|Title||Auxiliary variable-enriched biomarker-stratified design.|
|Publication Type||Journal Article|
|Year of Publication||2018|
|Authors||Wang, Ting, Xiaofei Wang, Haibo Zhou, Jianwen Cai, and Stephen L. George|
|Date Published||2018 Dec 30|
|Keywords||Bayes Theorem, Biomarkers, Cost Savings, Humans, Models, Statistical, Precision Medicine, Randomized Controlled Trials as Topic, Treatment Outcome|
Clinical trials in the era of precision medicine require assessment of biomarkers to identify appropriate subgroups of patients for targeted therapy. In a biomarker-stratified design (BSD), biomarkers are measured on all patients and used as stratification variables. However, such a trial can be both inefficient and costly, especially when the prevalence of the subgroup of primary interest is low and the cost of assessing the biomarkers is high. Efficiency can be improved and costs reduced by using enriched biomarker-stratified designs, in which patients of primary interest, typically the biomarker-positive patients, are oversampled. We consider a special type of enrichment design, an auxiliary variable-enriched design (AEBSD), in which enrichment is based on some inexpensive auxiliary variable that is positively correlated with the true biomarker. The proposed AEBSD reduces the total cost of the trial compared with a standard BSD when the prevalence rate of true biomarker positivity is small and the positive predictive value (PPV) of the auxiliary biomarker is larger than the prevalence rate. In addition, for an AEBSD, we can immediately randomize the patients selected in the screening process without waiting for the result of the true biomarker test, reducing the treatment waiting time. We propose an adaptive Bayesian method to adjust the assumed PPV while the trial is ongoing. Numerical studies and an example illustrate the approach. An R package is available.
|Alternate Journal||Stat Med|
|Original Publication||Auxiliary variable-enriched biomarker-stratified design.|
|PubMed Central ID||PMC6279614|
|Grant List||P30 ES010126 / ES / NIEHS NIH HHS / United States |
R21 AG042894 / AG / NIA NIH HHS / United States
P01 CA142538 / CA / NCI NIH HHS / United States
R01 ES021900 / ES / NIEHS NIH HHS / United States
Auxiliary variable-enriched biomarker-stratified design.