NHS stroke patients should be given genetic test to determine treatment

People who have had a stroke should have a genetic test to ensure they get the most appropriate treatment, according to new draft guidance by NICE.

Clopidogrel is the drug usually recommended to patients who have had a stroke or transient ischaemic attack (TIA, sometimes called a 'mini-stroke') to lower their risk of a secondary stroke. However, the drug is less effective in patients who carry particular genetic variants, leaving them at increased risk. It is estimated that 32 percent of people in the UK have at least one of these variants, and they even are more common in people with Asian ancestry.

Mark Chapman, interim director of medical technology and digital evaluation at NICE, said 'The recommendation is a step forward in ensuring people who have had a stroke receive personalised care thanks to a genetic test run after their DNA is sequenced using their blood or saliva. 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'.

Clopidogrel works by stopping platelets in the blood from clumping together, thereby preventing dangerous blood clots. However, it needs to be processed by enzymes in the liver to make it work. When people have certain variations in the gene CYP2C19, which encodes one of the enzymes, the drug is not converted to its active form, reducing its effectiveness.

These patients are 46 percent more likely to have a second stroke than those without the variants, when everyone is prescribed clopidogrel. However, alternative treatments are available, and can reduce that risk, when CYP2C19 variants are found.

Recurrent strokes make up nearly half of the 100,000 cases occurring in the UK each year, and the NHS spends £16 million each year on clopidogrel. The genetic test, which costs £139 per patient, or £197 with other available technology, would allow clinicians to recommend a different course of treatment immediately.

'This test ensures we're getting the best care to people quickly, while at the same time ensuring value for money for the taxpayer,' said Chapman.

Alex Matos, a specialist clinical pharmacist in stroke at NHS Tayside, who was involved in the pilot scheme evaluating the tests, told Pharmaceutical Journal: 'From my experience, patients welcome and are grateful to the NHS when this test is offered to them. This is the perfect example of considering the individual and providing person-centred care with improved outcomes'.

A consultation on the draft guidance is open until 8 June 2023.