Massimiliano Fabbiani

Comparison of HIV-1 genotypic resistance test interpretation systems in predicting virological outcomes over time

Background Several decision support systems have been developed to interpret HIV-1 drug resistance genotyping results. This study compares the ability of the most commonly used systems (ANRS, Rega, and Stanfords HIVdb) to predict virological outcome at 12, 24, and 48 weeks. Methodology/Principal Findings Included were 3763 treatment-change episodes (TCEs) for which a HIV-1 genotype was available at the time of changing treatment with at least one follow-up viral load measurement. Genotypic susceptibility scores for the active regimens were calculated using scores defined by each interpretation system. Using logistic regression, we determined the association between the genotypic susceptibility score and proportion of TCEs having an undetectable viral load (<50 copies/ml) at 12 (8–16) weeks (2152 TCEs), 24 (16–32) weeks (2570 TCEs), and 48 (44–52) weeks (1083 TCEs). The Area under the ROC curve was calculated using a 10-fold cross-validation to compare the different interpretation systems regarding the sensitivity and specificity for predicting undetectable viral load. The mean genotypic susceptibility score of the systems was slightly smaller for HIVdb, with 1.92±1.17, compared to Rega and ANRS, with 2.22±1.09 and 2.23±1.05, respectively. However, similar odds ratios were found for the association between each-unit increase in genotypic susceptibility score and undetectable viral load at week 12; 1.6 [95% confidence interval 1.5–1.7] for HIVdb, 1.7 [1.5–1.8] for ANRS, and 1.7 [1.9–1.6] for Rega. Odds ratios increased over time, but remained comparable (odds ratios ranging between 1.9–2.1 at 24 weeks and 1.9–2.2 at 48 weeks). The Area under the curve of the ROC did not differ between the systems at all time points; p = 0.60 at week 12, p = 0.71 at week 24, and p = 0.97 at week 48. Conclusions/Significance Three commonly used HIV drug resistance interpretation systems ANRS, Rega and HIVdb predict virological response at 12, 24, and 48 weeks, after change of treatment to the same extent.

Pharmacokinetic variability of antiretroviral drugs and correlation with virological outcome: 2 years of experience in routine clinical practice

OBJECTIVES To assess the inter-individual and intra-individual plasma concentration variabilities of non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs) in routine clinical practice and to investigate their relationships with virological failure. METHODS We retrospectively enrolled HIV-infected patients undergoing therapeutic drug monitoring (TDM) of NNRTIs and PIs during routine outpatient visits. Plasma drug concentrations were measured by HPLC-UV and were considered therapeutic if above the proposed minimum efficacy trough concentration. Inter-individual and intra-individual variabilities were evaluated through the coefficient of variation (CV). RESULTS A total of 457 PI and 172 NNRTI plasma concentrations were measured from 363 patients (HIV-RNA <50 copies/mL in 70.8%, median CD4 count 434 cells/mm(3)). NNRTIs showed less inter-individual (CV(inter) 54.8% versus 84.3%) and intra-individual (CV(intra) 19.0% versus 38.1%) pharmacokinetic variabilities than PIs. Intra-individual variability was constantly lower than inter-individual variability for each drug. Subtherapeutic drug concentrations were observed in 106 samples (16.9%). Older age (P = 0.020) and higher viral load (P = 0.013) were associated with subtherapeutic levels. Patients with therapeutic levels had a viral load of <50 copies/mL more frequently than those with subtherapeutic levels (74.8% versus 63.2%, P = 0.020). The estimated proportion with virological failure at 24 weeks was 0.21 in patients with suboptimal baseline drug levels and 0.08 in those with optimal levels (P < 0.001). In the multivariate analysis, therapeutic drug levels showed an independent negative association with virological failure (P = 0.004). CONCLUSIONS A wide inter-individual and limited intra-individual pharmacokinetic variabilities, together with the demonstration of a concentration-response relationship, suggest that TDM is a useful tool for the clinical management of patients treated with NNRTIs or PIs.

