CAMBRIDGE, Mass.--(BUSINESS WIRE)--Genzyme Corporation (Nasdaq: GENZ) today reported four-year follow-up data from its completed Phase 2 multiple sclerosis (MS) trial showing an estimated 71 percent of alemtuzumab treated patients remain free of clinically-active disease as much as three years after most patients received their last course of the investigational compound. The data were presented at the American Academy of Neurology annual meeting.