Regeneron Pharmaceuticals, Inc (TARRYTOWN, NY), a fully integrated biopharmaceutical company, announced that Arcalyst™ (rilonacept) injection for subcutaneous use is now available by prescription in the US for the treatment of cryopyrin-associated periodic syndromes (CAPS), including familial cold auto-inflammatory syndrome (FCAS) and Muckle-Wells syndrome (MWS) in adults and children ≥12 years. Arcalyst is not indicated for use in, and has not been studied in, CAPS patients with neonatal-onset multisystem inflammatory disease.

Regeneron was granted marketing approval for the agent, a potent long-acting inhibitor of interleukin-1 (IL-1), by the US FDA in February 2008, making it the only therapy approved for patients with CAPS, a group of rare, inherited, auto-inflammatory conditions characterized by life-long symptoms of rash, fever/chills, joint pain, eye redness/pain, and fatigue. Intermittent, disruptive exacerbations or flares can be triggered at any time by exposure to cooling temperatures, stress, exercise, or other unknown stimuli. The incidence of CAPS has been reported to be ~1 in 1,000,000 people in the US.

The company has introduced the Arcalyst resource center, a comprehensive support program for CAPS patients and their physicians, to assist CAPS patients gain access to Arcalyst treatment. In addition, the center provides assistance to help CAPS patients find appropriate medical care from trained healthcare providers, to prepare CAPS physicians to diagnose and appropriately treat these rare conditions, to help CAPS patients in securing insurance authorization, and to refer CAPS patients to company-sponsored and third-party financial assistance programs, when appropriate.

Arcalyst is being distributed through two specialty pharmacies, which will directly mail patients a monthly shipment of the agent and the supplies needed for self-injection. The pharmacies will also provide access to self-injection training and adherence counseling to patients who need those services.

Regeneron completed a phase III program evaluating self-administration by weekly subcutaneous injection of the agent in 47 adult patients suffering from FCAS or MWS. The double-blind, placebo-controlled trial, followed by a 24-week open-label extension phase, demonstrated rapid, substantial, and lasting reduction of clinical signs and symptoms, as well as laboratory measures of inflammation in patients. A favorable safety and tolerability profile was also observed. The most commonly reported adverse reactions with Arcalyst were injection-site reaction and upper respiratory tract infection.

CAPS are generally caused by autosomal-dominant mutations in the NLRP-3 (previously known as CIAS1) gene and resultant alterations in the protein, cryopyrin, which it encodes. These alterations in the cryopyrin protein lead to overproduction of IL-1, resulting in an inflammatory response and CAPS. Most, but not all, patients with CAPS have the NLRP-3 gene mutation.