A commentary notes that this landmark study has many strengths such as large sample size and long duration of treatment which provided sufficient power to show that add-on therapy with azithromycin in adult patients with uncontrolled asthma reduced exacerbation rates and improved quality of life in this study. In addition, all study patients were well phenotyped, including assessment of the asthma inflammatory phenotypes-unexpectedly, azithromycin reduced exacerbations in both eosinophilic asthma and non-eosinophilic asthma. By contrast, in the AZISAST study, azithromycin decreased the exacerbation rate in patients with non-eosinophilic but not eosinophilic asthma. It cautions however that since microbial resistance is a well-known side-effect of antibiotic use, add-on therapy with azithromycin in asthma needs to be restricted to those patients with the highest unmet medical need (e.g. frequent exacerbators) and to time periods with the greatest risk of exacerbations (i.e. winter). It suggests biomarkers that predict the therapeutic response to macrolides might facilitate optimal patient selection.
A Cochrane review from 2015 on use of macrolides for chronic asthma noted that the evidence at that time did not show macrolides to be better than placebo for the majority of clinical outcomes. However, they may have a benefit on symptom scales and some measures of lung function, and the possibility of other benefits or harms could not be ruled out because the evidence was of very low quality due to heterogeneity among patients and interventions, imprecision and reporting biases.