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Salvage therapy including foscarnet (PFA), zidovudine (ZDV) and an optimized background ART (OBT) has been shown to be effective in patients with advanced HIV infection, and no therapeutic options. Dolutegravir (DTG) may offer a more active combination. Objective was to describe efficacy and tolerability of PFA-ZDV-DTG containing regimen. In our cohort, we identified patients who: (i) had plasma HIV-1 RNA load (pVL) >50 c/ml (>100 for HIV-2) on combination ART (cART); (ii) had at least 1 PI/r, 1 NRTI, 1 NNRTI (for HIV-1), and at least 1 raltegravir resistance mutations; (iii) were naive to DTG; and (iv) initiated on a PFA-ZDV-DTG containing-regimen with 48 weeks (W48) of follow-up. Out of 5 patients, 2 were infected with HIV-2. At PFA-ZDV-DTG initiation, CD4 cell count was (/mm(3) ) of 64, 40, 10, in HIV-1, and 37, 199, in HIV-2 infected patients; and pVL (log10 c/ml) of 4.8, 5.1, 4.4, in HIV-1, and 3.6, 4.2, in HIV-2 infected patients, respectively. Median OBT genotypic sensitivity score was 1.5 [1-2]. PFA was discontinued in one patient, due to an acute renal failure. At W48, one HIV-1 infected patient had a pVL <50 c/ml and two <200 c/ml; the two HIV-2 infected patients had pVL >100 c/ml. No lack of treatment adherence was observed. In treatment experienced HIV-infected patients, failing cART and without other therapeutic options, a PFA-ZDV-DTG combination therapy could be effective. Renal adverse events should be monitored., (© 2015 Wiley Periodicals, Inc.)

Placental transfers of the HIV nonnucleoside reverse transcriptase inhibitor rilpivirine were investigated in 8 term human cotyledons perfused with rilpivirine (400 ng/ml) in the maternal-to-fetal direction. The mean fetal transfer rate (FTR) (fetal/maternal concentration at steady state from 15 to 90 min) was 26% ± 8% (mean ± standard deviation), and the clearance index (rilpivirine FTR/antipyrine FTR) was 61% ± 20%. This shows that rilpivirine crosses the placenta at a relatively high rate, suggesting that the fetus is exposed to the compound during treatment of the mother., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Background: Many HIV-treated patients travel to malaria-infected zones, but very few data are available on potential interactions between antiretroviral and antimalarial drugs., Method: We performed a pharmacokinetic study on the interaction of doxycycline (100 mg/d) on 2 protease inhibitors (PIs), atazanavir and lopinavir, and 2 non-nucleoside reverse transcriptase inhibitors (NNRTIs), efavirenz and nevirapine, given at usual daily doses in HIV-infected migrants native from sub-Saharan Africa included in the VIHVO ANRS-study before travelling to a sub-Saharan country. Antiretroviral trough plasma concentrations were measured at enrollment visit during the month preceding the travel before doxycycline introduction and on the week following the patients' return to France when they had been taking doxycycline for at least 15 days. Impact of doxycycline on antiretroviral concentrations was tested either with antiretroviral drugs separately or within the therapeutic classes (PI or NNRTI) in patients with an HIV RNA level <50 copies/mL at both visits and with good declared adherence. The Two One-Sided Test that was adapted to the Wilcoxon test was used to evidence the lack of interaction. Sixty-five patients receiving regimens containing atazanavir (n = 1), ritonavir-boosted atazanavir (n = 14), ritonavir-boosted lopinavir (n = 23), efavirenz (n = 17), nevirapine (n = 10) were included., Results: Lack of pharmacokinetic interaction was statistically significant when tested by therapeutic class (PI, P = .02; NNRTI, P = .005) and was not demonstrated for each antiretroviral when tested separately., Conclusion: This study is the first to assess the interaction of doxycycline on PI and NNRTI. This lack of pharmacokinetic interaction supports the choice of doxycycline as the antimalarial drug in patients treated with PI or NNRTI.

Background: Etravirine (ETR) is recommended as twice-daily dosing in pretreated patients. There are no data regarding the use of ETR once daily in HIV-experienced patients with prior resistance to first-generation non-nucleoside reverse transcripase inhibitors (NNRTIs)., Objectives: To evaluate the capacity of once-daily ETR to maintain suppressed viremia over 48 weeks after switching from ETR twice daily in NNRTI-experienced patients., Methods: In this pilot open-label study, patients with plasma viral load (pVL) <50 copies/mL on a stable ETR 200 mg bid regimen were enrolled to switch to ETR 400 mg qd and followed up over 48 weeks. The primary endpoint was the proportion of patients with pVL <50 copies/mL at week 24. Secondary endpoints included the rate of pVL< 50 copies/mL at week 48, ETR pharmacokinetic parameters, and tolerability and resistance profile., Results: Twenty-four patients were included. They had extensive antiretroviral treatment for a median of 14 years (range, 1-19). All except for 2 had prior resistance to NNRTIs. Seven patients discontinued ETR once daily prior to week 48 for virological failure (3), protocol deviation (3), and side effects (1). At week 24, 95% of patients maintained pVL< 50 copies/mL (95% CI, 78.4-99.7) and 85% at week 48 (95%CI, 65.6-95.8). Two of the 3 patients with virological failure had ETR resistance mutations prior to initiation. The median ETR C(trough) level remained stable after switching from twice daily 515 ng/mL (340-758) to once daily 422 ng/mL (264-655)., Conclusion: These results suggest that ETR is effective as a once-daily regimen in patients with prior NNRTI experience when HIV is sensitive to ETR. The stability of C(trough) concentrations on a once-daily regimen confirms the once-daily profile of the drug in experienced patients.

