# STAMP (EA6174)

Source: https://onco.cc/trials/stamp-merkel/  
OnCo record `stamp-merkel` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

STAMP asks whether a year of pembrolizumab after surgery for Merkel cell carcinoma, a skin cancer that often comes back, prevents recurrence; it is one of two randomised trials testing adjuvant immunotherapy in this disease.

## Summary

Merkel cell carcinoma recurs in a large share of patients after surgery and radiotherapy, and PD-1 blockade is highly active in advanced disease. STAMP is an ECOG-ACRIN phase 3 trial randomising 280 patients with completely resected stage I to III Merkel cell carcinoma to pembrolizumab every three or six weeks for one year or to observation, with radiotherapy permitted in both arms. The primary endpoint is recurrence-free survival.

The trial is ongoing and has not reported. The German ADMEC-O trial of adjuvant nivolumab reported a recurrence-free survival advantage in 2023, and STAMP is the larger confirmatory test of the approach.

## Fields

- Kind: Trial
- Status: active
- Last checked: 2026-09-17
- Also known as: STAMP; ECOG-ACRIN EA6174
- Tags: subtype-trials
- Registry id: NCT03712605
- Phase: 3
- Setting: Resected stage I to III Merkel cell carcinoma: one year of adjuvant pembrolizumab against observation
- Sponsor: ECOG-ACRIN (National Cancer Institute)
- Enrolled: 280

## Sources

- ClinicalTrials.gov NCT03712605: https://clinicaltrials.gov/study/NCT03712605

## Connected records

- cancers: [Merkel cell carcinoma](https://onco.cc/cancers/merkel-cell-carcinoma/), [Skin cancer (all types)](https://onco.cc/cancers/skin-cancer/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)
- people: [Shailender Bhatia](https://onco.cc/people/shailender-bhatia/)

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JSON: https://onco.cc/api/v1/entities/stamp-merkel.json