Tipping Point for Personalized Medicine?
It's been a busy week for personalized medicine! First, the FDA announced a black box for Plavix warning physicians of treament failures in CYP2C19 poor metabolizers representing up to 14% of their patients. See http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm203888.htm for more details. Plavix is currently one of the most commonly prescribed medications in the world so the impact of this label will be felt.
Just on the heels of this major announcement, Medco and Mayo presented study findings at the ACC today proving the cost effectiveness of warfarin genotyping. The study found that hospitalization rates were 31% lower when genetic test results were incorporated into warfarin management. See https://www.medcoresearch.com/community/pharmacogenomics/warfarin for more details.
The FDA should be applauded for this black box warning, and Medco and Mayo should be commended for their important research. Now it's time to move beyond the silo mentality and start realizing the full benefits of personalized medicine. “Properly” prescribed medications kill twice as many Americans as car accidents. This is often due to genetic factors; 59% of medications most often cited in adverse drug reactions (ADR) studies are drugs processed by pathways whose levels vary widely genetically- like Plavix and Warfarin. We put airbags and seatbelts in cars, but we won’t take less expensive measures to protect people from ADRs. A simple, fairly inexpensive DNA test that examined 2C19 (the pathway for Plavix and 10% of other meds), 2C9 (the main pathway for warfarin and another 10% of meds), and 2D6 (the main pathway for most pain killer and 25% of meds) could dramatically improve the safety of prescribing. It’s time to move past one size fits all prescribing, and the Plavix warning and Medco/Mayo study are two serious steps in the right direction!