Neoadjuvant immunotherapy for patients with resectable stage III/IV cutaneous melanoma - A Swedish retrospective real-world study (NEO-MEL)

Background: Recent clinical trials have demonstrated that neoadjuvant administration of PD-1 + /- CTLA-4 inhibitor is superior to adjuvant PD-1 inhibitors in patients with resectable stage III and IV cutaneous melanoma. However, the generalizability of these results to an unselected patient population treated in routine clinical settings remains unclear. Methods: A population-based study was conducted across three academic centers in Sweden, including all patients with advanced but resectable cutaneous melanoma treated with neoadjuvant ICI in the corresponding regions from January 1, 2022, to June 30, 2024. Data were retrospectively collected from medical records. Results: A total of 118 patients were included in the analysis. Patients received a median of two treatments of neoadjuvant ICI, 98 % received nivolumab monotherapy, and 88 % had surgery as planned. Among all patients who started treatment, 42 % experienced a major pathological response (MPR), 9 % a partial pathological response (pPR), 31 % no pathological response (pNR). At a median follow-up time of 12 months, the estimated 12-month event-free survival was 72 % (95 % CI, 63-82) and the recurrence-free survival (RFS) was 74 % (95 % CI, 65-83). The estimated 12-month RFS was 94 % in patients with an MPR, 91 % among those with a pPR, and 61 % among those with a pNR. Grade >= 3 immune-related adverse events occurred in 9 % of the patients. Conclusions: Early adoption of neoadjuvant ICI therapy in patients with resectable stage III and IV cutaneous melanoma treated in population-based routine clinical practice was feasible and provided beneficial efficacy and safety outcomes, similar to those seen in clinical trials.