Effectiveness of short-course therapy (5 days) with grepafloxacin in the treatment of acute bacterial exacerbations of chronic bronchitis

Three hundred eighty-nine patients were enrolled in a double-masked, multic enter, randomized clinical trial comparing the clinical and bacteriologic e fficacies and safety of a 5-day course (n = 195) versus a IO-day course (n = 194) of grepafloxacin 400 mg once dairy in the treatment of acute bacteri al exacerbations of chronic bronchitis (ABECB). Patients in the 5-day treat ment group received placebo on days 6 through 10. Bacteriologic assessments were based on cultures of sputum specimens obtained before and when possib le, during and after treatment. Organisms were isolated from the pretreatme nt sputum specimens of 332 of 388 (86%) patients, the primary pathogens bei ng Haemophilus parainfluenzae, Haemophilus influenzae, streptococcus pneumo niae, Moraxella catarrhalis, and Staphylococcus aureus (29%, 19%, 4%, 5%, a nd 5% of isolates, respectively). Among isolates tested for betalactamase p roduction, results were positive in 25% of H influenzae isolates and 90% of M catarrhalis isolates. Forty-two percent of S pneumoniae isolates demonst rated reduced susceptibility (intermediate or high-level resistance) to pen icillin. A satisfactory clinical outcome (cure or improvement) was achieved in 83% (128 of 155) and 81% (122 of 150) of clinically evaluable patients treated with grepafloxacin for 5 or 10 days, respectively. Pathogens were e radicated or presumed eradicated in 77% (106 of 138) and 80% (98 of 123) of bacteriologically evaluable patients treated with grepafloxacin for 5 or I O days, respectively. The 2 treatment groups were equivalent with respect t o both clinical and bacteriologic efficacy, and no statistically significan t differences in the incidence of drug-related adverse events were seen bet ween the 2 groups. Substantial symptom relief was evident with both treatme nt regimens by the first during-treatment measurement, which occurred betwe en days 3 through 5. These results indicate that treatment with 400 mg grep afloxacin once daily for 5 days is as well tolerated and effective as treat ment for 10 days in patients with ABECB. The lower cost compared with a 10- day regimen and the increased likelihood that patients will complete the en tire shorter, once-daily regimen make the 5-day grepafloxacin regimen a use ful therapeutic option in the treatment of ABECB.