Interferon ß-1b Treatment by Cyclical Administration

Inclusion Criteria: * Patients affected by remitting Multiple Sclerosis who had at least a relapse in the last year of the disease. * Satisfying general clinical conditions according to the researcher. Adequate hepatic function. Capacity to use adequate contraceptive techniques during the study. Exclusion Criteria: * Any other disease that might better explain signs and symptoms of the patient. * Any other disability condition that might interfere with the clinical evolution. * History of hypersensitivity to natural or recombinant interferon or to human albumin. * Clinically significant heart diseases and not controlled like dysrhythmias, angina pectoris or congestive heart failure. * Not adequately controlled epilepsy. * Inability, according to the examining commission, to grant a complete compliance with the protocol requirements for the whole study. * Previous therapies modifying the disease course in the last six months. * Steroid therapies in the last 3 months. * Pregnancy, lactation, serological positivity to the pregnancy test during the screening period.