Comparison of Alemtuzumab and Rebif® Efficacy in Multiple Sclerosis, Study Two

Every participant received active treatment; there was no placebo. After Amendment 2, the 24 mg alemtuzumab dose was closed to enrollment so newly enrolled participants were randomly assigned to treatment with either 12 mg alemtuzumab or interferon beta-1a in a 2:1 ratio (that is, 2 given 12 mg alemtuzumab for every 1 given interferon beta-1a). Alemtuzumab was administered in two annual courses, once at the beginning of the study and again 1 year later. Interferon beta-1a was self-injected 3 times per week for 2 years. All participants were required to return to their study site every 3 months for neurologic assessment. In addition, safety-related laboratory tests were performed at least monthly. Participation in this study ended 2 years after the start of treatment for each participant. Additionally, participants who received alemtuzumab might be followed in the CAMMS03409 Extension Study (NCT00930553) for safety and efficacy assessments. Participants who received interferon beta-1a and completed 2 years on study might be eligible to receive alemtuzumab in the Extension Study.

Inclusion criteria

• Signed informed consent form (ICF)
• Age 18 to 55 years (inclusive) as of the date the ICF was signed
• Diagnosis of MS per update of McDonald criteria
• Onset of MS symptoms (as determined by a neurologist; could be retrospectively) within 10 years of the date the ICF was signed
• Expanded Disability Status Scale (EDSS) score 0.0 to 5.0 (inclusive) at Screening
• Greater than or equal to (>=) 2 MS attacks (first episode or relapse) occurring in the 24 months prior to the date the ICF was signed, with >=1 attack in the 12 months prior to the date the ICF was signed, with objective neurological signs confirmed by a physician, nurse practitioner, or other Genzyme-approved health-care provider and the objective signs could be identified retrospectively
• >=1 MS relapse during treatment with a beta interferon therapy or glatiramer acetate after having been on that therapy for >=6 months within 10 years of the date the ICF was signed
• MRI scan demonstrating white matter lesions attributable to MS and meeting at least 1 of the following criteria, as determined by the neurologist or a radiologist: >=9 time constant 2 (T2) lesions at least 3 millimeter (mm) in any axis; a gadolinium- (Gd-) enhancing lesion at least 3 mm in any axis plus >=1 brain T2 lesions; and a spinal cord lesion consistent with MS plus >=1 brain T2 lesion

Exclusion criteria

• Received prior therapy with alemtuzumab
• Current participation in another clinical study or previous participation in CAMMS323 (Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis, CARE-MS I)
• Treatment with natalizumab, methotrexate, azathioprine, or cyclosporine in the past 6 months. Participants who received one of these medications more than 6 months before the date the ICF was signed were eligible for study entry if approval was granted by Genzyme
• Any progressive form of MS
• History of malignancy (except basal skin cell carcinoma)
• CD4 +, CD8 +, CD19 + (that is, absolute CD3 + CD4 + , CD3 + CD8 + , or CD19 + /mm 3 ) count, absolute neutrophil count less than (<) lower limit of normal (LLN) at screening; if abnormal cell count(s) returned to within normal limits (WNL), eligibility could be reassessed
• Known bleeding disorder (for example, dysfibrinogenemia, factor IX deficiency, hemophilia, Von Willebrand's disease, disseminated intravascular coagulation, fibrinogen deficiency, or clotting factor deficiency)
• Significant autoimmune disease including but not limited to immune cytopenias, rheumatoid arthritis, systemic lupus erythematosus, other connective tissue disorders, vasculitis, inflammatory bowel disease, severe psoriasis
• Presence of anti-thyroid stimulating hormone (TSH) receptor (TSHR) antibodies (that is, above the LLN)
• Active infection or at high risk for infection