This trial will evaluate safety, tolerability and effect on cranial magnetic resonance imaging (MRI) and immune response of CGP 77116 in patients with the demyelinating autoimmune disease, multiple sclerosis (MS). The purpose of the trial is to assess whether CGP 77116 modifies inflammatory disease activity as measured by MRI and immunological techniques, and to facilitate dose selection for future pivotal trials in progressive and relapsing-remitting MS.