HIV Nucleoside Reverse Transcriptase Inhibitors Research Articles

Mechanochemical synthesis and characterization of Zidovudine-lamivudine solid dispersion (binary eutectic mixture)

ObjectiveIn the present work, solid-state co-grinding also known as mechanochemistry is employed to investigate the co-crystal formation between two HIV nucleoside reverse transcriptase inhibitors lamivudine (3TC) and zidovudine (AZT). MethodsThermal analyses by DSC, HSM, and TGA provided thermodynamic parameters of the samples over the heating exercise. Infrared spectroscopy enabled the evaluation of structural information of LMZT (1:1) sample while its morphology was assessed using Scanning electron microscopy. Powder X-ray diffraction analysis confirmed the sample's identity. ResultsEutectic LMZT (1:1) was obtained from co-grinding. Its lower melting transition compared to pure lamivudine and zidovudine was confirmed by HSM and DSC. Scanning electron microscopy micrographs indicated that the LMZT (1:1) sample exhibits irregular, round-shaped particles with smooth surfaces. Infrared spectroscopy revealed weak interactions between 3TC and AZT and Powder X-rays diffraction pattern that's made of a summation of pure APIs diffraction peaks, confirming LMZT (1:1) as a eutectic mixture. Solubility at 37 °C, in different buffered solutions to mimic gastrointestinal, was established and the measurement by HPLC indicated that LMZT (1:1) dual-API solid dispersion exhibited enhanced solubility for both active pharmaceutical ingredients. ConclusionMechanochemistry is a potential and green method for co-crystal synthesis. Co-crystal formation attempt between 3TC and AZT, using solid-state co-grinding resulted into a eutectic LMZT (1:1). Characterization revealed a lower melting transition, enhanced solubility and a good dissolution profile associated with the resultant eutectic, making this an interesting dual-API delivery system. Further studies should highlight the stability and antiviral activity of this combination.

DYNAMICS OF CLINICAL LABORATORY PARAMETER IN HIV-INFECTED CHILDREN UNDERGOING DIFFERENT PATTERNS OF INITIAL HIGHLY ACTIVE ANTIRETROVIRAL THERAPY: RANDOMIZED CONTROLLED TRIAL

Background: Adverse course of HIV infection, rapid development of immunosuppression, severe opportunistic infections and malignant tumors and high mortality substantiate the importance of timely prescription of highly active antiretroviral therapy (HAART). The initial therapy pattern must remain efficient and safe in the long term. Objective: Our aim was to study effectiveness and safety of different patterns of initial HAART in HIV-infected children. Methods: The randomized controlled trial involved HIV-infected children aged 1–3 years. Clinical, immunological and virological examinations were conducted before and 12 months after HAART. The initial therapy pattern included 2 nucleoside HIV reverse transcriptase inhibitors — zidovudine and lamivudine. Children were randomized to the groups differing in the third therapy component: lopinavir/ritonavir or nevirapine. Results: 25 patients were randomized to the lopinavir/ritonavir group, 23 children — to the nevirapine group. After 12 months of treatment, HIV replication suppression (blood viral load < 50 copies/ml) was achieved in 25 (100%) lopinavir/ritonavir group patients and in 16 (70%) nevirapine group patients (p = 0.003). HIV infection did not progress clinically regardless of the pattern. The median number of CD4+CD3+ lymphocytes in the lopinavir/ritonavir group increased from 20.5% (12; 23) to 30% (27; 34) (p < 0,001), in the nevirapine group — from 21.5% (17; 23) to 29% (27; 38) (p < 0.001). Adverse events developed in 13 (27%) children. 3 and 2 children in the lopinavir/ritonavir group suffered from nausea and emesis, respectively. 1 and 1 patient in the nevirapine group suffered from allergic rash and drug-induced hepatitis, respectively. Conclusion: High effectiveness and safety of lopinavir/ritonavir allow recommending this drug as the third component of the initial HAART pattern for HIV-infected children.

Efficacy, safety, bone and metabolic effects of HIV nucleoside reverse transcriptase inhibitor BMS-986001 (AI467003): a phase 2b randomised, controlled, partly blinded trial

