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

e21563 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 macroscopic resectable cutaneous melanoma treated with neoadjuvant immune checkpoint inhibitor/-s (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. The median age was 71 years, with 69% having lymph node metastases (LN), 16% in-transit (ITM), 9% ITM and LN and 7% had stage IV disease. Patients received a median of two treatments of neoadjuvant ICI, 98% received nivolumab monotherapy, and 88% underwent surgery as planned. Among all patients who started treatment, 42% experienced a major pathological response (MPR), 9% a partial pathological response (pPR) and 31% no pathological response (pNR). The administration of adjuvant ICI treatment varied, and 18% of the patients with a MPR received no adjuvant treatment. 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 a 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.