Conclusion
Results from the rBMD method support the in vitro potency of telavancin against S. aureus.
Methods
Isolates from patients who participated in the phase 3 Assessment of Telavancin for Treatment of HAP Studies were retested using the rBMD method.
Results
Retesting of 647 isolates produced a range of telavancin MIC values from 0.015 µg/mL to 0.12 µg/mL with MIC50/90 values of 0.06/0.06 µg/mL for the total pool of samples. For methicillin-resistant S. aureus (MRSA), MIC50/90 values were 0.06/0.12 µg/mL. These values are up to 4-fold lower than MIC50/90 values obtained using the original method. These results were used in part to justify lowering the telavancin breakpoints. All tested isolates remained susceptible to telavancin at the revised susceptibility breakpoint of ≤0.12 µg/mL. Overall, the clinical cure rate for microbiologically evaluable telavancin-treated patients was 78% for S. aureus, 76% for patients with MRSA, and 79% for patients with isolates with reduced susceptibility to vancomycin (MIC ≥1 µg/mL).
Trial registration
ATTAIN (NCT00107952 and NCT00124020). Funding: Theravance Biopharma Antibiotics, Inc.