National Genetics Education and Development Centre
General public will expect pharmacists to know about pharmacogenetics
Alain Li Wan Po: consumers are much more aware [about pharmacogenetics]
and are much more demanding of health care providers |
Whether or not pharmacogenetics should be a specialist area was one
of the questions considered at a recent meeting held in London. Alain
Li Wan Po, lead professional specialist for pharmacy at the National
Genetics Education and Development Centre, believes that community pharmacists
should know about the subject. “Consumers are much more aware [about
pharmacogenetics] and are much more demanding of health care providers,” he
said.
He supported his suggestion by considering the pharmacogenetics of a
congenital condition called long QT syndrome, which affects one in 5,000
people in the US. Only a third of family members with the gene show clinical
symptoms and, often, people never learn that they have the condition
because they die suddenly.
Although the syndrome is relatively rare, it could be significant to
pharmacists because it overlaps with drugs that prolong the QT interval,
Professor Li Wan Po explained. Examples of these drugs that have been
withdrawn include terfenadine, sertindole, cisapride (which, at one point,
had been proposed for over-the-counter sale), and thioridazine, which
was discontinued last year.
He went on to give the following description of a customer in a pharmacy:
• Female and Japanese
• She is taking fluconazole, an antihistamine and a diuretic for premenstrual
tension
• Her cousin died suddenly at the age of 18 years running a marathon
The customer asks the pharmacist if she should be tested for long QT
genetic mutations and if there are any medicines or herbs that should
be avoided. “These are reasonable questions,” he said. “How
much should we expect pharmacists to know and how do health educators
help pharmacists in community practice?”
One problem Professor Li Wan Po pointed out is that the vast quantities
of data likely to be associated with pharmacogenetics may be too much
for pharmacists to take on board. At the same time there is “a
relative paucity of information that can help clinicians and patients
make optimal informed decisions”, he said. At the moment, community
pharmacists may not be able to separate the significant from the non-significant. “Drug
regulators should forget about the data sheet as a legal document and
translate it into a clinical document,” he added.
“Much of pharmacogenetics is to do with shifting the [dose-response]
curve and ensuring that we remain in the therapeutic window but, as a development
of pharmacogenetics, [pharmacists] probably have new professional responsibilities
and competencies,” he said.
David Pruce, director of practice and quality improvement at the Royal
Pharmaceutical Society, said that what pharmacists should know about
pharmacogenetics should not be defined by whether they work in community
or hospital. Rather, it is a generalist versus specialist issue. “What
the generalist probably needs to know is a background underlying that
pharmacogenetics exists and when to refer. Specialists need more detail,” he
said.
Pharmacists a priority group, says genetics centre
The National Genetics Education and Development Centre (NGEDC) has identified
four health professions as priority groups who need to be prepared for
predicted advances in pharmacogenetics: medical practitioners, nurses,
dietitians and pharmacists, said Peter Farndon, director of the NGEDC.
He added that many health care professionals may not see where the subject
fits into their jobs but the centre, together with Skills for Health,
has developed a set of nine competencies which covers the patient care
pathway, from identifying individuals with or at risk of genetic conditions,
to ordering a genetic laboratory test and communicating genetic information
to individuals, families and other health care staff.
Professor Farndon said that few health professionals would need all the
competencies; however, the first competency is for them to identify where
genetics is relevant to their areas of clinical practice.
The NGEDC is working to integrate genetics education into the training
of NHS health professionals but the aim is also to ensure that patients
get a good service now, Professor Farndon said. Signs in community pharmacies
today invite customers to “ask your pharmacist for any health advice
you want” and this could involve questions about genetics, he explained.
A workshop at the meeting looked at the skills pharmacists would need
to work with pharmacogenetics. Those identified included:
• Communication (including counselling and breaking bad news)
• Ability to identify patients or drugs at risk
• A recognition of where genetics matters
• Interpretation of results
• Application of basic scientific principles
• Point of care testing (eg, how to obtain and handle samples)
• Obtaining consent
Most of these skills were deemed desirable for both specialists and
generalists. “The difference is the knowledge and attitudes you
need to underpin these,” Professor Farndon said.
The meeting also looked at what core knowledge pharmacists would need.
A detailed report from the NGEDC is expected to be published this autumn.
Education now or later? What pharmacy thinks
New learning pack
Last month, the Centre of Postgraduate Pharmacy
Education launched an e-learning pack entitled “Pharmacogenetics: genetic approaches
to therapy”, which is a basic introduction to pharmacogenetics.
This is the centre’s first step into e-learning.
The pack is available to
any registered pharmacist |
All the attendees at the scoping meeting agreed that doctors, pharmacists
and nurse prescribers, as well as the recipient patients, will need to
understand the basis, reliability, sensitivity and specificity of pharmacogenetic
tests and the information they provide, and this will require an educational
programme. However, only a third thought that appropriate training for
pharmacists to become involved in pharmacogenetic testing is of most
immediate concern.
“In terms of practical implications, if [pharmacogenetics] does
not change the way we practise, then it is knowledge for knowledge’s
sake. I have other things on my agenda right now. My continuing professional
development cycles are jammed up to 2009 and more to do with things like
patients with coronary heart disease or diabetes. Somebody has to persuade
me that this will make a difference,” Liz Colling, head of pharmacy
at the Co-operative Group Pharmacy, said.
