Name: Bauer

Firstname: Peter

Title: Prof.

Institution: Department of Medical Statistics, University of Vienna

Street: Schwarzspanierstrasse 17

City: Vienna

Zip-Code: A-1090

Country: Austria

Phone: +43-1-4277-63200

Fax: +43-1-4277-9632


Authors: Brannath,W., P.Bauer, M.Posch, W. Maurer

Title: Sequential Tests for Noninferiority and Superiority

Abstract: The problem of simultaneous sequential tests for non­inferiority and superiority of a treatment as compared to an active control is considered in terms of continuous hierarchical families of one sided null hypotheses in the framework of adaptive two stage designs. The crucial point is that the decision boundaries for the individual null hypotheses may vary over the parameter space. This allows to construct designs where a rigid stopping criterion is fixed rejecting or accepting all individual null hypotheses simultaneously. Another possibility is to get monitoring type stopping boundaries, which leave some flexibility to the experimenter: he can decide at the interim analysis if he is satisfied with the non­inferiority margin achieved at this stage or if he wants to go for more at the second stage. In case of proceeding to the second stage he may perform mid­trial design modifications (e.g. reassess the sample size). The proposed approach allows to ``spend`` e.g. less of alpha for an early proof of non­inferiority than for an early proof of superiority. The approach is illustrated by typical examples.