High- and Low-Dose Interferon Alfa-2b in High-Risk Melanoma: First Analysis of Intergroup Trial E1690/S9111/C9190

PURPOSE: Pivotal trial E1684 of adjuvant high-dose interferon alfa-2b (IFNα2b) therapy in high-risk melanoma patients demonstrated a significant relapse-free and overall survival (RFS and OS) benefit compared with observation (Obs). PATIENTS AND METHODS: A prospective, randomized, three-arm, intergroup trial evaluated the efficacy of high-dose IFNα2b (HDI) for 1 year and low-dose IFNα2b (LDI) for 2 years versus Obs in high-risk (stage IIB and III) melanoma with RFS and OS end points. RESULTS: A total of 642 patients were enrolled (608 patients eligible), of whom a majority (75%) had nodal metastasis (50% had nodal recurrence). Unlike E1684, E1690 allowed entry of patients with T4 (> 4 mm) deep primary tumors, regardless of nodal dissection, and 25% of the patients entered onto this trial had deep primary tumors (compared with 11% in E1684). At 52 months’ median follow-up, HDI demonstrated an RFS benefit exceeding that of LDI compared with Obs. The 5-year estimated RFS rates for the HDI, LDI, and Obs arms ...