Alemtuzumab in multiple sclerosis: an update

Since the introduction of IFN-β, disease-modifying treatments, acting through various immune mechanisms, have been shown to reduce disease activity and severity in relapsing multiple sclerosis. Nevertheless, there remain patients for whom these treatments are incompletely effective, poorly tolerated or contraindicated. Alemtuzumab is a humanized monoclonal antibody that works by selectively depleting circulating lymphocytes. It is given as an intravenous infusion of 12 mg daily for 5 days, then a year later for 3 days. Effectiveness in patients with active relapsing-remitting multiple sclerosis has been demonstrated in two Phase III clinical trials, where it outperformed IFN-β-1a 44 mcg on clinical and radiographic efficacy measures. Its side effect profile, including infusion-associated reactions, infections and secondary autoimmunity, coupled with its long-lasting biological effect, requires patients to commit to close monitoring while on the drug and for 4 years after the final infusion. For select patients with active disease, alemtuzumab offers a powerful therapeutic option.