Multicenter phase 2 trial of neoadjuvant PD-1 blockade in surgically resectable desmoplastic melanoma

Cohort A of the phase 2 SWOG S1512 trial evaluated the pathological complete response (pCR) rate of neoadjuvant PD-1 blockade with pembrolizumab in surgically resectable desmoplastic melanoma. Twenty-eight patients received intravenous pembrolizumab 200 mg every 3 weeks three times, followed by excision. The primary endpoint of pCR rate by local pathological review among 22 evaluable patients was 71% (95% CI 51-87), which met the prespecified endpoint. There were two (7%) grade 3 treatment-related adverse events. At three years of follow-up, four participants had died, non known to be from melanoma or adverse events. The authors conclude that neoadjuvant pembrolizumab in patients with resectable desmoplastic melanoma results in a high pCR rate with acceptable safety.