Long-term subcutaneous interferon beta-1a therapy in patients with relapsing-remitting MS

Neurology. 2006 Sep 26;67(6):944-53. doi: 10.1212/01.wnl.0000237994.95410.ce.


Objective: To conduct systematic long-term follow-up (LTFU) of patients in the Prevention of Relapses and Disability by Interferon beta-1a Subcutaneously in Multiple Sclerosis (PRISMS) study to provide up to 8 years of safety, clinical and MRI outcomes on subcutaneous (s.c.) interferon (IFN) beta-1a in relapsing-remitting multiple sclerosis (RRMS).

Methods: The original cohort of 560 patients was randomized to IFNbeta-1a, 44 or 22 microg three times weekly (TIW) or to placebo; after 2 years, patients on placebo were rerandomized to active treatment and the blinded study continued for a further 4 years. The LTFU visit was scheduled 7 to 8 years after baseline.

Results: LTFU was attended by 68.2% of the original PRISMS study cohort (382/560 patients). 72.0% (275/382) were still receiving IFNbeta-1a s.c. TIW. Patients originally randomized to IFNbeta-1a 44 microg s.c. TIW showed lower Expanded Disability Status Scale progression, relapse rate and T2 burden of disease up to 8 years compared with those in the late treatment group. Brain parenchymal volume did not show differences by treatment group. Overall, 19.7% of patients progressed to secondary progressive MS between baseline and LTFU (75/381). No new safety concerns were identified and treatment was generally well tolerated.

Conclusions: Despite the limitations inherent in any long-term study (for example, potential differences between returning and nonreturning patients), these results indicate that patients with relapsing-remitting multiple sclerosis can experience sustained benefit over many years from early interferon beta-1a subcutaneous therapy three times weekly compared with patients whose treatment is delayed. This effect was more apparent in the patients receiving the higher dose.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / therapeutic use*
  • Adult
  • Analysis of Variance
  • Brain / pathology
  • Cohort Studies
  • Disability Evaluation
  • Disease Progression
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Drug Administration Schedule
  • Drug Evaluation
  • Female
  • Humans
  • Injections, Subcutaneous / methods
  • Interferon beta-1a
  • Interferon-beta / therapeutic use*
  • Magnetic Resonance Imaging / methods
  • Male
  • Multiple Sclerosis, Relapsing-Remitting / pathology
  • Multiple Sclerosis, Relapsing-Remitting / prevention & control*
  • Retrospective Studies
  • Secondary Prevention
  • Severity of Illness Index
  • Single-Blind Method
  • Time Factors
  • Treatment Outcome


  • Adjuvants, Immunologic
  • Interferon-beta
  • Interferon beta-1a