NEW YORK (Reuters Health) – Moxifloxacin is as effective as amoxicillin/clavulanic acid in the treatment of exacerbations of chronic obstructive pulmonary disease (COPD) in the outpatient setting, according to the results of the MAESTRAL trial reported in the European Respiratory Journal online December 1. “The good efficacy and tolerability of both drugs confirms their position as recommended treatments for exacerbations for outpatients with moderate-to-severe AECOPD (acute exacerbation of COPD) with a suspected bacterial aetiology,” the authors conclude. Dr. Robert Wilson, at Royal Brompton Hospital in London, UK, and colleagues note that antibiotics are recommended for more severely ill patients with COPD exacerbations, but few trials have demonstrated superiority of one antibiotic over another.  To compare moxifloxacin versus amoxicillin/clavulanic acid, they undertook a multicenter randomized double-blind non-inferiority trial involving 1492 patients in 30 countries. The participants were at least 60 years old with an FEV1 less than 60% predicted, and had had at least 2 exacerbations of COPD in the previous year.  They were stratified by steroid use and then randomized to receive moxifloxacin 400 mg/day for 5 days or amoxicillin/clavulanic acid 875/125 mg twice daily for 7 days. The primary endpoint was clinical failure at 8 weeks after treatment.  “The choice of an eight week timepoint captures relapses that are likely related to management of the initial exacerbation, but is not so long that other events, such as antibiotic treatment of a non-respiratory condition, make interpretation of results difficult,” the team explains. Ultimately, 1056 patients were valid for the per-protocol primary efficacy analysis.  The failure rate was 20.6% in the moxifloxacin and 22.0% in the amoxicillin/clavulanic acid group – a nonsignificant difference, the investigators found. Corresponding failure rates were higher in patients treated with oral corticosteroids (26.4% vs 32.8%; p=0.168) than among patients without steroid use (17.7% vs 15.8%; p=0.505), according to the report. “The differences between steroid and non-steroid users indicate that stratification is an important aspect of trial design and deserves further study,” the authors comment. They note that both treatments were well tolerated with no unexpected adverse events.  Premature discontinuation rates due to an adverse event were 1.8% with moxifloxacin and 1.3% in the amoxicillin/clavulanic acid arm. Dr. Wilson and colleagues conclude, “It is hoped that the outcomes of MAESTRAL will lead to further work to define clinical criteria and/or biomarkers to help clinicians identify both the most appropriate patients for antibiotic therapy and the most appropriate antibiotic therapy for individual AECOPD patients.” SOURCE: Moxifloxacin vs amoxicillin/clavulanic acid in outpatient AECOPD: maestral results Eur Resp J 2011