Statistics in medicine
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Statistics in medicine · Aug 2012
Adaptive extensions of a two-stage group sequential procedure for testing primary and secondary endpoints (II): sample size re-estimation.
In this part II of the paper on adaptive extensions of a two-stage group sequential procedure (GSP) for testing primary and secondary endpoints, we focus on the second stage sample size re-estimation based on the first stage data. First, we show that if we use the Cui-Huang-Wang statistics at the second stage, then we can use the same primary and secondary boundaries as for the original procedure (without sample size re-estimation) and still control the type I familywise error rate. This extends their result for the single endpoint case. ⋯ We show how to modify the boundaries of the original group sequential procedure to control the familywise error rate. We provide power comparisons between competing procedures. We illustrate the procedures with a clinical trial example.