The outcome of patients with mucosal
melanoma treated with
ipilimumab is not defined. To assess the efficacy and safety of
ipilimumab in this
melanoma subset, we performed a multicenter, retrospective analysis of 33 patients with unresectable or metastatic mucosal
melanoma treated with
ipilimumab. The clinical characteristics, treatments, toxicities, radiographic assessment of disease burden by central radiology review at each site, and mutational profiles of the patients'
tumors were recorded. Available peripheral blood samples were used to assess humoral immunity against a panel of
cancer-testis antigens and other
antigens. By the immune-related response criteria of the 30 patients who underwent radiographic assessment after
ipilimumab at approximately week 12, there were 1 immune-related complete response, 1 immune-related partial response, 6 immune-related stable disease, and 22 immune-related progressive disease. By the modified World Health Organization criteria, there were 1 immune-related complete response, 1 immune-related partial response, 5 immune-related stable disease, and 23 immune-related progressive disease. Immune-related adverse events (as graded by Common Terminology Criteria for Adverse Events version 4.0) consisted of six patients with
rash (four grade 1, two grade 2), three patients with
diarrhea (one grade 1, two grade 3), one patient with grade 1
thyroiditis, one patient with grade 3
hepatitis, and 1 patient with grade 2
hypophysitis. The median overall survival from the time of the first dose of
ipilimumab was 6.4 months (range: 1.8-26.7 months). Several patients demonstrated serologic responses to
cancer-testis antigens and other
antigens. Durable responses to
ipilimumab were observed, but the overall response rate was low. Additional investigation is necessary to clarify the role of
ipilimumab in patients with mucosal
melanoma.