View: Transitioning to precision medicine | Economic Times

How often do we look for medicines that are commonly used to treat a particular disease? What if we looked for medicines to treat a particular individual instead? Transitioning from the current one-cure-fits-all treatment model to a holistic approach that tailors the medical interventions to a particular individual is what precision medicine is all about.At the launch of the US Precision Medicine Initiative in 2015, Barack Obama had said, ‘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?’ Personalised treatments benefit health by avoiding wrong treatment and reducing the financial burden for those who can’t afford it. With an almost 72 million rare disease population in India, the right therapy — or preventing the occurrence itself — will go a long way to reduce the country’s health burden.The Human Genome Project started in 1990. Sequencing the human genome for the first time took 13 years, costing about $3 billion. Since then, sequencing technologies have undergone revolutionary changes, from sequencing one gene to a panel of genes by next-generation sequencing (NGS). The speed and cost-efficiency of sequencing a whole human genome, a major driver of precision medicine, has improved manifold — from $10,000 in 2011 to about $1,000 today.Understanding the genetic footprint of the patient is where genomic-based diagnostics comes in. Imagine the relief when an expecting couple with a first-born suffering from hearing and speech loss, gets to know through genetic testing of the foetus that their next-born child would be a carrier of the disease, but wouldn’t suffer from hearing loss. While prenatal testing detects genetic defects in a foetus before birth, there are various other clinical applications within reproductive genetics, such as carrier testing, pre-implantation testing and new-born screening.Cancer, largely a genetic disease, has been the first and most widely studied disease area in precision medicine, where diagnostics serves not as a one-time tool, but rather an ongoing process to assess the biology of the tumour as it changes and evolves. About 5-10% of all cancers are hereditary and occur due to inheritance of a genetic variation, mutation within families.In 2018, World Health Organisation (WHO) projected that 1 in 10 Indians will develop cancer during their lifetime, and 1 in 15 will die of the disease. Identifying genetic predispositions can have significant implications for treatment decisions, interventions for patients and testing for close relatives.Personalised cancer medicine also involves targeted therapy, which targets specific genes and proteins that allow certain cancers to grow and survive. Majority of cancers are also being successfully treated by immunotherapy, which boosts the body’s natural defences to fight cancer, though it remains very costly.Another breakthrough — liquid biopsy — has opened doors to a new era in precision oncology. A simple blood test can detect cancer much earlier, reduce the burden on the limited cancer hospitals, while saving many more lives at much lower costs.While we can’t change our genes (yet), we can change the environment we put them in, and make healthier lifestyle choices. Wellness-based genomic tests combined with the analysis of other risk factors can help tailor specific nutritional and lifestyle choices. With pharmacogenomics, it is now possible to identify how genetic variations affect a person’s ability to metabolise a drug and prescribe the right dosage.Research in precision medicine has been responsible in bringing many targeted therapeutics to the market. For a diverse country like India — with over 4,000 population groups, and a significant percentage of consanguineous (descended from the same ancestor) marriages — there is high prevalence of inherited genetic disorders that require attention for early diagnosis, right treatment and management. This opportunity to get access to data and understand disease-wise genetic variations will help develop better treatment, although managing this data will be just as critical.With the Covid-19 pandemic, mutants and variants have become household names. It highlights the role genomics plays in infections disease management at the individual and population levels. Point-of-care molecular tests tailored to individual pathogens have dramatically increased the speed and specificity of infectious disease diagnosis, such as tuberculosis and other non-communicable diseases.Embedding precision medicine principles at research, clinical, industry and regulatory levels, creating awareness, educating the general population, and making these tests affordable are the immediate challenges.