Current evaluation of alemtuzumab in multiple sclerosis

Alemtuzumab is a humanized IgG1 kappa monoclonal antibody approved for treatment of B-cell chronic lymphocytic leukemia. This cytolytic antibody is directed against CD52 and depletes lymphocytes, with monocytes, macrophages, natural killer cells and a subpopulation of granulocytes being affected to a much lesser degree. Alemtuzumab is currently under review to treat relapsing multiple sclerosis (MS) in the United States, based on positive Phase II and Phase III trials in both treatment-naïve and treated relapsing MS patients. There was excellent efficacy in suppressing both clinical and neuroimaging disease activities. In these trials, the comparator arm was not placebo, but high dose frequently dosed subcutaneous interferon beta 1a. Alemtuzumab has recently been approved by the European authorities for active relapsing MS, in essence as a first-line agent. It produces long-standing effects, consistent with an induction agent. Efficacy will have to be weighed against risk of adverse effects, which include autoimmune disorders and infection. Alemtuzumab joins an increasingly crowded market, and will add to the complexity of treating MS.

This review will discuss alemtuzumab as a therapy for MS, reviewing PubMed for clinical trials, publications and presentations at international meetings. It will focus on a United States market perspective.

Alemtuzumab offers induction strategy for very active relapsing MS patients who have failed conventional therapy, and possibly selected treatment-naive patients. Alemtuzumab use is likely to be restricted to specialized MS centers, with long-term monitoring to determine the true risk for adverse effects.