What Is Already Known About This Subject: • Lopinavir/ritonavir pharmacokinetics have been fully investigated in adults and children., What This Study Adds: • Lopinavir/ritonavir population pharmacokinetics in 96 neonates and infants from birth to less than 2 years (1.16 to 10.4 kg) showed that CL/F and V/F were dependent on body weight on an allometric basis and post-menstrual age., Aims: Because of immature hepatic metabolism, lopinavir could present specific pharmacokinetics in the first weeks of life. We aimed at determining the optimal dosing regimen in neonates and infants weighing 1 to 10.5 kg., Methods: Lopinavir/ritonavir (LPV/r) pharmacokinetics were studied in 96 infants using a population approach. RESULTS A one-compartment model described LPV/r pharmacokinetics. Normalized to a 70 kg adult using allometry, clearance (CL/F) and distribution volume (V/F) estimates were 5.87|h(-1) 70 kg(-1) and 91.7|70 kg(-1). The relative bioavailabilty, F, increased with post-menstrual age (PMA) and reached 50% of the adult value at 39.7 weeks., Conclusions: Size and PMA explained some CL/F and V/F variability in neonates/infants. Based upon trough concentration limitations, suggested LPV/r dosing regimens were 40 mg 12 h(-1), 80 mg 12 h(-1) and 120 mg 12 h(-1) in the 1-2 kg, 2-6 kg and 6-10 kg group, respectively., (© 2011 The Authors. British Journal of Clinical Pharmacology © 2011 The British Pharmacological Society.)

HIV-1 RNA level and darunavir concentration in the genital tract were measured in 45 men receiving darunavir-ritonavir mono- or tritherapy. At week 48, a low frequency (3/45) of HIV-1 RNA shedding was observed in patients (1 on monotherapy and 2 on triple therapy), although they had undetectable HIV-1 RNA in plasma. The median darunavir seminal plasma concentration was close to the blood plasma free fraction, demonstrating a good penetration of darunavir into the male genital tract.

The use of nonnucleoside reverse transcriptase inhibitor (NNRTI) + protease inhibitor regimen for the treatment of antiretroviral-naive patients was less successful than classical nucleoside reverse transcriptase inhibitor (NRTI) based regimen and associated with more resistance for protease inhibitors and NNRTIs. The selection for NNRTI resistance was particularly observed in patients with high viral load (>100 000 copies/ml) and low efavirenz trough levels (<1100 ng/ml). Contrary to the results observed in trials evaluating mono or dual protease inhibitors strategies, gag gene mutations were not involved in the low efficacy of this strategy. The NNRTI + protease inhibitor strategy should not be recommended as an antiretroviral first-line regimen, particularly in patients with high viral load at baseline.

Objectives: The aim of this study was to evaluate the impact on body fat of nucleoside reverse transcriptase inhibitor (NRTI)-sparing regimens compared with NRTI-containing therapy in HIV-1-infected antiretroviral (ARV)-naive patients., Methods: A randomized, multicentre, open-label trial in ARV-naive patients. Subjects were randomized (2:1:1) to receive: (i) an NRTI-sparing regimen consisting of a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus a boosted protease inhibitor (PI/r); or (ii) an NRTI-containing regimen of (a) a PI/r plus two NRTIs or (b) an NNRTI plus two NRTIs. The primary endpoint was the change in subcutaneous limb fat measured by dual-energy X-ray absorptiometry at week (W) 96. Secondary endpoints included the proportion of patients with treatment failure, plasma HIV-RNA (pVL) <50 copies/mL and safety., Results: One hundred and seventeen patients were enrolled between November 2003 and May 2004: 26% female; 42% from sub-Saharan Africa; median plasma HIV-RNA (pVL) 5.1 log(10) copies/mL; median CD4 count 207 cells/mm(3). A planned interim analysis demonstrated significantly lower treatment and virological responses with the NRTI-sparing strategy, resulting in premature study termination on 19 July 2005. The proportion of patients who remained on their assigned treatment strategy and had pVL <50 copies/mL on the NRTI-sparing regimen was 60.0%, compared with 82.5% on the NRTI-containing regimen at W24 (P = 0.009) and 66.7% and 82.5%, respectively, at W48 (P = 0.059). Treatment failure was associated with the NRTI-sparing strategy in patients with suboptimal adherence and with being from sub-Saharan Africa. No differences in fat distribution were noted., Conclusions: An initial NRTI-sparing regimen is less successful and virologically less potent than standard NRTI-containing regimen and should not therefore be used as the first line of treatment.

