BACKGROUND: A minority subset of immunotherapy patients manifests hyperprogressive disease (HPD), with the disparity in melanoma subtypes yet to be reported. This study aimed to delineate the proportion and prognosis of HPD in patients receiving anti-PD-1 monotherapy and to identify patient with HPD clinical characteristics across melanoma subtypes to inform clinical decision making. METHODS: Utilizing 4 established HPD definitions, the incidence of HPD in patients with advanced melanoma on anti-PD-1 monotherapy was determined. The incidence rates and prognostic abilities of various HPD definitions were compared to elect the most effective one. This facilitated a comparative analysis of subtypes and clinical features between patients with HPD and traditional progression. RESULTS: A total of 262 patients with advanced melanoma treated with anti-PD-1 monotherapy from 5 prospectively registered clinical trials were included in the study. The objective response rate (ORR) and disease control rate (DCR) was 21% and 58%, respectively, with 42% showcasing progression disease. The HPD incidences by 4 definitions were 13.2%, 16.8%, 10.8%, and 28.2%. All definitions effectively segregated HPD patients, with significantly poorer outcome than other progressive patients. The Delta TGR > 100 definition was the most indicative of a reduced overall survival, corroborated by the highest hazard ratio and statistical significance. The number of metastatic organs over 2 is a risk factor for HPD (OR = 4.18, P = .0103). Mucosal melanoma was the HPD prevalent subtype (OR = 3.13, P = .0489) in multivariable analysis, which is also indicated by RECIST criteria (P = .005). CONCLUSION: A delta TGR exceeding 100 best identified HPD patients in the advanced melanoma population treated with anti-PD-1 monotherapy. Hyperprogression was notably prevalent in mucosal melanoma patients with multiple metastatic organs. Caution against HPD is warranted when applying anti-PD-1 monotherapy in mucosal subtype.