This open-label, rater-blinded extension study will enroll patients who have 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 are:
1. To examine the long term safety and efficacy of alemtuzumab treatment in patients who received alemtuzumab as their study treatment in one of the prior studies.
2. To examine the safety and efficacy of initial alemtuzumab treatment in this study for patients who received Rebif® (interferon beta-1a) as their study treatment in one of the prior studies.
3. To determine if and when further alemtuzumab treatment is needed, and the safety and efficacy of this "as needed" treatment. This applies both to patients who received alemtuzumab for the first time in one of the prior studies or for the first time in this extension study.