Objectives: Stavudine (d4T) is a potent but potentially toxic nucleoside reverse transcriptase inhibitor that is still widely used in developing countries. This study's aim was to determine the efficacy and safety profile of lower-dose d4T., Methods: Multi-centre, open-label, single-arm, pilot, 48-week study in French patients weighing >60 kg with viral load <400 HIV-1 RNA copies/mL who were receiving d4T 40 mg twice daily and then switched to 30 mg twice daily. The primary endpoint was the proportion with plasma viral load <400 copies/mL at week 24. Secondary endpoints included the proportion with <50 copies/mL at weeks 24 and 48, changes in mitochondrial DNA, CD4 cell count and pharmacokinetics, and clinical and laboratory safety., Results: Fifty-seven patients enrolled. Baseline CD4 count was 584 cells/microL; viral loads were <400 copies/mL and <50 copies/mL in 100% and 89%, respectively. Prior antiretroviral drug exposure was 6.9 years, d4T exposure was 6.3 years. Fifty-six out of 57 (98%) patients had viral load <400 copies/mL and 51 (89%) had viral load <50 copies/mL at week 24. Median CD4 count increased by 63 cells/microL at week 48 (P=0.006). At 48 weeks, total cholesterol decreased by 0.24 mmol (P=0.02), high-density lipoprotein cholesterol by 0.15 mmol (P=0.0001) and alanine aminotransferase by 5.74 mg/dL (P=0.01). Paired baseline DNA and week 24 RNA mutations were unchanged. Mitochondrial DNA (copies/cell) content increased from 672+/-254 to 682+/-269. d4T area under the plasma concentration time curve (AUC) decreased by 31% (P=0.003) and C(max) by 44% (P=0.004). Clinical and laboratory parameters improved or were unchanged., Conclusions: Reduced-dose d4T is effective with improved safety parameters.

We evaluated the safety and efficacy of a twice daily regimen containing 400 mg of indinavir and 100 mg of ritonavir in 32 human immunodeficiency virus (HIV)-infected women during pregnancy. The median indinavir trough concentration was 208 ng/ml during the third trimester. At delivery, 26 of 28 women on indinavir-ritonavir had HIV RNA levels of <200 copies/ml. No infant was HIV infected. These data are encouraging for the use of this combination for prevention of mother-to-child transmission of HIV.

Early failures to stavudine/lamivudine/nevirapine used as a generic fixed-dose combination in Mali showed resistance mutations in 50% of cases (mostly M184V and Y181C). No thymidine analogue mutations were seen, suggesting that most nucleoside reverse transcriptase inhibitors could be used in a second-line regimen. This highlights the importance of the accessibility of HIV-RNA assays for monitoring treated patients in resource-poor countries to detect early virological failure in order to preserve future therapeutic options.

Drug resistance is an increasing problem in the treatment of HIV infection. Tenofovir has been shown to inhibit HIV replication even with thymidine-associated resistance mutations (TAMs) if they are limited to two or less. Double-dose of tenofovir disoproxil fumarate (TDF) (600 mg QD) was used to determine weather the drug could be virologically effective in patients harbouring HIV-strains resistant to nucleoside analogues (NRTI). A pilot, open, non-comparative add-on study, where patients failing a current antiretroviral regimen, with at least two TAMs, and naive for tenofovir, were given tenofovir 600 mg once-daily for 4 weeks, in addition to their current failing antiretroviral regimen. The primary end-point was the percentage of patients with plasma viral load (VL) reduction of at least 0.8 log(10) between baseline and week 4 (W4). Ten patients were enrolled. At baseline, the median viral load was 3.66 log(10) copies/ml (range 3.13-4.03) and the median CD4 cell count was 407/mm(3) (range 136-1102). The percentage of patients with reduction the viral load > or =0.8 log(10) was 40% at W4. After 4 weeks of treatment with tenofovir 600 mg, the median decrease in the viral load was -0.61 log(10) (range -0.05; -0.88) and the median gain of CD4 was +109/mm(3). Despite a twofold increase tenofovir plasma concentrations, no serious drug-related adverse event were recorded except for one patient experiencing an de Fanconi syndrome at week 2. This add-on pilot study supports the concept of double dose tenofovir to virologically overcome the decreased sensitivity of NRTI-resistant viruses. However, the safety of this regimen needs to be considered carefully.

Objective: Stavudine (d4T), a nucleoside reverse-transcriptase inhibitor (NRTI), can induce lipoatrophy, fatty liver, hyperlactataemia and abnormal liver tests. NRTI toxicity is usually ascribed to mitochondrial DNA (mtDNA) depletion and impaired mitochondrial respiration. However, NRTIs could have effects unrelated to mtDNA. Recently, we reported that 100 mg/kg/day of d4T stimulated fatty acid oxidation (FAO) in mouse liver, and reduced body fatness without depleting white adipose tissue (WAT) mtDNA. We hypothesized that higher d4T doses could further reduce adiposity, while inhibiting hepatic FAO., Methods: Mice were treated for 2 weeks with d4T (500 mg/kg/day), L-carnitine (200 mg/kg/day) or both drugs concomitantly. Body fatness was assessed by dual energy X-ray absorptiometry, and investigations were performed in plasma, liver, muscle and WAT., Results: D4T reduced the gain of body adiposity, WAT leptin, whole body FAO and plasma ketone bodies, and increased liver triglycerides and plasma aminotransferases with mild ultrastructural abnormalities in hepatocytes. Plasma lactate and respiratory chain activities in tissues were unchanged. Stearoyl-CoA desaturase (SCD-1), an enzyme negatively regulated by leptin, was overexpressed in liver. High doses of beta-aminoisobutyric acid (BAIBA), a d4T catabolite, increased plasma ketone bodies. Although L-carnitine did not correct body adiposity, it prevented d4T-induced impairment of FAO and liver abnormalities., Conclusions: D4T overdosage triggers fat wasting, leptin insufficiency and mild liver damage, without causing respiratory chain dysfunction. Overexpression of SCD-1 reduces fatty acid oxidation and overcomes the stimulating effect of BAIBA on hepatic FAO. L-carnitine does not correct leptin insufficiency but prevents d4T-induced impairment of FAO and liver damage.

