asthmaA simple spit test could identify thousands of children with severe asthma who are taking medication which will never help them, according to new research.

One in seven people will not respond to the most commonly used medication,  salmeterol, and a study of 62 children by Brighton & Sussex Medical School has shown that unrespondent patients could be identified and given effective treatment.

Salmeterol, which is found in Seretide and Servent inhalers, is used to relax the airways in the lungs. It is taken by children who cannot control their asthma just with a blue inhaler, which is given to all children when they are diagnosed with asthma.

Prof Somnath Mukhopadhyay who lead the research said: "For almost every clinical outcome we were looking at we found that salmeterol either wasn't working or was working very poorly. We've shown for the first time that personalised medicine can work in the field of childhood asthma."

Researchers found that the reason why some children do not respond to salmeterol is hidden in their genetic code. The drug acts on beta-2 receptors in the airways, however, one in seven people have a genetic mutation resulting in their receptors being a slightly different shape, which the drug struggles to recognise.

DNA taken from a child's spit can be tested to reveal the shape of their beta-2 receptor and whether salmeterol will work. It is estimated that the test, which is not yet available for use in GPs surgeries, would cost about £15.

Prof Mukhopadhyay added: "It's a common disease affecting a million children in this country, a common medicine is probably not working in a significant proportion of the population. I think we need to get some guidance from lead charities and from the Department of Health."

The Department of Health welcomed the research and said looking at genes may one day be used to tailor treatments. However, a spokesperson said more work still needed to be done before that stage was reached.

The exact number of children who have the mutation and are taking the drug is unknown, but could be up to 15,000 in the UK.

Posted 09/01/2013 by richard.hook@pavpub.com