A Phase II Study Comparing Low- and High-Dose Alemtuzumab and High-Dose Rebif® in Patients With Early, Active Relapsing-Remitting Multiple Sclerosis

Inclusion Criteria

• Signed informed consent form (ICF)
• Male or non-pregnant, non-lactating female participants, 18 to 50 years of age (inclusive) as of signing the ICF
• Diagnosis of MS per McDonald's update of the Poser criteria, including cranial MRI consistent with those criteria (McDonald, 2001, Ann Neurol)
• Onset of first MS symptoms within 3 years prior to Screening as of signing the ICF
• Expanded Disability Status Scale (EDSS) score 0.0 to 3.0 (inclusive) at the screening and Baseline visits
• At least 2 completed clinical episodes of MS in the 2 years prior to study entry (that is, the initial event if within 2 years of study entry plus at least 1 relapse, or at least 2 relapses if the initial event was between 2 and 3 years prior to study entry)
• In addition to the clinical criteria, at least 1 enhancing lesion on any 1 of up to 4 screening gadolinium-enhanced MRI brain scans during a maximum 3-month run-in period (inclusive of the Month 0 Baseline scan)

Exclusion Criteria

• Previous immunotherapy for MS other than steroids, including treatment with interferons, intravenous immunoglobulin (IVIG), glatiramer acetate, and mitoxantrone
• Personal history of thyroid autoimmune disease
• Personal history of clinically significant autoimmune disease (for example, inflammatory bowel disease, diabetes, lupus, severe asthma)
• History of thyroid carcinoma (previous thyroid adenoma was acceptable and was not considered an exclusion criterion)
• History of malignancy (except for basal cell skin carcinoma if disease-free for at least 5 years)
• Any disability acquired from trauma or another illness that, in the opinion of the Investigator, interfered with evaluation of disability due to MS
• Previous treatment with alemtuzumab
• History of anaphylaxis following exposure to humanized monoclonal antibodies
• Inability to undergo MRI with gadolinium administration
• Female participants of childbearing potential with a positive serum pregnancy test at screening or Baseline
• Male and female participants who did not agree to use effective contraceptive method(s) during the study
• Impaired renal function (that is, serum creatinine greater than or equal to 2 times the upper limit of normal [ULN])
• Untreated, major depressive disorder
• Epileptic seizures that were not adequately controlled by treatment
• Suicidal ideation
• Major systemic disease or other illness that, in the opinion of the Investigator, have compromised participant safety or interfered with the interpretation of study results
• Abnormal CD4 count or significantly abnormal thyroid function; presence of anti-thyroid stimulating hormone (TSH) receptor antibodies; known seropositivity for human immunodeficiency (HIV)
• Intolerance of pulsed corticosteroids, especially a history of steroid psychosis
• Presence of a monoclonal paraprotein
• Participants who had any form of MS other than relapsing-remitting
• Participants currently participating in a clinical study of an experimental or unapproved/unlicensed therapy