The 2nd UMBC–Stanford Workshop
on Clinical Trials and Regulatory Science

Event Summary: A one-day workshop organized by the Center for Interdisciplinary Research and Consulting at the University of Maryland, Baltimore County (UMBC), and the Center for Innovative Study Design (CISD) at Stanford University in the field of Clinical Trials and Regulatory Science.

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Organizing Committee:

Faculty from UMBC and Stanford University and leaders from FDA and industry.

For more information: Please contact Dr. Yi Huang, Department of Mathematics and Statistics, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD 21250.
E-Mail: yihuang@umbc.edu.

For any Technical difficulties Please contact Zana Coulibaly at czana1@umbc.edu.


Participant Information

Yijie Zhou from AbbVie.

Paper: Enrichment Design with Patient Population Augmentation

Clinical trials can be enriched on subpopulations that may be more responsive to treatments to improve the chance of trial success. In 2012 FDA issued a draft guidance to facilitate enrichment design, where it pointed out the uncertainty on the subpopulation classification and on the treatment effect outside of the identified subpopulation. We consider a novel design strategy where the identified subpopulation (biomarker-positive) is augmented by some biomarker-negative patients. Specifically, after sufficiently powering biomarker-positive subpopulation we propose to enroll biomarker-negative patients, enough to assess the overall treatment benefit. We derive a weighted statistic for this assessment, correcting for the disproportionality of biomarker-positive and biomarker-negative subpopulations under enriched trial setting. Screening information is utilized for weight determination. This statistic is an unbiased estimate of the overall treatment effect as that in all-comer trials, and is the basis to power for the overall treatment effect. For analysis, testing will be first performed on biomarker-positive subpopulation; only if treatment benefit is established in this subpopulation will overall treatment effect be tested using the weighted statistic. This design approach differs from typical enrichment design or stratified all-comer design in that the former enrolls only biomarker-positive patients and the latter enrolls a regular all-comer population. It also differs from adaptive enrichment by maintaining the trial design and analysis priority on biomarker-positive subpopulation. Therefore the proposed approach not only warrants a high probability of trial success on biomarker-positive subpopulation, but also efficiently assesses the overall treatment effect in the presence of an uncertain treatment benefit among biomarker-negative patients.


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