Treatment patterns of adjuvant interferon-α2b for high-risk melanoma: a retrospective study of the Grupo Español Multidisciplinar de Melanoma – Prima study

Adjuvant interferon-α2b (IFN-α2b) has been studied extensively in clinical trials, but there have been few studies of real-world use. The aim of this study is to describe the IFN-α2b real-world patterns in patients with high-risk melanoma in Spain. This was a retrospective and multicentre chart review study of an unselected cohort of patients with melanoma at high risk for relapse (stage IIB/IIC/III) treated with IFN-α2b. Patterns were assessed in terms of dose and compliance to planned treatment. A survival analysis was carried out for the full population and according to Kirkwood scheme compliance and the presence of ulceration. Of 327 patients treated with IFN-α2b, 318 received a high-dose regimen following the standard Kirkwood scheme; thus, patterns are described for this regimen. A total of 121 (38%) and 88 (28%) patients had at least one dose reduction during the induction and maintenance phases, respectively. Dose delay was required in fewer than 10% of patients. A total of 78, 40 and 38% of the patients completed the induction phase, maintenance phase and completed treatment, respectively. The median progression-free and overall survival for the full population were 3.2 and 10.5 years, respectively. There were no differences in progression-free survival and overall survival according to Kirkwood scheme compliance and the presence of ulceration. The most frequent adverse events were neutropenia (31%) and fatigue (30%). High-dose IFN-α2b is the most frequently used regimen in Spain as an adjuvant systemic treatment for high-risk melanoma. Despite poor compliance, in this retrospective study, IFN-α2b treatment provided a benefit consistent with that described previously.