Rationale: A number of immunopathogenic mechanisms have been hypothesized to figure prominently in the processes that culminate in the characteristic plaque lesion. These include the role of cytokines, chemokines, excitatory amino acids, free radicals, superoxides, and nitric oxide synthetase products. Recognizing that the disease process in MS involves a cascade of biological events, sets the stage for strategically targeting specific immunopathogenetic steps through rational combination therapy regimens. We now propose a combination clinical trial utilizing Avonex and mycophenolate mofetil (MMF), a novel agent with a broad spectrum of anti- inflammatory mechanisms.