Design and analysis of clinical trials in the presence of delayed treatment effect
- 2 February 2016
- journal article
- Published by Wiley in Statistics in Medicine
- Vol. 35 (11), 1774-1779
- https://doi.org/10.1002/sim.6889
Abstract
In clinical trials with survival endpoint, it is common to observe an overlap between two Kaplan-Meier curves of treatment and control groups during the early stage of the trials, indicating a potential delayed treatment effect. Formulas have been derived for the asymptotic power of the log-rank test in the presence of delayed treatment effect and its accompanying sample size calculation. In this paper, we first reformulate the alternative hypothesis with the delayed treatment effect in a rescaled time domain, which can yield a simplified sample size formula for the log-rank test in this context. We further propose an intersection-union test to examine the efficacy of treatment with delayed effect and show it to be more powerful than the log-rank test. Simulation studies are conducted to demonstrate the proposed methods.Keywords
Funding Information
- CUHK Direct (4053086)
- RGC ECS (24300514)
- NIH/NCI (R21CA169739, R37GM047845)
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