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Genomics

What does genomic medicine mean for pharmacy?

The concept of personalised medicine is not new; however, it is undergoing a revolution. For decades clinicians have tailored decisions about care and treatment to the patient sitting in front of them, be it by age, biochemistry or by understanding the individual’s lifestyle and preferences. Genomics is the latest tool guiding this personalised medicine approach. 

What is genomics?

Genomics is the study of the DNA in an organism and how it works. Every cell in the human body carries a 3.2 billion letter DNA code, called the genome. Rapid advancements in genomic technology and affordability of testing means that it is now possible to sequence and interpret the entire human genome in just a few days. Knowledge of the human genome and its variation has informed our understanding of health, the prediction and diagnosis of disease, and an individual’s response to treatment.

The NHS has committed to translating the benefits of genomic technologies into healthcare via the NHS Genomic Medicine Service, a network of seven Genomic Laboratory Hubs which provide testing according to a standardised national genomic test directory. These tests can range from looking at a single letter of the DNA code, an individual gene, a panel of multiple genes, or sequencing the whole genome. 

This testing must then be embedded into clinical pathways across different specialties to inform care for individual patients. New infrastructures across England – Genomic Medicine Service Alliances – will support the workforce in understanding and adapting to genomic advances and embedding genomics into pathways of care. 

How can genomics help with medicines optimisation?

Genomics has expanded our understanding of many diseases, particularly cancer and rare diseases. This is evidenced by the raft of new targeted therapies and gene therapies coming through drug development. Increasingly, new drugs approved by NICE are linked to specific genetic tests to stratify the target patient group. 

In cancer, the classification of the disease itself is shifting, moving away from an organ-based definition towards classification according to the genetic mutations present in the tumour. This has translated into a more targeted treatment approach, and the advent of histology independent drugs which are licensed for use based on tumour genetics rather than tumour site. In addition, greater understanding of the genetic basis of cancer has enabled early detection through screening programmes and given insights into tumour evolution and loss of treatment response. 

Pharmacogenomic testing allows healthcare professionals to predict patient response and tailor prescribing decisions to optimise treatment benefit and minimise risk of toxicity.

A key application of genomics for medicines optimisation is pharmacogenomics – the study of genetic variants which affect drug pharmacokinetics and pharmacodynamics, and the effect of these variants on an individual’s response to drug therapy. Pharmacogenomic testing allows healthcare professionals to predict patient response and tailor prescribing decisions to optimise treatment benefit and minimise risk of toxicity. Pre-emptive genotyping for adverse drug reactions is currently employed in specialist areas such as oncology to better manage toxicity profiles of chemotherapies. For example, testing for specific genetic variants in the DPYD gene in patients being initiated on fluorouracil-based chemotherapies can identify patients who lack the dihydropyrimidine dehydrogenase (DPD) enzyme which mediates 5-fluorouracil metabolism and elimination. This pharmacogenomic testing can identify patients at increased risk of experiencing severe or fatal toxicity and indicate whether a dose reduction or alternative drug is warranted.

Genomics is also starting to play a role in antimicrobial stewardship. Our understanding of the mechanisms of antimicrobial resistance is expanding through the study of bacterial and viral genomics. Genomic testing and molecular tracking of infections with high risk of resistance, such as Neisseria gonorrhoea and multi-drug resistant tuberculosis, can support tailored antimicrobial treatment choices and reduce unnecessary exposure to broad-spectrum antibiotics. 

What is the role for pharmacy in genomics?

Without doubt, pharmacists have a key role to play in advancing personalised medicine and linking genomic testing to medicines optimisation. Pharmacists are equipped with the specific knowledge, skills and abilities to deliver dose individualisation and therapeutic drug monitoring through their understanding of clinical pharmacology, medicines review and counselling skills. Pharmacists are experienced in combining pharmacokinetic, physiological and drug interaction factors to tailor treatment to an individual patient. Genomics and pharmacogenomic testing will provide an additional layer of information to support this personalised care. 

The new NHS Genomic Medicine Service Alliances aim to drive equitable access to personalised care and ensure genomic testing in the labs is translated into medicines optimisation. Pharmacists will be needed at the forefront of this transformation, supporting the spread of genomics education and training and working collaboratively across regional and national networks to embed genomic testing into treatment pathways. This important role has been outlined in a recent NHS briefing on Genomics Medicine Service Alliances and role of pharmacy within the new infrastructure.

International examples from America, Canada and the Netherlands demonstrate the successful delivery of pharmacogenomic testing via pharmacy-led services in both primary and secondary care settings and the specialist role of precision-medicine pharmacists. These services show the potential role of the pharmacy workforce in providing advice on when to offer a pharmacogenetic test, supporting the interpretation of genetic test results, recommending tailored treatment regimens and counselling patients on these changes. Importantly, pharmacists should be advocates for clinically appropriate and cost-effective use of pharmacogenomic and other genomic tests that guide medicines use and contribute to the research and evaluation of these new services. 

How can pharmacists get involved?

This is an early and exciting stage in the journey towards adopting genomics into mainstream medicines optimisation and recognising the benefits for patients. Collaboration, clinical leadership and sharing of good practice will be key to success. A national pharmacy genomics collaborative network, formed across the new Genomic Medicine Service Alliances, will support these advances in workforce transformation and embedding of genomics. 

The UKCPA have just launched a dedicated Genomics online forum for its members, which provides a platform for those involved in genomic medicine or have a specialist interest in the subject to collaborate, share best practice and shape the role of pharmacy within genomics. 

For individuals who are interested in learning more about genomics in healthcare, the Genomics 101 course is a great place to start as an introduction to the basics of genomics. Additionally, the Genomics Education Programme website offers a wide range of learning opportunities from videos and podcasts all the way through to taught academic courses in Genomic Medicine. Health Education England is currently providing (limited) funding opportunities for taught modules in Genomic Medicine. 

The new era of genomic medicine will cross multiple professions, clinical specialties and sectors of healthcare and shape the landscape of medicines and future treatment options. Now is the time for the pharmacy profession to engage and become familiar with the impact of genomics on medicines optimisation, as we will play a vital role in realising the benefits of personalised medicine. 

The opinions expressed in this article are those of the author. They do not purport to reflect the opinions or views of the UKCPA or its members. We encourage readers to follow links and references to primary research papers and guidance.

Competing interest statement: 

The author declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

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