Sample Size Analysis for Pharmacogenetic Studies

Pharmacogenetic studies identify the genetic factors that influence the intersubject variation in drug response. This article proposes a general framework to determine sample size in pharmacogenetic studies. Simple closed form solutions for the sample size are derived for continuous and binary outcomes. To extend the application to pharmacogenomic studies, where a large number of gene-treatment interactions are evaluated simultaneously, we advocate the use of false discovery rate (FDR) in controlling false positive proportion. We adapt the method proposed by Shao and Tseng (2007) to facilitate adjustment for correlation among multiple tests for better control of false positives and power. A real example is given and simulation studies are carried out to demonstrate the performance of the proposed method.