Anakinra

Interleukin-1 (IL-1) plays an important role in inflammation and immunological responses. Inflammatory stimuli trigger its production, and it binds to the IL-1 receptor to activate a wide variety of mechanisms. The activity of the IL-1 receptor is also regulated by a naturally occurring IL-1 receptor antagonist (IL-1Ra) that competes for the binding sites of the IL-1 receptor. In rheumatoid arthritis (RA) patients, IL-1 levels are elevated, inducing cartilage degradation and the stimulation of bone resorption, and the amount of IL-1Ra in the synovium and synovial fluid of RA patients cannot compete with the high level of IL-1 present. Anakinra is a recombinant, non-glycosylated form of IL-1Ra that competes with and inhibits IL-1 by binding to the IL-1 receptor; therefore, the administration of this drug reduces the inflammatory response in RA patients.

Anakinra can also be used in the treatment of neonatal-onset multisystem inflammatory disease (NOMID) and deficiency of interleukin-1 receptor antagonist (DIRA). Patients with NOMID have spontaneous mutations in CIAS1/NLRP3, a gene that encodes cryopyrin, an inflammasome component. When activated, the inflammasome enhances and promotes the production of IL-1β, an isoform of IL-1. DIRA is an autoinflammatory disease caused by mutations in the IL1RN gene. These mutations reduce the amount of IL-1Ra that is secreted, leading to the unopposed action of IL-1. Anakinra controls NOMID and DIRA symptoms by inhibiting IL-1 activity.