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

Abstract

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.

Keywords: Melanoma; adjuvant immunotherapy; anti-PD-1; melanoma recurrence; nivolumab; pembrolizumab.