Cryopyrin-associated periodic syndromes (CAPS) are a group of inherited 
inflammatory disorders consisting of familial cold-induced autoinflammatory 
syndrome (FCAS), Muckle-Wells syndrome (MWS), and neonatal-onset multisystem 
inflammatory disease (NOMID; also known as chronic infantile neurologic, 
cutaneous, articular [CINCA] syndrome). These rare disorders are associated with 
heterozygous mutations in the NLRP3 (CIAS1) gene, which encodes the protein 
NALP3 or cryopyrin, and inflammation driven by excessive production of the 
cytokine interleukin-1beta (IL-1beta). Amyloidosis is a serious complication 
with 25% of MWS patients developing amyloidosis, with occasional fatal 
consequences, whilst up to 20% of CINCA/NOMID patients die from various 
complications, before reaching the early adulthood. In some CINCA/NOMID adult 
survivors amyloidosis can also occur. Prior to the discovery of the CIAS1 gene 
mutations and the advent of IL-1 targeted therapy, treatment was aimed at 
suppressing inflammation, with limited success. The selective blockade of 
IL-1beta, with anakinra (IL-1 receptor antagonist), not only provided supportive 
evidence for the role of IL-1beta in CAPS, but also demonstrated the efficacy of 
targeting IL-1beta for treatment of these conditions. In February, 2008, 'Orphan 
Drug' approval from the Food and Drug Administration (FDA) for rilonacept (IL-1 
Trap/Arcalyst(), Regeneron Pharmaceuticals, Inc) was given for the treatment of 
two CAPS disorders, FCAS and MWS in adults and children 12 years and older, 
making rilonacept the first therapy approved for the treatment of CAPS.