Objective: Previous reports on interferon-alpha (IFN-alpha) were conflicting with respect to its efficacy in familial Mediterranean fever (FMF) refractory to colchicine treatment. We investigated the effect of IFN-alpha in patients with colchicine-resistant FMF.
Methods: In a prospective, patient self-controlled, open-label study evaluating the safety and efficacy of IFN-alpha in patients with FMF with a severe phenotype, refractory to intensified (oral plus intravenous) colchicine therapy, we advised patients to subcutaneously inject IFN-alpha, 3 million international units, at the onset of the FMF attack. Attacks not treated with IFN-alpha of the same patients and in the same sites served as control attacks. Features of each attack were recorded in a questionnaire, eventually used to compare between IFN-alpha-treated and non-treated attacks.
Results: Ten patients with a total of 80 attacks were recruited. Compared to 22 untreated attacks, a > 20% and > 50% reduction in the duration of the attacks was noted in 100% and 90% of the 58 IFN-alpha-treated attacks, respectively (p < 0.001 for both). The severity (degree of pain) of the IFN-alpha-treated attacks was attenuated by > 20% and > 50% in 88% and 49% of these attacks, respectively (p < 0.001 for both). The most common drug-related adverse events were chills and fatigue.
Conclusion: Early intervention with IFN-alpha injections was associated with reduced attack length and/or severity in a substantial number of bouts, with an acceptable cost of adverse events.