Real-world treatment patterns in stage III and IV melanoma patients: insights from a global multi-center chart review study.

Introduction: Anti-PD-1 immune checkpoint inhibitors have substantially changed melanoma management in both the adjuvant and advanced settings. This study aimed to estimate the percentage of stage III and IV melanoma patients exposed to different therapies and describe treatment patterns among anti-PD-1-treated patients. Methods: We performed a retrospective chart review across 22 centers in Australia, France, Germany, South Korea, the United Kingdom, and the United States. Two patient populations were analyzed: (1) an aggregate cohort with stage III/IV melanoma (2018-2021), and (2) patients who received anti-PD-1 therapy in adjuvant or advanced settings from January 2018-12 months before data collection. Treatment patterns were evaluated. Results: In the aggregate cohort (N = 16,260), observation/watchful waiting predominated in stage III patients (56.8%) in the adjuvant setting, whereas systemic therapy was most common for stage IV disease in the advanced setting. In the anti-PD-1 cohort (N = 738), anti-PD-1 monotherapy predominated in the adjuvant setting (97.5%), while both anti-PD-1 monotherapy (63.1%) and anti-PD-1 plus anti-CTLA-4 (36.9%) were commonly used in the advanced setting. Across successive lines of therapy, anti-PD-1-based regimens remained frequently used despite substantial attrition between treatment lines. Disease progression was the leading cause of treatment discontinuation in advanced disease. Discussion: This real-world study highlights the central role of anti-PD-1 therapy across disease stages. Anti-PD-1 retreatment and reuse of anti-PD-1-based regimens were frequently observed across treatment lines, highlighting the limited availability of established post-anti-PD-1 treatment options. Novel strategies are urgently needed for patients progressing after anti-PD-1 therapy.