A cheap and simple genetic test can guide the treatment of children with asthma, improving their quality of life, according to the results of the first clinical trial of personalised treatment of asthma.
The treatment of asthma hasn’t changed much in the last 20 or 30 years. People who show symptoms of asthma tend to first be prescribed a drug that works on receptors in the airways and blood vessels, called beta-2 receptors. If that doesn’t work, they tend to be given inhaled steroids, which stop inflammation in the airways.
But many people still struggle to manage their symptoms, says Somnath Mukhopadhyay, chair of paediatrics at the Royal Alexandra Children’s Hospital in Brighton, UK. About 17 per cent of people with asthma have a form that is “difficult to control”. Such individuals can end up having more severe and potentially life-threatening asthma attacks. “They can struggle to go up stairs, and have difficulty managing their social relationships,” says Mukhopadhyay. “They can have a very poor quality of life.”
Advertisement
Previous research suggests that a genetic factor might explain why some people do better on certain treatments than others. A region of the genetic code for the beta-2 receptor can vary between individuals – people with different versions of this code tend to respond .
This suggests that a genetic test to find out which form a person has could help guide an individual’s treatment, says Mukhopadhyay. To find out, Mukhopadhyay and his colleagues recruited 241 volunteers aged between 12 and 18 from 236 doctors’ surgeries around the UK.
At the start of the study, all of the children were already being treated with a first-line drug that acts on beta-2 receptors, as well as inhaled steroids, but still found their asthma difficult to control. At that point, around half of the volunteers continued receiving the treatments selected by their family doctor (GP) based on their symptoms. The other half were given a genetic test, which involved sending a sample of spit to a lab.
Within 10 days, those individuals and their doctors were told which form of the beta-2 receptor they had. Those that had a form that suggested they would be more likely to respond to beta-2-receptor-based treatments were given a drug that did just that, called salmeterol. The other teenagers were given a different drug – montelukast – which targets another receptor.
All of the volunteers were also asked to fill out a questionnaire to assess their quality of life, and how their asthma symptoms affect the way they feel and their ability to take part in various activities. This questionnaire was completed at the start of the study, and again 12 months later.
The team found that those who had been prescribed a treatment based on the results of a genetic test showed significant improvements in their quality of life compared with those who had received standard treatments. The greatest improvements were seen in the 15 per cent of young people with a specific genetic variation that meant they were least likely to benefit from drugs that target the beta-2 receptor.
Given that an estimated 150,000 children with asthma in the UK alone have this genetic variation, many children stand to benefit from the personalised approach to treatment, says Mukhopadhyay, who presented the results at the . The approach could also be used to treat adults with asthma.
The approach could also reduce the cost of asthma treatment, he says. “It costs about £15 or so for the whole process,” he says. “That’s much [cheaper] than an emergency visit to the GP, which costs at least £35, or a single visit to the hospital, which can cost hundreds of pounds.”
