Medical Advocates for Social Justice
Conference Abstract
 43rd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC)  
Chicago, IL USA
September 14-17 , 2003
 

 

Nevirapine And Efavirenz Have a Comparable Viral Decay Rate Which Is Not Associated With Virologic Failure
F. VAN LETH1, C. HUISAMEN 2, R. BADARO 3, B. VANDERCAM 4, J. DE WET 5, J. MONTANER 6, D. HALL 7, F. WIT 1, J. LANGE 1,8, 2NN study group;

1IATEC, Amsterdam, Netherlands, 2Molteno Road Practice, Cape Town, South Africa, 3Hospital Uni. Prof. E. Santos, Salvador, Brazil, 4Cliniques Uni. St. Luc, Brussels, Belgium, 5Virion Clinical Sciences, Vancouver, BC, Canada, 6St. Paul's Hosp., Vancouver, BC, Canada, 7Boehringer-Ingelheim, Ridgefield, CT, 8Uni. of Amsterdam, Amsterdam, Netherlands.

 

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Background:
We studied the first phase viral decay in ART-naive patients from the 2NN study who were treated with d4T and 3TC and either nevirapine (NVP) once or twice daily, efavirenz (EFV) or NVP+EFV, to determine whether it might predict 48 week ART response.

Methods:
HIV-1 RNA concentration (pVL) was measured at day 0, 3, 7 and 14 for patients on allocated treatment. A non-linear model was used to calculate the viral decay rate (VDR). Factors associated with a high VDR (upper quartile) were examined by logistic regression, as was the association between VDR and virologic failure. The NVP-only arms were combined since identical dosing was used in the first 2 weeks of the study.

Results:
There was no significant difference in VDR (proportion/day) between the study arms: NVP 0.24, EFV 0.23, and NVP+EFV 0.23 (p=0.299). In a multivariate analysis, factors independently associated with a higher VDR were baseline pVL >5log10 (OR=1.54, p<0.005), and baseline CD4+ cell count <50 cells /mm3 (OR=1.86, p<0.001) Study arm, gender, disease stage, region and risk behaviour were not. Higher VDR was not associated with a lower probability of virologic failure at week 48 (OR=1.25, p=0.194).

Conclusions:
NVP and/or EFV plus background therapy, resulted in a comparable VDR in the first 2 weeks of treatment in ART-naive patients, which was not associated with virologic failure at week 48. VDR was driven by the height of baseline pVL. The potency of each regimen probably overcame the ability of early VDR in predicting virologic failure. Virologic failure in potent regimens may be related to other factors like compliance or resistance.
 

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