Can pharmacogenetic testing decrease adverse events for new drugs prescribed to adults?
In this large multinational study, 12-gene pharmacogenetic testing resulted in a modest reduction in overall adverse events but had an unclear effect on serious adverse events.
Randomized controlled trial (nonblinded)
Participants in this multinational study were randomized to receive intervention (n = 3342) or control (n = 3602). At enrollment, all participants had blood or saliva collected for genetic testing. The tests assessed 12 specific genes (with 50 germline variants) associated with gene-drug interactions. The intervention group received a card with a QR code that stored the participants’ test results and a link to a website that provided the Dutch Pharmacogenetics Working Group’s specific recommendations whenever a new medication was prescribed. Among the recommendations were dose adjustments and alternative medications. The control group also received a card, but it merely indicated that they were part of the study. The control group also did not have their genetic testing until after the completion of the study. Finally, the researchers used standardized tools to assess patient-reported adverse events.
The researchers observed the participants for 12 weeks to 18 months. During the study period, 725 participants in the intervention group and 833 in the control group had “actionable” medication prescriptions. Overall, the guideline recommendations were followed 69.9% of the time. During the follow-up period, there were fewer clinically relevant adverse events in the intervention group than in the control group (21.5% vs 28.5%; number needed to treat = 15; 95% CI 11 - 21). However, the authors don’t report data on severe event rates for each group — just that the overall rate was 3.4%. Finally, the authors report that a cost analysis is in the works.
Henry C. Barry, MD, MS
Michigan State University
East Lansing, MI