Sanofi and its recently acquired Genzyme subsidiary reported positive topline data from the first of two Phase III studies comparing alemtuzumab with Rebif® in the treatment of relapsing-remitting multiple sclerosis (RRMS). The Care-MS I study showed that in comparison with Rebif therapy, treatment with alemtuzumab led to a 55% greater reduction in relapse rate over the two years of the study. However, statistical significance was not met for the comparative secondary endpoint of time to six-month sustained accumulation of disability. At the two-year time point, 8% of alemtuzumab-treated patients demonstrated a sustained increase in their expanded disability status scale (EDSS) score compared with 11% of patients receiving Rebif.
The Care-MS I study compared the anti-CD52 treatment with Rebif in 581 MS patients who had previously only received steroid therapy. Patients were treated either with subcutaneous Rebif three times a week or with two annual cycles of intravenous alemtuzumab, comprising an initial five-day course and a three-day course a year later.
“We treated patients in Care-MS I at a very early stage in the course of their illness when the natural history may be relatively quiet, and both groups were remarkably stable over the two years of observation,” notes Alastair Compston, M.D., chair of the trial’s steering committee and head of the department of clinical neurosciences at the University of Cambridge, U.K. “Very few patients accumulated disability at the rate expected from previous clinical trials, including our Phase II experience. While welcome from the clinical perspective, this much reduced our ability to detect a significant treatment effect on the disability endpoint.”
A second Phase III study, Care-MS II, is under way to compare alemtuzumab with Rebif in RRMS patients who have relapsed while receiving treatment. Topline results are expected before the end of 2011. Regulatory submissions for alemtuzumab in the U.S. and EU are projected to be filed during early 2012.
The humanized CD52-targeting monoclonal antibody alemtuzumab is already approved under the trade name Campath® as a single-agent therapy against B-cell chronic lymphocytic leukemia. Genzyme is developing the drug for the treatment of MS in collaboration with Bayer HealthCare, which has an option to co-promote the drug on regulatory approval. Genzyme predicts that global annual sales of alemtuzumab for the MS indication could peak at over $3 billion within a few years of approval.