Cryopyrin-associated periodic syndromes (CAPS) are a subgroup of the hereditary 
periodic fever syndromes, which are rare autoinflammatory and inherited 
disorders, characterized by recurrent inflammation and varying degrees of 
severity. CAPS are thought to be driven by excessive production of 
interleukin-1β (IL-1β), through over-activation of the inflammasome by gain of 
function mutations in the gene encoding cryopyrin (NLRP3). This conclusion is 
supported by the remarkable efficacy of IL-1β blockade in these conditions. 
Rilonacept (Arcalyst(TM); Regeneron) is the first us Food and Drug 
Administration-approved treatment for familial cold autoinflammatory syndrome 
and Muckle-Wells syndrome and the first in a new line of drugs designed for 
longer-acting IL-1 blockade. Rilonacept has been associated with a decrease in 
disease activity, high-sensitivity C-reactive protein (hsCRP) and serum amyloid 
A (SAA) in the treatment of CAPS. The clinical safety and efficacy of rilonacept 
in CAPS and non-CAPS populations will be summarized in this review. Rilonacept 
is also beneficial for patients who tolerate injections poorly, due to an 
extended half-life over the unapproved CAPS treatment, anakinra, requiring 
weekly rather than daily self-administration. Other autoinflammatory disorders 
may also benefit from rilonacept treatment, with clinical trials in progress for 
systemic onset juvenile idiopathic arthritis, gout and familial mediterranean 
fever.