Efficacy and tolerability of gatifloxacin in community treatment of acute exacerbations of chronic bronchitis

Background: Recognizing acute exacerbations of chronic bronchitis (AECB) and selecting appropriate antibiotic treatment for patients who would benefit most is a challenge for community-based physicians. Objective: The Tequin Clinical Experience Study, an open-label, noncomparative, post-marketing trial, assessed the efficacy and tolerability of gatifloxacin, an 8-methoxy fluoroquinolone, in the treatment of AECB in the community-practice setting. Methods: Consecutive patients with respiratory tract infections in community-based settings were eligible for participation. Treated patients (N = 2512) included 1107 men (44.1%) and 1405 women (55.9%) aged ≥18 years with a clinical diagnosis of chronic bronchitis. All participants received oral gatifloxacin 400 mg once daily for 7 to 10 days. Clinical response was determined via telephone contact conducted by the investigator or study coordinator using case-report forms or during an office visit after the last dose. The investigator or coordinator collected expectorated or induced sputum specimens that were then smeared on a microscope slide, stored in a tube, and transported to a central reference laboratory for Gram-staining and culture. Of 1388 pretreatment sputum specimens submitted, pathogens were isolated from 424. Results: The most frequently detected pathogens were Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae. All H influenzae and 99% of S pneumoniae isolates tested were susceptible to gatifloxacin. Of the 2267 patients with a determinable clinical response, 2084 (91.9% [95% CI, 90.8%-93.0%]) were cured (all acute symptoms improved or returned to baseline level, no new symptoms present, no additional antibiotic required). The 95.8% cure rate in 166 patients with H influenzae included 100% of those with beta-lactamase-positive strains. Overall, 89.2% of 111 patients with M catarrhalis were cured; rates were similar regardless of beta-lactamase production. The clinical cure rate in 74 patients with S pneumoniae was 98.6% and was independent of the degree of penicillin resistance (minimum inhibitory concentration ≥2.0 μg/mL). All 6 patients infected with S pneumoniae fully resistant to penicillin were cured. Gatifloxacin was generally well tolerated, and the majority of adverse events were mild to moderate; only 11 drug-related adverse events in 10 patients (0.4%) were serious. Drug-related nausea (3.0%), dizziness (1.5%), diarrhea (1.2%), and vomiting (0.9%) were the most common adverse events. Conclusions: The high clinical cure rate and favorable tolerability support gatifloxacin as a rational choice for the treatment of AECB in patients such as those in this community-based study.