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Adaptive Group Sequential Design

Classic group sequential design is a study design that has the option to

(1) review accumulating data (either safety or efficacy or both) at interim,
(2) stop the trial early due to safety, futility, or efficacy after review of the interim data, and (3) perform SSRE at interim to determine whether the study will achieve its objective if the observed treatment effect is preserved until the end of the study. Classic group sequential design with the above-described options is considered a well-understood design by the FDA (FDA 2010a) because the corresponding statistical methods and various stopping boundaries based on different boundary functions for controlling an overall type I error rate are well established and available in the literature (see e.g., Chow and Chang 2011).

Adaptive group sequential design, in contrast, is a classical group sequential design with prespecified options for additional adaptations (e.g., modifica- tion/deletion/addition of treatment arms, change of study endpoints, modification of dose and/or treatment duration, modification of randomization schedules, etc.) after interim analysis. With additional adaptations, adaptive group sequential design has become a less well-understood design. In this case, standard methods for the classical group sequential design may not be appropriate. For example, they may not be able to control the overall type I error rate at the desired level of 5%, owing to potential issues pertaining to adaptations of a given study design. Appropriate statistical procedures are necessary to avoid the potential increase in the study-wide type I error rate (FDA 2010a).

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Methods for Lowering the Type I Error (a), the Group Sequential Method with Adaptive Designs
So far decisions were limited to stopping or continuing a trial. Other decisions may be useful as well, e.g., change in sample size, in primary outcome parameter, in population, in treatments, in allocation rules. As long as blinding is maintained, many changes are allowed (using protocol-amendments),...
(Understanding Clinical Data Analysis: Learning Statistical Principles from Published Clinical Research)
Adaptive Clinical Trial Design
Shein-Chung Chow Duke University School of Medicine, Durham, NC Fuyu Song China Food and Drug Administration, Beijing, People's Republic of China CONTENTS 3.1 Introduction...................................................................................................42...
(Quantitative Methods for HIV/AIDS Research)
Methods for Lowering the Type I Error (a), the Armitage/Pocock Group Sequential Method
Interim analyses can be classified as follows: (1) group sequential design • Armitage et al/Pocock method for lowering the type I error • alpha spending function method for lowering the type I error (2) continuous sequential design. We will, first, addres the Armitage/Pocock group sequential method...
(Understanding Clinical Data Analysis: Learning Statistical Principles from Published Clinical Research)
Methods for Lowering the Type I Error (a), the Group Sequential Method with a-Spending Function Approach
The alpha spending function approach does not, necessarily, use the same significance level at each analysis. As an example, O’Brien & Fleming in the GroupSeq program of the R statistical software package can be used here. It calculates maximal sample sizes for various settings, such that the overall...
(Understanding Clinical Data Analysis: Learning Statistical Principles from Published Clinical Research)
A Group Randomized Design for School-Based Evaluation
R. Windsor, S. Middlestadt, and A. Radosh, “Evaluation of Secondary School HIV/STD Prevention Education Programs: Methodological and Design Issues to Improve the Science Base,” Project Report of the Academy for Educational Development (AED), to the CDC, Division of Adolescent and School Health (CDC,...
(Evaluation of health promotion and disease prevention programs : improving population health through evidence-based practice)
Sample Size Estimates for Group Randomized Design
The information needed for a sample size calculation for group randomized trials (GRT) is similar to that needed for a randomized clinical trial (RCT). A GRCT may be more appropriate than an RCT, because the E group program has to be implemented at a group level (e.g., health education for all students...
(Evaluation of health promotion and disease prevention programs : improving population health through evidence-based practice)
Exploratory Sequential Design
In an exploratory sequential design, qualitative data are collected prior to the collection of quantitative data (Figure 11.1). This type of design is likely to be familiar to many investigators as it is commonly used as a strategy to design an instrument or questionnaire or to gather information to...
(Behavioral Intervention Research: Designing, Evaluating, and Implementing)
Explanatory Sequential Designs
An alternative to the exploratory sequential design is the explanatory sequential design in which the quantitative data collection comes first, followed by qualitative data collection (Figure 11.1). Investigators who select this design often do so because there is some need for an explanation of the...
(Behavioral Intervention Research: Designing, Evaluating, and Implementing)
Equivalent Groups Posttest-Only Design
Pretests are not always possible, and in those instances, an equivalent-groups posttest-only design might be the only option. We can randomly assign a group of opioid-addicted individuals who are entering jail into a medication-assisted treatment program or the treatment-as-usual (counseling, Narcotics...
(Research Methods for Criminal Justice and Criminology: A Text and Reader)