Professor Matt Brown: Genomics 101 - What is personalised medicine?

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 info@genomicsengland.co.uk.


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.