1. Rituximab was found to significantly reduce median time to remission in new-onset myasthenia gravis.
2. Rituximab appeared to outperform conventional immunosuppressant therapy in terms of need for rescue therapy and adverse effects resulting in discontinuation.
Evidence Rating Level: 2 (Good)
Myasthenia gravis (MG) is a serious neuromuscular disease, resulting from an autoreactive humoral response in the neuromuscular junction, which can be sudden in onset. Oral immunosuppressants are generally the chosen treatment to avoid negative outcomes with corticosteroids. Other treatment options are generally reserved for treatment-refractory cases of MG, as such little is known about the effects of biologic agents on new-onset MG. This retrospective cohort study with data prospectively collected from a Swedish community sample sought to investigate the effects of rituximab, a chimeric monoclonal antibody targeting CD20 on B cells, on both types of MG as well as how it compares to conventional immunotherapy. A total of 72 participants were identified for this study (M [SD] age = 60  years, 43% female). Of these, 24 (33.3%) had received rituximab within one year of disease onset. Of the 48 (66.7%) who received rituximab at a later date, 34 had treatment-refractory MG. In the conventional immunosuppressant group, 26 participants were identified (M [SD] age = 68  years, 12% women). Researchers found that the median time to remission was shorter for new-onset MG compared to refractory MG after adjusting for sex, age, and disease severity (difference 6 months, HR 2.53, 95% CI 1.26 to 5.07, p = 0.009). Remission time was also shorter for the rituximab group compared to conventional treatment (difference 5 months, HR 2.97, 95% CI 1.43 to 6.18, p = 0.004). Those taking rituximab required fewer rescue therapy episodes in the first two years (M [SD] = 0.28 [1.10] times vs 1.31 [1.59], p < 0.001). Further, a larger number of MG patients had significantly less need for additional immunotherapies (difference 35%, OR 5.47, 95% CI 1.40 to 21.43, p = 0.02). The rituximab group also had significantly lower discontinuation rates (difference 43%, p < 0.001). These findings suggest that rituximab is likely a viable treatment for both new-onset and refractory MG, with improved outcomes compared to conventional immunotherapies and reduced adverse events resulting in discontinuation.
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