There has not yet been a clinical trial in which moderate to severe alcohol-dependent patients are prospectively randomized to naltrexone or placebo based on OPRM1 genotype. Such a study represents a critical step toward the FDA adoption of genetic tests and ultimately of a pharmacogenetic indication for naltrexone (Lesko and Zineh, 2010). Currently, there are a few genomic biomarkers used in the drug labels of psychiatric medications, most referring to the cytochrome P450 2D6 (CYP2D6) gene, which predicts drug metabolism and availability. As noted by Lesko and Woodcock (2004), most of the pharmacogenetics research to date has focused on drug safety, rather than efficacy, and the integration of genetic tests into routine clinical practice remains a major challenge, even for well-established biomarkers. While much research remains to be performed to determine whether a pharmacogenetic indication is warranted, it is useful to consider the overall status of pharmacogenetics research, including federal-regulatory issues.
