Benefit/risk of leflunomide in rheumatoid arthritis.

Leflunomide was first shown to have disease-modifying properties in a rat model of adjuvant-induced arthritis. Leflunomide has been subsequently used with success in several animal models of tissue and organ allograft and of autoimmune disease including collagen- and adjuvant-induced arthritis, interstitial nephritis, myasthenia gravis, and systemic lupus erythematosus. Based on its success as an immunosuppressive agent in these models, leflunomide was tested for the treatment of rheumatoid arthritis (RA).