Factors Associated With Successful Withdrawal of Biologic Agents in Children With Colchicine-Resistant Familial Mediterranean Fever

Background: Familial Mediterranean fever (FMF) is a monogenic autoinflammatory disease, and colchicine is the mainstay of treatment. Approximately 5%-10% of patients may respond inadequately to colchicine, and anti-interleukin-1 (anti-IL-1) agents are important treatment options in these patients. The aim of this study was to see whether there is any factor associated with the withdrawal of these anti-IL-1 agents and to investigate the characteristics of colchicine-resistant FMF patients who needed biological therapy. Methods: Demographic, clinical characteristics, and disease severity of patients, at 2 referral centers, between 2012 and 2022, in whom anti-IL-1 treatment was continued and discontinued, were compared in this study. The international severity scoring system for FMF (ISSF) was used for disease severity assessment. Results: In 64 colchicine-resistant FMF patients, the median (interquartile range) duration of biological treatment was 39 (45) months. Treatment of 26 patients (40.6%) was started with anakinra and 38 (59.4%) with canakinumab. During follow-up, anti-IL-1 treatment was discontinued in 23 patients (35.9%). High ISSF scores before biological treatment, presence of exertional leg pain, subclinical inflammation, and comorbidities were found to be statistically more frequent in the group whose biological therapy could not be discontinued (p = 0.009, p = 0.006, p = 0.026, p = 0.001, respectively). Conclusions: Low ISSF scores before biological treatment with no accompanying exertional leg pain, subclinical inflammation, and comorbidities may be stated as an associated factors in terms of the discontinuation of biological agents in colchicine-resistant pediatric FMF patients.