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Activity Number:
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377
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Type:
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Contributed
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Date/Time:
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Tuesday, August 4, 2009 : 2:00 PM to 3:50 PM
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Sponsor:
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Biopharmaceutical Section
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| Abstract - #304556 |
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Title:
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Effects of Sources of Variability on Sample Sizes Required for RCTs, Applied to Trials of Lipid-Altering Therapies on Carotid Artery Intima-Media Thickness (cIMT)
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Author(s):
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A. Lawrence Gould*+ and Joerg Koglin and Ray Bain and Cathy-Anne Pinto and Yale B. Mitchel and Richard C. Pasternak
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Companies:
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Merck Research Laboratories and Merck Research Laboratories and Merck Research Laboratories and Merck Research Laboratories and Merck Research Laboratories and Merck Research Laboratories
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Address:
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351 North Sumneytown Pike, UGD1-88, North Wales, PA, 19454,
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Keywords:
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Bayes ; Frequentist ; Uncertainty ; Trial Design
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Abstract:
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Bayesian and frequentist methods were used to determine sample size estimates that would provide adequate assurance of compensating for between-study variability of 1-year cIMT progression/regression using published data from 6 contemporary studies including 3563 patients. We show that future cIMT studies will require much larger than anticipated sample sizes in order to provide a sufficient degree of assurance (90% or more) of realizing 90% power for detecting a true treatment effect because of substantial observed within- and between-study variability, as well as uncertainty about progression rates in contemporary populations. This finding is anticipated to apply for other therapeutic areas as well, as information about therapeutic effects accumulates.
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