Boston, Massachusetts (PressExposure) December 16, 2009 -- Contrary to previous studies which suggest that asthma patients with a specific genetic mutation might respond less favorably to certain treatments than those with a different mutation, researchers at Brigham and Women's Hospital (BWH) found that patients with either mutation respond to combination treatment, and this treatment should be continued for these patients. These findings appear in the November 19 issue of The Lancet.
Some studies suggest that patients with the an amino-acid variation at a certain position in the Ã2-adrenergic receptor benefit less from treatment with long-acting Ã2 agonists than do those with a different mutation at the Ã2-adrenergic receptor. The authors investigated whether there is a genotype-specific response to treatment with a longacting Ã2 agonist in combination with an inhaled corticosteroid.
Adult patients with moderate asthma were enrolled in pairs of similar lung capacity and ethnic origin, according to which genetic mutation they had. Individuals in a matched pair were assigned to receive inhaled longacting Ã2 agonist or a placebo. An inhaled corticosteroid was given to all participants during the treatment periods. Researchers measured lung function with standard measure of lung function with morning peak expiratory flow (PEF).
The team found that lung function did not differ between groups, but participants with the genetic mutation arginine-arginine did not benefit from the addition of longacting Ã2 agonist in regards to airway hyperresponsiveness.
"Interestingly, we also found that African-Americans with one of the genetic variations did not improve with respect to lung function with the addition of the long-acting beta-agonist to the inhaled corticosteroid the way African-Americans with the other mutation did," said Michael Wechsler, MD, of the Pulmonary Division at BWH. This may modify the risk benefit ratio of longacting beta agonists in this population.