Children's characteristics may determine response to inhaled corticosteroid therapy for asthma

In a study published online in the Journal of Allergy and Clinical Immunology, researchers at Washington University School of Medicine in St. Louis and five other sites nationwide found that children who showed the most improvement in days without wheezing using an inhaled corticosteroid drug were caucasian boys who had allergies and had a hospitalization or emergency department visit for asthma symptoms in the year prior to the trial.

"We found characteristics that predicted a favorable response to inhaled corticosteroid therapy were actually markers of more severe disease overall," said Leonard B. Bacharier, M.D., a Washington University pediatric asthma and allergy specialist at St. Louis Children's Hospital and lead author of the study. "The degree to which children improved while receiving therapy was related in part to how sick they were - the sicker children had a greater response to the drug, while other children did not have as much room to improve."

Results come from another look at data collected in the three-year PEAK Study, or Prevention of Early Asthma in Kids, in which the researchers studied 285 children ages 2 and 3 at high risk for asthma - those who had recurrent wheezing and risk factors for subsequent asthma diagnosis, including a history of eczema or at least one parent with asthma. In that study, conducted in the early 2000s, half of the children were treated twice daily for two years with an inhaled corticosteroid drug, fluticasone propionate (Flovent), and half received a placebo. They were followed for a year after the treatment was stopped. Results of that study showed that the therapy did not prevent the development of asthma, but during the two years that the children received treatment, the group using the drug experienced significantly fewer asthma symptoms compared to children receiving the placebo.

About 6.7 million U.S. children, or 9.1 percent, suffer from asthma, according to the Centers for Disease Control and Prevention, making it the most common chronic childhood illness. About 75 percent of all patients with asthma first develop the disease in childhood.

Using data from the PEAK study, researchers used the percentage of "episode-free days," or days without asthma symptoms or need for medications, as a measurement of response to the drug or placebo. Boys who used the inhaled corticosteroid drug had 93 percent episode-free days, while boys using the placebo had 86 percent episode-free days. Girls, however, had 92 percent episode-free days whether they were using the drug or the placebo. White children who used the inhaled corticosteroid drug had 93 percent episode-free days, while those on placebo had 84 percent episode-free days. Nonwhite children had 92 percent and 93 percent episode-free days, respectively.

Bacharier, also associate professor of pediatrics at Washington University School of Medicine, said the study shows that not all children with asthma respond the same to a given medication, opening the door to further study into personalized medicine.

"Even within asthma, the ability to use these or other patient characteristics, now referred to as asthma phenotypes, should help us to deliver more personalized, accurate, effective and safe care for patients because we can look at each patient as an individual rather than the average child with asthma," Bacharier said. "There is a lot of emerging evidence that if we look beyond the diagnosis to the patient's characteristics, we may be able to choose better what therapy will work. That's the future of asthma care and all medical care."

The other participating medical centers in the PEAK study were the University of Arizona; the University of California, San Diego; Pennsylvania State University; the National Jewish Medical and Research Center; and the University of Wisconsin.