Almost 14 years have passed since the completion of the Human Genome Project, where the medical community has expected it to usher in a new era of precision healthcare. In fact, pharmacogenomics and personalised medicine are progressing by leaps and bounds today with many breakthrough discoveries being announced regularly. Healthcare professionals, particularly pharmacists, are equally excited to witness the progressive transformation of their practice to incorporate personalised medicine.

Should we fully embrace personalised medicine today?

Undeniably, personalised medicine offers a very interesting aspect to improve clinical decision-making, bringing diagnosis and drug therapies to a new level. For example, the discovery of a strong association between HLA-B*5801 allele with the development of allopurinol-induced Stevens-Johnson syndrome (SJS) is intimately connected to our local population, as the allele is most commonly found in the Han Chinese population (in addition to those of Korean and Thai descent).

Since allopurinol is the most common cause of severe cutaneous adverse drug reactions (SCAR, which include SJS and toxic epidermal necrolysis, TEN), and the HLA-B*5801 allele is strongly associated with SCAR (2,3), do healthcare professionals have the obligation to screen all patients, particularly those of Chinese descent, to look for the presence of such allele?

As it turns out, the allele was shown to be present in approximately 20% of Han Chinese population. If genetic screenings were to be performed to exclude patients with the allele from receiving allopurinol, almost one in five Han Chinese patients will be denied the treatment and left with other less effective alternatives.

Such decisions may not truly work in favour of the patients, and highlighted a critical knowledge gap in personalised medicine: we still do not fully understand the complex mechanisms of how genetic polymorphisms lead to diseases.

Potential pitfalls of personalised medicine

There are other concerns with regards to personalised medicine as well. The technology's expensive cost and complex economics being the primary reasons that prevent widespread adoption of personalised medicine. Critics of personalised medicine regularly point out that the true benefits of these individualised treatments fail to offer a good value for money to the society as a whole.

There are still much for the medical community to learn about the true economic benefits of personalised medicine, and the sustainability of such benefits in the society.

In addition to concerns about efficacy and costs of these genetic tests, there are practical issues with widespread genetic tests or screenings too. From the patients’ perspective, costs will still be a primary concern as many genetic tests are still not covered by insurers since these are not part of the standard treatment.

Pharmacists may face additional challenges when it comes to tailoring treatment to fit individual patient profiles too. Not only does such practice increases the complexity of patient care, these pharmacists may need to undergo further training in this area to become better qualified to serve their functions.

The development of personalised medicine, though hold much promise to revolutionise healthcare, is not without its pitfalls. There is much progress to be made in the scientific, economic and societal aspects, where members of the scientific and the medical community should engage with each other to overcome the hurdles before we take the plunge to embrace personalised medicine fully. MIMS

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Tassaneeyakul W, Jantararoungtong T, Chen P, Lin P-Y, Tiamkao S, Khunarkornsiri U, Chucherd P, Konyoung P, Vannaprasaht S, Choonhakarn C, Pisuttimarn P, Sangviroon A, Tassaneeyakul W. Strong association between HLA-B*5801 and allopurinol-induced Stevens–Johnson syndrome and toxic epidermal necrolysis in a Thai population. Pharmacogenet Genomics. 2009 Sep;19(9):704–9.
Hung S-I, Chung W-H, Liou L-B, Chu C-C, Lin M, Huang H-P, Lin Y-L, Lan J-L, Yang L-C, Hong H-S, Chen M-J, Lai P-C, Wu M-S, Chu C-Y, Wang K-H, Chen C-H, Fann CSJ, Wu J-Y, Chen Y-T. HLA-B*5801 allele as a genetic marker for severe cutaneous adverse reactions caused by allopurinol. Proc Natl Acad Sci. 2005 Mar 15;102(11):4134–9.
Lee MH, Stocker SL, Williams KM, Day RO. The Journal of Rheumatology HLA-B * 5801 Should Be Used to Screen for Risk of Stevens-Johnson Syndrome in Family Members of Han Chinese Patients Commencing Allopurinol Therapy The Journal of Rheumatology is a monthly international serial edited by Earl D . 2013;40(1):4–6.
Jakka S, Rossbach M. An economic perspective on personalized medicine. Hugo J. 2013;7(1):1.
Carrera PM. Personalized Medicine: Worth Its Cost? Health Aff. 2015 Jan 1;34(1):188–188.