Updated outcomes from STAMP: Surgically treated adjuvant Merkel cell carcinoma with pembrolizumab, a phase III trial—ECOG-ACRIN EA6174
Abstract
LBA9505
Background:
EA6174 (STAMP) is the first randomized phase III trial of adjuvant pembrolizumab (pembro) in resected Merkel cell carcinoma (MCC), a rare, aggressive skin cancer with high relapse risk after surgery. This abstract presents new analyses of MCC-specific outcomes and radiation therapy (RT) effects.
Methods:
Patients (pts) with resected stage I without a sentinel lymph node biopsy to IIIB MCC were randomized 1:1 to pembro 200 mg IV q3 weeks ×17 doses (n = 147) or standard of care (SOC) (n = 146). Randomization was stratified by stage (I/II vs III) and intended RT. Co-primary endpoints were relapse-free survival (RFS) and overall survival (OS). MCC-specific outcomes were captured as relapse due to recurrence or death due to any cause (RFS_a), and MCC-specific recurrence and death (RFS_b). Distant metastasis-free survival (DMFS) was defined as time to distant recurrence or death from MCC. 280 pts provided 80% power with one-sided type 1 error rate of 0.05 to evaluate the hazard ratio (HR) of 0.56 hierarchically (RFS before OS). One-sided p-values from the log-rank test are reported in the analysis (data as of 2/19/26, median follow-up 47 months).
Results:
293 pts enrolled (67.9% male; 84.3% stage III, median age 69, > 50% accrued during the COVID-19 pandemic). Overall RFS (RFS_a) was numerically improved with pembro but not statistically significant between arms (p = 0.10). DMFS was improved in pts treated with pembro (p = .05). Significant improvement was…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 147 participants or records.
Read the paper
Related studies
- Global, regional, and national burden of hepatitis B, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019
- A meta‐analysis of anal cancer incidence by risk group: Toward a unified anal cancer risk scale
- Global fertility in 204 countries and territories, 1950–2021, with forecasts to 2100: a comprehensive demographic analysis for the Global Burden of Disease Study 2021
- Exercise interventions in Alzheimer's disease: A systematic review and meta-analysis of randomized controlled trials
- Prognostic Significance of Carbonic Anhydrase IX Expression in Cancer Patients: A Meta-Analysis
- Glucocorticoid Resistance: Is It a Requisite for Increased Cytokine Production in Depression? A Systematic Review and Meta-Analysis
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.