Comparative determination of HIV-1 co-receptor tropism by Enhanced Sensitivity Trofile, gp120 V3-loop RNA and DNA genotyping

BackgroundTrofile® is the prospectively validated HIV-1 tropism assay. Its use is limited by high costs, long turn-around time, and inability to test patients with very low or undetectable viremia. We aimed at assessing the efficiency of population genotypic assays based on gp120 V3-loop sequencing for the determination of tropism in plasma viral RNA and in whole-blood viral DNA. Contemporary and follow-up plasma and whole-blood samples from patients undergoing tropism testing via the enhanced sensitivity Trofile® (ESTA) were collected. Clinical and clonal geno2pheno[coreceptor] (G2P) models at 10% and at optimised 5.7% false positive rate cutoff were evaluated using viral DNA and RNA samples, compared against each other and ESTA, using Cohens kappa, phylogenetic analysis, and area under the receiver operating characteristic (AUROC).ResultsBoth clinical and clonal G2P (with different false positive rates) showed good performances in predicting the ESTA outcome (for V3 RNA-based clinical G2P at 10% false positive rate AUROC = 0.83, sensitivity = 90%, specificity = 75%). The rate of agreement between DNA- and RNA-based clinical G2P was fair (kappa = 0.74, p < 0.0001), and DNA-based clinical G2P accurately predicted the plasma ESTA (AUROC = 0.86). Significant differences in the viral populations were detected when comparing inter/intra patient diversity of viral DNA with RNA sequences.ConclusionsPlasma HIV RNA or whole-blood HIV DNA V3-loop sequencing interpreted with clinical G2P is cheap and can be a good surrogate for ESTA. Although there may be differences among viral RNA and DNA populations in the same host, DNA-based G2P may be used as an indication of viral tropism in patients with undetectable plasma viremia.

Predictors of first-line antiretroviral therapy discontinuation due to drug-related adverse events in HIV-infected patients: a retrospective cohort study

BackgroundDrug-related toxicity has been one of the main causes of antiretroviral treatment discontinuation. However, its determinants are not fully understood. Aim of this study was to investigate predictors of first-line antiretroviral therapy discontinuation due to adverse events and their evolution in recent years.MethodsPatients starting first-line antiretroviral therapy were retrospectively selected. Primary end-point was the time to discontinuation of therapy due to adverse events, estimating incidence, fitting Kaplan-Meier and multivariable Cox regression models upon clinical/demographic/chemical baseline patients’ markers.Results1,096 patients were included: 302 discontinuations for adverse events were observed over 1,861 person years of follow-up between 1988 and 2010, corresponding to an incidence (95% CI) of 0.16 (0.14-0.18). By Kaplan-Meier estimation, the probabilities (95% CI) of being free from an adverse event at 90 days, 180 days, one year, two years, and five years were 0.88 (0.86-0.90), 0.85 (0.83-0.87), 0.79 (0.76-0.81), 0.70 (0.67-0.74), 0.55 (0.50-0.61), respectively. The most represented adverse events were gastrointestinal symptoms (28.5%), hematological (13.2%) or metabolic (lipid and glucose metabolism, lipodystrophy) (11.3%) toxicities and hypersensitivity reactions (9.3%). Factors associated with an increased hazard of adverse events were: older age, CDC stage C, female gender, homo/bisexual risk group (vs. heterosexual), HBsAg-positivity. Among drugs, zidovudine, stavudine, zalcitabine, didanosine, full-dose ritonavir, indinavir but also efavirenz (actually recommended for first-line regimens) were associated to an increased hazard of toxicity. Moreover, patients infected by HIV genotype F1 showed a trend for a higher risk of adverse events.ConclusionsAfter starting antiretroviral therapy, the probability of remaining free from adverse events seems to decrease over time. Among drugs associated with increased toxicity, only one is currently recommended for first-line regimens but with improved drug formulation. Older age, CDC stage, MSM risk factor and gender are also associated with an increased hazard of toxicity and should be considered when designing a first-line regimen.

Safety and feasibility of treatment simplification to atazanavir/ritonavir + lamivudine in HIV-infected patients on stable treatment with two nucleos(t)ide reverse transcriptase inhibitors + atazanavir/ritonavir with virological suppression (Atazanavir and Lamivudine for treatment Simplification, AtLaS pilot study)

