Immune checkpoint inhibitors retain effectiveness in older patients with cutaneous metastatic melanoma

Abstract

Introduction: Immune checkpoint inhibitors (ICIs) have dramatically changed the treatment landscape for advanced melanoma, but their use in older patients remains understudied. An age-related decline in immune function is of concern when treating older patients because host immune factors can influence clinical outcomes with immunotherapy. Therefore, we aimed to evaluate the effectiveness of ICIs in patients 65 years and older.

Methods: Using the SEER-Medicare data, we evaluated survival by first systemic treatment type in a retrospective cohort study of patients aged 65 years and older who were diagnosed with stage IV cutaneous melanoma between 2012 and 2015. Cox proportional hazards regression was used to estimate hazard ratios (HR) and their corresponding 95% confidence intervals.

Results: A total of 541 patients were included in this study. Median survival differed significantly between groups (p < 0.0001) and was longest in patients treated with PD-1 inhibitors (34.0 months), followed by CTLA-4 inhibitors (16.8 months), targeted therapy (9.7 months), chemotherapy (7.1 months), and no systemic therapy (3.6 months). The ICI survival benefit persisted after adjusting for age, sex, comorbidities, M stage, the presence of brain metastases, and evaluation at an NCI-designated cancer center. Hazard ratios comparing ICIs to no systemic therapy were 0.35 (95% CI: 0.24-0.52) for PD-1 inhibitors and 0.48 (95% CI: 0.37-0.63) for CTLA-4 inhibitors. We did not observe a difference in ICI effectiveness by age group (65-74 vs ≥75).

Conclusions: In a nationally representative cohort of patients with advanced melanoma, ICI therapy delivered in a real world setting significantly improved survival in patients aged 65 years and older.

Keywords: Aged; Chemotherapy; Immunological antineoplastic agents; Medicare; Melanoma; Molecular targeted therapy; Survival analysis.