Phenotypic Resistance Testing Significantly Improves Response to Therapy (Tx): A Randomized Trial (VIRA 3001)
C. COHEN*, S. HUNT, M. SENSION, C. FARTHING, M. CONANT, S. JACOBSON, J. NADLER, W. VERBIEST1, K. HERTOGS1, M. AMES2, A. RINEHART2, and N. GRAHAM2*.
1Virco, Belgium; 2Glaxo Wellcome, NC
Objective: Open-label, randomized comparison of phenotypic resistance
testing (Antivirogram(tm); AVG) guided Tx switch vs. standard of care
(SOC) in subjects failing first PI-containing HAART regimen.
Design: 271 subjects with >2 NRTIs and 1 PI prior Tx and
plasma viral load (VL) > 2,000 copies/mL were randomized to Tx based on
AVG results vs. SOC and followed for 16 wks. Outcomes include VL change
from baseline (BL) by ITT (observed and LOCF), and percent < 400 copies/mL.
Results: Preliminary analysis of first 127 subjects shows mean
BL CD4 cell counts of 339 and 345 for the AVG and SOC arms, respectively.
At BL, 38%, 32%, and 13% of subjects were resistant to >2, 1, and
0 drugs, respectively.
At wk 16, 62% and 33% of subjects in AVG and SOC arms, respectively, had
VL < 400 copies/mL. CD4 cell count increases were not different between
Conclusions: Preliminary analysis shows that AVG results significantly
improve virologic outcome when used by physicians to guide Tx choices
for subjects failing their first PI-containing regimen.
Key Words: antiretroviral therapy, antiretroviral therapy response, phenotypic resistance