NHS North West staff lead the charge in adopting genomic technologies in healthcare with pioneering use of new gene test
Ground-breaking examples of how genomics can deliver more personalised and precise diagnosis and treatment for NHS patients are exciting, but they can seem very distant from day-to-day reality for most health professionals – until now.
This week, a new initiative sees nurses at clinics in the Royal Liverpool University Hospital, Warrington Hospital and the Countess of Chester Hospital using a genetic test to inform warfarin prescription to patients with atrial fibrillation.
Scope for improvement
Warfarin is the most common anti-coagulant drug used in the NHS, thought to be prescribed in at least 1% of the UK population, and a much higher proportion of the elderly population. It is used to reduce the risk of blood clots in high-risk patients. This may be short-term use after surgery, or long-term in patients who have had a stroke, heart attack, DVT or pulmonary embolism, as well as to reduce the risk of blood clots in patients with replacement heart valves or atrial fibrillation.
Warfarin is an effective and affordable anticoagulant, but it takes time to establish the optimal dose; patients need regular monitoring and dose adjustment to achieve this and minimise the very real risk of dangerous side-effects such as bleeding in the brain or gastrointestinal tract; the drug is one of the most commonly associated with serious adverse effects requiring hospital admission. Although there are alternative drugs that do not require such intensive monitoring, such as dabigatran, they are significantly more expensive. Most patients therefore continue to receive warfarin, with monitoring frequently provided via outpatient anticoagulant clinics; it typically takes 6-8 appointments to stabilise their dose.
However, there is scope to improve warfarin prescribing. Some individuals have a genetic sensitivity to warfarin due to variants in the CYP2C9 and VKORC1 genes, which specify key enzymes involved in the drug’s metabolism. People with a genetic ‘fast’ metabolism profile may need higher doses than normal to achieve a therapeutic effect, whilst those with a genetic ‘slow’ or ‘sensitive’ profile need lower doses to avoid side-effects.
A ‘win-win’ for patients and the NHS
An international randomised control trial based in Liverpool, Newcastle and Sweden used genetic tests to determine patients’ warfarin sensitivity and included this information in a predictive algorithm to calculate the best warfarin dose for each patient – which proved to be effective.
Now nurses at the three North West hospitals will become the first front-line NHS staff to use a 45-minute saliva genotyping test to inform drug doses in a trial of clinical implementation led by the University of Liverpool’s Wolfson Centre for Personalised Medicine. Results will be reported in 2017, but one patient (Paul Downie, 56) has commented:
“My mum went on warfarin eight months ago and she was back and forward to the clinic at least four times on a weekly basis before they got the dose right. I went back once, which meant I could go back to work quicker, feeling well enough to go back to normal life. I think this a win-win, for me and for the health service.”
NHS England Chief Scientific Officer Professor Sue Hill OBE, who is leading the personalised medicine strategy, commented: “This is precisely the sort of personalisation of treatment that we want to see available and delivered across the NHS.”