Mario Castro, MD, director of the Asthma and Airway Translational Research Unit at Washington University School of Medicine, has reported exciting results from his recent studies. Castro was lead U.S. investigator for a study that led to approval in May 2010 of a new, drug-free treatment for patients whose asthma is not well controlled with inhaled corticosteroids and long-acting beta agonists. The treatment, called bronchial thermoplasty, involves a device (the Alair® Bronchial Thermoplasty System) that is inserted into the bronchial passages to release a controlled amount of heat, which reduces the amount of muscle tissue and inhibits narrowing of the airways.
A just-released study supported by the National Heart, Lung, and Blood Institute found that adding the drug tiotropium bromide, commonly used to treat chronic obstructive pulmonary disease, to low doses of inhaled corticosteroids was more effective at controlling asthma than doubling inhaled corticosteroids alone, and was as effective as adding the longacting beta agonist salmeterol.
For adults whose asthma is not wellcontrolled on low doses of inhaled corticosteroids, the two preferred treatment options currently available are increasing inhaled corticosteroids or supplementing low-dose corticosteroids with long-acting beta agonists like salmeterol. However, higher doses of corticosteroids do not improve symptoms for all patients and can have significant side effects, and long-acting beta agonists have come under scrutiny for their risk of worsening asthma symptoms enough to result in hospitalization and even, rarely, death.
“Because tiotropium works through a different mechanism than beta agonists, it may help people who do not respond well to currently recommended treatments,” says Castro.
A study to determine the efficacy of heartburn medication to reduce asthma symptoms found that participants who took the heartburn medication esomeprazole (Nexium®) had as many asthma episodes as participants who were given a placebo. Acid reflux has long been a suspected trigger for asthma, and it has become standard practice to prescribe heartburn medication to those with poorly controlled asthma.
“This study establishes that heartburn medications are not indicated for adults with uncontrolled asthma when they have mild or no symptoms of acid reflux,” says Castro.
Because a finding in adults does not always apply to children, Castro is doing a parallel study with children ages 6-17.
A comparative study overturned a widely held assumption that asthma patients with genes coding for the amino acid arginine at the B16 position of the beta-2- adrenergic receptor do not respond as well to inhaled salmeterol along with daily doses of inhaled corticosteroids as patients with two genes coding for the amino acid glycine at this position.
The study showed that patients with either genotype had similar improvement in airway function. “This provides reassurance that combination medications, inhaled steroids and long-acting beta-agonists such as Advair® or Symbicort® are safe in patients who have the B16 arginine genetic variation,” Castro says.