Comprehensive molecular and clinical characterization of Asian melanoma patients treated with anti-PD-1 antibody

Background Clinical features of Asian melanoma patients are distinct from those of Western patients. This study was designed to determine the molecular and clinical characteristics of Asian melanoma patients treated with anti-PD-1 antibody. Methods Patients with recurrent or metastatic melanoma who began anti-PD-1 antibody therapy between January 2015 and April 2018 were retrospectively reviewed. Patients who underwent next-generation sequencing were also analyzed. Results A total of 152 patients were included. The median age was 61 years, and 53% of patients were female. A total of 56 patients (37%) received immunotherapy as second-line or greater chemotherapy. Primary sites were acral (38%), mucosal (31%), cutaneous (24%), uveal (2%), and unknown (5%). The overall response rate was 17% (95% CI, 11-22%), and disease control rate was 60% (95% CI, 52-68%). The median progression-free survival (PFS) was 4.2 months (95% CI, 1.8-6.6 months), and median overall survival (OS) was 32.9 months (95% CI, 20.0-45.7 months). However, BRAF(V600) and KIT mutational statuses were not associated with response or survival. High neutrophil-lymphocyte ratio (NLR) was associated with poor PFS (median PFS 6.9 vs. 2.4 months, p = 0.015) and OS (median OS NR vs. 10.4 months, p < 0.001). In multivariate analysis, high NLR independently predicted poor survival. Conclusion This study includes the largest set of integrated genomic data analyzing Asian patients with melanoma treated with immunotherapy. BRAF(V600) and KIT mutational statuses were not associated with response or survival, and high NLR was a strong predictor of poor response to and survival with anti-PD-1 therapy.