The impact of proviral DNA reverse transcriptase mutations on virological failure was evaluated in 50 HIV-1 HAART-treated patients switching from a protease inhibitor to a non-nucleoside reverse transcriptase inhibitor. Neither the M184I/V mutation detected in 12 patients nor stop codons at tryptophane positions detected in 13 patients were associated with virological failure. Stop codons appeared under successful therapy in 12 patients. Their presence should be assessed in studies with higher statistical power.

The frequency of resistance mutations was estimated in the cohort of Agence Nationale de Recherches sur le SIDA Ditrame Plus, a study that evaluated the combination of short-course zidovudine (ZDV) plus lamivudine (3TC) and single-dose nevirapine (SD-NVP) followed by 3 days of postpartum ZDV plus 3TC for the prevention of mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1). The frequency with which resistance mutations were detected in mothers at week 4 postpartum was 1.14% (95% confidence interval [CI], 0.03%-6.17%) for NVP and 8.33% (95% CI, 3.66%-15.76%) for 3TC. In multivariate analysis, 3TC resistance was associated with a longer duration of ZDV plus 3TC prepartum prophylaxis (P=.009). This regimen, which is feasible in resource-limited settings, prevents most peripartum HIV-1 transmission and minimizes the development of NVP resistance.

Both highly potent antiretroviral drug rescue multi therapy and treatment interruption (TI) have been suggested to be effective in HIV-1 infected-patients with multiple treatment failure. GigHAART-ANRS 097 was the only randomized trial during which an 8-week TI was beneficial in heavily pre-treated patients with multi-drug resistant virus on resuming a multiple-drug salvage regimen. The aim of this study was to analyze virological and pharmacological factors associated with a virological response. Clonal resistance analysis showed that although the viral population was highly mutated and nearly monoclonal at baseline, the 8-week interruption therapy allowed the re-emergence of more susceptible quasispecies to the subsequent salvage therapy, which were not detected by classical genotypic resistance testing. The fact that not every viral clone harbored all resistance viral mutations could explain a part of the virological response to a six to eight drug regimen for patients enrolled in the TI group. This phenomenon was associated with a transient virological response after the use of a GigHAART therapy, but was followed by the re-emergence of baseline resistance pattern and acquisition of additional mutations in patients failing this strategy. A combined factor of protease inhibitor (PI) concentration and genotypic score, expressed as a genotypic inhibitory quotient (GIQ), was used to assess the importance of genotypic resistance and plasma drug levels in the rate of response to multiple PI combination. The GIQ of each PI used in the regimen was not associated with virological success. However, the sum of PI GIQs was predictive of a virological response. These results suggest that pharmacological enhancement might overcome viral resistance and that there is some benefit in adding the activity of several boosted-PIs to improve the response to a salvage regimen., ((c) 2005 Wiley-Liss, inc.)

Background: To assess the efficacy and safety of the triple NRTI combination of abacavir (ABC), lamivudine (3TC), and tenofovir (TDF) in a once-daily regimen., Method: 38 HIV-naive patients (pts) were treated in a prospective open-arm study over 48 weeks (W48). Virological failure was defined as never achieving plasma HIV-1 RNA < 400 copies/mL or rebound of > or = 0.7 log10., Results: 12/36 (33%) pts had virologic failure at W24 and 10 additional pts had HIV RNA > 50 copies/mL at W12 or W24. There was a significant association between baseline viral load (VL) and virologic failure in 0%, 29%, and 64% pts with baseline VL levels < 4, 4-5, and > 5 log10 copies/mL, respectively (p = .014). 76% of pts developed K65R and M184V/I mutations by W24, and 19% developed M184V/I alone. At W4, 86% of pts had adequate plasma Cmin for the 3 drugs. 14 pts with K65R and M184V/I were given a rescue therapy with a successful outcome (< 50 copies/mL; median follow-up 48 weeks)., Conclusion: Convergent genetic pathway to resistance, in conjunction with lower antiretroviral potency, may explain the high rate of selection K65R and M184V mutations. These mutations did not appear to have a negative effect on rescue therapy with a variety of regimens.

Tonus was a pilot study in which previously untreated human immunodeficiency virus type 1 (HIV-1)-infected patients received the combination of abacavir, lamivudine, and tenofovir once a day. There was a high rate of early virological failure, and the M184V and K65R mutations were frequently detected at week 12 (W12). The objective of this study was to examine the selection dynamics of the K65R and M184V/I mutations. Bulk sequencing of the reverse transcriptase (RT) gene was performed on plasma HIV-1 RNA at baseline, W4, and W12 for 21 patients with detectable viral loads. The RT genes from baseline, W4, and W12 plasma samples from five patients who developed both M184V and K65R but with different mutational patterns were also cloned and screened for the K65R mutation by selective real-time PCR. At baseline, bulk sequencing and clonal analysis showed only wild-type RT sequences. At W4, M184V/I was detected in 12/19 patients and K65K/R in 2 patients by bulk sequencing. At W12, M184V/I was found in 18/20 patient, together with the K65R in 13 patients. At W4, clonal analysis revealed the K65R mutation in 0.6 to 48% of clones in the five patients studied. At W12, the K65R mutation was found in 30 to 100% of clones. K65R and M184V/I seemed to arise in separate clones, followed by an enrichment of viruses containing both mutations. The clinical relevance of this independent evolution is unclear. M184V/I was selected more frequently than K65R at W4. However, K65R was also detected early using a clone-sensitive genotyping method. All three nucleoside analogs are known to select the K65R and/or M184V/I mutation. This convergent genetic pathway to resistance, associated with lower antiretroviral potency, may explain the high selection rate of these mutations in this trial.

