Giovanni Di Perri

Impairment in kidney tubular function in patients receiving tenofovir is associated with higher tenofovir plasma concentrations.

Tenofovir (TFV) is a nucleotide analogue active against HIV and hepatitis B virus. Although TFV rarely affects the glomerular function, abnormalities in the kidney tubular function appear to be quite common. The relationship between TFV exposure and kidney tubular dysfunction (KTD) was examined prospectively in 92 HIV-infected individuals. Median TFV plasma trough concentration was higher in patients with KTD than in the rest (182 vs. 106 ng/ml; P = 0.001). This dose-dependent effect further supports an involvement of TFV in KTD.

An HPLC-PDA Method for the Simultaneous Quantification of the HIV Integrase Inhibitor Raltegravir, the New Nonnucleoside Reverse Transcriptase Inhibitor Etravirine, and 11 Other Antiretroviral Agents in the Plasma of HIV-Infected Patients

A new method using high-performance liquid chromatography coupled with photo diode array detection was developed and validated for the quantification of plasma concentrations of the human immunodeficiency syndrome integrase inhibitor raltegravir (RGV), the new nonnucleoside reverse transcriptase inhibitor etravirine (ETV), and 11 other antiretroviral agents: ritonavir, atazanavir, lopinavir, nevirapine, efavirenz, saquinavir, indinavir, nelfinavir, and its metabolite M-8, amprenavir, and darunavir. A simple solid phase extraction procedure was applied to 500 μL aliquots of plasma, and chromatographic separation of the drugs and internal standard (quinoxaline) was achieved with a gradient (acetonitrile and phosphate buffer) on an C-18 reverse-phase analytical column with a 28-minute analytical run time. Calibration curves were optimized according to expected ranges of drug concentrations in patients, and the coefficient of determination (r2) was higher than 0.998 for all analytes. Mean intraday and interday precisions (percent relative SD) for all compounds were 3.67% and 6.39%, respectively, and mean accuracy (percent deviation from nominal concentration) was −1.17%. Extraction recovery ranged within 75% and 83% for all drugs analyzed. The solid phase extraction and high-performance liquid chromatography coupled with photo diode array method described allow a specific, sensitive, and reliable simultaneous determination of RGV, ETV, and 11 antiretroviral agents in plasma by a single assay. Good extraction efficiency and low limit of quantification make this a suitable method for use in clinical trials and for therapeutic drug monitoring of RGV, protease inhibitors, and nonnucleoside reverse transcriptase inhibitors, including ETV.

New HPLC-MS method for the simultaneous quantification of the antileukemia drugs imatinib, dasatinib, and nilotinib in human plasma.

A new method using high performance liquid chromatography coupled with electrospray mass spectrometry is described for the quantification of plasma concentration of tyrosine kinase inhibitors imatinib, dasatinib and nilotinib. A simple protein precipitation extraction procedure was applied on 250 microl of plasma aliquots. Chromatographic separation of drugs and Internal Standard (quinoxaline) was achieved with a gradient (acetonitrile and water + formic acid 0.05%) on a C18 reverse phase analytical column with 20min of analytical run, at flow rate of 1 ml/min. Mean intra-day and inter-day precision for all compounds were 4.3 and 11.4%; mean accuracy was 1.5%; extraction recovery ranged within 95 and 114%. Calibration curves ranged from 10,000 to 62.5 ng/ml. The limit of quantification was set at 78.1 ng/ml for imatinib and at 62.5 ng/ml for dasatinib and nilotinib. This novel developed methodology allows a specific, sensitive and reliable simultaneous determination of the three tyrosine kinase inhibitors imatinib, dasatinib and nilotinib in a single chromatographic run, useful for drugs estimation in plasma of patients affected by chronic myeloid leukemia.

Nevirapine versus atazanavir/ritonavir, each combined with tenofovir disoproxil fumarate/emtricitabine, in antiretroviral―naive HIV-1 patients: the ARTEN Trial