BMS-986001 is a thymidine analogue nucleoside reverse transcriptase inhibitor (NRTI) designed to maintain in-vitro antiviral activity while minimising off-target effects. We assessed the efficacy and safety of BMS-986001 versus tenofovir disoproxil fumarate in treatment-naive patients with HIV-1. In this phase 2b, randomised, active-controlled trial (AI467003), we recruited treatment-naive (no current or previous exposure to an antiretroviral drug for >1 week) adults (aged at least 18 years) with HIV-1 from 47 sites across Asia, Australia, Europe, North America, South Africa, and South America. Patients with plasma HIV-1 RNA greater than 5000 copies per mL and CD4 counts greater than 200 cells per μL were randomly assigned (2:2:2:3) to receive BMS-986001 100 mg, 200 mg, or 400 mg once a day or to receive tenofovir disoproxil fumarate 300 mg once a day; each allocation was given with efavirenz 600 mg once a day and lamivudine 300 mg once a day. Both patients and investigators were masked to BMS-986001 dose (achieved with similar looking placebo tablets), but not allocation up to and including week 48. The primary endpoints were the proportion of patients with plasma HIV-1 RNA less than 50 copies per mL and safety events (serious adverse events and adverse events leading to discontinuation) through week 24; the main analysis was with a modified intention-to-treat population. Resistance analysis was a secondary endpoint, and additional safety parameters were exploratory endpoints. This trial is registered with ClinicalTrials.gov, number NCT01489046, and the European Clinical Trials Database, number EudraCT 2011-003329-89. Patients were recruited between Jan 25, 2012, and Oct 3, 2012; 757 patients were assessed for eligibility and 301 were randomly assigned to receive either BMS-986001 once a day (67 patients to 100 mg, 67 to 200 mg, and 66 to 400 mg) or tenofovir disoproxil fumarate (n=101). 297 patients received at least one dose of study drug. At week 24, 57 (88%) of 65 patients for whom there were data in the 100 mg group, 54 (81%) of 67 in the 200 mg group, 62 (94%) of 66 in the 400 mg group achieved HIV-1 RNA less than 50 copies per mL, compared with 88 (89%) of 99 in the tenofovir disoproxil fumarate group (modified intention-to-treat population). BMS-986001 was generally well tolerated through week 48. Two patients had BMS-986001-related serious adverse events (atypical drug eruption and thrombocytopenia) and two in the tenofovir disoproxil fumarate group had study drug-related serious adverse events (potential drug-induced liver injury and depression or lipodystrophy) that led to discontinuation. NRTI resistance-associated mutations were reported in four (2%) of 198 patients, and non-NRTI mutations in 17 (9%) of 198 patients receiving BMS-986001 versus none of 99 and one (1%) of 99 patients receiving tenofovir disoproxil fumarate, respectively. Compared with tenofovir disoproxil fumarate, individuals in the BMS-986001 groups showed a smaller decrease in lumbar spine and hip bone mineral density but greater accumulation of limb and trunk fat, subcutaneous and visceral adipose tissue, and increased total cholesterol. BMS-986001 had similar efficacy to that of tenofovir disoproxil fumarate and was associated with a smaller decrease in bone mineral density; however, greater resistance and gains in both peripheral and central fat accumulation were recorded for the investigational drug. Bristol-Myers Squibb has discontinued its involvement in the development of BMS-986001, and future decisions on development will be made by Oncolys BioPharma. Bristol-Myers Squibb.

Pharmacokinetics and preliminary safety study of pod-intravaginal rings delivering antiretroviral combinations for HIV prophylaxis in a macaque model.

Preexposure prophylaxis using oral regimens involving the HIV nucleoside reverse transcriptase inhibitors tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) demonstrated efficacy in three clinical trials. Adherence was determined to be a key parameter for success. Incorporation of the TDF-FTC combination into intravaginal rings (IVRs) for sustained mucosal delivery could increase product adherence and efficacy compared with those of oral and vaginal gel formulations. A novel pod-IVR technology capable of delivering multiple drugs is described; this constitutes the first report of an IVR delivering TDF and FTC, as well as a triple-combination IVR delivering TDF, FTC, and the entry inhibitor maraviroc (MVC). The pharmacokinetics and preliminary local safety of the two combination pod-IVRs were evaluated in the pig-tailed macaque model. The devices exhibited sustained release at controlled rates over the 28-day study period. Median steady-state drug levels in vaginal tissues in the TDF-FTC group were 30 μg g(-1) (tenofovir [TFV], in vivo hydrolysis product of TDF) and 500 μg g(-1) (FTC) and in the TDF-FTC-MVC group were 10 μg g(-1) (TFV), 150 μg g(-1) (FTC), and 20 μg g(-1) (MVC). No adverse events were observed, and there were no toxicological findings. Mild-to-moderate increases in inflammatory infiltrates were observed in the vaginal tissues of some animals in both the presence and the absence of the IVRs. The IVRs did not disturb the vaginal microbiota, and levels of proinflammatory cytokines remained stable throughout the study. Pod-IVR candidates based on the TDF-FTC combination have potential for the prevention of vaginal HIV acquisition and merit clinical investigation.

