The Medicines and Healthcare Products Regulatory Agency (MHRA) in the UK has granted a licence to an interleukin-1 (IL-1) inhibitor Anakinra (Kineret) for the treatment of cryopyrin-associated periodic syndromes (CAPS) in adults and children as young as eight months.
Anakinra is an interleukin-1 (IL-1) receptor antagonist.Anakinra blocks the biologic activity of naturally occurring IL-1, including inflammation and cartilage degradation associated with rheumatoid arthritis, by competitively inhibiting the binding of IL-1 to the Interleukin-1 type receptor, which is expressed in many tissues and organs. IL-1 is produced in response to inflammatory stimuli and mediates various physiologic responses, including inflammatory and immunologic reactions. IL-1 additionally stimulates bone resorption and induces tissue damage like cartilage degradation as a result of loss ofproteoglycans. In patients with rheumatoid arthritis the natural IL-1 receptor antagonist is not found in effective concentrations in synovium and synovial fluid to counteract the elevated IL-1 concentrations in these patients.
Anakinra is not considered a ‘Disease-modifying antirheumatic drug‘ (DMARD) but rather a ‘Biological Response Modifier’ (BRM) because its able to selectively target the pathologic element of the disease.