An Adaptive Futility Monitoring Method with Time-Varying Conditional Power Boundary

• Activity Number: 504
• Type: Topic Contributed
• Date/Time: Wednesday, August 4, 2010 : 10:30 AM to 12:20 PM
• Sponsor: Biopharmaceutical Section
• Author(s): Ying Zhang*+ and William Clarke
• Companies: The University of Iowa and The University of Iowa
• Keywords: B-value ; Group sequential test ; Randomized clinical trial ; Stochastic curtailment

Abstract

For a long-term randomized clinical trial, it has become a well-accepted practice to include interim analysis in trial protocols. Conditional power is the probability that the final analysis will result in rejection of the null hypothesis given data accumulated at interim analysis and a pre-specified effect size. Because of its nice interpretation of the projection to the end of study, the conditional power is often built in decision rules to stop the trial for futility at interim analysis. An adaptive futility monitoring plan with a time-varying conditional power boundary is developed in this paper. This method maintains the overall size and power very well but has better chance to stop the trial earlier for futility compared to a conservative futility stopping rule of the conditional power.