Randomized, placebo‐controlled single‐ascending‐dose study to evaluate the safety, tolerability and pharmacokinetics of the HIV nucleoside reverse transcriptase inhibitor, BMS‐986001, in healthy subjects

The objectives of this study were to evaluate the safety, tolerability and pharmacokinetics (PK) of BMS-986001 as a single oral dose in healthy male subjects. Sixty-four healthy male subjects were randomized to receive a single dose of BMS-986001 or placebo in this single-blind, placebo-controlled, sequential ascending-dose study. There were eight treatment groups (10, 30, 100, 300, 600, and 900 mg fed; and 100 and 300 mg fasted) of eight subjects each (BMS-986001 n = 6/placebo n = 2). BMS-986001 was well tolerated, with no serious adverse events (AEs), deaths, or discontinuations due to AEs reported. AEs were experienced by 14.6% of subjects receiving BMS-986001; however, these did not appear to be dose related and were not considered to be related to study drug. BMS-986001 was rapidly absorbed and exhibited a linear dose-exposure relationship across the dose range studied. PK appeared similar whether administered with or without food. Administration of BMS-986001 as a single dose was generally safe and well tolerated. A linear dose-exposure relationship was seen across all doses studied, with no apparent food effect. Further clinical development is warranted.

BMS-986001, an HIV Nucleoside Reverse Transcriptase Inhibitor, Does Not Degrade Mitochondrial DNA in Long-Term Primary Cultures of Cells Isolated from Human Kidney, Muscle, and Adipose Tissue

Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) remain the cornerstone of HIV treatment; however, they are associated with toxicities attributed in part to inhibition of mitochondrial DNA (mtDNA) polymerase γ. In this study, we compared the in vitro toxicity profiles of structurally similar NRTIs (BMS-986001 to stavudine and tenofovir to adefovir) that differ by the presence of an acetylene or methyl group, respectively. Primary cultures of human renal proximal tubule epithelium, skeletal muscle myotubes, and differentiated adipocytes were exposed to the NRTIs at the maximum concentration (Cmax) reported for the clinically approved dose (investigational dose for BMS-986001, 600 mg) and a high equimolar concentration (200 μM) for 19 days. After 19 days, BMS-986001 did not significantly decrease mtDNA or cell protein at either concentration in any cell line. In contrast, stavudine significantly decreased mtDNA in all cultures (1.5- to 2.5-fold) (except at Cmax in renal cells) and cell protein in renal cells (1.4- to 2.4-fold). By day 19, at 200 μM, tenofovir significantly reduced mtDNA in adipocytes (1.9-fold) and adefovir significantly decreased mtDNA in all cultures (3.7- to 10.2-fold); however, no significant reduction in mtDNA was observed at Cmax in any cell line. Adefovir also significantly reduced cell protein at both concentrations in renal cells (2.2- to 2.8-fold) and at 200 μM in muscle cells (2.0-fold). In conclusion, BMS-986001 and tenofovir were considerably less cytotoxic than their respective structural analogs, demonstrating that small structural differences can contribute to significant differences in toxicity.

In vitro cross-resistance profile of nucleoside reverse transcriptase inhibitor (NRTI) BMS-986001 against known NRTI resistance mutations.

BMS-986001 is a novel HIV nucleoside reverse transcriptase inhibitor (NRTI). To date, little is known about its resistance profile. In order to examine the cross-resistance profile of BMS-986001 to NRTI mutations, a replicating virus system was used to examine specific amino acid mutations known to confer resistance to various NRTIs. In addition, reverse transcriptases from 19 clinical isolates with various NRTI mutations were examined in the Monogram PhenoSense HIV assay. In the site-directed mutagenesis studies, a virus containing a K65R substitution exhibited a 0.4-fold change in 50% effective concentration (EC50) versus the wild type, while the majority of viruses with the Q151M constellation (without M184V) exhibited changes in EC50 versus wild type of 0.23- to 0.48-fold. Susceptibility to BMS-986001 was also maintained in an L74V-containing virus (0.7-fold change), while an M184V-only-containing virus induced a 2- to 3-fold decrease in susceptibility. Increasing numbers of thymidine analog mutation pattern 1 (TAM-1) pathway mutations correlated with decreases in susceptibility to BMS-986001, while viruses with TAM-2 pathway mutations exhibited a 5- to 8-fold decrease in susceptibility, regardless of the number of TAMs. A 22-fold decrease in susceptibility to BMS-986001 was observed in a site-directed mutant containing the T69 insertion complex. Common non-NRTI (NNRTI) mutations had little impact on susceptibility to BMS-986001. The results from the site-directed mutants correlated well with the more complicated genotypes found in NRTI-resistant clinical isolates. Data from clinical studies are needed to determine the clinically relevant resistance cutoff values for BMS-986001.

