Saliva test could reduce school absences for asthma
Children who have asthma that fails to respond fully to inhaled steroids are often offered an additional second-line treatment. Several clinical trials have shown that in most children, the addition of a medicine called salmeterol works better than another called montelukast, but that a proportion fail to respond to salmeterol. Previously, researchers from the Brighton and Sussex Medical School and the University of Dundee had found that children who inherit a specific genetic make-up (β2 receptor genotype Arg16) from one parent have an increased risk of exacerbations of asthma when on salmeterol, while those who inherit Arg16 from both parents, about 15% of all children, have an even greater risk.
The Brighton and Dundee research workers published in Clinical Science on 8 January 2013 the results of a small randomised controlled trial that was designed to find out whether asthmatic children with Arg16 have better long-term asthma control with montelukast than with salmeterol as second-line treatment. Scottish children whose genetic tests on saliva specimens showed that they had inherited Arg16 from both parents were selected if they also met at least one of the following criteria: during the previous year they had, as a result of asthma, school absences, needed oral steroids or made unscheduled visits to their GP or to hospital. The 62 children who met these criteria, and whose parents agreed they could take part in the trial, were randomised to receive one of the two treatments in addition to inhaled steroids for one year. They were assessed clinically every three months.
Both groups of children had fewer school absences than in the previous year, but the reduction was significantly greater in the montelukast than in the salmeterol group. Children taking salmeterol needed to use an inhaler of salbutamol as ‘rescue’ treatment for wheezing as often as in the previous year, but inhaler use was significantly reduced in those taking montelukast. Those on montelukast also experienced reduced breathlessness and wheezing.
Stephen Holgate, MRC Clinical Professor of Immunopharmacology at Southampton University, observed that this was a wonderful example of stratified or personalised medicine working its way into practice. “The gene-based test is not yet available to doctors, but should become so if larger trials are equally positive.”