Comparison of Alemtuzumab and Rebif (registered trademark) Efficacy in Multiple Sclerosis, Study Two

The purpose of this study is to establish the efficacy and safety of two different doses of alemtuzumab as a treatment for relapsing-remitting multiple sclerosis (MS), in comparison with Rebif (Registered trademark for interferon beta-1a). The study will enroll patients who have received an adequate trial of disease-modifying therapies but continued to relapse while being treated, and who meet a minimum severity of disease as measured by MRI. Patients will have monthly laboratory tests and comprehensive testing every 3 months. Every patient will receive active treatment; there is no placebo. The 24 mg alemtuzumab dose is closed to enrollment so newly enrolled patients will be randomly assigned to treatment with either 12 mg alemtuzumab or Rebif (registered trademark) at a 2:1 ratio (ie, 2 given 12 mg alemtuzumab for every 1 given Rebif (registered trademark)). Patients will not be able to guess which treatment will be randomly assigned to them. Alemtuzumab will be administered in two annual cycles, once at the beginning of the study and again 1 year later. Rebif (registered trademark) will be self-injected 3 times per week for 2 years. All patients will be required to return to their study site every 3 months for neurologic assessment. In addition, safety-related laboratory tests will be performed at least monthly. Participation in this study will end 2 years after the start of treatment for each patient. Additionally, all patients who receive alemtuzumab will be followed in an extension study for safety and efficacy assessments. Patients who receive Rebif (registered trademark) and complete 2 years on study may be eligible to receive alemtuzumab in an extension study.