Effect of the HIV nucleoside reverse transcriptase inhibitor zidovudine on the growth and differentiation of primary gingival epithelium

Oral complications associated with HIV infection and with the antiretroviral drugs used to treat it are of increasing concern in HIV-infected patients. Protease inhibitors have been shown to change the proliferation and differentiation state of oral tissues but the effect of nucleoside reverse transcriptase inhibitors is currently unknown. This study examined the effect of zidovudine on the growth and differentiation of the gingival epithelium. Gingival keratinocyte organotypic (raft) cultures were established. The raft cultures were treated with a range of zidovudine concentrations. Haematoxylin and eosin staining was performed to examine the effect of zidovudine on gingival epithelium growth and stratification. Raft cultures were immunohistochemically analysed to determine the effect of this drug on the expression of key differentiation and proliferation markers, including cytokeratins and proliferating cell nuclear antigen (PCNA). Zidovudine dramatically changed the proliferation and differentiation state of gingival tissues both when it was present throughout the growth period of the tissue and when it was added to established tissue at day 8. Zidovudine treatment increased the expression of cytokeratin 10, PCNA and cyclin A. Conversely, cytokeratin 5, involucrin and cytokeratin 6 expression was decreased. The tissue exhibited characteristics of increased proliferation in the suprabasal layers as well as an increased fragility and an inability to heal itself. Zidovudine treatment, even when applied at low concentrations for short periods of time, deregulated the cell cycle/proliferation and differentiation pathways, resulting in abnormal epithelial repair and proliferation. Our system could potentially be developed as a model for studying the effects of HIV and highly active antiretroviral therapy in vitro.

Tenofovir Selectively Regulates Production of Inflammatory Cytokines and Shifts the IL-12/IL-10 Balance in Human Primary Cells

In this study, we aimed to investigate the possible immune modulatory effects of HIV nucleoside reverse transcriptase inhibitors during secondary infections and inflammation, focusing on inflammatory cytokine responses and the interleukin (IL)-12/IL-10 balance. We investigated the in vitro effect of tenofovir and zidovudine (AZT) on production of proinflammatory cytokines in monocytes and human peripheral blood mononuclear cells (PBMCs). Stimulation panels included Toll-Like receptor (TLR) ligands; the inflammation mediator tumor necrosis factor-α; and the pathogens cytomegalovirus, Neisseria meningitides, Escherichia coli, and Streptococcus pneumoniae. Cytokine levels were measured using enzyme-linked immunosorbent assay and luminex technology. RNA levels were assessed using real-time polymerase chain reaction. Activity of mitogen-activated protein kinase and NF-κB signaling was evaluated using flow cytometry and multispectral imaging cytometry, respectively. Tenofovir decreased and AZT increased both IL-8 and CCL3 production from monocytes after stimulation with TLR ligands, tumor necrosis factor-α, or live pathogens. Similarly, tenofovir decreased CCL3 levels in human PBMCs. Furthermore, tenofovir strongly decreased induction of IL-10 but increased levels of IL-12. AZT did not affect IL-12 or IL-10 levels. The observed drug-induced changes in cytokine production were independent from transcriptional regulation through the mitogen-activated protein kinase and nuclear factor kappa B pathways. Our data suggest divergent effects of tenofovir and AZT on proinflammatory responses in monocytes (CCL3 and IL-8) and PBMCs (CCL3). Moreover, tenofovir shifts the IL-10/IL-12 balance after cell stimulation with TLR ligands or infection with live bacteria, thus suggesting that the choice of nucleoside reverse transcriptase inhibitor affects overall inflammation and early immune responses against secondary pathogens.

Long-term CD4+ T-cell count evolution after switching from regimens including HIV nucleoside reverse transcriptase inhibitors (NRTI) plus protease inhibitors to regimens containing NRTI plus non-NRTI or only NRTI

BackgroundData regarding CD4+ recovery after switching from protease inhibitor (PI)-based regimens to regimens not containing PI are scarce.MethodsSubjects with virological success on first-PI-regimens who switched to NNRTI therapy (NNRTI group) or to nucleoside reverse transcriptase (NRTI)-only (NRTI group) were studied. The effect of the switch on the ongoing CD4+ trend was assessed by two-phase linear regression (TPLR), allowing us to evaluate whether a change in the CD4+ trend (hinge) occurred and the time of its occurrence. Furthermore, we described the evolution of the frequencies in CD4-count classes across four relevant time-points (baseline, before and immediately after the switch, and last visit). Finally, we explored whether the CD4+ counts evolved differently in patients who switched to NNRTI or NRTI-only regimens by considering: the overall CD4+ trends, the time to CD4+≥ 500/mm3 after the switch, and the area-under-the-curve (AUC) of the CD4+ after the switch.ResultsEight hundred and ninety-six patients, followed for a median of 2,121 days, were included. At TPLR, hinges occurred in 581/844 (68.9%), but in only 40/581 (6.9%) within a time interval (180 days) compatible with a possible relationship to the switch; furthermore, in 19/40 cases, CD4+ counts appeared to decrease after the hinges. In comparison with the NNRTI group, the NRTI group showed CD4+ count greater at baseline (P = 0.0234) and before the switch (P ≤ 0.0001), superior CD4+ T-cell increases after HAART was started, lower probability of not achieving CD4+ ≥ 500/mm3 (P = 0.0024), and, finally, no significant differences in the CD4+ T-cell AUC after the switch after adjusting for possible confounders (propensity score and pre-switch AUC). Persistence at CD4+ < 200/mm3 was observed in 34/435 (7.5%) patients, and a decrease below this level was found in only 10/259 (3.9%) with baseline CD4+ ≥ 350/mm3.ConclusionsSwitching from first-line PI to NNRTI- or NRTI-based regimens did not seem to impair CD4+ trend over long-term follow-up. Although the greater CD4+ increases in patients who switched to the NRTI-only regimen was due to higher CD4+ counts before the switch, several statistical analyses consistently showed that switching to this regimen did not damage the ongoing immune-reconstitution. Lastly, the observation that CD4+ T-cell counts remained low or decreased in the long term despite virological success merits further investigation.

