Interim Analyses in Group Sequential Trials

The purpose of interim analyses in group sequential trials is to determine if the clinical trial should be terminated at that point. The rationale for interim analyses of data that are accumulating over time in a clinical trial was established several decades ago, and considerable attention has subsequently focused on the development of statistical approaches and decision-making processes that facilitate the implementation of data monitoring and interim analyses for the early termination of a clinical trial (Chow and Liu 2004). 

6 Meta-analysis, Group Sequential Study Designs, and other topics 

A third reason for termination concerns the safety-risk dimension. If there is compelling evidence at the time of an interim analysis that the drug is unacceptably toxic, termination is appropriate. From the perspective of this book s discussions, the same logic would apply in cases where there was compelling evidence that the drug was acceptably safe, i.e., it is not associated with unacceptable cardiovascular risk. 

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