What is pharmacogenomics and how is it being implemented in medicine?

What is pharmacogenomics?

Pharmacogenomics combines pharmacology and genomics to analyse genetic variations which are then used to inform the choice of drug and dosage for a particular patient. This facilitates greater accuracy in prescribing medication and provides an increasingly personalised approach to drug therapy. Because genes hardly change throughout a person’s lifetime, a pharmacogenomic blood test only needs to be done once.

 

Currently, about 6.5% of UK hospital admissions are caused by ADRs. However, many complications from ADRs can potentially be avoided thanks to the latest pharmacogenomics research as it allows medical professionals to give patients appropriate drugs at suitable dosages. This will not only improve patient experiences but also streamline the prescription process, resulting in improved clinical outcomes.

 

How is pharmacogenomics currently being used in medicine?

Currently, a pharmacogenomic approach is used for a small number of drugs, such as those used for colon and breast cancer treatment. For example, pharmacogenomics is used to determine whether a patient can safely be prescribed the chemotherapy drug 5-fluorouracil. Human leukocyte antigen (HLA) testing is also mandated before starting Abacavir: one of the key drugs used to treat HIV.

 

Although pharmacogenomic testing is currently only used for a small number of drugs, scientists have determined that we have the technology to use genetic testing to guide the use of 40 of the most prescribed drugs in the UK.

 

Dr Andrew Goddard, President of the Royal College of Physicians, explained that:  “Pharmacogenomics has long been an area of limited and difficult access for health professionals – not just in its daily use, but also in the relevant training available on this subject. It is an area that has traditionally been absent from the online systems and tools used daily by doctors. Our hope is that this report will be the springboard to getting genomics working effectively in everyday clinical practice.”

 

What are the main challenges with widespread pharmacogenomics adoption?

Despite the potential benefits of pharmacogenomics, widespread implementation into any healthcare system has not yet been observed. There appear to be a number of reasons for this, including clinical implementation, concerns over patient privacy, scalability and reliability of testing, and an evolving regulatory environment, amongst others.

 

Currently there are several networks that focus on pharmacogenomic research, however these are often based within a single country, such as the Pharmacogenomics Global Research Network (PGRN) in the USA, or the Pharmacogenomics and Stratified Medicine Network in the UK. There is no unified global network of experts to help develop research and clinical implementation. Once this is developed, global pharmacogenomics adoption and implementation could be made possible, improving the uptake of clinical pharmacogenomics testing in both developed and resource limited countries.

 

There also seems to be limited availability of large datasets containing detailed phenotypic information across a variety of patients from diverse backgrounds. This makes it difficult to properly assess drug response. To aid pharmacogenomic adoption, the collection of publicly accessible datasets that include DNA, RNA and endogenous metabolites would be beneficial.

 

How will pharmacogenomics be used in the future?

More physician and pharmacist awareness of pharmacogenomics appears to be necessary before widespread testing can be rolled out. Research is already rapidly progressing, with the Genomic Medicine Service (GMS) planned to sequence 500,000 whole genomes by 2023-2024.

 

Given the current rate of research, genomic testing may become more widespread in the coming years. According to studies, the global pharmacogenomics market size is expected to reach $9.9 billion by 2025, and genomic testing could become a common practice for healthcare professionals.

 

According to Ravi Sharma, Director of England at the Royal Pharmaceutical Society, “At the moment, it’s [pharmacogenomics] very niche”, however in the coming years, “Genomics won’t just transform medicine for pharmacy; it will transform medicine for the whole healthcare system.”