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 < 2,0%(n=22; 2,41) (p=0,01), in GOLD 1-2 patients(n=16; 1,06) compared to GOLD 3-4 patients(n=31; 2,16) (p=0,03) and GOLD C group(n=11; 0,45) compared to GOLD D group(n=34; 2,18) (p<0,01). In the placebo group(n=45) there were no significant differences between serum eosinophils groups(p=0,78), GOLD stages(p=0,15) or GOLD groups(p=0,48). 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.