Clinical implementation of genetic testing in medicine: a US regulatory science perspective.

Heterogeneity of treatment effects in unselected patient populations has stimulated various strategic approaches to reduce variability and uncertainty and improve individualization of drug selection and dosing. The rapid growth of DNA sequencing and related technologies has ramped up progress in interpreting germline and somatic mutations and has begun to reshape medicine, especially in oncology. Over the past decade, regulatory agencies realized that they needed to be proactive and not reactive if personalized medicine was to become a reality. The US Food and Drug Administration, in particular, took steps to nurture the field through peer-reviewed publications, co-sponsoring public workshops and issuing guidance for industry. The following two major approaches to personalized medicine were taken: (i) encouragement of de novo co-development of drug-genetic test combinations by industry; and (ii) retrospective assessment of legacy genetic data for the purpose of updating drug labels. The former strategy has been more successful in getting new targeted therapies to the marketplace with successful adoption, while the latter, as evidenced by the low adoption rate of pharmacogenetic testing, has been less successful. This reflection piece makes clear that several important things need to happen to make personalized medicine diffuse in more geographical areas and among more therapeutic specialties. The debate over clinical utility of genetic tests needs to be resolved with consensus on evidentiary standards. Physicians, as gatekeepers of prescription medicines, need to increase their knowledge of genetics and the application of the information to patient care. An infrastructure needs to be developed to make access to genetic tests and decision-support tools available to primary practitioners and specialists outside major medical centres and metropolitan areas.