“Doctors have always recognised that every patient is unique, and doctors have always tried to tailor their treatments as best they can to individuals. You can match a blood transfusion to a blood type – that was an important discovery. What if matching a cancer cure to our genetic code was just as easy, just as standard?” said President Obama in his State of the Union address last year.

Innovative approaches by scientists and healthcare experts alike have evolved the field of medicine as we know it. However, despite these advancements, most medical treatments that are available have generalised “one-size-fits-all” approaches, which may be very successful for some patients, but not quite for others.

Personalised vs precision medicine

According to the National Research Council (NRC), "personalised medicine” holds a similar meaning to "precision medicine”, however, the word "personalised" could be misinterpreted that treatments are being specifically developed for each individual. An example of personalised treatment would include customised 3D-printed vascular stents to suit a specific individual.

The focus, however, lies in identifying effective approaches for patients based on genetic, environmental, and lifestyle factors. One example is pharmacogenomics, which combines pharmacology and genomics to study how genes affect an individual’s response to specific drugs, in order to develop effective, safe medications with doses tailored to suit variations in an individual’s genes. 

Imprecise diagnosis equals haphazard treatment

In 2015, President Obama announced that he was launching the Precision Medicine Initiative as a pioneer patient-centered research that addresses the differences in genes, environments and lifestyles, with hopes to bring forward biomedical discoveries and provide clinicians with new knowledge that will enable them to select the best treatments for individual patients.

“Precision medicine is a good term because current medicine is imprecise,” says Richard Smith, former editor of British Medical Journal (BMJ). “Because diagnosis is so imprecise it follows that treatment will be haphazard… There is big variation in how individuals respond to drugs and yet that variation is not usually recorded.”

The most progress in precision medicine is possibly in the study of cancer, with scientists comparing the healthy genome sequence of a cancer patient with the tumour genome sequence from the same patient in order to identify the existence and location of specific mutation or cancer marker. According to the Center for Personalised Diagnostics at the University of Pennsylvania, the standard of care in the following years would involve likely cancer tumour DNA sequencing.

Precision medicine: Where are we now?

Closer to home, researchers from the National Cancer Centre Singapore (NCCS), the National University Health System (NUHS) and the Singapore General Hospital (SGH) have recently been looking into conducting a study on personalised therapies for patients with hepatocellular carcinoma (HCC), the most common type of liver cancer.

The study is a part of a regional project involving neighbouring countries such as Malaysia, Thailand and the Philippines, in which researchers will take samples from the tumours that have been removed from participants to study genetic changes that resulted in the malignancy, how it functions and evolves, and how the cancer evades the body’s immune system.

According to principal investigator and senior consultant surgeon of NCCS professor Pierce Chow, HCC is “particularly complex at the genomic and immunology level”, with each patient requiring treatment targeted at his individual physical make up.

However, he added that there was not enough scientific evidence for “precision therapy” for individual patients with liver malignancy based on the characteristics of their cancer, such as the mutation type, at present.

Not a smooth journey

There are many formidable barriers to be met in the new and growing field of precision medicine. One such example is that many of the technologies required in this novel field have yet to be developed, including large databases with the capability to store large amounts of data collected from patients. This brings about ethical issues of protecting the confidentiality of patients’ healthcare information, especially in such a large pool of participants.

Researchers will have to develop a rigorous and thorough process of informed consent to ensure patients are well protected well informed before participating in studies. Healthcare providers will need to thoroughly understand and be up-to-date with information of molecular genetics and biochemistry, in order to convey relevant knowledge to patients and keep them informed.

Finances are also a challenge, as certain equipment used in the development of precision medicine – such as those used to sequence large amounts of DNA, are costly. Additionally, pharmaceutical drugs that are continuously being developed to target a specific genomic characteristic is also likely to incur a high cost.

Despite these challenges, there have been several examples of success in precision medicine, such as the use of herceptin in the treatment of breast cancer specifically in patients with overactive HER2 receptors. MIMS

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