Short-term and long-term outcomes of moxifloxacin compared to standard antibiotic treatment in acute exacerbations of chronic bronchitis

Study objectives: To compare the effectiveness of oral moxifloxacin with standard antibiotic therapy in acute exacerbation of chronic bronchitis (AECB). Design: Multicenter, multinational, randomized, double-blind study of two parallel treatment arms. Patients: Outpatients greater than or equal to 45 years old with stable chronic bronchitis, smoking history of 2: 20 pack-years, two or more AECBs in the previous year, and FEV1 < 85% of predicted value. Patients were enrolled when in a stable condition, and patients with exacerbations within 12 months of enrollment were randomized. Interventions: Randomization (stratified on steroid use) between moxifloxacin (400 mg qd for 5 days) and standard therapy (amoxicillin [500 mg tid for 7 days], clarithromycin [500 mg bid for 7 days], or cefuroxime-axetil [250 mg hid for 7 days]). Measurements: Assessment at enrollment, randomization (Anthonisen type 1 exacerbation), 7 to 10 days after treatment, and monthly until next AECB or up to 9 months. The primary efficacy variable was clinical success (sufficient improvement, no alternative antimicrobial therapy required) 7 to 10 days after therapy. Secondary predefined end points were clinical cure (return to pre-exacerbation status), further antimicrobial use, time to next AECB, and bacteriologic success. Results: Three hundred fifty-four patients received moxifloxacin, and 376 patients received standard therapy. At 7 to 10 days after therapy, clinical success rates were similar in intention-to-treat (ITT) patients (95% confidence interval [CI], - 0.7 to 9.5) and per-protocol (PP) patients (95% CI, -3.0 to 8.5). Moxifloxacin showed superior clinical cure rates over standard therapy in both ITT patients (95% CI, 1.4 to 14.9) and PP patients (95% CI, 0.3 to 15.6), and higher bacteriologic success in microbiologically valid patients (95% CI, 0.4 to 22.1). Fewer ITT patients required antimicrobials after treatment with moxifloxacin than standard therapy (p < 0.01). Time to next exacerbation was longer with moxifloxacin; median and mean times to new AECBs in ITT patients who did not require any further antibiotics were 131.0 days and 132.8 days in moxifloxacin, and 103.5 days and 118.0 days in standard therapy, respectively (p = 0.03). The occurrence of failure, new exacerbation, or any further antibiotic was less frequent in moxifloxacin-treated patients for up to 5 months of follow-up (p = 0.03). Conclusions: Moxifloxacin was equivalent to standard therapy for clinical success and showed superiority over standard therapy in clinical cure, bacteriologic eradication, and long-term outcomes.