Ana Barrios

Plasma Levels of Atazanavir and the Risk of Hyperbilirubinemia Are Predicted by the 3435C→T Polymorphism at the Multidrug Resistance Gene 1

The 3435C-->T polymorphism at the multidrug resistance gene 1 (MDR1) was examined in 74 patients with human immunodeficiency virus who initiated atazanavir therapy. The MDR1 genotype distribution at position 3435 was 28% CC, 45% CT, and 27% TT. Plasma levels of atazanavir were significantly higher in patients with genotype CC than in those with CT or TT, and bilirubin levels correlated with atazanavir concentrations.

Paradoxical CD4+ T-cell decline in HIV-infected patients with complete virus suppression taking tenofovir and didanosine.

Background: Tenofovir (TDF) and didanosine (ddI) are both adenosine analogues with convenient posology, strong potency and a relatively high genetic barrier for resistance. The popularity of this combination, however, has been questioned due to concerns about pharmacokinetic interactions and increased risk of pancreatitis and hyperglycemia. Less information is available about other possible side effects. Patients and methods: HIV-infected individuals who initiated a protease inhibitor-sparing regimen between September 2002 and June 2003 at five hospitals, and had at least one subsequent visit within the next 12 months, always with complete virus suppression, were retrospectively assessed. Only drug-naive individuals and patients who simplified a prior successful antiretroviral regimen were analysed. Results: Outcomes were analysed in 570 individuals according to treatment modality (98 drug-naive versus 472 simplified); the nucleoside analogue (NA) backbone (298 with TDF + ddI, 88 with ddI, 44 with TDF, and 140 with neither ddI nor TDF); and the third agent used (378 with non-nucleoside analogues versus 192 with NA). Significant CD4+ T-cell declines were seen in patients taking ddI + TDF with respect to all other NA combinations, including ddI or TDF separately. Patients exposed to high ddI doses or taking a third NA showed more pronounced CD4 declines. Plasma levels of ddI correlated with the extent of CD4+ T-cell loss. Conclusion: Patients receiving ddI + TDF-based combinations show CD4+ T-cell declines despite achieving complete virus suppression. This effect generally progresses with time. An imbalance in adenosine metabolites within CD4+ T lymphocytes may explain this phenomenon, which resembles the genetic purine nucleoside phosphorylase deficiency syndrome.

SENC (Spanish efavirenz vs. nevirapine comparison) trial: A randomized, open-label study in HIV-infected naive individuals

Abstract PURPOSE: A randomized, open-label, pilot study was undertaken to explore the antiviral activity and tolerability of two nonnucleoside reverse transcriptase inhibitors (NNRTIs), nevirapine (NVP) and efavirenz (EFV). METHOD: HIV-infected antiretroviral-naive adults with CD4 counts >100 cells/mm3 and detectable plasma HIV RNA below 100,000 copies/mL were randomized to receive didanosine (ddI) and stavudine (d4T) plus either NVP or EFV. Assessments were made every 12 weeks. Primary endpoints were the proportion of patients reaching plasma HIV RNA <50 copies/mL and/or developing NNRTI-related toxicities leading to drug discontinuation. Baseline characteristics were comparable for participants in the EFV (n = 31) and NVP arms (n = 36). RESULTS: At 48 weeks, 23/31 (74%) patients in the EFV group and 23/36 (64%) in the NVP group had <50 HIV RNA copies/mL (intention-to-treat analysis). Adverse events led to NNRTI discontinuation in 4 and 3 patients in the EFV and NVP arms, respectively. There were no statistically significant differences between groups regarding any primary endpoint. NVP and EFV along with two NRTIs may be equally well tolerated and effective at achieving <50 HIV RNA copies/mL in naive patients with CD4 counts >100 cells/mm3 and HIV RNA <105 copies/mL. CONCLUSION: A much larger study is needed to demonstrate any significant differences between NVP and EFV, if they exist at all.

