Inclusion Criteria:

• Signed informed consent form.
• Male or non-pregnant, non-lactating female patients, 18 to 50 years of age (inclusive).
• Diagnosis of MS per McDonald's update of the Poser criteria, including cranial MRI consistent with those criteria.
• Onset of first MS symptoms within 3 years prior to screening.
• 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 (ie, the initial event if within 2 years of study entry plus ≥1 relapse, or ≥2 relapses if the initial event was between 2 and 3 years prior to study entry).
• In addition to the clinical criteria (3 to 6 above), ≥1 enhancing lesion on any 1 of the up to 4 screening gadolinium-enhanced MRI 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, glatiramer acetate, and mitoxantrone.
• Personal history of thyroid autoimmune disease.
• Personal history of clinically significant autoimmune disease (eg, inflammatory bowel disease, diabetes, lupus, severe asthma).
• History of thyroid carcinoma (previous thyroid adenoma is acceptable and is not to be considered an exclusion criterion).
• History of malignancy (except for basal cell skin carcinoma in which situation the patient is eligible only if disease-free for more or equal to 5 years).
• Any disability acquired from trauma or another illness that, in the opinion of the investigator, could interfere with evaluation of disability due to MS.
• Previous treatment with CAMPATH.
• History of anaphylaxis following exposure to humanized monoclonal antibodies.
• Inability to undergo MRI with gadolinium administration.
• Female patients with childbearing potential with a positive serum pregnancy test at screening or baseline. (NB: Serum pregnancy testing will be performed on each occasion.).
• Male and female patients who do not agree to use effective contraceptive method(s) during the study.
• Impaired renal function (ie, serum creatinine larger or equal to 2 times the Institutional upper limit of normal [ULN]).
• Untreated, major depressive disorder (MDD).
• Epileptic seizures that are not adequately controlled by treatment.
• Suicidal ideation.
• Major systemic disease or other illness that would, in the opinion of the investigator, compromise patient safety or interfere with the interpretation of study results.
• Abnormal CD4 count or significantly abnormal thyroid function; presence of anti-TSH receptor antibodies; known seropositivity for HIV.
• Intolerance of pulsed corticosteroids, especially a history of steroid psychosis.
• Presence of a monoclonal paraprotein.
• Patients who, in the opinion of the investigator, have any form of MS other than relapsing-remitting
• Patients currently participating in a clinical trial of an experimental or unapproved/unlicensed therapy