STRATIFIED medicine is not a term everyone is familiar with, but it is something that could affect us all at one time or another in our lives.

Dr Diane Harbison, CEO of the Stratified Medicine Scotland Innovation Centre (SMS-IC) says it is like looking at the strata – or layers – of rocks in geology, except that in medicine it’s separating people into different sub-groups based upon genetics and how they respond to various treatments.

“Most people assume that if you have a type of cancer, for example breast cancer, that it’s all exactly the same, but as we look at all these diseases at the molecular level we’re starting to understand more and more that actually within the classification of a disease like breast cancer there are lots of different sub-types of the disease,” she says.

Using that approach, a drug that could treat one patient might not work in another, and an oft-used illustration is the BRCA (BReast CAncer) gene mutations. BRCA1 and BRCA2 are in a class of genes called tumour suppressors. When they function normally, they help keep breast, ovarian, and other cells from growing and dividing too rapidly or in a haphazard way. When changes or “mutations” occur, they are more likely to do this, which can lead to cancer developing.

“The person probably best known for carrying the BRCA mutation is Angelina Jolie, who had elective surgery to make sure that she wouldn’t develop ovarian and breast cancer,” Harbison says.

“What stratified or precision medicine enables you to do is make sure you have the right drug for the right patient at the right time, and what that can do is, for the patient, they get the right treatment and don’t end up in a situation where they might be being treated for a particular disease but the medicine doesn’t work for them.

“Also, there are impacts on the NHS – what is the point of a patient taking a drug that doesn’t work for them? If we can get the right drug for the right patient, that will have a positive impact on the drugs bill because you’ll only be giving patients drugs that work for them - not just a blockbuster approach to medicine.”

How many of us have been prescribed an antibiotic by our GP, only to have to make a return trip when it doesn’t work?

Harbison says it’s about getting it right first time, as much as possible: “The same is true of very many drugs like statins or anti-depressants. Very often you have to keep going back to your GP until you find one that works for you. What we should be able to do is by looking at your genome, or other ways of stratifying patients like imaging, you should be able to get the right drug for you at the right time so it’s better for your treatment.”

SMS-IC is a unique collaboration involving Scotland’s four medical universities – Glasgow, Edinburgh, Aberdeen and Dundee – and their associated health boards, working with industry partners such as Thermo Fisher Scientific, who provide the centre’s sequencing platforms and Aridhia Informatics who supply its informatics platform.

Harbison says engagement with clinical academics is important because that’s where SMS-IC’s projects come from. As the precision approach becomes more recognised many pharmaceutical companies are looking at how they can better use it, because: “It’s a case of making sure they have the right patients in clinical trials and have a better chance of having their drugs work in the patient population.”

Health informatics and data are also vital, and Scotland’s small, relatively stable population, gives us the “real opportunity” to be world leaders in precision medicine: “If you think of somewhere like London, you might have a particular patient with a particular disease but within six months or a year they might not be there anymore.

“Because our population tends to be stable you can often keep accessing that particular patient – and their extended family – so that gives us a lot of really useful health informatics data ... Unfortunately for us we also tend to be quite sick and have a high proportion of the diseases the pharma industry is interested in.

“The most recent example is non-alcoholic steatohepatitis (NASH) – a chronic liver disease that’s increasing in prevalence globally and is predicted to be the major cause of liver transplantation certainly in the US and around the rest of the world.

“We’re working with clinicians across Scotland looking to see if there’s a way to determine whether or not somebody will progress rapidly and potentially end up needing a liver transplant or might progress more slowly and might be able to be treated in a GP setting. Those sorts of projects are really exciting and the sort of thing we can do with the patient population and health data that we have.”