SUPPRESS

Treatment tested

• Alemtuzumab

  CAMPATH-1 antigen inhibitor

Other measures (3)

Inclusion Criteria: 1. Age between 18 and 60 years, inclusive. 2. Diagnosis of relapsing forms of MS using revised McDonald Criteria1. 3. Expanded Disability Status Scale (EDSS) 0 - 5.5 (note: functional system changes in cerebral (or mental) functions and in bowel and bladder functions not used in determining EDSS for protocol eligibility). 4. Has had a minimum of 12 monthly doses of continuous natalizumab therapy (300 mg/d). 5. Understands English, and gives informed consent. Exclusion Criteria: 1. Natalizumab failure based on clinician's discretion. 2. Any prior exposure to alemtuzumab. 3. Progressive MS. 4. A diagnosis of Progressive multifocal leukoencephalopathy (PML). 5. Known hypersensitivity to alemtuzumab. 6. Initiation of new immunosuppressant treatment after the subject becomes protocol-eligible (except for corticosteroids) or enrollment in a concurrent trial with immuno-active pharmacotherapies. 7. Uncontrolled diabetes mellitus defined as HbA1c > 8% and/or requiring intensive management. 8. History of cytopenia consistent with the diagnosis of myelodysplastic syndrome. 9. Clinically significant autoimmune disease other than MS that may affect the CNS, including neuromyelitis optica (NMO), systemic lupus erythematosus (SLE), or Behcet disease. 10. Active hepatitis B or C infection or evidence of cirrhosis. 11. HIV positivity. 12. Uncontrolled viral, fungal, or bacterial infection. 13. Positive pregnancy test or inability or unwillingness to use effective means of birth control. Effective birth control is defined as: 1. Refraining from all acts of vaginal intercourse (abstinence), 2. Consistent use of birth control pills, 3. Tubal sterilization or male partner who has undergone vasectomy 4. Placement of intrauterine device 5. Use, with every act of intercourse, of a diaphragm with contraceptive jelly and/or condoms with contraceptive foam. 14. Presence of metallic objects implanted in the body that would preclude the ability of the subject to safely have MRI exams. 15. Psychiatric illness, mental deficiency, or cognitive dysfunction making compliance with treatment or informed consent impossible.

The purpose of this study is to determine if a sequential combination therapy of natalizumab and alemtuzumab induces peripheral tolerance and reduces the annualized relapse rate (ARR) in patients with relapsing-remitting multiple sclerosis (RRMS).