Predictors of Virological Response to Atazanavir in Protease Inhibitor-Experienced Patients

Abstract Background: Atazanavir (ATV) is the latest approved HIV protease inhibitor (PI). Even though it is very convenient (only two capsules once a day), concerns have risen about its potency. Method: The clinical performance of ATV 400 mg once a day was examined in all PI-experienced patients who were included in the ATV expanded access program conducted in a single institution. The predictive value of baseline drug resistance HIV genotypes, ATV plasma trough levels, and the genotypic inhibitory quotient (GIQ) on the virological response at week 24 was assessed. Results: Data from 92 patients were analyzed. ATV was prescribed as part of a rescue intervention (45%), a simplification strategy (11%), or an attempt to ameliorate hyperlipidemias (23%) or other toxicities (16%). Tenofovir (TDF) was concomitantly used with ATV in 78% of patients. None received ritonavir boosting. In patients with detectable viremia at baseline (65%), the median HIV RNA drop was 0.7 logs. The median ATV Cmin was 0.12 μg/mL (IQR, 0.05-0.22 μg/mL), which is clearly above the IC90 (90% inhibitory concentration) for ATV in wild-type viruses. The virological response did not correlate significantly with ATV Cmin. The median number of protease resistance mutations was lower in patients showing virological response than in nonresponders (1 vs. 5; p = .07). A higher HIV RNA drop was associated with a higher GIQ (p = .02; β = –5.4; 95% CI, –10 to –1). Only 4 patients (4%) discontinued treatment due to ATV-related toxicities (hyperbilirubinemia in 1). Bilirubin levels were associated with ATV plasma concentrations (p = .05; β = 3.2; 95% CI, –0.1 to 6.5). The rate of hypertriglyceridemia and hypercholesterolemia declined significantly with respect to baseline. Conclusion: ATV is relatively safe and provides significant virological response in PI-experienced patients, mainly among those with a low number of protease resistance mutations. The GIQ predicts accurately the virological response in patients receiving ATV. Hyperbilirubinemia is associated with higher ATV plasma levels.

Effect of dietary intervention on highly active antiretroviral therapy-related dyslipemia.

Changes in cholesterol and triglyceride levels after prescribing a lipid-lowering diet were assessed in 230 HIV-infected patients with dyslipemia associated with antiretroviral therapy. Lipid levels decreased significantly in subjects having good diet compliance. The reduction in triglyceride levels was greater than in cholesterol levels. Patients on protease inhibitor-containing regimens experienced a slightly greater decline in lipid levels compared with the rest.

Role of Baseline Human Immunodeficiency Virus Genotype as a Predictor of Viral Response to Tenofovir in Heavily Pretreated Patients

ABSTRACT Human immunodeficiency virus (HIV)-infected patients (n = 153) failing antiretroviral therapy after exposure to compounds from all three drug families were monitored for 6 months after beginning a rescue intervention program including tenofovir (TDF). At 3 months, levels of HIV RNA in plasma dropped by a mean of 0.9 log10 and the mean CD4 count increased by 52 cells/μl. At 6 months, HIV RNA levels had dropped by a mean of 1.06 log10 and the mean CD4 count had increased by 49 cells/μl. Only five (3.7%) patients discontinued TDF use due to adverse events. In the multivariate analysis, the presence of M41L and/or L210W at baseline was the only viral determinant of a lower response to TDF.

Gynecomastia in HIV-infected patients receiving antiretroviral therapy.

Thirty-four HIV-positive men with gynecomastia were seen in an HIV outclinic during a 20-month period (incidence of 2.4 cases/100 patients receiving HAART per year). It developed mainly in subjects having good immunologic and virologic status, after an average of 3 years of HAART. No hormone abnormalities were found, or association with specific drugs. Although initially unilateral, more than half of cases progressed to bilateral gynecomastia. Spontaneous resolution occurred in most subjects with 12 months without modifying therapy.