The Science of Stratified Medicine

Paul Duhaney

Professor Munir Pirmohamed: “For stratified medicine approaches to succeed there is a need for multidisciplinary expertise”

The University of Liverpool welcomes academics from across the world today to discuss the ‘Science of Stratified Medicine’. The conference will include presentations on policy, implementation, research and innovation.

Here, Professor Munir Pirmohamed, the University’s  NHS Chair of Pharmacogenetics and lead for the Personalised Health Research Theme, assesses the latest developments.

When a patient is diagnosed with a particular condition, there may be a number of potential drug treatments available. The doctor has a crucial question to answer: which is most suitable?

“Most drugs are prescribed on the basis of evidence gathered from population studies. Yet these studies do not require a diagnostic test to be performed before treatment starts, nor do they take account of the variability which exists between people due to genetic and environmental factors. In individual cases, age, gender, race, co-existing conditions, kidney function and other drugs that a patient may already be taking will all influence prescription, and these factors will, of course, differ from one patient to the next.

Personalisation is limited

“But the degree of personalisation is limited – there is no guarantee that a drug will be successful, and a given starting dose of one drug may not have the same effect, if any, in all patients. Worse still, a patient may suffer a side effect from the drug prescribed. While these are usually mild, they can, on occasion, be severe enough to warrant hospital admission. A 2008 study by Compass estimated that the NHS spends nearly £2 billion a year treating patients who have an adverse reaction to prescribed drugs. 

6.5% of hospital admissions are the result of adverse reactions to prescribed drugs

“Work carried out at the University of Liverpool, meanwhile, has shown that 6.5% of hospital admissions are the result of such reactions, while 15% of patients suffer adverse reaction as in-patients.

“There is an important question, therefore, about how we can improve the ability of doctors to more accurately determine the correct drug and dose required to maximise its effectiveness and minimise any side effects. Pharmacogenomics is the study of genetic variation on drug response in patients by correlating gene expression or single-nucleotide polymorphisms with a drug’s efficacy or toxicity. It aims to develop a rational means of optimising drug therapy, with respect to the patient’s genotype, to ensure maximum efficacy with minimal adverse effects. These studies have the ability to deliver personalised or stratified medicine; in which drugs and drug combinations are optimised for each individual’s unique genetic makeup. 

A rapid transfer from bench to bedside

“For stratified medicine approaches to succeed there is a need for multidisciplinary expertise. This approach ensures that discoveries in the laboratory can be transferred rapidly to the bedside, and that biomarkers can be developed into diagnostic tests that are easy to implement, access and interpret. To this end, the University has fostered collaborations both nationally and internationally with industry representatives from the diagnostic and pharmaceutical sectors. We are keen to further develop our collaborations with academia and industry – this is going to be instrumental in taking the field forward.

“So what are the long-term ambitions in this area? The ultimate aim is that in 50 years’ time we can carry our own genetic codes around with us on a smart card. This could be handed to a GP, who would put it into a computer to instantly ascertain the best available drug for any given condition.

Leave a comment