Program Schedule

Identifying Optimal HIV Viral Load (VL) Thresholds for Predicting Antiretroviral Treatment Failure (TF) Using ROC Curve Analysis

Session: Poster Abstract Session: HIV Treatment: Outcomes, Adherence, and Toxicities
Saturday, October 11, 2014
Room: The Pennsylvania Convention Center: IDExpo Hall BC
  • 1565_IDWPOSTER.pdf (122.7 kB)
  • Background: Guidelines on HIV treatment differ in recommended VL thresholds indicative of TF. Improvements in VL assay sensitivity and worldwide scale-up of VL monitoring make it increasingly important to determine optimal VLs thresholds for guiding treatment changes. Receiver operating characteristic (ROC) curves can identify optimal VL thresholds which maximize sensitivity and specificity for predicting TF. The BRAVO study was a retrospective study, using the Roche COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test, v2.0, to explore thresholds of VL that might predict subsequent TF.

    Methods: Longitudinal patient specimens were collected through the VERxVE study, a randomized, double-blind (DB) study in treatment-naïve patients treated with nevirapine immediate-release or extended-release (VIRAMUNE IR or XR), plus emtricitabine and tenofovir DF. Stored plasma samples from up to 24 timepoints (pre-treatment through 144 weeks of DB treatment), were tested with the Roche COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test, v2.0. The BRAVO patient endpoints of TF (which differed from the primary VERxVE endpoints) were determined by two independent HIV physicians based on VL trajectories. A simple logistic regression model and ROC curves were created to determine the optimal VL thresholds for predicting TF at each study timepoint.

    Results: Of 526 evaluable patient-series, 71 patients (13%) were TF by BRAVO criteria. By ROC curve analysis, a VL threshold of 95 copies/ml at week 24 maximized the sensitivity (88%, 95% CI: 84-90%) and specificity (56%, 95% CI:41-70%) of predicting eventual TF [AUC (Area Under Curve):0.75]. Overall sensitivity and specificity were similar (overlapping 95% CIs for the sum of sensitivity and specificity) when compared to ROC curves for commonly used VL thresholds of 50 or 200 copies/ml.

    Conclusion: ROC curve analysis identified a VL threshold that maximized sensitivity and specificity in predicting TF. Viral load thresholds of 50 or 200 copies/ml can also be used without a significant decrease in overall sensitivity and specificity. As VL assays may differ in sensitivity, ROC curve analysis can be help optimize the clinical utility of VL monitoring.

    Robert Luo1, Shagufta Aslam1, Patrick Robinson2, Anne-Marie Quinson2 and Tri Do1, (1)Roche Molecular Systems, Pleasanton, CA, (2)Boehringer Ingelheim, Ridgefield, CT


    R. Luo, Roche Molecular Systems: Employee, Salary

    S. Aslam, Roche Molecular Systems: Employee, Salary

    P. Robinson, Boehringer Ingelheim: Employee, Salary

    A. M. Quinson, Boehringer Ingelheim: Employee, Salary

    T. Do, Roche Molecular Systems: Employee, Salary

    Findings in the abstracts are embargoed until 12:01 a.m. EDT, Oct. 8th with the exception of research findings presented at the IDWeek press conferences.

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