Study objectives: To compare the efficacies of 10-day regimens of grepafloxacin (GFX) (Raxar or Vaxar; Glaxo Wellcome; Greenford, UK), 600 qd, and clarithromycin (CLA) (Klacid, Biaxin, or Klaracid; Abbott Laboratories; Chicago, IL), 500 mg bid, in patients with community-acquired pneumonia (CAP), on the basis of clinical response, including radiographic evidence, and bacteriologic efficacy. Design: Phase IIIb, double-blind, double-dummy, randomized, prospective, parallel-group, comparative study conducted at 58 centers in 11 countries. Patients and setting: Adult patients with signs and symptoms of CAP that was confirmed by radiographic evidence and who did not require parenteral therapy were included in the study. Assessments: Patients were assessed before treatment, during treatment, after treatment, and at follow-up (28 to 35 days after treatment completion). Clinical response was evaluated. Blood and sputum samples were cultured for bacterial pathogens, and serology testing was performed to detect atypical pneumonia. Results: A total of 504 patients were enrolled into the trial: 251 were randomly assigned to receive GFX and 253 to receive CLA. In patients able to be clinically evaluated, clinical success rates at follow-up were 147 of 163 patients (90%) in the GFX group and 148 of 167 patients (89%) in the CLA group (95% confidence interval, -6% to 9%). Pretreatment pathogens were confirmed in 131 of 504 patients (26%), either by culture or serology testing, the primary pathogens being Streptococcus pneumoniae (22%), Haemophilus influenzae (17%), Mycoplasma pneumoniae (25%), and Chlamydia pneumoniae (11%). For patients able to be evaluated who had typical pathogens, bacteriologic success was achieved in 92% of the patients in each treatment group. For patients able to be evaluated who had atypical pathogens, 18 of 18 patients (100%) in the GFX and 23 of 26 patients (88%) in the CLA group had a successful clinical outcome. There were similar rates of adverse events in each group, resulting in ≤ 7% withdrawal from treatment; gastrointestinal events were the most common. Conclusions: GFX, 600 mg qd, was equivalent to CLA, 500 mg bid, in treating adult patients with CAP. Both treatments were well tolerated.
