The company identifies Rilonacept as "a weekly, subcutaneously-injected, recombinant fusion protein that blocks inflammatory cytokines interleukin-1α (IL-1α) and interleukin 1β (IL-1β) signaling." Rilonacept in recurrent pericarditis is at present still classified as an investigational drug. Kiniksa exclusively licensed rilonacept from Regeneron Pharmaceuticals Inc. for recurrent pericarditis and certain other indications. The company noted that "rilonacept was discovered and developed by Regeneron and is approved by the FDA under the brand name ARCALYST for the treatment of Cryopyrin-Associated Periodic Syndromes, which includes Familial Cold Autoinflammatory Syndrome and Muckle-Wells Syndrome."