Optimal adaptive group sequential design with flexible timing of sample size determination

2017 ◽  
Vol 63 ◽  
pp. 8-12 ◽  
Author(s):  
Lu Cui ◽  
Lanju Zhang ◽  
Bo Yang
Keyword(s):  
Sample Size ◽  
Sequential Design ◽  
Sample Size Determination ◽  
Size Determination ◽  
Group Sequential Design ◽  
Group Sequential

scholarly journals Sample size determination in group-sequential clinical trials with two co-primary endpoints

2014 ◽  
Vol 33 (17) ◽  
pp. 2897-2913 ◽  
Author(s):  
Koko Asakura ◽  
Toshimitsu Hamasaki ◽  
Tomoyuki Sugimoto ◽  
Kenichi Hayashi ◽  
Scott R. Evans ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Sample Size ◽  
Sample Size Determination ◽  
Size Determination ◽  
Group Sequential ◽  
Primary Endpoints

Group sequential design for time-to-event data using the concept of proportional time

2019 ◽  
Vol 29 (7) ◽  
pp. 1867-1890
Author(s):  
Milind A Phadnis ◽  
Matthew S Mayo
Keyword(s):  
Sample Size ◽  
Sequential Design ◽  
Event Data ◽  
Efficacy And Safety ◽  
Group Sequential Design ◽  
Time To Event ◽  
Group Sequential ◽  
Generalized Gamma ◽  
Interim Monitoring ◽  
Time To Event Data

Sequential monitoring of efficacy and safety is an important part of clinical trials. A Group Sequential design allows researchers to perform interim monitoring after groups of patients have completed the study. Statistical literature is well developed for continuous and binary outcomes and relies on asymptotic normality of the test statistic. However, in the case of time-to-event data, existing methods of sample size calculation are done either assuming proportional hazards or assuming exponentially distributed lifetimes. In scenarios where these assumptions are not true, as evidenced from historical data, these traditional methods are restrictive and cannot always be used. As interim monitoring is driven by ethical, financial, and administrative considerations, it is imperative that sample size calculations be done in an efficient manner keeping in mind the specific needs of a clinical trial with a time-to-event outcome. To address these issues, a novel group sequential design is proposed using the concept of Proportional Time. This method utilizes the generalized gamma ratio distribution to calculate the efficacy and safety boundaries and can be used for all distributions that are members of the generalized gamma family using an error spending approach. The design incorporates features specific to survival data such as loss to follow-up, administrative censoring, varying accrual times and patterns, binding or non-binding futility rules with or without skips, and flexible alpha and beta spending mechanisms. Three practical examples are discussed, followed by discussion of the important aspects of the proposed design.

Information-based sample size re-estimation in group sequential design for longitudinal trials

2014 ◽  
Vol 33 (22) ◽  
pp. 3801-3814 ◽  
Author(s):  
Jing Zhou ◽  
Adeniyi Adewale ◽  
Yue Shentu ◽  
Jiajun Liu ◽  
Keaven Anderson
Keyword(s):  
Sample Size ◽  
Sequential Design ◽  
Group Sequential Design ◽  
Group Sequential
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