Successful Target Attainment of Telavancin at Elevated MICs: Fact or Fiction?

Lodise et al. aimed to characterize the pharmacokinetics andpharmacodynamics of telavancin among patients with complicated skin and skin structure infections (cSSSIs) and various degrees of renal function (6). During evaluation, an area under the concentration-time curve (AUC)/MIC ratio of 219 or more was selected as the pharmacodynamic target. The authors concluded that all proposed dosing regimens would achieve a 93 % or higher coverage in the population when the MIC is equal to 2 mg/liter (6). First, Lodise et al. referenced the target AUC/MIC ratio of 219 or more as the exposure target associated with a 1-log-unit de-crease in colony count from the baseline for methicillin-resistant Staphylococcus aureus (MRSA) (6). Inmultiple publications, there is evidence of significant variability between strains for the mag-nitude of the pharmacokinetic/pharmacodynamic (PK/PD) index needed to achieve the same pharmacodynamic endpoint (5, 8). A