Background: It has been demonstrated that, in patients treated by protease-inhibitor-based regimen, intermittent viraemia occurred frequently and was associated with higher concentrations of residual replication but not with virological failure. Risk factors associated with intermittent viraemia and its impact in patients treated by non-nucleoside-reverse-transcriptase-inhibitor-based (NNRTI) regimen need to be evaluated., Methods: We analyzed the occurrence of blips (one HIV-1 RNA > 50 copies/ml with a subsequent value < 50 copies/ml), the level of these blips (between 3 and 50 copies/ml) and their effect on CD4 cell count and the occurrence of virological failure in 43 patients with stable suppression of HIV-1 plasma viraemia (< 50 copies/ml) under NNRTI-based therapy., Results: Eight out of 43 patients had one episode of blips during the follow-up (median = 350 copies/ml). Comparing patients with and without blips, the median level of HIV-1 RNA at baseline was 7.5 versus 3 copies/ml (P = 0.008), respectively. Patients with blips had a significantly lower CD4 cell count after 12 and 18 months than the others. Plasma concentrations of NNRTI before, during, and after the blips were adequate. In addition, the occurrence of blips was not associated with virological failure., Conclusion: These results suggest that blips may reflect ongoing viraemia of below 50 copies/ml and can impair the CD4 cell count recovery under an NNRTI regimen. The impairment of CD4 cell count recovery seems to be affected more by the occurrence of blips than by the level of viraemia (< 50 copies/ml) itself. Nevertheless, despite a tight genetic barrier for resistance with NNRTI drugs, no virologic failure occurred during the follow-up.

Background: In HIV-infected patients on first-line antiretroviral therapy, the significance of intermittent viremia and their relationship with drug resistance remain unclear., Objective: To study the virological characteristics of intermittent viremia (IV) and the association between IV and later virological failure (VF) in patients on a first-line, PI-containing therapy., Study Design: Antiretroviral-naive patients were enrolled in the APROVIR substudy of the prospective, multicenter APROCO cohort at the time they initiated a PI-containing therapy and were followed-up at month 1 and every 2 months. IV was defined as plasma HIV-1 RNA > 500 copies/ml on a single specimen. VF were defined as: (1) viral rebound on two consecutive plasma specimens with HIV-1 RNA > 500 copies/ml after an initial response below 500 copies/ml, or (2) persistence of plasma HIV-1 RNA> or =500 copies/ml during the first year of follow-up. Genotypic resistance analysis was performed at baseline and at the time of IV. PI plasma concentrations were determined at the time of IV., Results: IV was found in 20/219 patients in a 2 years follow-up. The occurrence of IV in the first year of therapy was associated with a higher risk of virological failure during the second year (p = 0.03). Genotypic resistance at the time of IV was found in only 4/16 patients and was not predictive of a subsequent virological failure. PI plasma levels suggested lack of adherence in 50% of patients with IV., Conclusion: The occurrence of IV > 500 copies/ml among patients on first-line, PI-containing ART is suggestive of a lack of adherence rather than the selection of resistant variants and should lead to an intensification of adherence monitoring in order to reduce the risk of subsequent VF.

In HIV-2 infection, many studies have reported a high frequency of selection of the Q151M mutation, but its impact on phenotypic susceptibility of HIV-2 isolates remains unclear. Four HIV-2 infected patients from the French ANRS HIV-2 cohort, with evidence of Q151M mutation in both plasma and available peripheral blood mononuclear cells (PBMCs) co-cultivated supernatants, were selected. In vitro phenotypic susceptibilities to different nucleoside reverse transcriptase inhibitors (NRTIs) were determined using a PBMC assay. In HIV-2 isolates, the Q151M mutation alone impacts only the phenotypic susceptibility to stavudine and abacavir. A decrease in susceptibility to all NRTIs was observed when Q151M was selected with V111I, a mutation of unknown impact on HIV-1 resistance. Clinical relevance of these phenotypic susceptibility results needs to be evaluated in HIV-2 treated patients.

The consensus of current international guidelines for the treatment of HIV infection is that data on therapeutic drug monitoring (TDM) of non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (Pls) provide a framework for the implementation of TDM in certain defined scenarios in clinical practice. However, the utility of TDM is considered to be on an individual basis until more data are obtained from large clinical trials showing the benefit of TDM. In April 2004, a panel of experts met for the second time in Rome, Italy. This was following the inaugural meeting in Perugia, Italy, in October 2000, which resulted in the manuscript published in AIDS 2002, 16(Suppl 1):S5-S37. The objectives of this second meeting were to review and update the numerous questions surrounding TDM of antiretroviral drugs and discuss the clinical utility, current concerns and future prospects of drug concentration monitoring in the care of HIV-1-infected individuals. A major focus of the meeting was to discuss and critically analyse recent and precedent clinical drug-drug interaction data to provide a clear framework of the pharmacological basis of how one drug may impact the disposition of another. This report, which has been updated to include material published or presented at international conferences up to the end of December 2004, reviews recent pivotal pharmacokinetic interaction data and provides advice to clinical care providers on how some drug-drug interactions may be prevented, avoided or managed, and, when data are available, on what dose adjustments and interventions should be performed.

