Personalised Prescribing and the NHS: 'This is the Moment'

Dr Sheena Meredith

March 29, 2022

Pharmacogenetics influence the way in which an individual's genes can affect their response to different drugs, and using this knowledge can play a role in improving healthcare and treatment options for patients, says  Personalised prescribing : Using pharmacogenomics to improve patient outcomes , a new report published today. 

Much of the enormous variation from person to person in drug efficacy, optimum dose, and side effect profile is down to genetics: "99.5% of people have at least one gene variant that means that if we come across the wrong medicine, it either won’t work or will actively cause us harm," according to Professor Sir Munir Pirmohamed, the David Weatherall chair of medicine at the University of Liverpool,speaking at a news briefing for the Science Media Centre. Most such variants "have real clinical consequences".

The briefing introduced the launch today of the joint report from the British Pharmacological Society (BPS) and the Royal College of Physicians (RCP), which explores potential benefits of pharmacogenomics to the NHS. Its authors envisaged an expanded and integrated use of this technology throughout the NHS to reduce serious adverse reactions, improve patient outcomes, and save resources. Around 6.5% of hospital admissions are to manage adverse reactions. A conservative estimate from the National Institute for Health and Care Excellence (NICE) of the annual costs to the NHS is £530 million - and it could be as high as £2 billion, added Sir Munir.

"The moment is right," said Sir Munir, chair of the report’s working party, former president of the BPS, and non-executive director for NHS England. He believes that pharmacogenetic testing should be "a pre-emptive strategy, available at the point of prescribing". A recent study at the Mayo Clinic suggested that pre-emptive pharmacogenomic testing could benefit nearly every patient at some point.

"We want to make testing ubiquitously available," said Sir Mark Caulfield, vice principal for health and professor of clinical pharmacology at Queen Mary University of London, current president elect of the BPS and former chief scientist for Genomics England, responsible for the 100,000 Genomes Project, who also contributed to the report. 

'Springboard' to Genomics in Everyday Practice

Dr Andrew Goddard, president of the RCP, said: "Pharmacogenomics has long been an area of limited and difficult access for health professionals – not just in its daily use, but also in the relevant training available on this subject. It is an area that has traditionally been absent from the online systems and tools used daily by doctors. Our hope is that this report will be the springboard to getting genomics working effectively in everyday clinical practice."

Whilst already used within the NHS in limited cases, the report supports much more extensive use of pharmacogenetic testing, saying that it could potentially save the NHS money, as well as enhancing care and reducing harms to patients.

"Personalised testing for safety and effectiveness of common medicines must be offered throughout the NHS," the report’s authors said. "Testing patients for genetic variations that affect how their body will respond to common medicines must be integrated fully, fairly, and swiftly into the NHS."

Scientists have established a genetic cause for variation in responsiveness for over 40 medicines, the panel told the meeting. These are among the 100 most commonly prescribed medicines in the UK. For example, about 8% of the UK population has a genetic variant meaning they do not produce the cytochrome P450 2D6 (CYP2D6) enzyme, which, among other effects, breaks down codeine to morphine. Codeine is the 10th most commonly prescribed drug in the UK, yet it will not work to induce an analgesic effect for this segment of the population.

Another example is that around 1 person in every 500 carries a gene variant that predisposes them to hearing loss with gentamicin. Also, a genetic variant leading to deficiency of the enzyme dihydropyrimidine dehydrogenase (DPD) makes patients more at risk of severe side effects from the chemotherapy drug capecitabine. It occurs in 5-8% of the population and can be detected by a £60 blood test. However, for most of the 40 medicines where pharmacogenetics are known to be important, tests are not yet available in the NHS. These include analgesics, beta blockers and antidepressants.

Pharmacogenomics Could Become 'Usual Care'

A small number of pharmacogenomic tests is available in the NHS already, Sir Munir said, but "this needs to be expanded". Typically with age, people develop more conditions requiring treatment and need to take more drugs, with polypharmacy increasingly common. By age 70, individuals have a 70% chance of being on at least one drug that is influenced by pharmacogenomics.

"The UK is a world leader in genomic medicine, and the implementation of a wider range of pharmacogenomic tests would further demonstrate UK leadership, he said. "Today we are calling on Government and the health service to ensure that patients across the UK are offered these tests where there is evidence to show their utility. For patients, this will mean the medicines they take are more likely to work and be safer. In the 21st century, we need to move away from the paradigm of ‘one drug and one dose fits all’ to a more personalised approach where patients are given the right drug at the right dose to improve the effectiveness and safety of medicines."

In his foreword to the report, Chair of NHS England Lord David Prior said: "This will revolutionise medicine and, combined with a digitally driven population health approach, fundamentally change the traditional model of care…[Pharmacogenomics] is the future, it can now help us to deliver a new, modern personalised healthcare system fit for 2022."

Initially testing is likely to be reactive to clinical needs, and will not necessarily at first involve whole genome testing, Sir Munir said. "But instead of the trial-and-error approach that we often adopt at the moment, we are going to have a new era of medicine," he forecasted.

The pharmacogenomic approach could mean a single blood or saliva test carried out once in a person’s lifetime to determine optimum drug prescribing and dosing. Sir Mark looked forward to a time when: "Individual pharmacogenomics could be evaluated early in life, with genomic testing in the form of newborn screening.

"We could then go back and ask questions because we would have the entirety of [an individual’s] genetic code," he said, acknowledging that "this would require ethical and societal debate".

Patient and public involvement, clear communication, and transparency will be vital. Co-author Dr Emma Magavern, a clinician at Queen Mary University of London, said: "The public need to feel confident that their genetic data will remain secure and confidential, and we need patient and public input to make sure our pharmacogenomic testing service is fit for purpose and meets their needs."

Sir Mark added: "The UK is at the forefront of adoption of genomics in healthcare. This means we can be the first in the world to integrate pharmacogenomic testing into the NHS. This report provides the blueprint and identifies the resources and actions needed to ensure pharmacogenomics becomes 'usual care' in the NHS over the next 3 years."

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