Safety and Efficacy Study of Doxycycline in Combination With Interferon-B-1a to Treat Multiple Sclerosis

Inclusion Criteria: * age 18-55 * Relapsing-Remitting Multiple Sclerosis (RRMS) * Avonex therapy for 6 months prior continuous * annualized relapse rate \>2 during Avonex therapy * most recent relapse within 60 days of baseline * entry Expanded Disability Status Scale (EDSS) 1.5-4.5 * one or more gadolinium (Gd+) MRI lesions on a baseline MRI * no history of immune modulator or immunosuppressant therapy used in combination with Avonex (other then GSC administer for clinical relapses) * not participating in any other study of ms therapeutics * Serum neutralizing antibodies (NABs) titer to Avonex \<20 Exclusion Criteria: * Medical or Psychiatric conditions that will affect patients ability to provide informed consent * inability to undergo MRI * clinically serious medical conditions or significantly abnormal labs * no use of these medications or procedures within six months prior to study: \*monoclonal antibodies,total lymphoid radiation,systemic steroids,cytotoxic or immunosuppressive medications such as mitoxantrone or cyclophosphamide or any other investigational drugs * Interferon neutralizing antibody titers \>20 * no breast feeding or pregnant * no patients with any systemic illness,psychiatric condition or other disorder that would concern safety of patient to complete procedures of protocol * abnormal blood test * clinically significant abnormality on chest x-ray (CXR)