Will pharmacogenetics lead to colour-coded medicine?

The 10 May evening debate Will Pharmacogenetics Lead to Colour-Coded Medicine?, organised by the Progress Educational Trust (PET) at the University of Liverpool's Foresight Centre and supported by the Wellcome Trust, formed part of PET's project Genes, Ancestry and Racial Identity: Does it Matter Where Your Genes Come From?.

The panel, which was chaired by PET Director Sarah Norcross, featured Munir Pirmohamed (Professor of Molecular and Clinical Pharmacology and NHS Chair of Pharmacogenetics at the University of Liverpool), Dr Richard Tutton (Senior Lecturer in Sociology at Lancaster University) and Stephen Wilkinson (Professor of Bioethics and co-Director of the Research Centre for Law, Ethics and Society at Keele University).

Professor Pirmohamed began his talk by explaining the term 'pharmacogenetics': in short, genetic variations can lead to differential responses to drugs. But genetic variation is only one factor affecting drug response. A person's lifestyle, physique and environment all contribute to determining optimum dosage of drugs.

Drawing on examples from practice, Professor Pirmohamed argued that race or ethnicity is not necessarily helpful for establishing someone's ideal drug therapy. 'There is more variation between individuals than between races', he emphasised. 'Race is being used as a poor surrogate for the genetic make-up of a patient'. Professor Pirmohamed concluded that, as more is learnt about human genetics, medicine will move away from the 'colour-coded' approach used by clinicians and pharmaceutical companies.

Sociologist Dr Tutton began his talk by asking 'Does race exist?' Dr Tutton explained that personalised medicine is targeted at populations, not individuals, and race has been used to describe groups. He identified two possible concerns about the effectiveness of 'colour-coded' medicine. First, a lack of fit between concepts of race and genetic variation, and secondly, questions about how to assign race. Like Professor Pirmohamed, he concluded that further study will lead to a more sophisticated understanding of personalised medicine, but that environmental factors shouldn't be overlooked when determining effective therapies.

Professor Wilkinson sought to address some of the ethical issues that might arise if a link existed between genetic variation and racial group. He raised three issues. First, the quest for NHS cost effectiveness might favour some groups for treatment. This strategy could only be justified if there was solid evidence of cost-effectiveness, and if groups were assigned with due care, he said.

Second, like Professor Pirmohamed, Professor Wilkinson said pharmaceutical companies might focus their research and development efforts towards wealthy populations, increasing health inequalities. Third, fewer products might be developed for small racial groups. Like poor people, small groups have limited buying power. The only way to fight these health inequalities was through market intervention - perhaps using incentives, said Professor Wilkinson.

A lively and varied question and answer session followed the speaker presentations. Among the issues discussed were the power of the market to direct healthcare nationally and globally; and the importance of non-genetic factors in determining drug response - such as whether a patient actually completes a course of drugs!

One interesting point raised was how knowledge of genetic variation would be managed in the clinical setting and beyond. The first challenge is disseminating knowledge among medical practitioners so they may prescribe appropriate treatments. But such knowledge is also interesting to health insurers, for example. Managing their interests and information presents a different challenge.

Throughout the presentations and discussion, it was clear that all three speakers agreed our understanding of the complexities of genetic variation is in its early days. Race (as we currently understand it) is too blunt a category to be of much use and will be superseded by more nuanced categories based on stronger evidence of genetic variation.

But it is important to remember, as Dr Tutton pointed out, that studying human genetics has found differences and commonality between us - both are important in the development of pharmacogenetics. As Sarah Norcross concluded in her closing remarks, quoting the author Kenan Malik: 'Geneticists...can distinguish between all sorts of populations. Some of these distinctions are useful scientifically, some are not. Whether or not they are useful depends on the question we want to ask and the context in which we ask it'.