Adjuvant Therapy for Melanoma

Systemic adjuvant therapy for surgically resected cutaneous melanoma that is at high risk for disease recurrence and death targets residual micrometastatic disease which is the source of future local or distant relapse. Interferon-alfa (IFNα) has been the most extensively studied in regimens that varied by dosage, route of administration, formulation, and duration of therapy. Most regimens have demonstrated improvements in relapse-free survival (RFS), while the regimen administered at high dosage (HDI) showed improvements in overall survival (OS) in two out of three RCTs. HDI benefits as measured by the hazard ratios (HR) in E1684 (vs. observation), E1690 (vs. observation), and E1694 (vs. vaccine) trials were estimated at 0.61, 0.78, and 0.67 (RFS) and 0.67, 1.0, and 0.72 (OS) when first reported with lesser estimates on later updates. Pegylated IFNα (peg-IFN) as studied in the European Organisation for Research and Treatment of Cancer (EORTC) 18991 trial in patients with stage III melanoma significantly reduced the risk of relapse (HR 0.87) with no impact on OS. More recently (EORTC 18071), ipilimumab at the high dose of 10 mg/kg was shown to significantly improve RFS (HR 0.76) and OS (HR 0.72) of stage III melanoma patients but at a significant cost in terms of immune-related toxicities. Ongoing adjuvant studies are testing ipilimumab at 3 or 10 mg/kg versus HDI (E1609) and the anti-PD-1 antibodies nivolumab (CheckMate 238) and pembrolizumab (KEYNOTE-054 and S1404).