Evaluation of HIV protease and nucleoside reverse transcriptase inhibitors on proliferation, necrosis, apoptosis in intestinal epithelial cells and electrolyte and water transport and epithelial barrier function in mice

BackgroundProtease inhibitors (PI's) and reverse transcriptase drugs are important components of highly active antiretroviral therapy (HAART) for treating human acquired immunodeficiency syndrome (AIDS). Long-term clinical therapeutic efficacy and treatment compliance of these agents have been limited by undesirable side-effects, such as diarrhea. This study aims to investigate the effects of selected antiretroviral agents on intestinal histopathology and function in vivo and on cell proliferation and death in vitro.MethodsSelected antiretroviral drugs were given orally over 7 days, to Swiss mice, as follows: 100 mg/kg of nelfinavir (NFV), indinavir (IDV), didanosine (DDI) or 50 mg/kg of zidovudine (AZT). Intestinal permeability measured by lactulose and mannitol assays; net water and electrolyte transport, in perfused intestinal segments; and small intestinal morphology and cell apoptosis were assessed in treated and control mice. In vitro cell proliferation was evaluated using the WST-1 reagent and apoptosis and necrosis by flow cytometry analysis.ResultsNFV, IDV, AZT and DDI caused significant reductions in duodenal and in jejunal villus length (p < 0.05). IDV and AZT increased crypt depth in the duodenum and AZT increased crypt depth in the jejunum. NFV, AZT and DDI significantly decreased ileal crypt depth. All selected antiretroviral drugs significantly increased net water secretion and electrolyte secretion, except for DDI, which did not alter water or chloride secretion. Additionally, only NFV significantly increased mannitol and lactulose absorption. NFV and IDV caused a significant reduction in cell proliferation in vitro at both 24 h and 48 h. DDI and AZT did not alter cell proliferation. There was a significant increase in apoptosis rates in IEC-6 cells after 24 h with 70 ug/mL of NFV (control: 4.7% vs NFV: 22%) while IDV, AZT and DDI did not show any significant changes in apoptosis compared to the control group. In jejunal sections, IDV and NFV significantly increased the number of TUNEL positive cells.ConclusionThe PI's, NFV and IDV, increased cell apoptosis in vivo, water and electrolyte secretion and intestinal permeability and decreased villus length and cell proliferation. NFV was the only drug tested that increased cell apoptosis in vitro. The nucleoside reverse transcriptase inhibitors, AZT and DDI, did not affect cell apoptosis or proliferation. These findings may partly explain the intestinal side-effects associated with PI's.

Insulin Sensitivity in Multiple Pathways Is Differently Affected During Zidovudine/Lamivudine-Containing Compared With NRTI-Sparing Combination Antiretroviral Therapy

The extent and manner by which HIV nucleoside reverse transcriptase inhibitors contribute to insulin resistance is unclear. We evaluated the effect of zidovudine/lamivudine (ZDV/3TC) on glucose metabolism. combination antiretroviral therapy-naive men were randomized to lopinavir/ritonavir (LPV/r, 400/100 mg twice a day) + ZDV/3TC or LPV/r (533/133 mg twice a day) + nevirapine (NVP). Computerized tomography, dual-energy X-ray absorptiometry scans, and hyperinsulinemic euglycemic clamps using stable isotopes were performed before and after 3, 12, and 24 months of combination antiretroviral therapy. Insulin-stimulated peripheral glucose disposal decreased by 25% after 3 months in patients on zidovudine/lamivudine/lopinavir/ritonavir (ZDV/3TC/LPV/r) (P < 0.001) and this decreased rate persisted thereafter, followed by a transient decrease in insulin-mediated inhibition of lipolysis. In the nevirapine/lopinavir/ritonavir (NVP/LPV/r) group, hepatic insulin sensitivity had improved compared with baseline after 24 months. After the initial 3 months, limb fat decreased in the ZDV/3TC/LPV/r arm up to 24 months [-849 +/- 345 g (P = 0.017)], and visceral adipose tissue increased over 2 years [+36.2 +/- 13.3 cm2 (P = 0.009)]. In the NVP/LPV/r group, a generalized increase in fat mass was observed. Treatment with ZDV/3TC/LPV/r versus NVP/LPV/r differentially affects glucose and lipid metabolism. The ZDV/3TC/LPV/r regimen induced peripheral insulin resistance, a transient increase in basal lipolysis and a transient decrease in insulin-mediated inhibition of lipolysis, whereas hepatic insulin sensitivity improved with the NVP/LPV/r regimen.

