Tolerability and Quality of Life Study in Participants Who Switched to Avonex Pen

Key Inclusion Criteria: * Continuous treatment with Rebif, Betaferon or Copaxone over at least the past year. * Injections site tolerability issues documented in medical records or by a nurse at inclusion. * Clinically stable (free from relapses and 6-month confirmed disability progression for at least 6 months) while on therapy. * Documented neurological history at least for the year prior to study entry. * Qualification for Avonex® (Avonex Pen) according to the approved indication (Clinical Isolated Syndrome) or Relapsing Remitting Multiple Sclerosis (RRMS). * Acceptance of magnetic resonance imaging. Key Exclusion Criteria: * Patients who have previously entered this study. * Treatment with Avonex during the 12 months prior to the study. * One or more relapses and/or 6-month confirmed disability progression during the 6 months prior to the study. * Patient on Betaferon with Neutralizing Antibodies (NAbs) more than 400 TRU (tenfold reduction units) and patients on Rebif with NAbs with more than 100 TRU. * Secondary progressive multiple sclerosis. * Primary progressive multiple sclerosis. * Pregnancy or breast feeding. * History of severe depression or attempted suicide or current suicidal ideation. * Medical or psychiatric conditions that compromise the ability to give informed consent, to comply with the protocol, or to complete the study. * Uncontrolled seizure disorder. * Myopathy or clinically significant liver disease. * Inability, in the opinion of the principal investigator or staff, to comply with protocol requirements for the duration of the study. * Known hypersensitivity to interferon-beta or other human proteins including albumin. * A history of drug abuse in the 6 months prior to screening. * Treatment with any of the following in the 30 days before day 1: systemic corticosteroids, ACTH, or other investigational drugs. * Participation in any other study involving investigational or marketed products, concomitantly or within 30 days prior to entry in the study. * Likelihood of requiring treatment during the study period with drugs not permitted by the study protocol. NOTE: Other protocol-defined inclusion/exclusion criteria may apply.