Outcomes of immunotherapy in advanced melanoma in relation to age.

Abstract

187 Background: Older age is a risk feature in melanoma. Elderly are more likely to have immunosenescence, which could help melanoma cells escape immune surveillance. Hence, there is a belief that elderly people cannot mount a potent immune response to checkpoint inhibitors (CPI) to fully eliminate melanoma. The objective of the study was to investigate age-related differences in the time to progression (TTP), overall survival (OS), and immunotherapy related adverse events (irAEs) among patients with metastatic melanoma who received CPI. Methods: We retrospectively identified patients with stage IV melanoma who received at least 1 dose of ipilimumab, pembrolizumab, nivolumab, or combined ipilimumab and nivolumab. Demographics, pathologic, and clinical characteristics were obtained. Immune-related response criteria were utilized to define responses. Results: Sixty patients were included; 29 were less than 65 years old and 31 were 65 years or older. No significant differences, when adjusted for gender, type of melanoma and presence of brain metastasis, in TTP [HR 0.79; 95% CI (0.371.70); p = 0.46] and OS [Hazard ratio (HR) 0.75; 95% CI (0.31-1.82); P = 0.491] was observed between the < 65 and ≥65 year-old groups who received CPI for metastatic melanoma. Overall irAEs in two groups was comparable with 62% in the younger patients and 45% in the older patients (P = 0.19). Thirty responders had a median age of 66.9 (54.3-73.3 years old) and 30 non-responders had a median age of 62.7 (54-69.1 years old). Non-responders, regardless of age, were more likely to have BRAF mutated melanomas (53.3% vs. 27.6%; P = 0.04) and less likely to have irAEs (40% vs. 66.7%; P = 0.04) than responders. Conclusions: No difference in TTP, OS or irAEs was observed between the elderly and the young patients who received CPI for metastatic melanoma. In general, responders had higher irAEs and less BRAF mutated melanomas than non-responders.