Characterization of the patterns of drug-resistance mutations in newly diagnosed HIV-1 infected patients naïve to the antiretroviral drugs

BackgroundThe transmission of HIV-1 drug-resistant strains in drug naive patients may seriously compromise the efficacy of a first-line antiretroviral treatment. To better define this problem, a study in a cohort of newly diagnosed HIV-1 infected individuals has been conducted. This study is aimed to assess the prevalence and the patterns of the mutations recently associated with transmitted drug resistance in the reverse transcriptase (RT) and in protease (PR) of HIV-1.MethodsPrevalence of transmitted drug resistant strains is determined in 255 newly diagnosed HIV-1 infected patients enrolled in different counselling and testing (CT) centres in Central Italy; the Avidity Index (AI) on the first available serum sample is also used to estimate time since infection. Logistic regression models are used to determine factors associated with infection by drug resistant HIV-1 strains.ResultsThe prevalence of HIV-1 strains with at least one major drug resistance mutation is 5.9% (15/255); moreover, 3.9% (10/255) of patients is infected with HIV nucleoside reverse transcriptase inhibitor (NRTI)-resistant viruses, 3.5% (9/255) with HIV non-NRTI-resistant viruses and 0.4% (1/255) with HIV protease inhibitor (PI)-resistant viruses. Most importantly, almost half (60.0%) of patients carries HIV-1 resistant strains with more than one major drug resistance mutation. In addition, patients who had acquired HIV through homosexual intercourses are more likely to harbour a virus with at least one primary resistance mutation (OR 7.7; 95% CI: 1.7–35.0, P = 0.008).ConclusionThe prevalence of drug resistant HIV-1 strains among newly diagnosed individuals in Central Italy is consistent with the data from other European countries. Nevertheless, the presence of drug-resistance HIV-1 mutations in complex patterns highlights an additional potential risk for public health and strongly supports the extension of wide genotyping to newly diagnosed HIV-1 infected patients.

Longitudinal effects of thymidine analogues on mtDNA, mtRNA and multidrug resistance (MDR-1) induction in cultured cells

HIV nucleoside reverse transcriptase inhibitors (NRTIs) can cause mitochondrial toxicity. In spite of several studies performed on cells, little is known about their long-term effects on mitochondrial DNA (mtDNA), mitochondrial gene expression (mtRNA) and cellular protective mechanisms that such exposure may trigger. Our aim was to investigate the longitudinal effects of two thymidine analogue NRTIs, zidovudine and stavudine, on human cells, measuring their effects on the levels of mtDNA, mtRNA and on induction of the multidrug resistance (MDR) gene MDR-1. K562 lymphoblastoid cells were treated for 74 days with zidovudine or stavudine concentrations corresponding to approximately 1x, 20x and 400x those measured in plasma. Samples were collected longitudinally and assayed for mtDNA, mtRNA and MDR-1 mRNA levels by real-time quantitative PCR. mtDNA deletions were investigated by long PCR. Upon exposure to both zidovudine and stavudine, an early dose-dependent and transient increase in mtDNA content was observed. This was followed by a concurrent and transient elevation in both mtRNA and MDR-1 mRNA levels. Interestingly, the increase in mtRNA was most pronounced at low concentrations, whereas that of MDR-1 expression occurred at the highest concentrations only. No mtDNA deletions were detected under any conditions. Cellular response to thymidine analogue NRTI exposure showed a complex, time- and dose-dependent pattern over time. We report for the first time that NRTIs can induce MDR-1 expression; however, this effect is delayed, possibly in response to oxidative damage or mitochondrial dysfunction. Our results indicate that longitudinal experiments may refine our knowledge about NRTI toxicity.

Combination antiretroviral therapy without a nucleoside reverse transcriptase inhibitor: experience from 334 patients in three cohorts.

