Familial Mediterranean fever (FMF)-response to TNF-blockers used for treatment of FMF patients with concurrent inflammatory diseases

Objective: Familial Mediterranean fever (FMF) is the most common interleukin 1 (IL-1)-driven monogenic autoinflammatory disease. Yet published data also suggest that tumor necrosis factor (TNF) may have a role in the pathogenesis of FMF and may serve as a target for treatment. In the present study we evaluate this hypothesis. Methods: To this goal, we studied the incidental effect on FMF of TNF-directed treatment, administered to colchicine-refractory FMF patients for the management of a concurrent inflammatory disease. The rates of FMF patients and of treatments with complete or nearly complete FMF response were determined, based on the number of FMF attacks during TNF-blocker exposures. The possible effect of various FMF and non-FMF features on the outcome was determined using comparative analysis. Patients were identified and data were retrieved using electronic files from the FMF clinic. Results: Twenty-six patients were identified, each receiving ≥ 1 of four TNF-blockers for a mean duration of 27.6 ± 16.4 months. The TNF-blockers were found to induce complete or nearly complete FMF response in 10 (38.5%) of the patients, and in 13 of 50 (26%) exposures. No clinical, genetic, demographic, or therapeutic feature could predict which FMF patient would respond favorably to TNF-blocker therapy. Conclusion: This study suggests that TNF-blockers may be beneficial for a small proportion of colchicine-resistant FMF patients.