Comparing Safety and Efficacy of Rituximab and Eculizumab in Treating Refractory Myasthenia Gravis: A Systematic Review

Abstract

Introduction: Myasthenia gravis is a common autoimmune disease in which patients experience weakness primarily in the ocular, respiratory, bulbar, and limb muscles. Although the symptoms of most patients with myasthenia gravis are well controlled with conventional immunotherapies, about 15% of them experience a refractory disease. This systematic review will focus on the safety and efficacy of monoclonal antibodies, specifically rituximab and eculizumab, in treating myasthenia gravis. Methods: A thorough search for relevant research papers was conducted utilizing PubMed and Google Scholar. A comparative investigation of published research studies was carried out, with only articles published in the last five years being selected. The primary terms that were chosen were "myasthenia gravis, monoclonal antibodies, rituximab, eculizumab, and refractory myasthenia gravis" as keywords and medical subject headings (MeSH). A total of 11 papers were selected for inclusion in this review, with the primary outcomes focusing on the safety and efficacy of rituximab and eculizumab, as subjectively and objectively noted in various scales used to quantify improvement or deterioration. Results: Eleven studies that were either systematic reviews, meta-analyses, or randomized control trials were selected for this study. They analyzed the effect of rituximab, eculizumab, or both on patients with refractory generalized myasthenia gravis. Each study concluded that both drugs showed improvement in patients via their MG-ADL, MG-QOL, MMS, or QMG scores. Adverse events were seen in both groups of patients, with discrepancies between studies regarding which drug caused more. Multiple studies determined that the development of myasthenia crisis in both groups was insignificant. In terms of the safety profile of rituximab it is important to note that infusion reactions, infection, immunosuppression, and cardiovascular events have been seen to occur. For eculizumab, infections including meningococcal, hypertension and infusion related injuries have also been seen to occur. Conclusion: Many patients with myasthenia gravis experience a refractory disease that requires additional or conjunctive treatment. Monoclonal antibodies have been used for these cases, and there is an ongoing investigation as to which one is most safe and most effective. There are many discrepancies in current research on whether rituximab or eculizumab is superior, and there are still many unanswered questions. Both therapies successfully improve clinical manifestations of the disease objectively and subjectively. Rituximab, in particular, was seen to have a safer safety profile in some studies; however, it remains to potentially cause a life-threatening disease known as progressive multifocal leukoencephalopathy (PML) in a meniscal number of patients.