LEFLUNOMIDE PREVENTS THE DEVELOPMENT OF EXPERIMENTALLY-INDUCED MYASTHENIA-GRAVIS

Myasthenia gravis is an autoimmune disease in which autoantibodies spe cific to the acetylcholine receptor (AChR) are formed, leading to a gr adual destruction of the receptors in muscles that are responsible for picking up nerve impulses, and results in weakness and eventual loss of muscle function. The novel immunomodulating drug leflunomide (HWA 4 86) has been shown to be very effective in preventing and halting ongo ing disease in an array of experimental autoimmune disorders and react ions leading to organ graft rejection. Further, recent data From phase II clinical trials indicate that this drug is efficacious and is safe in humans with rheumatoid arthritis. In the studies reported here, we found that rats immunized with AChR-protein and not receiving lefluno mide developed experimental myasthenia gravis (EMG) between day 7 and 11 post-immunization, and about 79% of these animals expressed clinica l signs of disease. Treatment of AChR-protein immunized rats with lefl unomide, from the day of disease induction, totally suppressed the dev elopment of EMG. Thus, the results we have obtained using leflunomide in EMG indicate that this drug could be beneficial in combating myasth enia gravis in humans.