Interpreting the clinical utility of a pharmacogenomic marker based on observational association studies.

It is increasingly recognized that the clinical utility of a pharmacogenomic marker is a fundamental characteristic influencing the likelihood of successful clinical translation. Although appropriately designed and executed randomized controlled trials generally provide the most valid evidence for the clinical utility of a pharmacogenomic marker, such evidence may not always be available. Observational pharmacogenomic association studies are a common form of evidence available, but the assessment of clinical utility based on such evidence is often not straightforward. This paper aims to provide insight into this issue using a range of illustrative examples.