Could tocilizumab be used in familial Mediterranean fever? A systematic review

Introduction: Familial Mediterranean Fever (FMF) is the most common monogenic autoinflammatory disease characterized by recurrent fever and serosal inflammation. Although colchicine is the primary treatment, around 10% of FMF patients do not respond to it, necessitating alternative therapies. Biologic treatments, such as IL-1β, TNF-α and IL-6 inhibitors, have been considered. However, the accessibility and cost of IL-1β inhibitors may limit their use in certain regions. Tocilizumab (TCZ), an IL-6 receptor inhibitor, offers an alternative, but its efficacy in FMF is not well-documented. Objective: To evaluate the efficacy and safety of TCZ in the treatment of FMF. Methods: Following PRISMA guidelines, we identified 237 articles on the use of TCZ in FMF. Results: After selection, 14 articles were included: two double-blind RCTs, two retrospective studies and 10 case reports. Multicentre double-blind RCTs reported mixed results in FMF patients without AA amyloidosis due to genetic/classification heterogeneity of the available studies, possible misdiagnosed FMF patients and study design. Retrospective studies suggest that TCZ may benefit FMF patients with established renal AA amyloidosis, potentially preventing progression and managing flares more effectively. TCZ showed a safe profile with no specific adverse events, but data on its use during pregnancy or breastfeeding are lacking. There was no available data on the use of TCZ in paediatric FMF. Conclusion: This review summarizes the current state of research, safety and efficacy of TCZ in FMF. While IL1β inhibitors remain the first choice for colchicine-resistant or intolerant FMF patients, TCZ might be of interest in some selected FMF patients with established AA amyloidosis and resistance to colchicine and interleukin 1 inhibitors.