Stopping oral steroid-sparing agents at initiation of rituximab in myasthenia gravis

Abstract

Rituximab is a chimeric monoclonal antibody that binds CD20 and causes the depletion of B-cell subsets. Although initially designed to treat lymphoma, it has found wide use in the management of various autoimmune conditions, including myasthenia gravis (MG), an autoimmune disorder of the neuromuscular junction. Treated myasthenia patients are often on an oral steroid-sparing agent. To determine the safety of stopping oral steroid-sparing agents at the initiation of rituximab therapy and its effectiveness we reviewed the records of 27 MG patients with rituximab, including 13 with anti-MuSK+ MG, 10 with anti-AChR+ MG, and 4 double seronegative MG patients. All patients that were on an oral steroid-sparing agent (21 of 27) were able to stop it, and they did not require re-introduction of the medication. Also, the daily prednisone dosage was significantly decreased in 20/24 patients across all three serotype groups. MGFA post intervention status analysis also showed 15/27 of all patients achieved minimal manifestation status or remission across all groups. Antibody titers decreased dramatically and promptly in anti-MuSK+ MG patients. Our data suggests that stopping oral steroid-sparing agents at initiation of rituximab therapy is safe. Also, our data indicates that rituximab is highly effective in the management of seropositive MG patients.

Keywords: Acetylcholine receptor; Muscle specific kinase; Myasthenia gravis; Rituxan; Rituximab.