Effective sample size for computing prior hyperparameters in Bayesian phase I-II dose-finding
Effective sample size for computing prior hyperparameters in Bayesian phase I-II dose-finding
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DOI:
10.1177/1740774514547397
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发表时间:
2014-12-01
期刊:
影响因子:
2.7
通讯作者:
Norris, J. Clift
中科院分区:
文献类型:
--
作者:
Thall, Peter F.;Herrick, Richard C.;Norris, J. Clift
Background: The efficacy toxicity trade-off based design is a practical Bayesian phase I-II dose-finding methodology. Because the design's performance is very sensitive to prior hyperparameters and the shape of the target trade-off contour, specifying these two design elements properly is essential.Purpose: The goals are to provide a method that uses elicited mean outcome probabilities to derive a prior that is neither overly informative nor overly disperse, and practical guidelines for specifying the target trade-off contour.Methods: A general algorithm is presented that determines prior hyperparameters using least squares penalized by effective sample size. Guidelines for specifying the trade-off contour are provided. These methods are illustrated by a clinical trial in advanced prostate cancer. A new version of the efficacy toxicity program is provided for implementation.Results: Together, the algorithm and guidelines provide substantive improvements in the design's operating characteristics.Limitations: The method requires a substantial number of elicited values and design parameters, and computer simulations are required to obtain an acceptable design.Conclusion: The two key improvements greatly enhance the efficacy toxicity design's practical usefulness and are straightforward to implement using the updated computer program. The algorithm for determining prior hyperparameters to ensure a specified level of informativeness is general, and may be applied to models other than that underlying the efficacy toxicity method.