Multicenter phase 2 trial of pembrolizumab monotherapy for metastatic desmoplastic melanoma

Desmoplastic melanoma (DM) is a subtype of melanoma with high tumor mutation burden due to ultraviolet light damage. The multicenter prospective S1512 trial cohort B evaluated pembrolizumab monotherapy for metastatic DM. The ORR was 85%, with complete response in 26% of patients. The authors conclude that patients with metastatic DM are exceptional responders to single-agent PD-1 blockade with pembrolizumab. Based on these data, the pathologic subtype of melanoma can be used as a predictive biomarker of response to single agent pembrolizumab.