Prospective assessment of changing from placebo to IFN beta-1a in relapsing MS: the PRISMS study.

Abstract

The efficacy of interferon (IFN) beta has been shown in several placebo-controlled, parallel-group studies in relapsing-remitting multiple sclerosis (RRMS). PRISMS, the largest such study to date, clearly demonstrated the efficacy of IFN beta-1a on all outcome measures over 2 years during the placebo-controlled, parallel-group phase. However, this study's placebo-crossover design also provided us with a unique opportunity to conduct a prospective within-group assessment, eliminating the impact of inter-patient variability. At the start of year 3, patients receiving placebo during years 1-2 were re-randomized in a dose-blinded fashion to receive IFN beta-1a, 22 or 44 mcg subcutaneously three times weekly, during years 3 and 4. Clinic visits occurred 3-6 monthly and T2 MRI scans were obtained after 1 and 2 years on therapy. Comparison of the mean relapse count per patient over 2 years (the primary outcome measure) during time on placebo (years 1 and 2) with that during active treatment (years 3 and 4) revealed a decrease from 2.6 to 1.2 in both dose groups (54% relative reduction; p<0.001). Disability progression, T2 MRI lesion activity and accumulation of T2 lesion burden were also significantly improved with therapy (p<0.01). No new safety issues were noted. These data provide further support for IFN beta-1a's efficacy in RRMS. The ability to detect significant treatment effects with reduced patient numbers in this type of before/after analysis, may be due to the reduction in inter-patient variability.

• Authors: J Oger, G Francis, P Chang, PRISMS Study Group
• Journal: Journal of the neurological sciences (J Neurol Sci) Vol. 237 Issue 1-2 Pg. 45-52 (Oct 15 2005) ISSN: 0022-510X [Print] Netherlands
• PMID: 16026803 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Interferon Type I
• Recombinant Proteins
• Interferon-beta
• Interferon beta-1a

Topics

• Adult
• Cross-Over Studies
• Disability Evaluation
• Disease Progression
• Dose-Response Relationship, Drug
• Double-Blind Method
• Female
• Humans
• Interferon Type I (administration & dosage, adverse effects, therapeutic use)
• Interferon beta-1a
• Interferon-beta (administration & dosage, adverse effects, therapeutic use)
• Magnetic Resonance Imaging
• Male
• Multiple Sclerosis, Relapsing-Remitting (drug therapy)
• Prospective Studies
• Recombinant Proteins
• Recurrence
• Research Design
• Treatment Outcome