Background: Clinical trials have shown that therapeutic drug monitoring (TDM) of antiretrovirals (ARV) improves patient care. However, little is known about the usefulness of TDM in routine practice., Method: We reviewed all the trough concentrations of protease inhibitors and nonnucleoside reverse transcriptase inhibitors that were performed for therapeutic failure, suspected drug toxicity, or routine purposes., Results: Between 1998 and 2001, 146 TDMs were done in 109 HIV patients. Of the 48 patients with therapeutic failure, 62% had resistance to ARV with adequate ARV concentrations, 16% had insufficient drug exposure without any ARV resistance mutations, and 16% combined both resistance and suboptimal drug concentrations. Subsequent therapeutic interventions (increasing adherence and/or changing HAART) resulted in an undetectable viral load in 37.5% of the patients (14/48). Five (24%) of 21 patients with suspected drug toxicity had high drug concentrations associated with side effects. In all the cases, adverse events regressed after reduction of drug dosage. Of the 77 TDMs done for routine purposes, 26% were outside the therapeutic range., Conclusion: The data show that TDM of ARVs in the clinical setting provides important information that can be used to improve the management of HIV patients receiving antiretroviral therapy.

Objective: To assess the genotypic determinants of the virological response to tenofovir disoproxil fumarate (TDF) in a multicentre cohort of antiretroviral (ARV)-experienced patients receiving TDF as a part of a salvage therapy., Methods: HIV-1 genotype was assessed at baseline in a subgroup of 161 patients of the French expanded access program receiving a stable TDF-including regimen for 3 months or more. Reverse transcriptase mutations associated with the viral load decrease at month 3 with a P-value <0.15 were retained for the construction of a mutation score. The score was then validated using a multivariate analysis and bootstrap resampling method., Results: The strongest association with decrease in viral load was observed with a set of seven mutations (TDF mutation score) that consisted of M41L, E44D, D67N, T69D/N/S, L74V, L210W and T215Y/F RT mutations. The RT K65R mutation and the insertions at codon 69 were not included in the analysis due to low prevalences. A TDF mutation score of < or = 2 predicted the absence of resistance to TDF and > or = 6 mutations predicted resistance to TDF with corresponding reductions in viral load of -1.3 +/- 1.1, and +0.1 +/- 0.7 log10 copies/ml, respectively. In patients with a TDF mutation score of 3-5, the decrease in viral load was -0.8 +/- 1.0 log10 copies/ml and was considered possibly resistant. In the multivariate analysis, a TDF mutation score > or = 6, previous use of amprenavir, indinavir and lopinavir, and co-prescription of didanosine were associated with a worse virological response. The bootstrap analysis showed the robustness of the TDF mutation score., Conclusion: In ARV-experienced patients receiving TDF-containing regimens, a score derived from seven reverse transcriptase mutations was shown to be independently predictive of the virological response.

We studied the evolution of nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations among 29 human immunodeficiency virus type 1 (HIV-1)-infected patients who experienced virologic failure when receiving an NNRTI-containing regimen (nevirapine, delavirdine, or efavirenz) and subsequently switched to antiretroviral therapy without NNRTIs. Genotypic resistance was determined from plasma samples collected at the time of NNRTI withdrawal (baseline) and during follow-up. At baseline, 83% of patients had more than two thymidine analog resistance mutations (TAMs), and all had NNRTI resistance mutations. Mutations at codons 103, 181, and 190 were found in 62, 62, and 34% of the patients, respectively. Follow-up samples were available after a median time of 6 months in all patients and at 12 months in 22 patients. The mean number of resistance mutations to NNRTIs was significantly lower at months 6 (1.34 +/- 1.04) and 12 (1.18 +/- 1.05) than at month 0 (2.03 +/- 1.02) (P < 0.009). The percentages of patients with at least one NNRTI resistance mutation were 100, 76, and 73% at baseline, month 6, and month 12, respectively (P < 0.0044). Overall, 70% of the patients had a mutation at codon 103 or 181 at month 12. The mean number of TAMs did not vary significantly during follow-up. Our data show that, in the context of maintained antiretroviral therapy, NNRTI resistance mutations persist in two-thirds of the patients in spite of NNRTI withdrawal. These results argue for the low impact of NNRTI resistance mutations on viral fitness and suggest that resistance mutations to different classes of drugs are associated on the same genome, at least in some of the resistant strains.

Tenofovir disopril fumarate, a new nucleotide analogue against human immunodeficiency virus-1 (HIV-1), can induce hypophosphataemia, the mechanism of which is unclear. Moreover, a renal tubulopathy can occur in long-term treated patients, as observed in 2 HIV-1-infected patients after 12 months of tenofovir therapy, with polyuria-polydipsia, proteinuria, glycosuria and amino-aciduria, which resolved after discontinuation of tenofovir. The risk of renal tubulopathy symptoms in patients on long-term tenofovir therapy should be noted.