Toxicity and resistance may limit the use of HIV nucleoside reverse transcriptase inhibitors (NRTIs). We assessed the safety and activity of regimens that did not include an NRTI. We analysed NRTI-sparing regimens using pooled data from three cohorts in Australia and France where HIV RNA viral load, CD4 lymphocyte count and metabolic parameters are assessed prospectively. The inclusion criterion was the commencement of any antiretroviral combination excluding NRTIs. A total of 334 (3.9%) of 8477 patients were included in the present study for a median follow-up time of 105 weeks. Therapeutic combinations were one nonnucleoside reverse transcriptase inhibitor (NNRTI) plus one protease inhibitor (PI) (58%), two PIs (26%), one PI (16%), and one NNRTI plus two PIs (8%). At baseline, the median CD4 lymphocyte count was 264 cells/muL (interquartile range 164-446 cells/muL) and 25% of patients had plasma HIV RNA below 500 HIV-1 RNA copies/mL. In intent-to-treat analysis, 64% of patients had HIV RNA <500 copies/mL at 6 months and 68% at 24 months. The mean CD4 lymphocyte count increase was 60 cells/microL (95% confidence interval 41-76 cells/microL) at 6 months and 111 cells/microL (95% confidence interval 82-140 cells/microL) at 24 months. Prognostic factors for having HIV RNA <500 copies/mL at 6 months included independently having undetectable HIV RNA at baseline and being naïve for NNRTIs. The proportion of patients with triglycerides >2.3 mmol/L increased from 32% to 63% at 6 months and to 62% at 24 months (P-trend=0.002), and those with total cholesterol >6.2 mmol/L increased from 18% to 38% at 6 months and to 44% at 24 months (P-trend <0.001), with an increased risk for patients treated with NNRTI+PIs. Forty-one per cent of patients discontinued their NRTI-sparing regimen. In these antiretroviral-experienced patients, NRTI-sparing therapy appeared to have satisfactory virological and immunological efficacy. However, hyperlipidaemia was frequent and requires monitoring of cardiovascular risk factors.

Oxidant Stress and Peripheral Neuropathy During Antiretroviral Therapy

Peripheral neuropathy that complicates HIV nucleoside reverse transcriptase inhibitor (NRTI) therapy is likely caused by mitochondrial injury. Mitochondria play a central role in regulating oxidant stress. We explored the relationships between oxidant stress and NRTI-induced peripheral neuropathy. The AIDS Clinical Trials Group (ACTG) studied the cases of 384 antiretroviral-naive individuals randomized to receive didanosine/stavudine or zidovudine/lamivudine, plus efavirenz, nelfinavir, or both. The participants were followed for up to 3 years. Peripheral neuropathy was ascertained by signs and symptoms. We performed a case-control study of ACTG 384 participants. Peripheral neuropathy cases and nonneuropathy control subjects were selected from didanosine/stavudine recipients. Alternate control subjects were selected from zidovudine/lamivudine recipients who developed peripheral neuropathy. Oxidant stress was assessed by quantifying F2-isoprostanes (F2-IsoPs) in cryopreserved plasma. Seventy-five cases, 71 control subjects, and 18 alternate control subjects were identified. The median baseline F2-IsoP values were 53 (interquartile range [IQR], 40-85), 57 (IQR, 41-77), and 53 (IQR, 47-101) pg/mL, respectively, and did not differ between cases and control subjects (P = 0.78) or alternate control subjects (P = 0.60). Changes in F2-IsoPs from baseline to time of peripheral neuropathy did not differ significantly between cases (median, 10 [IQR, -17 to 26] pg/mL) and control subjects (median, 4 [IQR, -11 to 17] pg/mL; P = 0.48) or alternate control subjects (median, 1 [IQR, -48 to 10] pg/mL; P = 0.21). Peripheral neuropathy that complicates antiretroviral therapy with NRTIs was not associated with increased systemic oxidant stress assessed by plasma F2-IsoPs.

Mitochondrial haplogroups and peripheral neuropathy during antiretroviral therapy: an adult AIDS clinical trials group study

HIV nucleoside reverse transcriptase inhibitors (NRTI) can cause peripheral neuropathy that is a result of mitochondrial injury. Polymorphisms in the mitochondrial genome define haplogroups that may have functional implications. The objective of this study was to determine if NRTI-associated peripheral neuropathy is associated with European mitochondrial haplogroups. Case-control study of Adult AIDS Clinical Trials Group (ACTG) study 384 and ACTG Human DNA Repository participants. ACTG study 384 was a treatment strategy trial of antiretroviral therapy with didanosine (ddI) plus stavudine (d4T) or zidovudine plus lamivudine given with efavirenz, nelfinavir, or both. Subjects were followed for up to 3 years. Peripheral neuropathy was ascertained based on signs and symptoms. For this analysis, polymorphisms that define European mitochondrial haplogroups were characterized in a majority of ACTG 384 participants, and associations with peripheral neuropathy were assessed using logistic regression. A total of 509 subjects were included in this analysis of whom 250 (49%) were self-identified as white, non-Hispanic. Mitochondrial haplogroup T was more frequent in subjects who developed peripheral neuropathy. Among 137 white subjects randomized to receive ddI plus d4T, 20.8% of those who developed peripheral neuropathy belonged to mitochondrial haplogroup T compared to 4.5% of control subjects (odds ratio, 5.4; 95% confidence interval, 1.4-25.1; P = 0.009). Independent predictors of peripheral neuropathy were randomization to receive ddI plus d4T, older age, and mitochondrial haplogroup T. A common European mitochondrial haplogroup may predict NRTI-associated peripheral neuropathy. Future studies should validate this relationship, and evaluate non-European mitochondrial haplogroups and other NRTI toxicities.

