randomizing 147 to pembrolizumab and 146 to observation.
- At two years, recurrence-free survival was 73% with pembrolizumab versus 66% with observation, a difference that was not statistically significant.
- Patients who received pembrolizumab had a 42% lower risk of developing distant metastases to organs such as the liver, lungs, or bones.
- Interim findings were presented in Berlin by lead investigator Janice M. Mehnert at the ESMO 2025 Congress, with overall survival as a co-primary endpoint still under follow-up.
- Pembrolizumab is a PD‑1 inhibitor already approved by the FDA for recurrent locally advanced or metastatic Merkel cell carcinoma.