Biomedical subjects

Diane Descamps

Publications and source records attributed to Diane Descamps.

42 records · Page 3Linked to original sources

PubMed2002

Efficacy of zidovudine compared to stavudine, both in combination with lamivudine and indinavir, in human immunodeficiency virus-infected nucleoside-experienced patients with no prior exposure to lamivudine, stavudine, or protease inhibitors (novavir trial).

We compared the efficacy and the toxicity of zidovudine (AZT) versus stavudine (d4T), in combination with lamivudine (3TC) and indinavir, in AZT-, dideoxyinosine (ddI)-, and/or dideoxycytosine (ddC)-experienced patients in a randomized comparative multicenter trial. One hundred seventy human immunodeficiency virus type 1 (HIV-1)-infected patients, who had received AZT, ddI, and/or ddC for at least 6 months but were naive for d4T, 3TC, and protease inhibitors, were randomized to AZT at 250 to 300 mg twice daily, 3TC at 150 mg twice daily, and indinavir at 800 mg every 8 h or to d4T at 40 mg twice daily, 3TC at 150 mg twice daily, and indinavir at 800 mg every 8 h. The primary endpoint was time to virological failure, defined as plasma HIV-1 RNA levels of >5,000 copies/ml after at least 8 weeks of antiretroviral therapy. Additional endpoints were change from baseline in CD4 cell counts, AIDS-defining events and adverse events, and proportion of patients with HIV-1 RNA levels of <500 copies/ml and HIV-1 RNA levels of <50 copies/ml. At week 80, 15 patients in the AZT arm and 14 patients in the d4T arm had reached the primary endpoint, and time to virological failure did not differ between the two arms (P = 0.98). In the d4T and in the AZT arms, 67 and 73% of patients, respectively, had HIV-1 RNA levels of <500 copies/ml (P = 0.50). The median change from baseline in CD4 cell count was 195 x 10(6) and 175 x 10(6)/liter for the d4T- and AZT-containing arms, respectively. The proportions of patients with HIV-1 RNA levels of <50 copies/ml at weeks 8, 16, and 24 were similar in the two arms. The occurrence of serious adverse events was not significantly different between arms. In conclusion, in these patients heavily pretreated with AZT, switching from AZT to d4T when initiating indinavir and 3TC did not bring any additional benefit compared to maintaining AZT.

Adult↗

PubMed2002

Plasma RNA viral load in human immunodeficiency virus type 2 subtype A and subtype B infections.

Human immunodeficiency virus type 2 (HIV-2) is much less pathogenic than HIV-1, and HIV-2 infection is associated with plasma viral loads significantly lower than those found in HIV-1 infection. We have developed a real-time quantitative PCR method for measuring the HIV-2 RNA load that covers the range of genetic diversity of HIV-2 isolates and that detects extremely low viral loads. Samples from 49 patients were studied. Proviral DNA was first detected and quantified. The strains that were detected were then genotyped: 21 patients were infected with HIV-2 subtype A and 15 patients were infected with HIV-2 subtype B; 1 patient was infected with a highly divergent strain. Env PCR failed for the remaining 12 patients, so subtypes could not be determined. For viral RNA quantification, a stock of HIV-2 strain NIHZ, which was counted by electron microscopy, was used as the standard. Several primer sets targeting the highly conserved gag region were evaluated. Various primer combinations failed to amplify subtype B strains. With the final primer pair selected, which detected both subtype A and subtype B strains, the sensitivity of the assay was 100% at a viral load of 250 copies/ml and 66% at a viral load of 125 copies/ml. We found a correlation between the CD4(+)-cell count, the clinical stage, and the plasma HIV-2 RNA level. The median plasma HIV-2 RNA value for the 33 asymptomatic patients was 2.14 log(10), whereas it was 3.1 log(10) for the 16 patients with AIDS (P < 0.01). Proviral DNA was detectable in 18 symptom-free patients with high CD4(+)-cell counts, in whom viral RNA was undetectable.

Base Sequence↗

PubMed2002

Adherence to antiretroviral therapy and outcomes in HIV-infected patients enrolled in an induction/maintenance randomized trial.

OBJECTIVE: To examine the effect of adherence to therapy on early virological response, later virological failure, and occurrence of adverse events in HIV-infected patients. DESIGN: A randomized trial of 3-month induction period of zidovudine/lamivudine/indinavir followed by a maintenance phase of zidovudine/lamivudine/indinavir, zidovudine/lamivudine or zidovudine/indinavir. MAIN OUTCOMES: Adherence was assessed by pill count. In the induction phase, early virological response was defined as plasma HIV-RNA<500 copies/ml at month 2 and in the maintenance phase, virological failure was defined as plasma HIV-RNA >500 copies/ml in two consecutive specimens. RESULTS: The median adherence rate was 97% in both induction (n=366) and maintenance phase (n=237). In the maintenance phase, pairwise comparisons showed a lower adherence rate in zidovudine/lamivudine/indinavir versus zidovudine/lamivudine (P=0.03), or versus zidovudine/indinavir (P=0.05). Only 13% of patients had an adherence over the maintenance phase of 80% or lower, while 40% of patients occasionally had an adherence rate of 80% or lower during this phase. Among the 362 patients with documented HIV-RNA at month 2, 86% had an early virological response. Adherence of 80% or greater was the only variable statistically predictive to early virological response (P<0.001), while baseline CD4, baseline HIV-RNA, and adherence of 95% or greater were not associated to virological response. In the maintenance phase, adherence, baseline HIV-RNA, HIV-RNA at month 3 and treatment groups were independently predictive to time to virological failure. Analysis by randomized groups indicated that difficulty in adherence (<80%) was predictive to time to failure (P<0.001) only in both indinavir-containing regimens. Occurrence of two or more severe adverse events (grade 3 and 4) was higher in patients with poor adherence although not statistically associated (P=0.12), while no association was found with minor adverse events. CONCLUSION: Adherence rate was globally lower in patients maintaining the original triple-drug therapy compared with those receiving less intensive regimens. Adherence rate was a time-dependent variable. Adherence to antiviral regimen of 80% or greater was predictive to early virological response, and adherence rate lower than 80% or 95% was predictive to virological failure, especially in indinavir-containing regimens. Occurrence of adverse events was not clearly associated to adherence.

