A randomized, double-blind, Phase 2 study to evaluate subjective and objective outcomes in patients with acute bacterial skin and skin structure infections treated with delafloxacin, linezolid or vancomycin

OBJECTIVES: Delafloxacin is an investigational anionic fluoroquinolone being developed to treat infections caused by Gram-positive and -negative organisms. This clinical trial evaluated the efficacy and safety of delafloxacin in the treatment of acute bacterial skin and skin structure infections (ABSSSIs). METHODS: In a double-blind, Phase 2 trial, 256 patients were randomized (1 : 1 : 1) to 300 mg of delafloxacin, 600 mg of linezolid or 15 mg/kg vancomycin (actual body weight), each administered intravenously twice daily for 5–14 days. Randomization was stratified by infection category. The primary endpoint was the investigator's assessment of cure, defined as complete resolution of baseline signs and symptoms at follow-up. Secondary endpoints included reductions in the total areas of erythema and induration and assessments of bacterial eradication. This trial has been registered at ClinicalTrials.gov under registration number NCT01283581. RESULTS: Cure rates were significantly greater with delafloxacin versus vancomycin (mean difference: −16.3%; 95% CI, −30.3% to −2.3%; P = 0.031); differences were significant for obese patients (BMI ≥30 kg/m(2); mean difference: −30.0%; 95% CI, −50.7% to −9.3%; P = 0.009), but not for non-obese patients. Cure rates with delafloxacin and linezolid were similar. Using digital measurement, the percentage decrease in total erythema area was significantly greater with delafloxacin versus vancomycin at follow-up (−96.4% versus −84.5%; P = 0.028). There were no differences in bacterial eradication among the treatment groups. The most frequently reported treatment-emergent adverse events were nausea, diarrhoea and vomiting. CONCLUSIONS: These data show that delafloxacin is effective in the treatment of ABSSSIs and is well tolerated.