Genomics and Precision Medicine

On Saturday, 27 February 2021, we had a get together with Folefac Aminkeng, an Assistant Professor of the Yong Loo Lin School of Medicine, National University of Singapore (NUS). He presented the idea of personalised medicine (or ‘precision medicine’), whose ultimate goal is to give every patient the right medicine with the right dose based on one’s genes and lifestyle. This could be contrasted with the current practice of medicine which although is evidence-based but still not yet ‘personalised’ or ‘precise’. Interestingly, the philosophy of precision medicine could be traced back to the time of the Greek physician Hippocrates (460 – 370 BC), who had advised: “give different ones to different patients, for the sweet ones do not benefit everyone, nor do the astringent ones, nor are all the patients able to drink the same things.”

Folefac mentioned that clinical trials are currently performed on subsets of the population which are not necessarily representative. As a result, the effectiveness of a medicine, which has been proven in the clinical trials, may not occur at the same degree once the medicine is released to the public. Even worse, some medicines may trigger unexpected adverse body responses for certain patients. For instance, immunotherapy may help patients to fight cancer, but, as a side effect, the modified immune system may possibly attack certain vital organs, such as the heart or lungs. The health authorities have the task of monitoring the cases of adverse reactions reported, and also regulating the use of certain medicines by recommending testing of genetic biomarkers before the drug can be prescribed. He gave the example of carbamazepine, a medicine for epilepsy-related disorders, which now requires compulsory testing of a genetic biomarker of its feared side effect Steven Johnsons Syndrome. 

In his opinion, some serious side effects may be related to genetic peculiarities, and thus they should be able to be predicted based on the genetic data of the patients. In fact the efficacy of certain drugs (e.g. antipsychotic medications) may also be related to the genetic predisposition of patients to metabolise the drug in different ways. The information would be important to doctors and pharmaceutical companies. They would be able to predict better which chemicals would be effective, and at what doses, to treat certain conditions in different sub-populations of patients.

The practice of personalised medicine, according to Folefac, is generally still limited to cancer treatments. However, there is a growing awareness to expand its practice to treat non-cancer patients. With the tremendously-reduced price of genome sequencing over the years, hospitals and authorities may in future be able to store the genetic data of every patient, and hence personalise treatment for each one. There would obviously be technical and ethical challenges to be overcome before this programme can be rolled out.