Successful treatment of refractory generalized myasthenia gravis with rituximab

Abstract

Objective: Myasthenia gravis (MG) is an autoimmune neuromuscular disorder for which current therapies carry a high risk of side-effects and may be insufficient in stabilizing the clinical status. Many therapeutic options can be ruled, such as thymectomy, corticosteroids, azathioprine, cyclophosphamide, mycophenolate mofetil, methotrexate, intravenous immunoglobulin (IVIg) or less frequently plasmapheresis must be ruled.

Methods: We followed prospectively six patients with MG who presented with a poor response to two or three lines of immunosuppressive conventional drugs associated with oral corticosteroids. All but one were acetylcholine receptor negative and three were anti-MuSK positive. IVIg did not improved the neurological status and all patient required high doses of cholinesterase inhibitors.

Results: Rituximab was introduced with a mean follow-up of 1.5 years (375 mg/m(2), days 1, 8, 15, 28 during the first month and then one dose every 2 months). After 2 years of follow-up, all patients stopped corticosteroids and tapered off cholinesterase inhibitors from 60 to 180 mg/day without severe infectious events.

Conclusion: Rituximab, a chimeric IgG k monoclonal antibody that target CD20 is used for the treatment of relapsing/refractory CD20 positive low-grade non-Hodgkin's lymphoma and other autoimmune neuromuscular diseases. Four previous short reports have described a good response of MG associated with lymphoma with rituximab. It appears to be a promising and effective drug for the treatment of MG without lymphoma, with a substantial benefit to the clinical status and good tolerability.