Response of patients with refractory myasthenia gravis to rituximab: A retrospective study

Introduction: Myasthenia gravis, an autoimmune disorder of neuromuscular transmission, is treated by an array of immunomodulating therapies. A variable response is observed with certain patients being medically refractory. Methods: We report the results of 14 refractory generalized myasthenia gravis patients (6 AChR+; 8 MuSK+) treated with rituximab. Results: Sustained clinical improvement was observed in all patients as well as a reduction of conventional immunotherapies. Prednisone dose decreased a mean of 65.1%, 85.7%, and 93.8% after cycle 1, 2, and 3 of rituximab therapy, respectively. A statistically significant reduction in plasma exchange sessions was seen after cycle 1 with all patients being off of plasma exchange after cycle 3. Acetylcholine receptor antibody titers decreased a mean of 52.1% (p = 0.0046) post-cycle 2. Conclusion: Our results support the hypothesis that rituximab is beneficial and well tolerated in managing refractory myasthenia gravis and nearly doubles published cases. We propose that B-cell-directed therapies may become an attractive option and suggest pursuit of a prospective trial.