Pembrolizumab Versus High-Dose Interferon-2b as Adjuvant Therapy for Pediatric Melanoma: A Retrospective Study

Introduction: Pembrolizumab is well-tolerated in pediatric patients with advanced tumors, consistent with results in adults. However, information on the safety and efficacy of adjuvant pembrolizumab in children and adolescents with melanoma is lacking. Objectives: To compare pembrolizumab versus high-dose interferon-alpha 2b (HDI) as adjuvant therapy in pediatric patients with melanoma. Methods: We performed a retrospective study of pediatric patients diagnosed with melanoma be-tween January 2008 and April 2022. Relapse-free survival (RFS) and the 1-year RFS rate were com-pared between patients receiving adjuvant pembrolizumab or HDI. Results: Seventy-five pediatric patients with melanoma were screened from a database of 6,013 pa-tients. Twenty-four patients were finally enrolled, of whom 9 received pembrolizumab and 15 received HDI as adjuvant therapy. By August 31, 2022, the median follow-up times were 23.6 months and 98.7 months in the pembrolizumab and HDI groups, respectively. There was no significant difference in me-dian RFS between two groups (not reached versus 38.7 months, P = 0.11). The median overall survival was not reached in either group. The 1-year RFS rates were 88.9% and 66.7% in the pembrolizumab and HDI groups, respectively. All adverse events in the pembrolizumab group were grade 1 or 2, but grade 3-5 adverse events occurred in two (13%) patients receiving HDI Conclusions: RFS was similar in pediatric patients with melanoma receiving adjuvant pembrolizumab or HDI, but pembrolizumab was associated with a reduced risk of recurrence and a more favorable safety profile. However, due to the small sample size and differences in follow-up time, larger and prospective studies are still warranted to explore better adjuvant therapies for pediatric melanoma