Genetic test for asthma may improve treatment

Testing children with asthma for a variant in the beta-2 receptor
gene may help clinicians determine the most suitable medication, especially in
children who respond poorly to standard treatment.

The researchers, from the University of Dundee and the Brighton and
Sussex Medical School, said that the results were 'a step towards personalised
and tailored medicine for asthma'.

The arginine-16 genotype of the beta-2 receptor gene is carried by
one in seven asthma sufferers. The usual treatment for children where standard
treatment with a reliever inhaler is not effective is a combination of a steroid
inhaler and salmeterol, which is a beta receptor stimulant. However, previous
studies have shown that people with the gene variant may respond poorly to salmeterol and there have been concerns that this drug may even make their
symptoms worse.

With this is mind, the researchers decided to test whether children
with the arginine-16 variant would respond better to an alternative treatment
called Montelukast (also known as Singulair). Sixty-two children agreed to
take part in the study and were randomly separated into two groups. The first
received the standard treatment of fluticasone (a steroid inhaler) and
salmeterol, and the second group received fluticasone and Montelukast. The
participants were then followed up every three months over the course of a year.

The study showed that the number of school days missed over the year
was found to be significantly lower in the Montelukast group. The researchers
also looked at asthma exacerbations, salbutamol use, asthma symptom scores,
lung function and quality of life scores.

Professor Somnath Mukhopadhyay of the Brighton and Sussex Medical
School, who was involved in the study, said: 'For almost every symptom we were
looking at there was a significant difference and it was always in the favour
of Montelukast' — although there was no observed significant difference in lung
function between the two groups.

The researchers concluded that asthmatic children with this specific
genetic variation 'appear to fare better on Montelukast than salmeterol' when
this is combined with a corticosteroid. They added that treatment of these
children may be made more effective with the help of a simple relatively
inexpensive genetic test.

Malayka Rahman from Asthma Research UK said: 'This exciting area of
research has the potential to lead to the tailoring of better treatments for an
individual based on their genetic make-up, ultimately keeping more people out
of hospital and preventing unnecessary asthma deaths in the long term'.

The present research was a proof of principle study to determine if
an alternative treatment was more successful in certain patients and, as such,
had a very small sample size of people with a known genetic variant. The results will therefore need to be confirmed in larger studies before changes in
treatment regimen can be decided upon.