BACKGROUND Selection of first-line antiretroviral therapy requires consideration of efficacy as well as effects on lipids given the increased concern about cardiovascular risk in HIV-1 patients. METHODS ARTEN is a randomized, open-label, non-inferiority trial that compares nevirapine (NVP) 200 mg twice daily or 400 mg once daily to atazanavir/ritonavir (ATZ/r) 300 mg/100 mg once daily, each combined with fixed-dose tenofovir disoproxil fumarate (TDF) 300 mg/emtricitabine (FTC) 200 mg once daily, in antiretroviral-naive HIV-1 patients with CD4(+) T-cell counts <400 (men) and <250 cells/mm(3) (women). The primary end point was plasma HIV RNA<50 copies/ml at two consecutive visits prior to week 48. RESULTS A total of 569 patients were randomized and treated. Overall, 66.8% of NVP and 65.3% of ATZ/r patients achieved the primary end point (difference 1.9%, 95% CI -5.9-9.8%). Similar rates of serious adverse events were observed (9.6% on NVP versus 8.8% on ATZ/r), although discontinuations due to adverse events were more frequent with NVP than ATZ/r (13.6% versus 3.6%, respectively). None of the 28 patients virologically failing ATZ/r selected resistance mutations, while they were selected in 29/44 patients virologically failing NVP. NVP induced a significantly greater increase in high-density lipoprotein cholesterol (HDL-c) and apolipoprotein A1 from baseline than ATZ/r, whereas triglycerides increased significantly more with ATZ/r than NVP. Mean change from baseline in TC:HDL-c ratio was -0.24 for NVP and 0.13 for ATZ/r (P=0.0001). CONCLUSIONS NVP demonstrated at week 48 non-inferior antiviral efficacy compared with ATZ/r when given along with TDF/FTC, despite more drug-related discontinuations with NVP than ATZ/r. NVP was associated with a lower atherogenic lipid profile than ATZ/r although resistance mutations were more frequently selected with NVP than ATZ/r.

Genetic Variants of ABCC10, a Novel Tenofovir Transporter, Are Associated With Kidney Tubular Dysfunction

BACKGROUND Tenofovir (TFV) causes kidney tubular dysfunction (KTD) in some patients, but the mechanism is poorly understood. Genetic variants in TFV transporters are implicated; we explored whether ABCC10 transports TFV and whether ABCC10 single-nucleotide polymorphisms (SNPs) are associated with KTD. METHODS TFV accumulation was assessed in parental and ABCC10-transfected HEK293 cells (HEK293-ABCC10), CD4(+) cells and monocyte-derived macrophages (MDMs). Substrate specificity was confirmed by cepharanthine (ABCC10 inhibitor) and small interfering RNA (siRNA) studies. Fourteen SNPs in ABCC10 were genotyped in human immunodeficiency virus-positive patients with KTD (n = 19) or without KTD (controls; n = 96). SNP and haplotype analysis was performed using Haploview. RESULTS TFV accumulation was significantly lower in HEK293-ABCC10 cell lines than in parental HEK293 cells (35% lower; P = .02); this was reversed by cepharanthine. siRNA knockdown of ABCC10 resulted in increased accumulation of TFV in CD4(+) cells (18%; P = .04) and MDMs (25%; P = .04). Two ABCC10 SNPs (rs9349256: odds ratio [OR], 2.3; P = .02; rs2125739, OR, 2.0; P = .05) and their haplotype (OR, 2.1; P = .05) were significantly associated with KTD. rs9349256 was associated with urine phosphorus wasting (P = .02) and β2 microglobulinuria (P = .04). CONCLUSIONS TFV is a substrate for ABCC10, and genetic variability within the ABCC10 gene may influence TFV renal tubular transport and contribute to the development of KTD. These results need to be replicated in other cohorts.

Therapeutic immunization with hiv-1 tat reduces immune activation and loss of regulatory t-cells and improves immune function in subjects on HAART

Although HAART suppresses HIV replication, it is often unable to restore immune homeostasis. Consequently, non-AIDS-defining diseases are increasingly seen in treated individuals. This is attributed to persistent virus expression in reservoirs and to cell activation. Of note, in CD4+ T cells and monocyte-macrophages of virologically-suppressed individuals, there is continued expression of multi-spliced transcripts encoding HIV regulatory proteins. Among them, Tat is essential for virus gene expression and replication, either in primary infection or for virus reactivation during HAART, when Tat is expressed, released extracellularly and exerts, on both the virus and the immune system, effects that contribute to disease maintenance. Here we report results of an ad hoc exploratory interim analysis (up to 48 weeks) on 87 virologically-suppressed HAART-treated individuals enrolled in a phase II randomized open-label multicentric clinical trial of therapeutic immunization with Tat (ISS T-002). Eighty-eight virologically-suppressed HAART-treated individuals, enrolled in a parallel prospective observational study at the same sites (ISS OBS T-002), served for intergroup comparison. Immunization with Tat was safe, induced durable immune responses, and modified the pattern of CD4+ and CD8+ cellular activation (CD38 and HLA-DR) together with reduction of biochemical activation markers and persistent increases of regulatory T cells. This was accompanied by a progressive increment of CD4+ T cells and B cells with reduction of CD8+ T cells and NK cells, which were independent from the type of antiretroviral regimen. Increase in central and effector memory and reduction in terminally-differentiated effector memory CD4+ and CD8+ T cells were accompanied by increases of CD4+ and CD8+ T cell responses against Env and recall antigens. Of note, more immune-compromised individuals experienced greater therapeutic effects. In contrast, these changes were opposite, absent or partial in the OBS population. These findings support the use of Tat immunization to intensify HAART efficacy and to restore immune homeostasis. Trial registration ClinicalTrials.gov NCT00751595

Impact of highly active antiretroviral therapy on the presenting features and outcome of patients with acquired immunodeficiency syndrome–related Kaposi sarcoma†‡§

The objective of the current study was to evaluate the impact of highly active antiretroviral therapy (HAART) on clinical characteristics of presentation and the natural history of Kaposi sarcoma (KS) in patients already receiving HAART at the time of KS diagnosis.

