Inclusion Criteria:

• Subject has a relapsing form of Multiple Sclerosis (MS); diagnosis of MS is in accordance with the McDonald criteria
• Subject is eligible for interferon therapy
• Subject is between 18 and 60 years old
• Subject has an Expanded Disability Status Scale (EDSS) < 6.0.
• Subject is willing to follow study procedures
• Subject has given written informed consent
• Female subjects must be neither pregnant nor breast-feeding, and must lack childbearing potential, as defined by either:
• Being post-menopausal or surgically sterile, or
• Using a hormonal contraceptive, intra-uterine device, diaphragm with spermicide or condom with spermicide for the duration of the study.
• Confirmation that the subject is not pregnant must be established by a negative serum or urinary hCG test within 7 days prior to start of study treatment. A pregnancy test is not required if the subject is post-menopausal or surgically sterile.

Exclusion Criteria:

• Subject has a Clinically Isolated Syndrome (CIS), Primary Progressive MS, or Secondary Progressive MS without superimposed relapses.
• Subject had any prior interferon beta therapy (either beta-1b or beta-1a)
• Subject has an ongoing MS relapse.
• Subject received any other approved disease modifying therapy for MS (e.g. glatiramer acetate) or any cytokine or anti-cytokine therapy within the 3 months prior to SD1.
• Subject had prior use of cladribine or has previously received total lymphoid irradiation.
• Subject received oral or systemic corticosteroids or adrenocorticotropic hormone (ACTH) within 30 days of SD1.
• Subject received intravenous immunoglobulins or underwent plasmapheresis within the 6 months prior to SD1.
• Subject received immunomodulatory or immunosuppressive therapy (including but not limited to cyclophosphamide, cyclosporin, methotrexate, azathioprine, linomide, mitoxantrone, teriflunomide, natalizumab, laquinimod, Campath) within the 12 months prior to SD1.
• Subject requires chronic or monthly pulse corticosteroids during the study.
• Subject received any investigational drug or experimental procedure within 12 weeks of SD1.
• Subject has inadequate liver function, defined by a total bilirubin, aspartate aminotransferase (AST) or alanine aminotransferase (ALT) or alkaline phosphatase > 2.5 times the upper limit of the normal values.
• Subject has inadequate bone marrow reserve, defined as a white blood cell count less than 0.5 x lower limit of normal.
• Subject suffers from current autoimmune disease.
• Subject suffers from major medical or psychiatric illness that in the opinion of the investigator creates undue risk to the subject or could affect compliance with the study protocol.
• Subject has a known allergy to IFN or the excipients.