Optimization of testing times and critical values in sequential equivalence testing.
In long-term clinical trials, interim analyses are planned to reduce the number of patients needed. To meet this issue in a practical way, group sequential designs are used. Most of these trials are conducted with the objective of demonstrating differences in efficacy of treatments, for example, to show superiority of a new drug or experimental treatment to a control. However, an increasing number of trials are designed to establish equivalence in efficacy or bioequivalence. This paper deals with group sequential test procedures in two-sided equivalence trials. Optimized designs with respect to sample size behaviour are constructed. Tables containing optimal testing times and corresponding optimal critical values or values to construct an underlying alpha-spending function, respectively, are provided. An example illustrates their use when planning interim analyses in equivalence trials.
Institute of Medical Biometry, Philipps-University of Marburg, Bunsenstrasse 3, D-35037 Marburg, Germany.
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D000420:Albuterol / Q000009:adverse effects / Q000031:analogs & derivatives / Q000493:pharmacokinetics / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy; D001993:Bronchodilator Agents / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use; D003198:Computer Simulation; D006801:Humans; D008954:Models, Biological; D016011:Normal Distribution; D016032:Randomized Controlled Trials as Topic / Q000379:methods / Q000706:statistics & numerical data*; D000068299:Salmeterol Xinafoate; D018401:Sample Size; D013810:Therapeutic Equivalency; D013997:Time Factors
D001993:Bronchodilator Agents; D000068299:Salmeterol Xinafoate; D000420:Albuterol