Long-Term Efficacy and Safety Profile of Rilonacept in the Treatment of Cryopryin-Associated Periodic Syndromes: Results of a 72-Week Open-Label Extension Study

Background: Cryopyrin-associated periodic syndromes (CAPS) are rare, inherited autoinflammatory disorders associated with considerable hardship to patients. The interleukin-1 inhibitor rilonacept has been shown to be well-tolerated and effective in preventing CAPS symptoms in 2 pivotal studies. Objective: In this study, the long-term effects of rilonacept for improvement in CAPS symptoms and its safety and tolerability were evaluated during extended treatment. Methods: Patients with CAPS entered a 72-week open-label extension (OLE) following 2 sequential placebo-controlled Phase III studies (n = 44), or entered directly into the OLE (n = 57). Adults received weekly subcutaneous rilonacept 160 mg, and pediatric patients received subcutaneous rilonacept 2.2 mg/kg, up to 160 mg/week. Safety was evaluated in all patients, and efficacy was evaluated using a validated composite key symptom score in 56 patients. Results: After rilonacept treatment for 72 to 96 weeks mean key symptom score at OLE Week 72 was reduced from 2.6 to 0, and the mean number of multisymptom flare days was reduced from 7.3 (34.8% of days) at baseline to 0.6 (2.9% of days) at end point. Elevated levels of inflammatory markers (eg, high sensitivity-C reactive protein and serum amyloid A, were normalized. Adverse events were generally mild to moderate, the most common being injection site reactions and upper respiratory tract infections. The incidence of these events was similar to or lower than the rate reported in the pivotal studies. Conclusions: Long-term treatment with rilonacept of up to 96 weeks resulted in improvements in clinical signs and symptoms of CAPS and normalized biomarkers of inflammation. Rilonacept exhibited a generally favorable safety and tolerability profile in adult and pediatric patients with CAPS throughout the extended treatment period. ClinicalTrials.gov identifier: NCT 00288704. (Clin Ther. 2012;34: 2091-2103) (C) 2012 Elsevier HS Journals, Inc. All rights reserved.