Mucosal melanoma is rare and an aggressive malignancy with poor response compared with cutaneous melanoma. The prospective trial on immune-checkpoint inhibitors in unresectable or metastatic mucosal melanoma has not been reported except pooled analysis. The aim of this phase II trial was to assess the efficacy and safety of nivolumab monotherapy for unresectable or metastatic mucosal melanoma.
Eligibility criteria were as follows: histological diagnosis of unresectable or metastatic mucosal melanoma; age ≧ 20 years; ECOG performance status 0 or 1; and with measurable lesions. Patients received nivolumab 2 mg/kg every 3 weeks. The primary endpoint was response rate (RR) according to Response Evaluation Criteria in Solid Tumors version 1.1(≧ 20%). The secondary endpoints were overall survival, progression-free survival, disease control rate, and toxicity.
A total of 20 patients were enrolled between December 2014 and July 2017. Two patients without measurable lesion were excluded from analysis of efficacy. The RR was 22%, suggesting that the primary endpoint was met. One patient achieved a complete response, three patients achieved partial response, and six patients achieved stable disease as their best response. The median progression-free survival was 1.4 months (95% CI, 1.15 to 5.47). The median overall survival was 12.03 months (95% CI, 3.50 to not reach). The 1-year overall survival data was 52.6% (95% CI, 28.5 to 72.0). Treatment-related adverse events of grade 3 or 4 occurred in 15% (3/20) of the patients. Grade 3 diarrhea was observed in two patients and grade 3 adrenal insufficiency was observed in one patient. They were resolved by corticosteroid.
Although this trial met the primary endpoint, the RR was still unsatisfactory. Therefore, the further treatment development is required.
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All authors have declared no conflicts of interest.