Retrospective Assessment of Noninferiority in Rare Disease of Guillian-Barre Syndrome

• Activity Number: 547
• Type: Contributed
• Date/Time: Wednesday, August 7, 2013 : 10:30 AM to 12:20 PM
• Sponsor: Biopharmaceutical Section
• Author(s): Chunqin Deng*+ and Junliang Chen and Kim Hanna
• Companies: Grifols Inc. and Grifols Inc. and Grifols Inc.
• Keywords: Non-inferiority margin ; Rare Disease ; Guillian-Barre Syndrome ; Plasma Exchange ; Intravenous Immunoglobulin ; Cochrane Systematic Review

Abstract

Guillian-Barre Syndrome (GBS) is an orphan disease. Treatment for GBS involves PE (Plasma Exchange) or Immunoglobulin (IGIV). Both PE and IGIV are widely accepted as standards of care for GBS treatment. Efficacy of PE has been demonstrated in randomized, controlled studies comparing to the control group. The efficacy of IGIV has been mainly based on the comparison to PE. Due to the rarity of the disease and the large sample size requirement, studies comparing IGIV with PE were not formally designed as a therapeutical equivalence trial or non-inferiority trial. Cochran review indicated IGIV is comparable to PE even though meta-analyses did not formally assess the therapeutical equivalence or non-inferiority. We showed that the non-inferiority margin can be derived using two 95% confidence interval approach from the meta-analysis results of PE versus control group in Cochrane review of PE in GBS and then retrospectively applied these non-inferiority margins to the meta-analysis results of IGIV versus PE in Cochrane review of IGIV in GBS. The results demonstrated non-inferiority of IGIV to PE in treatment of GBS when the non-inferiority margins were retrospectively applied.