Pharmacogenomics (PGx) is the study of how genetic factors influence the way a person uniquely respond to medications. It combines what we know about how medications work in the body with genomics - the study of genes and their functions.
People have different genes which produce enzymes with varying levels of activity - slow, normal or fast. This controls how fast medications are broken down and cleared from their body, which has an implication on how well a medicine will work for a person, or what their risk of side effects may be.
While there is ever growing local and international evidence around PGx, the adoption and use of it as a daily tool is under developed. Generally most GPs in New Zealand haven't had a lot of exposure to PGx and there is very little training on this topic.
We now know initially starting medications are only effective in 30-50 per cent of people, and even less effective in non-Caucasian people, such as Māori and Pacific Island peoples. With this in mind for the past two years Ventures has been exploring the role PGx can play in mainstream health services within New Zealand.
There is no community laboratory that processes DNA for genomics in New Zealand, so Ventures have formed a partnership with an Australian-based genomics company to make full medication PGx and sub-speciality panels available within New Zealand. This introduces precision based prescribing, helping to avoid some of the guess work and complications.
The test itself involves a simple, self-administered cheek swap which is then posted away for processing. The test focuses on the exome only, where all protein coding genes are found. Specifically the test involves looking at eight genes which cover around 60-70 per cent of all commonly prescribed medications in New Zealand, including commonly used antidepressants, antipsychotics, pain relief medications, acid reflux medications and statins. The result is a medication management report only, there is no screening for risk of disease or any other uses of the DNA.
Patients or their doctors will register the test kit via an indiciTM platform, with only a secure 'key' provided to the Australian lab for processing, meaning the offshore partner has no ability to associate a patient's identity with a sample. The DNA sample is held indefinitely unless the patient wishes to destroy their sample, which can be requested at any time. (Samples are stored to enable further testing for new markers without the need to re-collect the sample, which can be inconvenient and inefficient.)
Ventures have collaborated with iwi and Māori health providers in this work to ensure culturally appropriate procedures are in place alongside this initiative. They are also working with researchers to evaluate the impact of PGx in New Zealand.
Ventures are in the final stages of securing non-health sector funding which will enable them to subsidise approximately 3,500 PGx panels. These will be used to screen high risk Midlands patients (defined as quintile five with long term conditions and polypharmacy). This funding allows GPs in the Pinnacle network to explore and further understand the potential of using PGx as a new tool for enhanced medication management, alongside improved prescribing and health gains for those who are part of this pilot.
At a launch event last week Ventures hosted over 60 GPs from across the Pinnacle network, with 90 per cent of attendees indicating interest in the project going forward.
Dr Kerry Macaskill-Smith, GP advisor for Ventures presented at the event. Kerry has been involved in the first wave of approximately 100 tests which has been carried out as part of internally validating the work alongside discovering what it means for a GP in practice.
"It was so awesome to see how engaged the GPs at our launch event were. I could look around the room and see specific patients were coming to my colleague's minds and light bulbs were going off as they connected the theory we presented to the practical applications," says Kerry.
"I feel like we've had a real eye opener. It feels like this area of medicine moved from being experimental to something real and practical very quickly and almost without us noticing. Luckily we've found this opportunity to catch up and start using these tests to really make a difference."
"The ability to bring a new tool to GPs that will help them personalise patient care is a really exciting area to be working in," says Kerry. "We could make a really huge difference for complex patients whose medications aren't working for them. Immediately my patients with pain or mental health issues come to mind. This can help me uncover the reasons why."
"As a pragmatic GP I need to know two things primarily - can I trust this, and how do I apply this in my day to day practice. Working with the Australian team is wonderful. They have a very robust approach to the clinical evidence, and keep practical application firmly in mind."
Kerry is also passionate about the next steps Ventures has in mind. "We're working together to develop panels for smoking cessation. We know not all interventions help, and every failed attempt to quit can make the quit smoke journey even harder for a smoker. Getting people quickly to the medication that will support them best, with no adverse side effects should make a massive difference."
For GPs to be able to deliver the medication reports to patients a short online training module needs to be completed. "The training is really well designed, and doesn't take too long to work through. After delivering my first three or four medication reports to patients I felt confident. Plus the medication reports are very well laid out, so it is very easy to get a handle on it," says Kerry.
Ventures will also be working with the patient management system indiciTM to integrate prescribing advice automatically for patients who have had a PGx test. This means in the future GPs will not need to refer to medication reports stored as PDFs, the advice will be at their fingertips.