Development and validation of a liquid chromatographic/tandem mass spectrometric assay for the quantitation of nucleoside HIV reverse transcriptase inhibitors in biological matrices

Besides liquid chromatographic (LC)/UV methods adapted to therapeutic drug monitoring, there is still a need for more powerful techniques that can be used for pharmacological research and clinical purposes. We developed an LC method coupled with tandem mass spectrometry (MS/MS) to separate, detect and quantify with high sensitivity the nucleoside analogues used in multitherapies (zidovudine, stavudine, zalcitabine, didanosine, lamivudine and abacavir) in plasma and in the intracellular medium. We worked on two essential issues: (i) the need to use two ionization modes in order to achieve the best sensitivity, which leads to the optimization of the chromatographic separation of drugs detected in the positive ionization mode and drugs detected in the negative ionization mode, and (ii) the need to optimize the extraction step in order to enhance sample recovery. The peripheral blood mononuclear cells were lysed in Tris buffer-MeOH. A clean-up procedure was performed by solid-phase extraction only for plasma samples. The LC separation was carried out on a Zorbax Stable Bond C(18) column followed by MS/MS analysis after electrospray ionization in either the negative or positive mode. The positive ionization mode was applied at the beginning of the run to detect zalcitabine and lamivudine, then the ionization mode was changed to negative for the detection of didanosine, stavudine, internal standard and zidovudine. The calibration range for all the analytes was 0.5-200 ng ml(-1). The recoveries were between 64 and 90%, with coefficients of variation (CVs) lower than 15%. The inaccuracy (bias) was +/-15% with CVs always lower than 12%. The analytes were stable at room temperature and in the extraction solvent for at least 24 h, after storage at -80 degrees C for 3 months, after three freeze-thaw cycles and in the injection solvent after 48 h at 4 degrees C. Together with the measurement of intracellular triphosphorylated metabolites thanks to the powerful plasma and intracellular assay method for intact drugs, it is possible to describe the behaviour of nucleoside analogues against HIV through plasma pharmacokinetics, cell membrane diffusion including drug transport involvement, and also the intracellular metabolism.

366 Combination studies involving entecavir and HIV nucleoside reverse transcriptase inhibitors showed no antagonistic effects on HBV or HIV activity in vitro

366 Combination studies involving entecavir and HIV nucleoside reverse transcriptase inhibitors showed no antagonistic effects on HBV or HIV activity in vitro

Atp Binding Cassette Multidrug Transporters Limit the Anti-HIV Activity of Zidovudine and Indinavir in Infected Human Macrophages

To investigate whether P-glycoprotein (P-gp) and multidrug resistance proteins (MRPs), which limit the bioavailability of HIV protease inhibitors (PIs) and nucleoside reverse transcriptase inhibitors (NRTIs), modulate the anti-HIV activity of NRTIs, non-NRTIs and PIs in vitro. We used primary cultures of major HIV target cells: human monocyte-derived macrophages (MDMs) and lymphocytes. P-gp and MRP expression in response to long-term zidovudine (3'-azido-3'-deoxythymidine; AZT) or indinavir treatment was quantified by RT-PCR. MDM and lymphocytes were infected in vitro with HIV-1/Ba-L and HIV-1-LAI, respectively, and treated with antiretroviral drugs. We evaluated the activity of these drugs in combination with PSC833, a P-gp inhibitor, and/or probenecid, an MRP1 inhibitor. Intracellular AZT triphosphate derivative (AZT-TP) was quantified by HPLC-MSMS. P-gp ATPase activity was measured with inside-out native membrane vesicles enriched in P-gp. Levels of MDR1, mrp4 and mrp5 mRNA were high following AZT treatment. In infected MDM, PSC833 and probenecid increased the anti-HIV activity of AZT and indinavir. AZT (5 nM) decreased HIV replication by 34% alone and by 72% in combination with P-gp/MRP inhibitors. Indinavir (10 nM) gave 14% inhibition alone and 81% in combination. The increase in anti-HIV activity of AZT was correlated with an increase in intracellular AZT-TP concentration. However, unlike PIs, neither AZT nor its metabolites interacted with P-gp. AZT increases the expression of multidrug transporters, thereby decreasing its pharmacological activity. The cellular efflux of AZT probably involves MRP4 or MRP5. In contrast, increases in indinavir anti-HIV activity require the inhibition of both P-gp and MRP1.