NEW YORK – The UK National Institute for Health and Care Excellence (NICE) said Friday that it recommends genetic testing for patients with ischemic stroke or transient ischemic attack prior to prescribing clopidogrel because the drug is less effective at preventing subsequent strokes in patients with certain genetic variations in the CYP2C19 gene.
In a draft guidance, NICE recommended laboratory-based genetic testing using blood or saliva samples prior to administering the antiplatelet therapy to patients who have had an ischemic stroke or transient ischemic attack. Those with certain variations of the CYP2C19 gene cannot convert the drug to the active form, and testing allows selection of an alternative therapy that will be more effective at preventing blood clots, the organization said.
About 32 percent of UK residents have at least one of the CYP2C19 gene variants, which are more common among people of Asian descent but can occur in people of any ethnicity, NICE said. People with these variants have an estimated 46 percent increased risk of subsequent stroke when taking clopidogrel compared to those without the variants, according to the draft guidance.
Mark Chapman, NICE's interim director of medical technology and digital evaluation, said in a statement that the recommendation will help ensure people receive personalized care.
"Treatment with clopidogrel is effective in preventing further strokes for the majority of people who don’t have the gene variant," he said. "But until now doctors have not known who cannot be treated with clopidogrel until after they’ve had a second stroke or TIA, and that could be too late."
NICE, which is part of the UK Department of Health and Social Care, said in August it was assessing genotyping approaches that could help physicians gauge how well patients might respond to clopidogrel. That assessment followed a suggestion from the Clinical Pharmacogenetics Implementation Consortium that CYP2C19 genotyping could help doctors select more effective antiplatelet therapies.
Laboratory testing costs an estimated £139 ($173), and the Genomadix Cube point-of-care test is available for £197 and can be used when the laboratory test is unavailable, NICE said.