Professor Matt Brown: Genomics 101 - What is personalised medicine?
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In this explainer episode, we’ve asked Professor Matt Brown, Chief Scientific Officer at Genomics England, to explain what personalised medicine is and how it could change the way we treat genetic conditions and cancer.

You can also find a series of short videos explaining some of the common terms you might encounter about genomics on our YouTube channel).

If you’ve got any questions, or have any other topics you’d like us to explain, feel free to contact us on [email protected]).

You can download the transcript) or read it below.

Naimah: What is personalised medicine? I’m joined by Matt Brown, chief scientific officer for Genomics England, to find out more. So, first of all, Matt, can you tell me, what is personalised medicine?  

Matt: So, personalised medicine is about giving the right dose of a medicine and the right medicine to the right person. So, it’s exactly the opposite of one size fits all. It’s what doctors have been trying to do ever since we had effective medicines, that is generally looking at the patient, what disease have they got, what factors are there about the patient that can help judge what dose they should give and for how long, of which medicine.  

Naimah: So, people often refer to this as precision medicine. Is this the same thing?  

Matt: Generally, the two terms are used interchangeably. I think precision medicine is more specifically about the dose perhaps, but effectively they both mean the right medicine at the right dose for the right person.  

Naimah: And how can we predict what treatment will suit each individual patient best?  

Matt: Well, to some extent, of course, this depends on the disease the patient actually has. We also know from a patient’s history how they’ve reacted to similar medications in the past. So for example, some patients have lots of problems with anti-inflammatories, other patients don’t, so if you give an anti-inflammatory to somebody who’s had problems with them before, you’re likely to cause the same problems all over again. So nowadays, we have much, much better ways, other than trial and error, to predict what treatment will suit a patient best, and in particular, development of genetic markers to look at how their condition is going to respond best, and how the patient is going to tolerate the medicine you give them, and what dose you should be giving them.  

Naimah: How could personalised medicine change the way we treat genetic conditions and cancer?  

Matt: So, I’ll talk about cancer first up. In the past, we used to treat cancers based on the organ from which the cancer actually arose, and the more we’ve learnt about what the genetic mutations are that cause cancers, the more cancer treatments are being decided based on the genetic mutation which is driving the cancer, and this has proven to be more effective than just looking at the organ from which the cancer arose. It turns out then that some medications which were only being used for specific cancers, are actually useful across multiple cancers that are driven by the same genetic mutations.  

In lots of other common diseases though, we now know a lot about genetic variants which predispose people to adverse drug reactions, and so we can use genetic tests to predict who’s going to get those adverse drug reactions and avoid them. And similarly, we also know about genetic determinants of how people metabolise and, in many cases, activate medications, and that helps us a lot learning about what dose to give people.  

Naimah: And how far away are we from seeing this routinely in clinical care?  

Matt: We are seeing it in routine clinical care in some pretty narrow settings. So, there are genetic tests available for enzymes which are involved in activation of particular chemotherapy 5 agents. So, DPYD testing, for example, is widely used to predict people’s likely response to a class of chemotherapy agent called fluoropyrimidines, or 5-Fluorouracil is a common one, and the genetic test basically picks out a group of people, a small number of people who are likely to have severe adverse drug reactions to that class of medication, and that’s been a really big success.  

We also use it for picking some other severe adverse drug reactions to medications like gout medications, HIV medications and so on, but generally it’s pretty narrow. What we want to get to the point is where we have people tested in advance of them needing medications, so that when they go to the doctor to be seen about a particular condition, the doctor already has the genetic test available to them, so the doctor can say if the medication is safe and what dose to use. This is what we call pre-emptive testing.  

Naimah: That was Matt Brown explaining what is personalised medicine. If you’d like to hear more explainer episodes like this, you can find them on our website at www.genomicsengland.co.uk. Thank you for listening.