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Mov Disord. 2019 Feb;34(2):274-280. doi: 10.1002/mds.27595. Epub 2019 Jan 14.

Sample enrichment for clinical trials to show delay of onset in huntington disease.

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Departments of Neurology, Psychiatry, and Psychological and Brain Sciences, University of Iowa, Iowa City, Iowa, USA.
Department of Biostatistics, Indiana University Fairbanks School of Public Health and School of Medicine, Indianapolis, Indiana, USA.
Department of Neurology, University of Rochester Medical Center, Rochester, New York, USA.



Disease-modifying clinical trials in persons without symptoms are often limited in methods to assess the impact associated with experimental therapeutics. This study suggests sample enrichment approaches to facilitate preventive trials to delay disease onset in individuals with the dominant gene for Huntington disease.


Using published onset prediction indexes, we conducted the receiver operating curve analysis for diagnosis within a 3-year clinical trial time frame. We determined optimal cut points on the indexes for participant recruitment and then conducted sample size and power calculations to detect varying effect sizes for treatment efficacy in reducing 3-year rates of disease onset (or diagnosis).


Area under the curve for 3 onset prediction indexes all demonstrated excellent value in sample enrichment methodology, with the best-performing index being the multivariate risk score (MRS).


This study showed that conducting an intervention trial in premanifest and prodromal individuals with the gene expansion for Huntington disease is highly feasible using sample enrichment recruitment methods. Ongoing natural history studies are highly likely to indicate additional markers of disease prior to diagnosis. Statistical modeling of identified markers can facilitate participant enrichment to increase the likelihood of detecting a difference between treatment arms in a cost-effective and efficient manner. Such variations may expedite translation of emerging therapies to persons in an earlier phase of the disease.


PREDICT-HD is registered with, number NCT00051324. © 2019 International Parkinson and Movement Disorder Society.


Clinical trials methodology/study design; genetics; huntington disease; movement disorders; prevention


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