Background

Multiple sclerosis is a progressive disease of the central nervous system where the person’s own body destroys the coating that protects nerves. The disease may go into remission (where the symptoms reduce or stop) and then relapse (where the symptoms return). This is called relapsing-remitting multiple sclerosis (RRMS). Medicines called monoclonal antibodies (such as alemtuzumab) could be a possible alternative immunotherapy (treatment to stimulate the immune system) to interferon beta treatment (one of the usual treatments) in people with RRMS. In this review, we aimed to compare the effectiveness, side effects and safety of alemtuzumab versus interferon beta 1a in the treatment of people with RRMS.

Study characteristics

We searched medical databases and found three studies involving 1694 participants (CAMMS223, CARE-MS I and CARE-MS II). CAMMS223 involved people with previously untreated, early RRMS. Participants received either subcutaneous (under the skin) interferon beta 1a (at a dose of 44 μg) three times per week or annual intravenous (into a vein) courses of alemtuzumab (at a dose of either 12 mg per day or 24 mg per day). CARE-MS I enrolled adults aged 18 to 50 years with previously untreated RRMS. Participants received annual intravenous courses of alemtuzumab 12 mg per day or subcutaneous interferon beta 1a 44 μg three times per week. CARE-MS II enrolled adults aged 18 to 55 years with RRMS and at least one relapse on interferon beta or glatiramer (another medicine that alters the immune response) treatment. Participants received subcutaneous interferon beta 1a 44 μg three times per week, annual intravenous courses of alemtuzumab 12 mg per day or annual intravenous courses of alemtuzumab 24 mg per day. The evidence is current to 1 February 2017.

Key results

In the alemtuzumab 12 mg per day group, the results showed that alemtuzumab was better than interferon beta 1a in reducing relapses, preventing disease progression and developing new lesions in nerve coatings after 24 and 36 months of assessment, but found no difference in the changes of Expanded Disability Status Scale (EDSS; a measurement of disability) score. In the alemtuzumab 24 mg per day group, alemtuzumab was better than interferon beta 1a in reducing relapses, preventing disease progression and the changes of EDSS score after 36 months of assessment.

All three trials reported side effects and serious side effects. Alemtuzumab did not increase the total risk of having side effects compared with interferon beta 1a.

Quality of the evidence

We considered all three studies to be of high quality. But the overall quality of the evidence was low to moderate, which was limited by the low number of included studies.