Long-term safety evaluation of natalizumab for the treatment of multiple sclerosis

AbstractIntroductionNatalizumab is a humanized monoclonal antibody highly effective in relapsing-remitting multiple sclerosis (MS). Important concerns about its safety have been pointed out because of the risk of progressive multifocal leukoencephalopathy (PML), caused by the opportunistic John-Cunningham virus (JCV).Areas coveredThis review analyzes all the safety aspects related to the use of natalizumab in MS patients. Fatigue and allergic reactions are not-severe adverse events (AEs) occurring more frequently than placebo and no differences in serious AEs (SAE) have been observed comparing to interferon-β1a during clinical trials. No clear teratogenic effects have been observed, but natalizumab is still considered a pregnancy category “C” drug.The risk of PML depends on 3 factors: concomitant or previous immunosuppression, exposure duration, and anti–JCV antibody level. In natalizumab-related PML the average survival is 77%; prognostic features and information for the earliest identification of PML ha...