Adult↗

PubMed2002

Impact of stavudine phenotype and thymidine analogues mutations on viral response to stavudine plus lamivudine in ALTIS 2 ANRS trial.

OBJECTIVE: Stavudine-based antiretroviral combinations are less effective in zidovudine-experienced patients than in naive subjects and recently, mutations have been described to be associated to the use of both stavudine and zidovudine. In the ALTIS 2 trial, it was shown that a combination of stavudine and lamivudine is less effective in zidovudine-experienced patients than in naive patients. We conducted a retrospective genotypic and phenotypic resistance study (expressed as stavudine phenotypic index, calculated by dividing the inhibitory concentrations 50% [IC50] by the mean value of the sensitive viruses) to evaluate the factors associated with decrease in plasma HIV-1 RNA. DESIGN: Associations with continuous variables were studied using non-parametric Spearman correlation coefficients. Associations with categorical variables were studied using non-parametric Mann-Whitney tests. Multivariate stepwise regression analyses were used to determine independent prognostic factors of the virological response. RESULTS: At baseline, most of the subjects harboured zidovudine-associated mutations in plasma and peripheral blood mononuclear cells. Zidovudine and stavudine IC50 and IC50 were strongly associated with response. It appears that a cut-off of stavudine phenotypic index of 1.8-fold of IC50, much lower than the usually used value, could be clinically significant for response to stavudine. In the multivariate analysis, the stepwise model with the higher multiple correlation coefficient (R2 = 0.742) included the presence of a 215 Y/F mutation, the number of previously used nucleoside analogues and a resistant stavudine phenotype. CONCLUSION: These results argue for a phenotypic and genotypic cross resistance between stavudine and zidovudine. Modest increases of IC50 and IC50 for stavudine had an important impact on the virological response during the trial and plead for a new definition of the threshold value for stavudine phenotypic index.

Adult↗

PubMedDate not supplied

Analyzing plasma HIV-1 RNA measurements as multiple recurrent events in clinical trials.

Primary endpoints based on levels of HIV-1 RNA are currently used to evaluate efficacy of antiretroviral therapy in AIDS/HIV clinical trials. These endpoints, however, are generally based on few HIV-1 RNA measurements. More specifically, when the endpoint is the time to virologic failure (usually defined as two consecutive HIV-1 RNA levels above a threshold value), viral load measurements recorded after failure are simply ignored in the analysis. Instead of one virologic failure used in a classical survival analysis, we suggest that a failure be defined as any plasma HIV-1 RNA level above a predefined threshold value. This then becomes an analysis of multiple events of the same type, that is, recurrent virologic failures. Many survival models based on the Cox proportional hazards model have been proposed to handle multiple event data. The two distinct classes of models (marginal and conditional) answer two distinct types of clinical question and should be considered as complementary rather than competing models. We applied the different models to data from a clinical trial in HIV-1-infected patients.

Anti-HIV Agents↗

PubMedDate not supplied

NNRTI plus PI combinations in the perspective of nucleoside-sparing or nucleoside-failing antiretroviral regimens.

Although not yet recommended, regimens combining both a non-nucleoside reverse transcriptase inhibitor (NNRTI) and protease inhibitors (PI) can be used as first-line therapy, or as second-line or salvage therapy in patients who need to change antiretroviral treatment because of nucleoside reverse transcriptase inhibitors (NRTI) intolerance or virological failure with resistance to NRTI. Such combinations should not be used in patients infected with HIV-1 group O and HIV-2, due to the natural resistance to NNRTI of these subtypes. Dual NNRTI and PI combinations used as first-line therapy allow to spare NRTI, leaving a fully active class of drugs for later use, and delaying the risk of toxicity related to NRTI exposure, particularly mitochondrial toxicity. Several studies have shown that adding a NNRTI improves the efficacy of a second-line or salvage therapy based on a new combination of PI(s) and new or recycled NRTI(s). A possible explanation for the efficacy of NNRTI-containing regimens in NRTI-pretreated patients is that mutations conferring resistance to NRTI can increase the susceptibility of the viruses to the NNRTI. However, the decision to use a NNRTI in a salvage regimen needs to be weighed against the concern that subsequent failure will exhaust therapeutic options with any compound of this class, due the large degree of cross-resistance between the three available NNRTI. NNRTI and PIs are extensively metabolized in the liver through cytochrome P450, leading to pharmacokinetic interactions. The decrease in PIs plasma concentrations observed when they are combined with nevirapine or efavirenz is reduced when low doses of ritonavir, which strongly inhibits cytochrome P450, are associated with the combination of PI and NNRTI.

Anti-HIV Agents↗