World Health Day 2023 | Personalized medicine and the future of diagnostics and drug therapy

In contemporary diagnostics and drug therapy, the ‘one size fits all’ approach is being turned on its head. It is being individualized: understand the patient’s genetic profile and then pick the right drug at the right dose for each person. Drop the ‘one size fits all’ method. Think genetic fingerprints. Combine biology and technology. The upside? Better treatment and less trial and error in prescribing medicine.

That is personalized medicine. Also called precision or individualized medicine, personalized medicine is the tailoring of interventions for prevention or treatment of disease to the individual characteristics of each patient. Being advanced through data from the Human Genome Project that was completed in 2003, this emerging practice is moving beyond the genome into the entire spectrum of molecular medicine.

Though personalized medicine is being touted as an emerging science, according to the American College of Cardiology (ACC), this practice of medicine is not entirely new. The discovery of DNA, in 1869 by the Swiss chemist Friedrich Miescher, based on analysis of pus-coated surgical bandages, set the stage for future studies in molecular medicine. “The identification of the ABO blood group system, in 1901 by Karl Landsteiner at the University of Vienna, may be one of the first instances of recognizing differences in each patient’s biology. Landsteiner’s discovery of why some blood transfusions were successful and others were not led to him winning the Nobel Prize in physiology and medicine in 1930,” ACC says.

In December 2015, the then US President Barack Obama had signed the bipartisan Precision Medicine Initiative and defined the effort as “delivering the right treatments, at the right time, every time to the right person.” According to a report published by the Personalized Medicine Coalition (PMC), nearly 35 percent of United States Food & Drug Administration (USFDA) new drug approvals in 2017 were personalized medicines.

In the US, the PMC has been active for two decades, but in India, this stream of diagnostics and drug therapy is still sparingly used. A quick web crawl will indicate the presence of personalized medicine clinics and laboratories, mostly in metropolitan cities, as well as an Indian Society of Personalised Medicine but the pathway to mass acceptance is still too long.

Founded by Dr Sooraj Ratnakumar, Swagene (Swa = Self in Sanskrit; Swagene = My Gene), a Chennai-headquartered genetics and molecular diagnostics laboratory, has developed novel tests to guide physicians prescribing therapy and dosage of medicines according to a patient’s genes for highest efficacy. For several conditions like rare cancers (sarcomas), and for infertility, among other specialties, Swagene offers test panels in India and, in some cases, internationally.

“An example is the test for NUDT15 mutation. One of the popular chemotherapy drugs, especially for children, is thiopurines which include mercaptopurine and azathioprine. These cause high toxicity in a lot of patients leading to hospitalization and high expenses, which among Indians and Asians are mostly due to a mutation in NUDT15 gene. Doctors used to routinely test for TPMT gene, but its mutations are very rare among Indians and other Asians accounting for only 1-2 percent. Whereas NUDT15 mutation has 15-20 percent prevalence and Swagene was the first lab to offer the test since early 2016. Many oncologists now routinely use this test before starting chemotherapy,” says Dr Ratnakumar, the founder and scientist.

Precision medicine in India

“Personalized medicine is in its infancy in India. The ability to offer personalized medicine solutions to Indian patients in the ‘traditional’ sense of the term requires widespread infrastructure for multi-omic testing in addition to the ability to analyse the data, all at considerable cost,” a paper titled “Personalised Medicine in India: Mirage or Viable Goal?” published in Indian Journal of Rheumatology, states.

“It’s still used very sparingly and awareness is low. It’s mostly used by oncologists, but that too only for modern therapies that require these tests before prescription. The scope, however, is huge for even chemotherapy drugs for oncologists, and also for all medical specialties where its usage is currently only after emergency hospitalization or severe side-effect has already occurred,” Dr Ratnakumar adds.

Genome India Project

The launch of Genome India Project (GIP) in January 2020 will give a fillip to personalized medicine in India. Inspired by the Human Genome Project (HGP 1990-2003), the GIP aims to collect 10,000 genetic samples from across the country to build a reference genome to understand the type and nature of diseases and traits that comprise the diverse Indian population.

GIP will help in the development of personalized medicine, anticipating diseases and modulating treatment according to the genome of patients. With this, the likelihood of a disease can be mapped to variations across genomes and public health interventions can be targeted better, and diseases anticipated before they develop.

“When burned on a CD, the human genome is smaller than Microsoft Office,” venture capitalist Steve Jurvetson had famously said. But the future of diagnostics and drug therapy lies in the that smaller-than-MS Office genome. After all, the story of evolution is carried in the genomes and written in DNA, the language of molecular genetics that is the base of personalised medicine.

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