Ruth Wakeman, information pharmacist at the National Pharmacy Association,
told The Journal that, so far, the NPA has not had any specific queries
about pharmacogenetics from its members. “But it does not take
much of a leap to envisage queries as soon as the public and pharmacists
become more aware about the topic,” she said. “The NPA has
had lots of calls about linked topics, such as when the Herceptin stories
broke.”
David Pruce, director of practice and quality improvement at the Royal
Pharmaceutical Society, expressed concern that making pharmacogenetics
a special case will cause it to be seen as a specialist subject beyond
normal practice and there is a danger that people will not engage with
it. “At the end of the day, it [means using] a test with probabilities
attached to it like any other test. We have to be careful not to make
this too big a deal,” he said.
Soraya Dhillon, head of the school of pharmacy, University of Hertfordshire,
agreed. She made a comparison to the teaching of pharmacokinetics: “Many
pharmacists hated kinetics but when explained in terms of therapeutic
drug monitoring and dose optimisation, they realised they were doing
it already. Now it is embedded in their minds.” She added that
the amount of detail that pharmacists need to know about pharmacogenetics
depends on their level of practice, but it is fundamental that they have
a level of understanding to keep patients safe from drugs.
With regard to future pharmacists, the new MPharm degree at Hertfordshire
covers aspects of pharmacogenetics in its cell biology and immunology
modules, but is not taught as a sole topic. However, this could be a
possibility in three years, Professor Dhillon told The Journal.
In terms of pharmacogenetic advances, Mr Pruce said: “The nightmare
scenario is if genetic screening kits become widely available. Health
care professionals who sell them have a moral obligation to provide support,
but this raises huge ethical issues.”
Tony Moffat, head of the Centre for Pharmaceutical Analysis at the School
of Pharmacy, University of London, called for pharmacists to champion
the area. “Secondary care is [using pharmacogenetics] now, for
example, in oncology, but it is less obvious in the primary care sector.
It has got to be embedded in the industry now. Who is going to lead us?
Who is going to make a difference in this? It may well be that there
are pharmacists in the regulatory authorities who will champion this.
Or is this an area that community pharmacists could drive through? Its
an area of expertise we need to have,” he said.
Key questions for NHS pharmacogenetic testing
An example of pharmacogenetic testing already used in the NHS is the
measurement of thiopurine methyltransferase (TPMT) enzyme levels to inform
the prescribing of azathioprine. The drug is currently introduced in
a step-wise manner with blood monitoring. It is effective in 55 to 70
per cent of patients. There is a relationship between TPMT activity and
the risk of profound neutropenia. However, use of this phenotype-based
test is not routine — a recent survey indicated that only 67 per
cent of clinicians use TPMT tests in secondary care, said Katherine Payne,
a pharmacist and health economist at the North West Genetics Knowledge
Park, University of Manchester.
Before a pharmacogenetic test is used, key questions need to be asked,
said Dr Payne. The main question is “what is the predictive power
of the test” but often this information is not available. Other
questions include:
• Are there alternative medicines?
• How serious are the side effects of the drug?
• How much does the test cost? (Tests for azathioprine cost about £30
per patient.)
• How long does it take to get the result?
• How will the result affect the prescribing decision?
• Who will interpret the result?
• Who will tell the patient the result and answer his or her questions?
In addition, key economic questions arise, Dr Payne said. For example:
• Does the test decrease the incidence of adverse drug reactions and
improve associated health outcomes?
• What is the impact on health-related quality of life?
• What are the health care costs?
• What is the added value of providing a test compared with standard
care?
• What are the preferences of health care professionals and patients
for the characteristics of a test (eg, where the test will be conducted)?
• When and how should the test be introduced into the NHS clinical practice?
However, Dr Payne said, there is little or no robust evidence to answer
these questions.
The Department of Health has funded six projects looking at using pharmacogenetics
to reduce side effects of drugs. One of these projects, based at the
University of Manchester, is investigating a genotype-based test for
azathioprine (the TARGET study).
In the Manchester project, patients are given the genotype test, which
assesses for three gene variants, before azathioprine is prescribed.
If the patient is classed “TPMT homozygous mutant”, it is
recommended to the clinician that azathioprine is not prescribed because
of the high risk of death from neutropenia. If the patient is found to
be “TPMT heterozygous mutant”, the starting dose is decreased
and titrated up. Most patients are found to be “TPMT wild type” and
can be started at the normal dose of azathioprine.
In the US, the Food and Drug Administration has changed the licensing
for azathioprine and related drugs, and product labels now suggest considering
pharmacogenetic testing before use. However, in the UK there has been
no change to the product label.
Over 70 per cent of attendees at the scoping meeting were of the opinion
that genetic testing is unlikely to remove the need for monitoring and
at best, it will only indicate which patients are more or less likely
to respond well to a drug.
Relying on genetic tests alone could do more harm than good if it means
that signs of a dangerous drug reaction are ignored, the group thought. |
The
Pharmaceutical Journal