biostudies-literatureKendra KLU.S. Department of Health & Human Services | NIH | National Cancer InstituteNCI NIH HHS272-282https://www.ebi.ac.uk/biostudies/studies/S-EPMC12948668biostudies-literatureUnknown7(2)The phase 2 SWOG S1512 trial ( NCT02775851 ) was designed to evaluate the response to pembrolizumab (anti-PD-1) in individuals with desmoplastic melanoma. Here we report the results of cohort A of the trial, evaluating the pathological complete response (pCR) rate of neoadjuvant PD-1 blockade in surgically resectable desmoplastic melanoma. Secondary endpoints included clinical response rate, overall survival and toxicities. Twenty-eight eligible individuals with resectable desmoplastic melanoma received intravenous pembrolizumab (200 mg) every 3 weeks three times, followed by excision. Tissue samples before treatment, at 3-5 weeks after treatment initiation and at the time of surgery were reviewed. The primary endpoint of pCR rate by local pathological review was 71% (95% confidence intervNature cancerNeoadjuvant PD-1 blockade in surgically resectable desmoplastic melanoma: cohort A of the phase 2 SWOG S1512 trial.PMC12948668R35 CA197633P01 CA244118Ribas AKhushalani NIPlaza JAContreras CMBrohl ASWu MCChen JMGonzalez CRVega-Crespo ANorman KBaselga-Carretero ISondak VKEroglu ZIkeguchi AChmielowski BCarson WEHu-Lieskovan SPatel SPSharon EGrossmann KFWada DAIn GKKendra KLBellasea SLCampbell KMHyngstrom JMarkowitz JMonroe MBowles TDeen NNAMedina EGarcilazo IPMoon JfalseNeoadjuvant PD-1 blockade in surgically resectable desmoplastic melanoma: cohort A of the phase 2 SWOG S1512 trial.The phase 2 SWOG S1512 trial ( NCT02775851 ) was designed to evaluate the response to pembrolizumab (anti-PD-1) in individuals with desmoplastic melanoma. Here we report the results of cohort A of the trial, evaluating the pathological complete response (pCR) rate of neoadjuvant PD-1 blockade in surgically resectable desmoplastic melanoma. Secondary endpoints included clinical response rate, overall survival and toxicities. Twenty-eight eligible individuals with resectable desmoplastic melanoma received intravenous pembrolizumab (200 mg) every 3 weeks three times, followed by excision. Tissue samples before treatment, at 3-5 weeks after treatment initiation and at the time of surgery were reviewed. The primary endpoint of pCR rate by local pathological review was 71% (95% confidence interv2026-01-01T00:00:00Z2026 Feb2026-07-16T23:35:48.643Z2026-07-12T03:11:21.608ZS-EPMC129486684161199810.1038/s43018-025-01113-y