OBJECTIVES To explore 48 week safety and efficacy of treatment simplification to atazanavir/ritonavir + lamivudine in HIV-infected patients with virological suppression on a stable atazanavir/ritonavir-based standard triple regimen. METHODS This was a single-arm pilot study, enrolling 40 patients on atazanavir/ritonavir + two nucleos(t)ide reverse transcriptase inhibitors (NRTIs), without previous treatment failure, with HIV-RNA <50 copies/mL for >3 months and CD4 >200 cells/mm(3). At baseline, patients were switched to 300/100 mg of atazanavir/ritonavir + 300 mg of lamivudine once daily. Laboratory parameters, atazanavir plasma levels, self-reported adherence, quality of life, neurocognitive performance, bone composition and body fat distribution were monitored. Virological failure was defined as HIV-RNA >50 copies/mL on two consecutive determinations or a single level >1000 copies/mL. RESULTS After 48 weeks, 4/40 (10%) regimen discontinuations occurred: 1 death (brain haemorrhage), 1 study withdrawal (inadequate atazanavir plasma levels), 1 re-induction with two NRTIs due to pregnancy and 1 virological failure without development of resistance. Seven moderate to severe adverse events were recorded (including four renal colics, possibly treatment-related) in six patients. At week 48, increases in total (mean change +17 mg/dL, P = 0.001), high-density lipoprotein (+6 mg/dL, P < 0.001) and low-density lipoprotein (+8 mg/dL, P = 0.052) cholesterol were observed. The glomerular filtration rate improved (+7 mL/min/1.73 m(2), P < 0.001), as did scores exploring self-reported physical and mental health (+11, P = 0.009 and +13, P < 0.001 on a 0-100 scale), neuropsychological performance (-1 pathological task, P = 0.002) and total bone mineral density (+0.03 g/cm(2), P = 0.026). There were no significant changes in CD4 cell count, bilirubin, atazanavir plasma levels, adherence and body fat distribution over time. CONCLUSIONS Simplification to atazanavir/ritonavir + lamivudine was apparently safe and associated with rare virological failure, without resistance selection. This strategy deserves further investigation in a randomized trial.

Cardiovascular risk factors and carotid intima‐media thickness are associated with lower cognitive performance in HIV‐infected patients

The aim of the study was to investigate the relationship between metabolic comorbidities, cardiovascular risk factors or common carotid intima‐media thickness (cIMT) and cognitive performance in HIV‐infected patients.

Factors influencing the normalization of CD4+ T‐cell count, percentage and CD4+/CD8+ T‐cell ratio in HIV‐infected patients on long‐term suppressive antiretroviral therapy

We evaluated factors associated with normalization of the absolute CD4+ T-cell counts, per cent CD4+ T cells and CD4+/CD8+ T-cell ratio. A multicentre observational study was carried out in patients with sustained HIV-RNA <50 copies/mL. Outcomes were: CD4-count >500/mm(3) and multiple T-cell marker recovery (MTMR), defined as CD4+ T cells >500/mm(3) plus%CD4 T cells >29%plus CD4+/CD8+ T-cell ratio >1. Kaplan-Meier survival analysis and Cox regression analyses to predict odds for achieving outcomes were performed. Three hundred and fifty-two patients were included and followed-up for a median of 4.1 (IQR 2.1-5.9) years, 270 (76.7%) achieving a CD4+ T-cell count >500 cells/mm(3) and 197 (56%) achieving MTMR. Using three separate Cox models for both outcomes we demonstrated that independent predictors were: both absolute CD4+ and CD8+ T-cell counts, %CD4+ T cells, a higher CD4+/CD8+ T-cell ratio, and age. A likelihood-ratio test showed significant improvements in fitness for the prediction of either CD4+ >500/mm(3) or MTMR by multivariable analysis when the other immune markers at baseline, besides the absolute CD4+ count alone, were considered. In addition to baseline absolute CD4+ T-cell counts, pretreatment %CD4+ T cells and the CD4+/CD8+ T-cell ratio influence recovery of T-cell markers, and their consideration should influence the decision to start antiretroviral therapy. However, owing to the small sample size, further studies are needed to confirm these results in relation to clinical endpoints.

