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The National Institute for Health and Care Excellence (NICE) has recommended that a pharmacogenomic test to assess whether patients at risk of stroke should be treated with clopidogrel should be “phased” in to address concerns around testing capacity.
Clopidogrel, an antiplatelet medication, is currently recommended for these patients to reduce the risk of a future stroke, but around 32% of people in the UK have a variant of the CYP2C19 gene, meaning that the drug will not be as effective for them.
Evidence has suggested that people with variants of the CYP2C19 gene have around a 46% increased risk of another stroke when taking clopidogrel, compared to those without them.
In May 2023, NICE recommended in draft guidance that all patients who have had an ischaemic stroke or transient ischaemic attack (TIA) should be offered the CYP2C19 genotype test before being prescribed clopidogrel.
However, in updated draft guidance, published on 3 April 2024, NICE said that “several stakeholders highlighted that there would be considerable challenges to implementing a new laboratory-based test for all people who have a stroke or TIA”.
In response, NICE said the roll out of CYP2C19 genotype testing could occur “in a stepwise process”.
“This would involve a gradual increase in numbers tested while capacity was established,” the draft guidance said, adding that the phased roll out could mean initially offering testing “to people with a higher risk of stroke recurrence who could benefit most from it, such as people who have had a non-minor stroke”.
The guidance also said that point-of-care testing could be offered “as an alternative if laboratory-based testing is not feasible at this scale, or while capacity for laboratory-based testing is increased”.
In these cases, NICE recommended the use of the Genedrive CYP2C19 ID Kit point of-care test, followed by the Genomadix Cube as the second-line point-of-care test, noting that the Genedrive ID Kit can detect more CYP2C19 alleles than the Genomadix Cube.
NICE had previously recommended the use of the Genomadix Cube over the Genedrive ID Kit owing to lack of evidence on its accuracy and failure rate for CYP2C19 genotype testing.
In a statement published alongside the draft guidance, Jonathan Benger, chief medical officer at NICE, said: “We recognise that capacity within laboratories will need to increase before everyone who has had a new stroke or ‘mini-stroke’ can receive testing.
“While point of care testing is an alternative, our committee has identified that initially those people who could benefit most from laboratory-based testing are those who have had a non-minor stroke.”
“Anyone who is currently being treated with clopidogrel should continue with the treatment. They should only stop after discussing the options with their clinician,” said Benger.
It is estimated that around 35,850 people in England, Wales and Northern Ireland have a non-minor stroke each year, with about 11 million items of clopidogrel dispensed each year, at a cost of around £16m to the NHS.
Commenting on the draft guidance, Juliet Bouverie, chief executive officer of the Stroke Association, said: “We know that many stroke survivors spend the rest of their lives fearing another stroke, so it’s great to see that more people could be given appropriate help to significantly cut their risk of recurrent stroke.
“Getting on the right medication and taking it as advised can really go far to prevent further strokes.”
The final NICE guidance is expected to be published on 10 July 2024.
