Efficiency of antibody therapy in demyelinating diseases

Monoclonal antibody therapy is a new treatment strategy for many types of diseases including cancers and autoimmune diseases, realizing a high efficacy and tolerability. In multiple sclerosis (MS) and neuromyelitis optica (NMO) spectrum disorders, several monoclonal antibodies have been suggested to decrease the incidence of clinical relapse and the disease activity. In MS, anti-α4 integrin (natalizumab), anti-CD52 (alemtuzumab), anti-CD25 (daclizumab) and anti-CD20 (ocrelizumab) have been shown to effectively reduce the relapses in randomized controlled trials and have been approved by the Food and Drug Administration. Specifically, ocrelizumab is the first drug that has shown significant suppression of brain volume loss and suppression of chronic disability progression. In NMO, though there have yet to be any approved monoclonal antibodies, rituximab, anti-complement C5 (eculizumab), anti-IL-6 receptor (tocilizumab), anti-CD19 (inebilizumab) and non-pathogenic anti-aquaporin 4 (aquaporumab) have been suggested to be effective, and some of these are now under clinical trials. Aquaporumab is a non-pathogenic recombinant human monoclonal antibody that competitively inhibits the binding of the pathogenic auto-antibody against aquaporin 4 in NMO patients; thus, it is expected to be highly disease specific with less non-specific adverse events. Some of these monoclonal antibodies in MS and NMO are known to cause several notable adverse events. Natalizumab and rituximab increase the risk of progressive multifocal leukoencephalopathy. Eculizumab increases the risk of meningococcal infection. Tocilizumab is known to cause intestinal diverticulitis that can cause intestinal perforation. In this review, we summarize the characteristics of, evidence for and notable adverse events of each monoclonal antibody in MS and NMO.