Adjuvant pembrolizumab versus interferon alfa-2b or ipilimumab in resected high-risk melanoma.

We conducted a randomized phase 3 trial to evaluate whether adjuvant pembrolizumab for one year (648 patients) improved recurrence-free survival (RFS) or overall survival (OS) in comparison to high-dose interferon alfa-2b for one year or ipilimumab for up to three years (655 patients), the approved standard-of-care adjuvant immunotherapies at the time of enrollment for patients with high-risk resected melanoma. At a median follow-up of 47.5 months, pembrolizumab was associated with significantly longer RFS than prior standard-of-care adjuvant immunotherapies (hazard ratio [HR] 0.77; 99.62% confidence interval [CI] 0.59-0.99; P=0.002). There was no statistically significant association with OS among all patients (HR, 0.82; 96.3% CI 0.61-1.09; P=0.15). Proportions of treatment-related adverse events of grades 3 to 5 were 19.5% with pembrolizumab, 71.2% with interferon alfa-2b, and 49.2% with ipilimumab. Therefore, adjuvant pembrolizumab significantly improved RFS but not OS compared to the prior standard-of-care immunotherapies for patients with high-risk resected melanoma.