Simplification to coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir versus continuation of ritonavir-boosted protease inhibitor with emtricitabine and tenofovir in adults with virologically suppressed HIV (STRATEGY-PI): 48 week results of a randomised, open-label, phase 3b, non-inferiority trial

BACKGROUND Patients with HIV on antiretroviral therapy might benefit from regimen simplification to reduce pill burden and dosing frequency. We aimed to assess the safety and efficacy of simplifying the treatment regimen for adults with virologically suppressed HIV infection from a ritonavir-boosted protease inhibitor and emtricitabine plus tenofovir disoproxil fumarate (tenofovir) regimen to coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir. METHODS STRATEGY-PI is a 96 week, international, multicentre, randomised, open-label, phase 3b trial in which HIV-infected adults with a plasma HIV-1 RNA viral load of less than 50 copies per mL for at least 6 months who were taking a ritonavir-boosted protease inhibitor with emtricitabine plus tenofovir were randomly assigned (2:1) either to switch to coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir or to continue on their existing regimen. Key eligibility criteria included no history of virological failure, no resistance to emtricitabine and tenofovir, and creatinine clearance of 70 mL/min or higher. Neither participants nor investigators were masked to group allocation. The primary endpoint was the proportion of participants with a viral load of less than 50 copies per mL at week 48, based on a US Food and Drug Administration snapshot algorithm for the modified intention-to-treat population, which excluded major protocol violations (prohibited resistance or not receiving a protease inhibitor at baseline). We prespecified non-inferiority with a 12% margin; if non-inferiority was established, superiority was tested as per a prespecified sequential testing procedure. This trial is registered at ClinicalTrials.gov, number NCT01475838. FINDINGS Between Dec 12, 2011, and Dec 20, 2012, 433 participants were randomly assigned and received at least one dose of study drug. Of these participants, 293 were assigned to switch to the simplified regimen (switch group) and 140 to remain on their existing regimen (no-switch group); after exclusions, 290 and 139 participants, respectively, were analysed in the modified intention-to-treat population. At week 48, 272 (93·8%) of 290 participants in the switch group maintained a viral load of less than 50 copies per mL, compared with 121 (87·1%) of 139 in the no-switch group (difference 6·7%, 95% CI 0·4-13·7; p=0·025). The statistical superiority of the simplified regimen was mainly caused by a higher proportion of participants in the no-switch group than in the switch group discontinuing treatment for non-virological reasons; virological failure was rare in both groups (two [1%] of 290 vs two [1%] of 139). We did not detect any treatment-emergent resistance in either group. Adverse events leading to discontinuation were rare in both groups (six [2%] of 293 vs four [3%] of 140). Switching to the simplified regimen was associated with a small, non-progressive increase from baseline in serum creatinine concentration. Nausea was more common in the switch group than in the no-switch group, but rates of diarrhoea and bloating decreased compared with baseline from week 4 to week 48 in the switch group, whereas there were generally no changes for these symptoms in the no-switch group. INTERPRETATION Coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir might be a useful regimen simplification option for virologically supressed adults with HIV taking a multitablet ritonavir-boosted protease inhibitor regimen. FUNDING Gilead Sciences.

Association of a single-nucleotide polymorphism in the pregnane X receptor (PXR 63396C-->T) with reduced concentrations of unboosted atazanavir.

This study investigated pregnane X receptor polymorphisms in relation to unboosted atazanavir plasma concentrations in 2 cohorts of patients. The polymorphism 63396T-->C predicted concentrations below the minimum effective concentration (150 ng/mL) with odds ratios of 18 (P = .008) and 5.13 (P = .02). Prospective studies determining potential clinical usefulness are now warranted.

Clinical use of lopinavir/ritonavir in a salvage therapy setting: pharmacokinetics and pharmacodynamics.

Lopinavir/ritonavir was administered to 35 HIV-infected patients after therapeutic failure with other protease inhibitors. The pharmacokinetics (trough concentrations) and baseline viral genotype were determined, together with the immunovirological outcome. The 22 responders had significantly higher mean lopinavir concentrations and lower baseline numbers of mutations. On multivariate analysis, a lopinavir concentration of 5.7 microg/ml or greater was an independent predictor of viral suppression over a 9-month follow-up period.