Interleukin-1 (IL-1) is one of the main inflammatory mediators associated with 
development of rheumatoid arthritis (RA). Deficiency in secretion of the natural 
IL-1 antagonist was found in RA patients, and enhanced joint inflammation. This 
finding was confirmed by numerous studies using the animal model of the disease. 
Two randomized, multicenter clinical trials with anakinra, a recombinant IL-1 
receptor antagonist (rHHHuIL-1Ra), revealed that application of anakinra with or 
without methotrexate induces remission (ACR 20) in 38-71% of patients with RA. 
Induction of remission was dose and treatment-time-dependent. The present paper 
reviews theoretical application of rHuIL-1Ra in patients with RA and summarizes 
results of published clinical trials of the drug.