Anakinra - An interleukin-1 receptor antagonist for treatment of rheumatoid arthritis

The interleukin-1 receptor antagonist (IL-1Ra) anakinra is a biologic agent designed to antagonize the joint destruction, inflammation, and pain assoc iated with progression of rheumatoid arthritis. Pending FDA approval, anaki nra will be the first IL-1Ra available to treat rheumatoid arthritis. It wa s developed to block the proinflammatory effects of interleukin-1, a cytoki ne present in synovial fluid. A large placebo-controlled trial showed that anakinra significantly reduces joint destruction over 6 to 12 months, while an additional study showed significant clinical improvement when anakinra was added to methotrexate therapy. A transient local injection-site reactio n is the primary adverse effect. Because anakinra is primarily eliminated r enally, dosing adjustment may be needed in the elderly and in patients with renal impairment. Administration is by subcutaneous injection once daily; the optimal dosage appears to be 75 or 150 mg/day. Anakinra promises to be another effective treatment option in a disease with no cure.