 This open-label, rater-blinded extension study enrolled participants who had relapsing-remitting multiple sclerosis RRMS and who participated in one of three prior Genzyme-sponsored studies of alemtuzumab CAMMS223 NCT00050778, CAMMS323 NCT00530348 also known as CARE-MS I, or CAMMS324 NCT00548405 also known as CARE-MS II. The purposes of this study were: 