Emerging therapies for autoimmune myasthenia gravis: Towards treatment without corticosteroids

Myasthenia gravis is an autoimmune disease characterized by dysfunction of the neuromuscular junction. Current treatment is based on lifestyle advice, symptomatic treatment, immunosuppressive drugs and thymectomy. Corticosteroids remain the cornerstone of treatment beside symptomatic medication due to their low cost, wide availability and fast mode of action. However, long term steroid use carries substantial risks of severe adverse side effects. Therefore, non-steroidal immunosuppressive drugs are commonly added to the treatment. Unfortunately, they have a delayed-onset effect and evidence of their efficacy appears to be difficult to obtain. Several trials using drugs that have had clear positive results in other immunological disorders have failed in myasthenia. This failure may in part be related to difficulties in the design of clinical trial for myasthenia, which has a fluctuating disease course involving weakness that may be difficult to assess quantitively. This problem is exacerbated by the tendency of most clinical trials to select patients with a stable, but severe disease. Future trials should: select patients with weakness and fatigability that is completely explained by their myasthenia gravis, use a design that avoids the exclusion of patients with recent changes in medication, and explore the possibilities to completely avoid the use of corticosteroids.