Article

Both baseline HIV-1 drug resistance and antiretroviral drug levels are associated with short-term virologic responses to salvage therapy

Stanford University, Stanford, California, United States
AIDS (Impact Factor: 5.55). 06/2002; 16(8):1131-8. DOI: 10.1097/00002030-200205240-00006
Source: PubMed

ABSTRACT

To determine the impact of HIV-1 drug resistance at baseline and antiretroviral drug levels (DL) during follow-up on virologic response to the next antiretroviral regimen.
Baseline genotypic and phenotypic susceptibility was obtained for plasma virus from patients failing a protease inhibitor-containing regimen. Untimed plasma antiretroviral DL were performed and the distribution of DL after 12 weeks of follow-up was classified as above (DLHigh) or below (DLLow) the median. Inhibitory quotients [IQ = (DL at week 12)/(fold change in IC50 to wild-type)] were determined for each drug in the regimen. Primary outcome was change in log10 plasma HIV-1 RNA viral load (DeltaVL) from baseline to 12 weeks.
There were 137 patients who had baseline resistance data available for the antiretroviral drugs used in the salvage regimen, and DL at week 12. Each drug with DLHigh was associated with DeltaVL = -0.40 (P = 0.0002) while each drug with DLLow had DeltaVL = -0.16 (P = 0.11). In multivariate models DeltaVL associated with each active drug (defined by genotype) with DLHigh was -0.48 log10 (P < 0.0001), and with each active drug with DLLow was -0.22 (P = 0.03). The DeltaVL was -0.18 if no drugs in the regimen had an IQ > median, compared to -0.58 for one drug, -1.06 for two drugs, -0.86 for three drugs, and -1.44 for four or five drugs with IQ > median (P < 0.0001 for trend).
In salvage therapy, both the number of active drugs and the DL for each drug in the new regimen determine the antiviral response.

Download full-text

Full-text

Available from: Douglas Mayers
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tesis Univ. Granada. Departamento de Microbiología. Leída el 4 de junio de 2007
    Preview · Article ·
  • [Show abstract] [Hide abstract]
    ABSTRACT: A randomized study to evaluate the usefulness of protease inhibitor (PI) therapeutic drug monitoring (TDM) in antiretroviral-experienced HIV-infected patients. In the control arm, treatment was modified according to genotypic resistance testing. In the TDM arm, therapy was modified on the basis of genotypic resistance testing and at week 8 according to PI plasma trough levels measured at week 4. The major endpoint was the change in HIV-RNA levels at week 12. A total of 183 patients, 96 in the control arm and 87 in the TDM arm, were included in the study. Low-dose ritonavir to enhance the associated PI was prescribed to 62.5% of patients in the control arm and 65.5% of patients in the TDM arm. Using our PI concentration targets, 17/81 patients (21%) in the TDM arm were considered to have suboptimal or partly optimal PI plasma levels at week 4. Physician and protocol-driven PI modifications were performed in 18/85 patients (23.5%) in the TDM arm, and in seven of 94 patients (7%) in the control arm (P < 0.01). Week 12 HIV RNA dropped 2 log10 copies/ml in the control arm and 1.7 log10 copies/ml in the TDM arm, respectively. We found no statistically significant difference between the TDM arm and control arm in virological outcome at week 12. The utility of TDM could be dependent on the presence of low-dose ritonavir as a booster and the antiretroviral experience of the studied population. Effective non-toxic target concentrations for resistant viruses have still to be determined.
    No preview · Article · Nov 2002 · AIDS
  • Article: PharmAdapt
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective: A randomized study to evaluate the usefulness of protease inhibitor (PI) therapeutic drug monitoring (TDM) in antiretroviral-experienced HIV-infected patients. Methods: In the control arm, treatment was modified according to genotypic resistance testing. In the TDM arm, therapy was modified on the basis of genotypic resistance testing and at week 8 according to PI plasma trough levels measured at week 4. The major endpoint was the change in HIV-RNA levels at week 12. Results: A total of 183 patients, 96 in the control arm and 87 in the TDM arm, were included in the study. Low-dose ritonavir to enhance the associated PI was prescribed to 62.5% of patients in the control arm and 65.5% of patients in the TDM arm. Using our PI concentration targets, 17/81 patients (21%) in the TDM arm were considered to have suboptimal or partly optimal PI plasma levels at week 4. Physician and protocol-driven PI modifications were performed in 18/85 patients (23.5%) in the TDM arm, and in seven of 94 patients (7%) in the control arm (P < 0.01). Week 12 HIV RNA dropped 2 log10 copies/ml in the control arm and 1.7 log10 copies/ml in the TDM arm, respectively. Conclusion: We found no statistically significant difference between the TDM arm and control arm in virological outcome at week 12. The utility of TDM could be dependent on the presence of low-dose ritonavir as a booster and the antiretroviral experience of the studied population. Effective non-toxic target concentrations for resistant viruses have still to be determined.
    No preview · Article · Nov 2002 · AIDS
Show more