Rituximab for severe myasthenia gravis - experience from five patients

Background - Rituximab (RTX), a monoclonal antibody directed against CD20+ B cells, is used in the treatment of several autoimmune disorders including severe generalized myasthenia gravis (MG). Aims of the study - To describe the experience with RTX in five MG patients treated at our Neuromuscular Centre. Methods - Effect of RTX treatment was monitored by quantitative MG score (QMG score), forced vital capacity (FVC) and records of clinical parameters. Three patients had thymoma. Duration of MG prior to the first course of RTX was 3, 7, 26, 26 and 38 years. Results - We found favourable response to RTX treatment in all five patients. QMG score was markedly lower after RTX and in the three patients with respiratory muscle affection the FVC was increased. A good relief of bulbar, respiratory or extremity MG weakness was thus also found in the three patients who had long-standing severe MG. Repeated RTX treatment was needed in four patients. Conclusions - We conclude that RTX is effective in recent onset MG as well as in long-standing cases. As thymoma is prevalent in patients with severe MG, further studies are needed to evaluate the risk of thymoma recurrence following RTX treatment.