Revised central nervous system neuropenetration-effectiveness score is associated with cognitive disorders in HIV-infected patients with controlled plasma viraemia

BACKGROUND The objective of our study was to compare two different central nervous system penetration-effectiveness (CPE) scores for the prediction of cognitive dysfunction in HIV-infected patients. METHODS We performed a cross-sectional single cohort study, consecutively enrolled during routine outpatient visits. HIV-infected subjects on antiretroviral therapy with plasma HIV RNA<50 copies/ml were included. A neuropsychological battery was administered. Each patient was classified as cognitively impaired on the basis of results obtained in age-, gender-, education- and nationality-matched healthy HIV-negative subjects. Self-reported adherence to antiviral therapy was measured on a 0-100 visual analogue scale. CPE rank was calculated for each antiretroviral regimen based on rules proposed by the CHARTER group in the 2008 original version (orCPE rank) and the 2010 revised version (revCPE rank). Neuroeffectiveness categories were analysed based on cutoffs of ≥1.5 (orCPE rank) or ≥6 (revCPE rank). RESULTS A total of 101 patients were enrolled (66% male, median age 47 years, median education 13 years); mean adherence was 81%. orCPE rank ≥1.5 and revCPE rank ≥6 were observed in 85.0% and 78.2% of patients, respectively (P=0.31). Asymptomatic neurocognitive impairment (ANI) was diagnosed in 50 (49.5%) subjects. In a multivariable model, after adjusting for nationality, adherence and nadir CD4(+) T-cell count, orCPE rank did not show an association with cognitive performance (P=0.704). By contrast, patients with revCPE rank ≥6 (OR 0.32, 95% CI 0.11, 0.95; P=0.039) and adherence ≥80% (OR 0.39, 95% CI 0.15, 0.99; P=0.047) showed a decreased risk of cognitive impairment. CONCLUSIONS A high prevalence of ANI was observed in virologically suppressed HIV-infected individuals. The revCPE rank showed improved association with neurocognitive dysfunction over the orCPE rank. Moreover, a relationship between cognitive impairment and adherence to antiretroviral therapy was found.

Immune response to influenza A (H1N1)v monovalent MF59-adjuvanted vaccine in HIV-infected patients

Immunogenicity of influenza A (H1N1)v MF59-adjuvanted vaccine was studied in HIV-infected patients. The vaccine was effective in inducing a protective immune response in patients with a CD4 >200 cells/μL while individuals with CD4 <200 cells/μL showed lower rates of seroconversion and seroprotection. These results underscore the usefulness of immunization against influenza in HIV-infected patients, though a boosting dose of vaccine may be required in seriously immunocompromised patients.

Efficacy and safety of treatment simplification to atazanavir/ritonavir + lamivudine in HIV-infected patients with virological suppression: 144 week follow-up of the AtLaS pilot study

OBJECTIVES AtLaS was a single-arm pilot study that demonstrated promising efficacy and safety of treatment simplification to a dual regimen with atazanavir/ritonavir + lamivudine in virologically suppressed HIV-positive patients. Here, we report data from the 144 week follow-up. METHODS At baseline, patients treated with a three-drug atazanavir/ritonavir-based regimen were switched to 300/100 mg of atazanavir/ritonavir plus 300 mg of lamivudine once daily. Major clinical events, laboratory parameters, neurocognitive performance, bone composition and body fat distribution were monitored. Treatment failure was defined as a discontinuation/switch of the regimen or virological failure (HIV-RNA >50 copies/mL in two consecutive determinations or a single level above 1000 copies/mL). RESULTS After 144 weeks, 9/40 (22.5%) treatment failures occurred, including two virological failures (Weeks 48 and 53, without resistance). A significant increase in the CD4 count was observed at Week 96 (+124 cells/mm(3); P = 0.002) and Week 144 (+94 cells/mm(3); P = 0.008). After 144 weeks, a significant increase in total cholesterol (+25 mg/dL; P = 0.001), HDL cholesterol (+6 mg/dL; P = 0.024) and LDL cholesterol (+12 mg/dL; P = 0.008) was observed, without any change in triglyceride levels, total cholesterol/HDL ratio or LDL/HDL ratio. A significant increase in the estimated glomerular filtration rate (+25 mL/min/1.73 m(2); P < 0.001) and lumbar spine T-score and Z-score (+0.2, P = 0.011; and +0.35, P = 0.001, respectively) and a decrease in trunk fat (-1.898 g; P = 0.005) were also observed. Neurocognitive function did not decline over time. Concerning safety, 10 moderate to severe adverse events were recorded in eight patients; overall seven cases of renal colic (possibly treatment related) were observed, leading to a discontinuation of treatment in two patients. CONCLUSIONS Data from the 144 week follow-up suggested good long-term efficacy of the simplification strategy that was investigated, with rare virological failure and a potential for improvement of the CD4 count, renal function and bone mineral density. This strategy warrants further investigation in a randomized trial.