Although treatments with nucleoside reverse transcriptase inhibitors (NRTIs) can modify fat metabolism and fat distribution in humans, the mechanisms of these modifications and the roles of diverse NRTIs are unknown. We studied the mitochondrial and metabolic effects of stavudine (d4T), zidovudine (AZT), didanosine (ddI), lamivudine (3TC), zalcitabine (ddC), and three combinations (AZT-3TC, d4T-3TC, and d4T-ddI) in mice treated for 2 weeks with daily doses equivalent to the human dose per body area. Concentrations of AZT and d4T in plasma were lower when these drugs were administered with 3TC or ddI. Whatever the treatment, mitochondrial DNA was not significantly decreased in muscle, heart, brain, or white adipose tissue but was moderately decreased in liver tissue after the administration of AZT, 3TC, or d4T alone. Blood lactate was unchanged, even when NRTIs were administered at supratherapeutic doses. In contrast, the level of plasma ketone bodies increased with the administration of AZT or high doses of d4T but not with ddC, 3TC, or ddI, suggesting that the thymine moiety could be involved. Indeed, the levels of plasma ketone bodies increased in mice treated with beta-aminoisobutyric acid, a thymine catabolite. Treatment with AZT, d4T, or beta-aminoisobutyric acid increased hepatic carnitine palmitoyltransferase I (CPT-I) mRNA expression and the mitochondrial generation of ketone bodies from palmitate. In conclusion, therapeutic doses of NRTIs have no or moderate effects on mitochondrial DNA and no effects on plasma lactate in mice. However, AZT and high doses of d4T increase the levels of hepatic CPT-I, mitochondrial fatty acid beta-oxidation, and ketone bodies, and these catabolic effects are reproduced by beta-aminoisobutyric acid, a thymine metabolite.

Objective: To identify predictors of the virological response to antiretroviral therapy in patients in whom initial therapy has failed., Methods: The Narval trial was designed to compare phenotyping, genotyping and standard of care for the choice of antiretroviral therapy in patients in whom a protease inhibitor (PI)-containing regimen had failed. Virological success was defined as viral load below 200 copies/ml at week 12. Baseline variables including demographic, clinical and biological characteristics, HIV reverse transcriptase and protease mutations, the randomization arm, the drugs prescribed, as well as adherence to treatment and plasma concentrations of PIs and non-nucleoside reverse transcriptase inhibitors (NNRTIs) at week 12 were tested in the model. Variables that were significantly associated with virological success in univariate analysis were included in a logistic regression model., Results: Five-hundred-and-forty-one patients were randomized. Virological success at week 12 was obtained in 200 patients. In multivariate analysis, the following factors were significantly associated with virological success: prescription of efavirenz to NNRTI-naive patients (OR=4.37; 95% CI: 2.76-6.90), randomization to the genotyping arm (OR=2.13, 1.20-3.79), prescription of lamivudine (OR=1.69, 1.01-2.83) and prescription of abacavir to abacavir-naive patients (OR=1.66, 1.02-2.72). Factors significantly associated with virological failure were prescription of nelfinavir (OR=0.30, 0.13-0.68), a high baseline viral load (OR=0.37, 0.28-0.50), the presence of at least five PI mutations (OR=0.42, 0.26-0.66), the presence of at least three thymidine analogue mutations (OR=0.61, 0.39-0.97) and at least 30 months of prior PI exposure (OR=0.64, 0.41-0.99)., Conclusions: These results confirm that among heavily pretreated patients, prescription of efavirenz to NNRTI-naive patients is associated with a good virological response, while a high baseline viral load, a large number of PI mutations and nelfinavir prescription at baseline are associated with a poor virological response. Genotyping was found to be beneficial, while this was not the case for phenotyping. This work was presented at the XI International HIV Drug Resistance Workshop, Sevilla, Spain, July 3-6 2002 (Abstract N(o)133); and at the XIV International Conference on AIDS, Barcelona, Spain, July 7-11 2002 (Abstract N(o)ThOrB138).

Objective: To develop a stepwise methodology for the development and validation of clinically relevant genotypic score for resistance to antiretroviral drugs and to apply this approach to the genotypic resistance to abacavir., Methods: All patients having received abacavir during the Narval trial were included in this study. The impact of each nucleoside analogue resistance mutation on the virologic response to abacavir was studied in a univariate analysis. Mutations with a P value < 0.20 and those selected by abacavir were retained. According to the number of mutations three levels of resistance were defined. A multivariate analysis accounting for confonding variables assessed whether the genotypic score was an independent predictor of the response. The robustness of the score was analysed using the bootstrap resampling method., Results: In the 175 patients exposed to abacavir, the strongest association between the decrease in viral load and the number of mutations was observed with a set of six mutations at codons 41, 67, 210, 215, 74 and 184 of the reverse transcriptase gene. In patients with fewer than four mutations (no evidence of resistance) the median decrease in viral load was -1.64 log(10) copies/ml while it was -0.69 log(10) and -0.19 log(10) in those with four (possible resistance) and five or six (resistance) mutations respectively. In the multivariate analysis this score was an independent predictor of the response. The bootstrap analysis showed the robustness of the score., Conclusions: We developed a new strategy for the analysis of correlation between genotype profile at baseline and virologic response.

A 2-month interruption of only nonnucleoside reverse transcriptase inhibitors (NNRTIs) for patients carrying mutations associated with resistance to NNRTIs was followed by no change in either viral load or CD4 cell counts. These data suggest that these compounds have lost all of their in vivo antiviral activity in such cases.

Adefovir dipivoxil (ADV) at a suboptimal concentration for human immunodeficiency virus type 1 (HIV-1) (10 mg once daily) can be used to treat hepatitis B virus (HBV) infection in HIV-1-HBV-coinfected patients and does not, even in the case of uncontrolled HIV-1 replication, select for either ADV mutations at codons 65 and 70 or any other particular HIV-1 reverse transcriptase resistance profile.

