Data-Driven Analysis Strategies for Proportion Studies in Adaptive Group Sequential Test Designs

• Activity Number: 64
• Type: Topic Contributed
• Date/Time: Monday, August 12, 2002 : 8:30 AM to 10:20 AM
• Sponsor: Biopharmaceutical Section*
• Author(s): Gernot Wassmer*+
• Affiliation(s): Institut fur Medizinische Statistik Informatik und Epidemiologie
• Keywords: Sample Size Adjustment ; Group Sequential Design ; Adaptive Design ; Proportion Studies ; Conditional Error Function

Abstract

Using multistage adaptive group sequential test designs, the investigator may perform changes in the design during the course of the trial without inflation of the Type I error rate. This is possible, for example, through the use of the inverse normal method of combining the p-value from the separate stages of the trial. The conditional error function is a useful instrument, too.

Particularly, it is worthwhile to consider sample size reassessment strategies based on conditional power arguments. In this talk, approximate techniques will be proposed for the application of the inverse normal combination testing principle in superiority and non-inferiority proportion studies. Planning facilities and the adaptive analysis strategy will be discussed in terms of the Type I error rate, the necessary sample size, and the power within the adaptive design. Furthermore, it is shown how to calculate confidence intervals and p-values.