Treatment of acute uncomplicated cystitis with faropenem for 3 days versus 7 days: multicentre, randomized, open-label, controlled trial

Objectives The increasing prevalence of resistant bacteria such as fluoroquinolone-resistant or extended-spectrum β-lactamase-producing strains in pathogens causing acute uncomplicated cystitis has been of concern in Japan. Faropenem sodium is a penem antimicrobial that demonstrates a wide antimicrobial spectrum against both aerobic and anaerobic bacteria. It is stable against a number of β-lactamases. Methods We compared 3 and 7 day administration regimens of faropenem in a multicentre, randomized, open-label, controlled study. Results In total, 200 female patients with cystitis were enrolled and randomized into 3 day (N = 97) or 7 day (N = 103) treatment groups. At the first visit, 161 bacterial strains were isolated from 154 participants, and Escherichia coli accounted for 73.9% (119/161) of bacterial strains. At 5–9 days after the completion of treatment, 73 and 81 patients from the 3 day and 7 day groups, respectively, were evaluated by intention-to-treat analysis; the microbiological efficacies were 58.9% eradication (43/73), 20.5% persistence (15/73) and 8.2% replaced (6/73), and 66.7% eradication (54/81), 6.2% persistence (5/81) and 7.4% replaced (6/81), respectively (P = 0.048). The clinical efficacies were 76.7% (56/73) and 80.2% (65/81), respectively (P = 0.695). Adverse events due to faropenem were reported in 9.5% of participants (19/200), and the most common adverse event was diarrhoea. Conclusions The 7 day regimen showed a superior rate of microbiological response. E. coli strains were in general susceptible to faropenem, including fluoroquinolone- and cephalosporin-resistant strains.