Conference Coverage

Amoxicillin/clavulanate emerges as best antibiotic for childhood bronchiectasis



– A placebo-controlled trial has confirmed that amoxicillin/clavulanate is beneficial for resolution of acute exacerbations in nonsevere bronchiectasis while also demonstrating a greater relative effect than azithromycin, based on data presented at the annual congress of the European Respiratory Society.

Dr. Vikas Goyal Senior Lecturer, Children’s Health Clinical Unit, University of Queensland, Brisbane, Australia

Dr. Vikas Goyal

“We now have robust data with which to support our guidelines,” reported Vikas Goyal, MD, of the Children’s Health Clinical Unit, University of Queensland, Brisbane, Australia.

The study addresses a knowledge gap. Antibiotics are already recommended by many guidelines for treatment of acute exacerbations in children with bronchiectasis, but Dr. Goyal said that no controlled trials have ever been performed in this age group to confirm superiority to placebo.

In this multicenter study, called BEST-1, 197 children with bronchiectasis were randomized at the start of an exacerbation to placebo, 45 mg/kg per day of amoxicillin/clavulanate, or 5 mg/kg per day of azithromycin. To maintain blinding, patients in the active treatment groups received a dummy for the opposite antibiotic while patients on placebo received dummies for both active agents.

For the primary outcome, 65% of children randomized to amoxicillin/clavulanate had resolution of their exacerbation by day 14 versus 61% of those randomized to azithromycin and 43% of those randomized to placebo. On the basis of relative risk for reaching this end point, the outcome was superior to placebo for amoxicillin/clavulanate (RR, 1.5; P = .015).

Although the relative risk for azithromycin (RR, 1.4; P = .042) was only slightly lower, it did not reach a prespecified level of significance set at P = .025. Dr. Goyal did report that the resolution rate at 14 days in the placebo group was “higher than expected.”

In this trial, 53% of the 154 children who were tested for respiratory viruses with nasal swabs on day 1 of the exacerbation were found to have respiratory viruses. Of these viruses, rhinovirus was the most common, according to Dr. Goyal, whose data were published just prior to his presentation (Lancet Respir Med. 2019;7:791-801).

The median durations of the exacerbations were 7 days, 8 days, and 10 days for those treated with amoxicillin/clavulanate, azithromycin, and placebo, respectively. The difference between amoxicillin/clavulanate and placebo, but not that between azithromycin and placebo, reached statistical significance, Dr. Goyal said.

There were no between group differences in the time to next exacerbation.

In discussing limitations of this study, Dr. Goyal pointed out that the optimal doses of amoxicillin/clavulanate or azithromycin have never been established for the treatment of exacerbations in children with bronchiectasis. He noted that some infectious disease specialists have advocated higher doses of both than those employed in this trial, but dose-ranging studies have never been conducted in this age group.

In this study, adverse events were less common on azithromycin than amoxicillin/clavulanate (21% vs. 30%), but none were severe, according to Dr. Goyal. He said treatment with azithromycin was associated with increased macrolide-resistant bacteria.

On the basis of these data, Dr. Goyal concluded that amoxicillin/clavulanate should remain, as already specified in some guidelines, the standard first-line therapy for nonsevere exacerbations in nonhospitalized children with bronchiectasis. He recommended reserving azithromycin as an alternative therapy.

Dr. Goyal reports no potential conflicts of interest.

SOURCE: Goyal V et al. Lancet Respir Med. 2019;7:791-801.

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