Science fiction to fact: personalised medicine with primary care-based pharmacogenomics

A couple of years ago I would have said that personalised medicine sounds like a ‘nice’ idea but is probably science fiction – sitting far enough in the future for me not to have to think about it. Now I know differently. By 2025 I believe every doctor will be using Pharmacogenomics (Pgx) – a personalised medicine tool – for all of their patients in the same way that doctors use any other lab test (e.g. a blood count or liver function test).

I am a GP working in a small, high needs practice in Hamilton, New Zealand. I also work for Ventures – a medical innovation company that brings the future to primary care for the busy teams who don’t have the time or energy to think about it, designing and building systems and technologies which help patients and providers in big and small ways.

… but most prescribing is based on trial and error…

The need for personalised medicine is clear; on average, 50 per cent of medication prescribed doesn’t work at all. We know that doctors try to personalise our medication by asking about our family history (to get clues into genetic makeup), or our personal habits (such as smoking), but most prescribing is based on trial and error, using dosing averages figured out from population-based studies.

I learnt more, and experienced, the trial-and-error approach to prescribing as a patient when I developed gastric reflux – where your stomach acid splashes back up into your food pipe and causes burning pain. My GP started me on Omeprazole – the most commonly known anti-reflux medication.

But it gave me horrible headaches.

I stopped the medication, and the headaches went away. But the reflux came back.

I restarted the medication – the headaches came back.

We experimented with my dose and with different anti-reflux medication until we got it right – but it took weeks, if not months.

That was when I began learning about pharmacogenomics. So, I’m sitting in a meeting hearing about pharmacogenomics for the first time thinking “this is a nice idea but surely not ready for primary care (and I sure could have used it when I first got my reflux!)”. But a quick Google search showed me that the FDA, American Federal Drug Agency, requires Pgx marker information on over 250 medicines.

Pgx is being actively used to help patients in the US, Europe, UK, Asia, and Australia – and has been for over 10 years for some of them.

What I thought was science fiction is science fact. I wanted to know more.

“Maybe this could help my patient Julie,” I wondered. Julie* is a 48-year-old school principal with depression. We had come to the point where it was clear she would benefit from anti-depressant medication. But it worried us. Julie has epilepsy – and antidepressants can lower the seizure threshold, increasing the chance of an epileptic seizure. We were about to start a trial-and-error approach with possibly disastrous consequences if we didn’t get it right first time – maybe Pgx could help her?

So, what exactly is pharmacogenomics?

This means that you can get on the right treatment quickly…

Pharmacogenomics is the study of how your genetic makeup affects the way your body metabolises (breaks down) medication. It’s a DNA test that allows you and your doctor to tailor your medication to your body at an individual level.

This means that you can get on the right treatment quickly, avoiding the trial-and-error approach and many adverse effects and side effects of medication that isn’t right for you.

Why aren’t New Zealand GPs already using this? Simply, we needed to get the ball rolling, and at Ventures we have been breaking down barriers to implementation.

One barrier is that there is no commercial lab in NZ capable of processing human genetic material and data (different if you are a cow but that’s another story). After two years of due diligence, Ventures partnered with Melbourne-based genetic company myDNA – led by clinical geneticist Associate Professor Les Sheffield. They had been providing genomic testing for over 10 years in Australia and had a proven track record in clinical genetics.

Implementing any new medical test such as Pgx requires an education programme. GPs are rightfully wary of anything that might be ‘woo‘ [lacking substantive evidence]. They need to see and understand the evidence. Ventures have developed a comprehensive education programme for prescribers that GPs need to go through before they can start using Pgx with their patients. This is to make sure they understand it themselves and can help their patients with questions.

We also needed to make sure that the new information integrated with current systems. GPs want the right information at their fingertips when they need it. It’s all very well to have these results but they are not much use hidden in a pdf filed somewhere in the medical record. Ventures are working with myDNA to integrate the Pgx results into the electronic health record Indici. This will allow prescribers to have evidence-based prescribing guidelines when they go to write a prescription.

Finally, cost has been another big barrier. Genomic testing has become exponentially cheaper over the past 25 years – and the cost can be reduced further by testing panels of genes rather than the whole genome. But each test still costs several hundred dollars. The Ventures Pgx programme works to reduce the equity gap by targeting funded kits to Maori, Pacific, and high needs patients in our area.

…my challenge to funders is to see the big picture …

However, my challenge to funders is to see the big picture – there are significant savings for the system in avoiding the trial-and-error approach to prescribing by funding support of Pgx – whether that be funding the tests themselves or funding Pgx related prescribing information in our medicines information systems.

So, how’s it going so far?

Ventures now have 40 GPs trained and delivering Pgx to their patients in the central North Island with another 40 in the training pipeline. GPs all over New Zealand are upskilling and learning about Pgx via Ventures. Organisations like Habit are working across the country with patients experiencing chronic pain and now using Pgx.

As a GP, I’m using it, of course, and my patients love it.

Julie agreed to be one of our early adopters and did one of our first Pgx tests. Using Pgx allowed us to avoid the medications that would have built up too quickly in her body and cause problems and enabled us to get her on the right medication and dose straight away. She is now stable on her antidepressant medication (the first one we chose after analysis of the Pgx results). She is thrilled to have been able to return to her usual high level of functioning so quickly.

And that’s why we do it, isn’t it? GPs want our patients to be at the best level of wellness they can achieve as quickly as possible. Pharmacogenomics can get us so much closer.

*Details altered, story used with permission.