Effect of Interleukin-1 Inhibition in a Cohort of Patients with Colchicine-Resistant Familial Mediterranean Fever Treated Consecutively with Anakinra and Canakinumab

Objective. To evaluate the efficacy of IL-1 blockers in a cohort of patients with colchicine-resistant familial Mediterranean fever (crFMF) treated consecutively with anakinra and canakinumab. Methods. Patients with crFMF treated with anakinra and canakinumab in any order were identified using the computerised database of Sheba Medical Center. Background characteristics of the patients, reason for switching IL-1 inhibitor, and frequency of attacks under colchicine only, anakinra, and canakinumab were extracted from the computerised patient files. Patients were then interviewed for patient-reported outcomes. Results. A total of 46 patients in our clinic were prescribed canakinumab for crFMF after previous anakinra treatment, whereas no patients who switched treatment from canakinumab to anakinra were identified. Of those, 23/46 patients (50%) discontinued anakinra due to inadequate response (11 of them with secondary failure after a good initial response). Frequency of flares was significantly decreased following switch to canakinumab from anakinra treatment (p<0.01). After the switch to canakinumab, the median duration of flares, the severity of pain during a flare, and the patient's global assessment of disease activity were all significantly decreased (p=0.01), according to the reports from the patients. Conclusion. Canakinumab is an effective treatment for FMF after failure of anakinra due to any cause.