The Republic's 250,000 asthmatics may benefit from novel research in the United States, which, for the first time, offers the possibility of personalising medication.
Dr Stephen Liggett, Professor of Medicine at the University of Cincinnati College of Medicine, and colleagues have discovered four different patterns of DNA in a gene that helps to relax muscle in a person's lungs.
People with asthma have reduced elasticity in the large- and medium-sized air passages. When asthma flares up, these passages narrow as their controlling muscles contract, giving rise to wheeziness and shortness of breath. The drug Salbutamol, commonly known as Ventolin, is used to make the airways relax.
Professor Liggett measured lung function before and after treatment with Salbutamol in 121 patients. He found four different DNA sequence patterns among the group.
He correlated the lung function findings with the DNA patterns, according to the report in the Proceedings of the National Academy of Sciences. Salbutamol worked very well in those with one DNA pattern, not at all in those with another and moderately well in the other two groups.
The researchers concluded that the different patterns of DNA in the gene that controls lung muscle relaxation determined how well the patient responded to the drug. This represents a good example of how drug treatment could be tailored to suit the individual. It has been made possible by the sequencing of the human genome.
It offers the prospect of matching patients to particular medications, using their DNA as a guide to potential effectiveness.
An extension of these findings to other drugs and diseases could represent a new era of medicine, in which the individual rather than the generic becomes the focus. Research is underway with those infected with hepatitis C and HIV to enhance patient response by making subtle alterations in their drugs.
Researchers are also looking to correlate measurements of disease activity during treatment with ongoing changes in drug cocktails for HIV and AIDs.
The latest findings also have implications for the way drug research is carried out. At present, medicines are tested on large numbers of people with the emphasis very much on the average response of those tested. By using DNA analysis, it may be possible to identify subgroups of patients who benefit from a drug, even if the overall average response to the drug is inconclusive.