Objective: To assess the respective value of phenotype versus genotype versus standard of care for choosing antiretroviral therapy in patients failing protease inhibitor-containing regimens., Methods: Patients with plasma HIV-1 RNA exceeding 1000 copies/ml were randomly allocated to phenotyping, genotyping, or standard of care., Results: Five-hundred and forty-one patients were randomized, 190 to phenotyping, 192 to genotyping and 159 to standard of care. The baseline median CD4 cell count (280 x 106 cells/l), the plasma HIV-1 RNA level (4.3 log10 copies/ml), and the number of drugs previously received (n = 6) were similar in the three arms. More patients in the standard-of-care arm received at least three new drugs (55% versus 20% in the other arms; P < 0.001) and a regimen containing drugs from the three different classes. Plasma HIV-1 RNA was < 200 copies/ml at week 12 in 35% of patients in the phenotyping arm, 44% in the genotyping arm and 36% in the standard-of-care arm (phenotyping versus standard of care, P = 0.918; genotyping versus standard of care, P = 0.120). In a secondary analysis of 179 patients experiencing a first protease inhibitor failure, the percentage of patients achieving HIV-1 RNA < 200 copies/ml was significantly higher in the genotyping arm (65%) than in the phenotyping (45%) and the standard-of-care arms (45%) (genotyping versus standard of care, P = 0.022)., Conclusions: Overall, resistance assays did not demonstrate benefit over standard of care. In patients with the most limited protease inhibitor experience, a significant benefit was observed in the genotyping arm.

Background: First results of Trilège demonstrated that the strategy of less intensive antiviral therapy is less effective than continuation of triple-drug therapy., Objective: To compare the final number of failures at month 18 and to study viral dynamics in patients experiencing a virological failure., Design: Longitudinal follow-up from a randomized controlled trial., Setting: Forty-three AIDS clinical-trial units., Patients: A total of 279 HIV-1 infected adults randomized in Trilège., Measurements: Analysis of recurrent values of HIV RNA > 500 copies/ml beyond time to virologic failure., Results: A total of 83 patients experienced virological failure by month 18; 10 in the zidovudine (ZDV) + lamivudine (3TC) + indinavir (IDV) arm, 46 in the ZDV + 3TC arm, and 27 in the ZDV + IDV arm, confirming previous results. Whatever the treatment ultimately received, 87% of patients had an HIV RNA < 500 copies/ml at month 18 with no statistical difference between randomized arms. Patients experiencing a failure in the triple-drug regimen had a greater tendency to maintain HIV RNA > 500 copies/ml beyond the time of virological failure than patients in both less intensive treatment groups who experienced failure. Lower levels of HIV RNA at failure and reinitiating of either the original triple-drug regimen or a new combination of nucleoside analogue reverse transcriptase inhibitors and protease inhibitors were associated with lower hazard ratios for developing recurrent HIV RNA > 500 copies/ml., Conclusion: Results confirmed the failure of a less intensive regimen to maintain patients with a viral suppression (HIV RNA < 500 copies/ml). Although there is a lower incidence of failure in the triple-drug regimen, randomization to a less intensive regimen of ZDV + 3TC or ZDV + IDV was not detrimental, as treatment modification, either to the original triple regimen, or a different regimen was successful.

Purpose: Adherence to antiretroviral medications is critically important for the success of therapy in patients treated for HIV infection. Patient self-report is a simple method to measure and explore adherence. Even though a variety of surveys have been developed to monitor self-reported adherence, there is no standardized instrument that may be used in routine clinical practice. The usefulness of the Patient Medication Adherence Questionnaire (PMAQ) was evaluated in HIV-infected patients on protease inhibitor (PI)-containing regimens., Method: Data from 149 patients were collected. Study participants completed the PMAQ and provided blood samples to measure plasma HIV-1 RNA concentrations and trough plasma levels of PI. Patients were considered adherent if they had a virologic response and/or had an adequate trough plasma level of PI., Results: A close relationship was found between patient reports of adherence during the previous 4 days and objective measures such as HIV RNA level and plasma levels of PI. Motivation with regard to antiretroviral treatment, confidence in personal skills, and an optimistic attitude to life were identified as important determinants of adherence. On the other hand, sociodemographic background, social support, alcohol and illicit drug use, bothersome symptoms, and depression were not associated with a lower medication adherence., Conclusion: Patients' psychological and behavioral factors are central in the acceptance and adherence to antiretroviral therapy. To improve the feasibility and the reproducibility of the PMAQ, we propose a revised form of the PMAQ, focusing on the variables identified as strong predictors of adherence.

Background: In Africa a high percentage of HIV-infected children continue to experience HIV treatment failure despite enormous progress. In Benin (West Africa), there are currently no data on HIV drug resistance at failure in paediatric populations.Objectives: To assess the frequency and patterns of HIV drug resistance among children with virological ART failures.Methods: Dried blood spots from 62 HIV-infected children with virological failure were collected at the paediatric clinic of the National Hospital Center in Cotonou for genotyping and plasma drug concentration determination.Results: Characteristics of the population show a median age of 10 years (IQR 6-13) and a median duration on ART of 5 years (IQR 3-7). Viruses from 53 children were successfully amplified. Of these, 76% of patients were on an NNRTI-based regimen and 24% on a boosted PI-based regimen. NRTI, NNRTI and dual-class resistance was present in 71%, 84% and 65% of cases, respectively. Only 4% of the children had major resistance mutations to PIs and none had major resistance mutations to integrase inhibitors. Among the participants, 25% had undetectable antiretroviral concentrations.Conclusions: Our results showed that the development of drug resistance could be one of the main consequences of high and continuous viral replication in HIV-infected children in Benin. Thus, inadequate attention to monitoring lifelong ART in children may prevent achievement of the goal of the United Nations Program on HIV and AIDS (UNAIDS) of 90% viral suppression among patients receiving ART. [ABSTRACT FROM AUTHOR]