London, Jan 11 : Researchers have challenged earlier studies about a widely used asthma combination therapy, by demonstrating that one of the most commonly used asthma medicines, long-acting beta-agonists, may not be linked to adverse effects in people based on their gene variation.
Previous studies on beta-agonists have shown evidence for an adverse genotypic effect.
However, researchers from the Wake Forest University Baptist Medical Center have questioned the findings, by demonstrating conflicting results in their experiments.
For the study, the team analyzed the effects of long-acting beta-agonist therapy, used in combination with inhaled corticosteroids, in asthmatics who have a specific beta-2 adrenergic receptor (ADRB2) genotype.
They looked at data from two clinical trials performed by AstraZeneca Pharmaceuticals LP. In each trial, patients were randomised to receive one of two different long-acting beta-agonists.
Results showed that in the case of each of the therapies, asthma symptoms and control improved, but no differences were observed based on the ADRB2 genotype.
"These results are extremely important because previous studies on short-acting beta-agonists showed evidence for an adverse genotypic effect," The Lancet quoted lead-investigator for the study Eugene R. Bleecker, as saying.
"Smaller studies on long-acting beta-agonists have produced conflicting results," Bleecker added.
Current guidelines advocate the use of combination therapy, with long-acting beta-agonists and inhaled corticosteroids, to control moderate to severe persistent asthma.
"With over 2,000 patients in this study receiving combination therapy, it was reassuring that no adverse safety effects could be attributed to an individual's genotype," said Bleecker.
The findings are published in The Lancet.