Abstract
IMPORTANCE: Long-term survival data from clinical trials show that survival curves of patients with advanced melanoma treated with immune checkpoint inhibitors (ICIs) gradually reach a plateau, suggesting that patients have a chance of achieving long-term survival. OBJECTIVE: To investigate long-term survival in patients with advanced melanoma treated with ICIs outside clinical trials. DESIGN, SETTING, AND PARTICIPANTS: Cohort study using prospectively collected data from the nationwide Dutch Melanoma Treatment Registry, including patients in the Netherlands with advanced melanoma treated with first-line ICIs from 2012 to 2019. Data were analyzed from January to September 2023. EXPOSURES: Patients were treated with first-line ipilimumab-nivolumab, antibodies that target programmed cell death (anti-PD-1), or ipilimumab. MAIN OUTCOMES AND MEASURES: Progression-free survival (PFS) and melanoma-specific survival were analyzed, and a Cox proportional hazards model was used to investigate factors associated with PFS after reaching partial response (PR) or complete response (CR). RESULTS: A total of 2490 patients treated with first-line ICIs were included (median [IQR] age, 65.0 [55.3-73.0] years; 1561 male patients [62.7%]). Most patients had an Eastern Cooperative Oncology Group Performance Status of 1 or lower (2202 patients [88.5%]) and normal lactate dehydrogenase levels (1715 patients [68.9%]). PFS for all patients was 23.4% (95% CI, 21.7%-25.2%) after 3 years and 19.7% (95% CI, 18.0%-21.4%) after 5 years. Overall survival for all patients was 44.0% (95% CI, 42.1%-46.1%) after 3 years and 35.9% (95% CI, 33.9%-38.0%) after 5 years. Patients with metastases in 3 or more organ sites had a significantly higher hazard of progression after reaching PR or CR (adjusted hazard ratio, 1.37; 95% CI, 1.11-1.69). CONCLUSIONS AND RELEVANCE: This cohort study of patients with advanced melanoma treated with ICIs in clinical practice showed that their survival reached a plateau, comparable with patients participating in clinical trials. These findings can be used in daily clinical practice to guide long-term surveillance strategies and inform both physicians and patients regarding long-term treatment outcomes.