Phase 3 Randomized, Rater- and Dose-Blinded Study Comparing 2 Annual Cycles of IV [Low]- and High-Dose Alemtuzumab to 3x Weekly SC Interferon Beta-1a (Rebif®) in Relapsing-Remitting Multiple Sclerosis Patients Who Have Relapsed on Therapy

Inclusion Criteria:

- Diagnosis of MS and MRI scan demonstrating white matter lesions attributable to MS

- Onset of MS symptoms within 10 years

- EDSS score 0.0 to 5.0

- ≥2 MS attacks within 24 months, with ≥1 attack within 12 months

- ≥1 MS attack (relapse)during treatment with a beta interferon therapy or glatiramer
acetate after having been on that therapy for at least 6 months within 10 years

Exclusion Criteria:

- Previous treatment with alemtuzumab

- Previous treatment with any investigational drug (i.e. a medication that is not
approved at any dose or for any indication)

- Treatment with natalizumab, methotrexate, azothioprine or cyclosporine in the past 6
months

- Previous treatment with mitoxantrone, cyclophosphamide, cladribine, rituximab, or any
other immunosuppressive, or cytotoxic therapy (other than steroid treatment)

- Any progressive form of MS

- Any disability acquired from trauma or another illness that could interfere with
evaluation of disability due to MS

- Major systemic disease that cannot be treated or adequately controlled by therapy

- Active infection or high risk for infection

- Autoimmune disorder (other than MS)

- Impaired hepatic or renal function

- History of malignancy, except basal skin cell carcinoma

- Medical, psychiatric, cognitive, or other conditions that compromise the patient's
ability to understand the patient information, to give informed consent, to comply
with the trial protocol, or to complete the study

- Known bleeding disorder

- Of childbearing potential with a positive serum pregnancy test, pregnant, or
lactating

- Current participation in another clinical study or previous participation in CAMMS323
(NCT00530348)

- Previous hypersensitivity reaction to any immunoglobulin product

- Known allergy or intolerance to interferon beta, human albumin, or mannitol

- Intolerance of pulsed corticosteroids, especially a history of steroid psychosis

- Inability to self-administer subcutaneous (SC) injections or receive SC injections
from caregiver

- Inability to undergo MRI with gadolinium administration

- Unwilling to use a reliable and acceptable contraceptive method throughout the study
period (fertile patients only)