Sequential Natalizumab - Alemtuzumab Therapy in Patients With Relapsing Forms of Multiple Sclerosis

Inclusion Criteria

• Age between 18 and 60 years, inclusive.
• Diagnosis of relapsing forms of MS using revised McDonald Criteria1.
• 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).
• Has had a minimum of 12 monthly doses of continuous natalizumab therapy (300 mg/d).
• Understands English, and gives informed consent.

Exclusion Criteria

• Natalizumab failure based on clinician's discretion.
• Any prior exposure to alemtuzumab.
• Progressive MS.
• A diagnosis of Progressive multifocal leukoencephalopathy (PML).
• Known hypersensitivity to alemtuzumab.
• Initiation of new immunosuppressant treatment after the subject becomes protocol-eligible (except for corticosteroids) or enrollment in a concurrent trial with immuno-active pharmacotherapies.
• Uncontrolled diabetes mellitus defined as HbA1c > 8% and/or requiring intensive management.
• History of cytopenia consistent with the diagnosis of myelodysplastic syndrome.
• Clinically significant autoimmune disease other than MS that may affect the CNS, including neuromyelitis optica (NMO), systemic lupus erythematosus (SLE), or Behcet disease.
• Active hepatitis B or C infection or evidence of cirrhosis.
• HIV positivity.
• Uncontrolled viral, fungal, or bacterial infection.
• Positive pregnancy test or inability or unwillingness to use effective means of birth control. Effective birth control is defined as:
• Refraining from all acts of vaginal intercourse (abstinence),
• Consistent use of birth control pills,
• Tubal sterilization or male partner who has undergone vasectomy
• Placement of intrauterine device
• Use, with every act of intercourse, of a diaphragm with contraceptive jelly and/or condoms with contraceptive foam.
• Presence of metallic objects implanted in the body that would preclude the ability of the subject to safely have MRI exams.
• Psychiatric illness, mental deficiency, or cognitive dysfunction making compliance with treatment or informed consent impossible.