Multiple sclerosis (MS) is an auto-immune disease in which the myelin sheaths surrounding nerve fibres are destroyed. The disease affects millions of people worldwide and can lead to loss of sight and mobility as well as depression, fatigue and problems with cognition. There is currently no cure, and few truly effective treatments.
A study published in the New England Journal of Medicine describes the results of a randomized, blinded, phase II clinical trial examining the effects of alemtuzumab in patients with previously untreated, early, relapsing-remitting multiple sclerosis. Alemtuzumab is a humanized monoclonal antibody that targets the CD52 receptor on lymphocytes and monocytes and is prescribed for the treatment of chronic lymphocytic leukemia and T-cell lymphoma. Patients with scores of 3.0 or less on the Expanded Disability Status Scale and disease duration of 3 years or less were assigned to receive either subcutaneous interferon β-1a, (44 µg) three times per week, or annual intravenous cycles of alemtuzumab (either 12 mg or 24 mg per day) for 36 months. Interferon β-1a is one of the most effective licensed therapies for similar cases of MS. Alemtuzumab therapy was suspended in September 2005 after immune thrombocytopenic purpura developed in three patients, one of whom died. Treatment with interferon β-1a continued for the full duration of the study.
Alemtuzumab treatment was found to significantly reduce the rate of sustained accumulation of disability by 71% and the annualized rate of relapse by 74% compared with interferon β-1a treatment. Importantly, the mean disability score on a 10-point scale improved by 0.39 point in the alemtuzumab group and worsened by 0.38 point in the interferon β-1a group. The lesion burden was also reduced in the alemtuzumab group compared with the interferon β-1a group and, from month 12 to month 36, brain volume increased in the alemtuzumab group but decreased in the interferon β-1a group.
The incidence of side effects was somewhat higher in the alemtuzumab group compared with the interferon β-1a group. Adverse events included thyroid disorders (23% vs 3%), immune thrombocytopenic purpura (3% vs 1%) and infections (66% vs 47%). There were no significant differences in outcomes between the 12-mg dose and the 24-mg dose of alemtuzumab.