Efficacy and safety of tigecycline compared with vancomycin or linezolid for treatment of serious infections with methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci: a Phase 3, multicentre, double-blind, randomized study.

INTRODUCTION Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) are causing serious nosocomial infections. Tigecycline was evaluated in hospitalized patients with MRSA or VRE infection. PATIENTS AND METHODS A randomized (3:1), double-blind, multicentre, Phase 3 study compared the safety and efficacy of tigecycline with vancomycin or linezolid in hospitalized patients with MRSA or VRE infection, respectively. Patients were treated for 7-28 days and the test-of-cure (TOC) assessment was made 12-37 days after the last dose. The primary efficacy endpoint was the clinical response (cure, failure and indeterminate) in the co-primary, microbiologically evaluable (ME) and microbiologically modified intent-to-treat (m-mITT) populations at the TOC assessment. RESULTS For MRSA infection, clinical cure rates in the ME population (n = 117) were 81.4% (70 of 86 patients) with tigecycline and 83.9% (26 of 31 patients) with vancomycin. In the m-mITT population (n = 133), clinical cure occurred in 75 of 100 tigecycline-treated patients (75.0%) and in 27 of 33 vancomycin-treated patients (81.8%). In patients with complicated skin and skin structure infections caused by MRSA, cure rates were similar with tigecycline or vancomycin (86.4% versus 86.9% in ME population; and 78.6% versus 87.0% in m-mITT population). In patients with MRSA infection, nausea or vomiting occurred more frequently with tigecycline than with vancomycin (41.0% versus 17.9%); most cases were mild, with only three patients discontinuing treatment. In patients with VRE (total enrollment, 15), 3 of 3 and 3 of 8 patients in the ME and m-mITT populations, respectively, were cured by tigecycline, compared with 2 of 3 patients in the ME and m-mITT populations treated with linezolid. CONCLUSIONS Tigecycline is safe and effective in hospitalized patients with serious infection caused by MRSA. There were too few cases of VRE to draw any conclusions.