At a time when harmful drug reactions are thought to rank just after strokes as a leading cause of death in the U.S., the potential benefits of tailoring drugs to a patients genetic makeup have been confirmed in a systematic study led by University of California, San Francisco scientists.
The quantitative assessment of the promise of this new approach known as pharmacogenomics confirms that many harmful drug reactions previously thought to be non-preventable may now actually be averted using genetic information about patients to select their drug therapies.
The study, the first systematic assessment of pharmacogenomics potential, is paired with an analysis of many remaining hurdles: questions about the effectiveness of the practice, inadequate training, funding and sites for carrying out patient genotyping; and the risk of creating inequities when developing drugs to avert problems caused by natural genetic differences linked to race.
The report appears in the November 14 issue of JAMA, the Journal of the American Medical Association.
The researchers first conducted two independent systematic literature reviews: one on studies reporting adverse drug reactions (ADRs) and one on studies reporting natural genetic variation, or variant alleles in genes for enzymes that metabolize drugs.
They then linked these two studies by focusing on the enzymes from the second search known to metabolize the drugs identified in the first search. This allowed them to assess the possible contribution of genetic variability to ADRs.
The results highlight a strong potential link between the genetic variants and adverse drug reactions. The scientists found that 59 percent of the drugs cited in the ADR study are metabolized by at least one enzyme with a naturally occurring variant known to cause poor metabolism.
Conversely, only 22 percent of randomly selected drugs sold in the U.S. and only 7 percent of randomly selected top-selling
Contact: Wallace Ravven
University of California - San Francisco