Many drugs are effective in only a subset of patients.
Pharmacogenomics can be used to identify these patients, allowing better overall response rates in clinical trials. By conducting a trial with patient populations enriched for responders, one can reduce the size, and therefore the cost, of clinical trials. These typically encompass the drug target, genes involved in the metabolism of the drug, and genes in the biological pathway of drug action. Once genes are screened and SNPs and haplotypes are identified, the appropriate assays are developed. Once drug response in the patient population has been determined, correlations between genetic markers and drug response are derived using statistical analysis.