based on data from 280 children aged 5-11 years with at least one grandparent identified as black.
Previous studies have suggested that long-acting beta2-agonists (LABAs) may be more effective for patients with poorly controlled asthma, but such step-up therapy has not been well studied in black patients, wrote Michael E. Wechsler, MD, of National Jewish Health, Denver, and colleagues.
In a study published in the New England Journal of Medicine, the researchers reported results of two parallel BARD (Best African American Response to Asthma Drugs) trials conducted at nine centers between January 2014 and March 2016 of individuals with poorly controlled asthma. One trial included 280 children aged 5-11 years (average age, 8.5 years); the second trial included adolescents aged 12 years and older and adults (average age, 37 years) who had family backgrounds that were similar to those of the children.
The researchers randomized the children to four groups to compare the following protocols: doubling the dose of a glucocorticoid (fluticasone propionate) to a dose of 100 mcg, twice daily (the double-fluticasone group); doubling the dose of fluticasone to 100 mcg and adding 50 mcg of the LABA salmeterol (the salmeterol/double-fluticasone group); quintupling the dose of fluticasone to 250 mcg (the quintuple-fluticasone group); or quintupling the dose of fluticasone to 250 mcg and adding 50 mcg of salmeterol (the salmeterol/quintuple-fluticasone group). The trial consisted of a four-way crossover design with each treatment period lasting 14 weeks.
The primary outcome was a composite measure including asthma exacerbations, asthma control days, and percentage of predicted forced expiratory volume in the first second at the end of each treatment.
Overall, a superior response occurred in 53% of the salmeterol/double-fluticasone group, 41% of the double-fluticasone group, 43% of the salmeterol/quintuple fluticasone group, and 47% of the quintuple-fluticasone group.
The superior response was 46% for both groups when the researchers compared a quintupled dose of fluticasone propionate (250 mcg) with a two step–up strategy of adding salmeterol at a dose of 50 mcg and increasing the dose of fluticasone to 100 mcg.
“In contrast to black adults and white persons of all ages, almost half the children who had at least one grandparent who identified as black and who had poorly controlled asthma had a superior response to an increased dose of an inhaled glucocorticoid over the addition of a LABA,” Dr. Wechsler and coauthors wrote. No more than 12% of the children in any treatment group did not have a superior response. No significant differences in reports of respiratory tract infections or pneumonia were seen between the groups. Children younger than 8 years showed a decrease in the ratio of urinary cortisol to creatinine with an increased dose of inhaled glucocorticoids.
In the adolescent and adult study using the same treatment protocols, 20%-25% of patients did not have a differential outcome between treatments. “In adolescents and adults, the addition of a LABA was more likely to produce superior responses than increasing the dose of an inhaled glucocorticoid,” Dr. Wechsler and coauthors wrote.
The study findings were limited by several factors, including the inability to assess long-term effects on growth and inability to detect biomarkers associated with responses to specific therapies, the researchers noted. However, the results suggest that black children with poorly controlled asthma can benefit from additional inhaled glucocorticoids, and larger studies are needed to identify the best treatment for this patient population.
The study was supported by the National Heart, Lung, and Blood Institute. Dr. Wechsler reported relationships with companies including AstraZeneca, Equillium, Genentech, GlaxoSmithKline, Mylan, Novartis, Regeneron, resTORbio, Sanofi, and others. Coauthors identified relationships with numerous pharmaceutical companies.
SOURCE: Wechsler ME et al. N Engl J Med. 2019 Sep 25. doi: 10.1056/NEJMoa1905560.