BHT-3009 Immunotherapy in Relapsing Remitting Multiple Sclerosis

Inclusion Criteria: 1. Definite diagnosis of multiple sclerosis by the McDonald criteria. 2. Screening cranial MRI demonstrating lesions consistent with MS. 3. One or more relapses within the previous year. 4. Clinically stable (no relapses) for \> 50 days before beginning screening procedures and during the screening period. 5. EDSS 0 to 3.5 inclusive. 6. Age \> 17 years and \< 56 years. 7. Willing and able to give informed consent. 8. WBC \>3,000; platelets \>100,000; hemoglobin \> 10.0 g/dl. 9. AST, ALT, bilirubin \< 2.0 x upper limit of normal. 10. Creatinine \< 2.0 x upper limit of normal. 11. Negative test for HIV. Exclusion Criteria: 1. Primary progressive, secondary progressive or progressive relapsing MS. 2. More than 5 gadolinium-enhancing lesions on the first screening MRI. 3. High-dose corticosteroids (e.g. \> 500 mg methylprednisolone or equivalent per day for 3 or more days) within 50 days prior to beginning screening procedures. 4. Previous stem cell transplantation, total lymphoid radiation, or cytotoxic therapy. 5. Treatment with interferon, glatiramer acetate or other approved disease-modifying agent for \> 180 days (lifetime total of all agents). 6. Treatment with an approved disease modifying agent within 180 days of beginning screening procedures. 7. Previous treatment of MS with an experimental agent including off-label use of approved drugs. (Allowed with approval of the Medical Monitor.) 8. Prior therapy with natalizumab (Tysabri). 9. Pregnant or lactating women. 10. Unwilling to use a medically acceptable form of birth control (e.g. hormonal contraception, intrauterine device, double barriers, sterilization of self or partner). 11. Clinically significant ECG abnormalities (e.g. acute ischemia or life-threatening arrhythmia). 12. Medical condition or social circumstances that would in the opinion of the investigator prevent full participation in the trial or evaluation of study endpoints. 13. Implanted pace makers, defibrillators or other metallic objects on or inside the body that limit performing MRI scans. 14. Known hypersensitivity or allergy to gadolinium.