Outcomes of adjuvant immune checkpoint inhibitor therapy in melanoma: a retrospective study.

BACKGROUND Adjuvant treatment of malignant melanoma has improved the outcomes for patients. However, real-world data on efficacy and safety are limited. We investigated outcomes of melanoma patients treated with adjuvant immune checkpoint inhibitors (ICI) in the Ghent University Hospital. METHODS Patients with melanoma (stage III-IV), who received at least one cycle of ICI as adjuvant treatment between 2018 and 2021 were included in this retrospective cohort study. Primary outcomes were recurrence-free (RFS) and overall survival (OS). Other outcomes of interest were relapse patterns and safety. RESULTS 59 patients were included, with a median follow-up of 36 months. Disease recurrence or death of any cause was observed in 25/59 (42.4%) of the patients. The median RFS was 56.0 months (95%CI 36.1-75.9 months). At 48 months, RFS and OS were 55.9% and 84%, respectively. 9/23 (39%) recurrences were locoregional and 14/23 (60.9%) patients developed distant metastasis as first recurrence, including 2 (3.4%) with brain metastasis. Median time to recurrence was 9 months (range 2-56 months). 35/59 (59.3%) completed one year of adjuvant treatment, 12/59 (20.3%) stopped because of recurrence and 10/59 (16.9% because of toxicity. Immune-related adverse events wereseen in 29/59 (49.4%) patients, 10/59 (16.9%) developed grade 3-4 toxicity. CONCLUSION This study confirms the real-world efficacy and safety of adjuvant ICI for melanoma, achieving RFS and OS comparableto the pivotal clinical trials. About 40% of patients develop arelapse, mainly during the adjuvant treatment. The outcomes ofpatients progressing during adjuvant ICI are poor, emphasizing the need of prospective and real-world studies on optimal management after progression on (neo)adjuvant treatment.