Daptomycin is a lipopeptide antibiotic active against gram-positive organisms and recently approved for marketing in Japan. This study investigates the efficacy and safety of daptomycin in Japanese patients with skin and soft tissue infections (SSTIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) for regulatory filing in Japan. Overall, 111 Japanese patients with SSTI were randomized in this open-label, randomized, active-comparator controlled, parallel-group, multicenter, phase III study. Patients received intravenous daptomycin 4 mg/kg once daily or vancomycin 1 g twice daily for 7-14 days. Efficacy was determined by a blinded Efficacy Adjudication Committee. Among patients with SSTIs caused by MRSA, 81.8 % (95 % CI, 69.1-90.9) of daptomycin recipients and 84.2 % (95 % CI, 60.4-96.6) of vancomycin recipients achieved a successful clinical response at the test-of-cure (TOC) visit. The microbiological success rate against MRSA at the TOC visit was 56.4 % (95 % CI, 42.3-69.7) with daptomycin and 47.4 % (95 % CI, 24.4-71.1) with vancomycin. Daptomycin was generally well tolerated; most adverse events were of mild to moderate severity. The measurement of daptomycin concentration in plasma revealed that patients with mild or moderate impaired renal function showed similar pharmacokinetics profiles to patients with normal renal function. Clinical and microbiological responses, stratified by baseline MRSA susceptibility, suggested that patients infected with MRSA of higher daptomycin MIC showed a trend of lower clinical success with a P value of 0.052 by Cochran-Armitage test. Daptomycin was clinically and microbiologically effective for the treatment of MRSA-associated SSTIs in Japanese patients.
Trial registration: ClinicalTrials.gov NCT00770341.