Alemtuzumab May Suppress Disease Activity for Four Years

INDIANAPOLIS—Most patients with relapsing-remitting multiple sclerosis (MS) remain free of new MRI activity for four years after initiating treatment with alemtuzumab, according to data presented at the 2015 CMSC Annual Meeting. Alemtuzumab also appears to slow the rate of brain volume loss, compared with interferon beta. The drug’s durable effects may result from the distinct pattern of lymphocyte depletion and repopulation that follows treatment, said Anthony Traboulsee, MD, Associate Professor of Neurology at the University of British Columbia in Vancouver.

The data result from four-year follow-up of participants in the CARE-MS II trial. In that study, patients with relapsing-remitting MS who had had an inadequate response to prior therapy (defined as at least one relapse) were randomized to alemtuzumab or subcutaneous interferon beta-1a. After two years, patients receiving alemtuzumab had a 49% decrease in annualized relapse rate and a 42% decrease in six-month sustained accumulation of disability, compared with patients who received interferon beta-1a. In addition, more patients in the alemtuzumab group were free of MRI activity, compared with the interferon group.

The open-label extension study was designed to observe the effect of alemtuzumab on MRI outcomes over four years. In this study, patients randomized to interferon had the option of receiving alemtuzumab, and patients randomized to alemtuzumab were allowed to receive additional treatment if they had breakthrough clinical or MRI activity.

About 93% of the original alemtuzumab group entered the extension study. Approximately 68% of these participants were clinically and radiologically stable and did not require further treatments during the two years of the extension. The proportion of participants receiving alemtuzumab who were free of MRI activity was 68.4% in Year 3 and 69.9% in Year 4. This proportion remained stable, compared with that of the original study. The proportion of patients receiving alemtuzumab with no evidence of disease activity (ie, clinical or MRI activity) was 52.9% at Year 3 and 54.5% at Year 4.

The median yearly loss in brain volume was smaller in Years 3 and 4 than during the original study for patients receiving alemtuzumab. Median yearly brain volume change was –0.22% at Year 2, –0.10% at Year 3, and –0.19% at Year 4. “These results reflect a reduction in focal inflammation with alemtuzumab treatment,” said Dr. Traboulsee. “Together, these findings indicate that alemtuzumab represents a novel and durable treatment approach for relapsing-remitting MS.”

—Erik Greb