Adding the long-acting beta-agonist salmeterol to fluticasone in a fixed-dose combination didn’t increase serious asthma-related events among children aged 4-11 years, according to a report published online Sept. 1 in the New England Journal of Medicine.
After long-acting beta-agonists were introduced as add-on therapy for uncontrolled asthma, two large studies involving adults linked the treatment to an increase in asthma-related death. Other studies found no such association.
The FDA mandated that all four manufacturers of those agents in the United States perform large postmarketing safety trials to establish the noninferiority of the approach. In response, GlaxoSmithKline, the only maker of a long-acting beta-agonist with a pediatric indication (salmeterol), performed this international randomized, double-blind, controlled trial at 567 medical centers in 32 countries, said David A. Stempel, MD, of Respiratory Clinical Development, GSK, Research Triangle Park, N.C., and his associates.
The trial involved 6,208 children aged 4-11 years who had controlled or uncontrolled asthma with a history of exacerbations during the preceding year. The participants were randomly assigned to receive 26 weeks of a lower fixed-dose combination of salmeterol plus fluticasone, a higher fixed-dose combination, a lower dose of fluticasone alone, or a higher dose of fluticasone alone, delivered twice daily via a disk device.
The primary safety endpoint was a composite of death, endotracheal intubation, and hospitalization. No deaths or intubations occurred.
A total of 27 patients taking combined therapy and 21 taking fluticasone alone required hospitalization for asthma (hazard ratio, 1.28). The number of severe asthma exacerbations was 14% lower when salmeterol was added to fluticasone, a nonsignificant difference.
The results demonstrate the noninferiority of the combined therapy, Dr. Stempel and his associates said (N Engl J Med. 2016 Sep 1;375[9]:840-9).
The percentage of children who withdrew from the study because of asthma exacerbations was identical in the two groups (1.1% of each), and the percentage who had a serious adverse event was nearly identical (1.8% vs 1.7%, respectively). The mean percentage of rescue therapy–free days also was similar (83.0% vs 81.9%), as was the mean percentage of days in which asthma was controlled (74.8% vs. 73.4%).
At the conclusion of the study, 88.1% of the fluticasone-plus-salmeterol group had controlled asthma, as did 88.5% of the fluticasone-only group. Meaningful differences between the two treatments could not be identified among various subgroups of patients – defined by age, sex, and race – because the overall number of adverse events was so low, the investigators added.
They cautioned that the trial excluded children who had a history of multiple asthma-related hospitalizations and intubations. Therefore, the findings may not be applicable to patients with very severe asthma, the researchers cautioned.
GlaxoSmithKline sponsored the trial in response to a Food and Drug Administration mandate for large postmarketing safety studies from the marketers of long-acting beta agonist–containing products sold in the United States. Dr. Stempel is an employee of GSK; his associates reported ties to numerous industry sources.