Clinical and Pharmacokinetic Outcomes of Peak-Trough-Based Versus Trough-Based Vancomycin Therapeutic Drug Monitoring Approaches: A Pragmatic Randomized Controlled Trial.

Background: Vancomycin therapeutic drug monitoring (TDM) is based on achieving 24-h area under the concentration-time curve to minimum inhibitory concentration cure breakpoints (AUC/MIC). Approaches to vancomycin TDM vary, with no head-to-head randomized controlled trial (RCT) comparisons to date.

Objectives: We aimed to compare clinical and pharmacokinetic outcomes between peak-trough-based and trough-only-based vancomycin TDM approaches and to determine the relationship between vancomycin AUC/MIC and cure rates.

Methods: A multicentered pragmatic parallel-group RCT was conducted in Hamad Medical Corporation hospitals in Qatar. Adult non-dialysis patients initiated on vancomycin were randomized to peak-trough-based or trough-only-based vancomycin TDM. Primary endpoints included vancomycin AUC/MIC ratio breakpoint for cure and clinical effectiveness (therapeutic cure vs therapeutic failure). Descriptive, inferential, and classification and regression tree (CART) statistical analyses were applied. NONMEM.v.7.3 was used to conduct population pharmacokinetic analyses and AUC calculations.

Results: Sixty-five patients were enrolled [trough-only-based-TDM (n = 35) and peak-trough-based-TDM (n = 30)]. Peak-trough-based TDM was significantly associated with higher therapeutic cure rates compared to trough-only-based TDM [76.7% vs 48.6%; p value = 0.02]. No statistically significant differences were observed for all-cause mortality, neutropenia, or nephrotoxicity between the two groups. Compared to trough-only-based TDM, peak-trough-based TDM was associated with less vancomycin total daily doses by 12.05 mg/kg/day (p value = 0.027). CART identified creatinine clearance (CL), AUC/MIC, and TDM approach as significant determinants of therapeutic outcomes. All patients [n = 19,100%] with CL ≤ 7.85 L/h, AUC/MIC ≤ 1256, who received peak-trough-based TDM achieved therapeutic cure. AUC/MIC > 565 was identified to be correlated with cure in trough-only-based TDM recipients [n = 11,84.6%]. No minimum AUC/MIC breakpoint was detected by CART in the peak-trough-based group.

Conclusion: Maintenance of target vancomycin exposures and implementation of peak-trough-based vancomycin TDM may improve vancomycin-associated cure rates. Larger scale RCTs are warranted to confirm these findings.