LATE-BREAKING ABSTRACT: Which predictors in COPD patients with the frequent exacerbator phenotype predict the treatment response to maintenance therapy with azithromycin?

Background: It is unclear which COPD patients are most likely to benefit from long-term treatment with macrolides in order to reduce exacerbation frequency. Aims and objectives: We investigated which biomarkers and characteristics of COPD patients with frequent exacerbations have the best treatment response to maintenance therapy with azithromycin. Methods: This analysis was part of the COLUMBUS trial(Clinicaltrials.gov, NCT00985244), a randomized double-blind, placebo controlled, single-center trial, which investigated azithromycin maintenance therapy compared to placebo in 92 COPD patients with frequent exacerbations during 1 year. At baseline data for spirometry, white blood cell count, concentrations of CRP-reactive protein, mid-regional pro-adrenomedullin and sputum cultures were collected. Primary endpoint was the number of exacerbations in the year of treatment. Results: In the azithromycin group(n=47) a significant lower mean number of exacerbations was observed in patients with a level of serum eosinophils ≥2,0%(n=25; 1,24) compared to patients with serum eosinophils Conclusions: In COPD patients with the frequent exacerbator phenotype a higher level of serum eosinophils, mild to moderate lung function impairment and fewer complaints show the best response to maintenance therapy with azithromycin.