Antiretroviral Plasma Concentrations Research Articles

Plasma concentrations of antiretroviral drugs in a successful 4-days-a-week maintenance treatment strategy in HIV-1 patients (ANRS 170-Quatuor trial).

Charaterization of the plasma concentrations of antiretrovirals in a 4-days-a-week maintenance treatment strategy in the ANRS-170-QUATUOR study. Patients were randomized in two groups receiving triple therapy taken 4-days-ON and 3-days-OFF (4/7) or continuous therapy (7/7). Plasma antiretroviral concentrations were monitored during the 'ON-treatment period' (Day 3 or 4 of the 4-day treatment block) and the 'OFF-treatment period' (Day 3 of the 3-day drug cessation) for the 4/7 group, or before the daily drug intake for the 7/7 group, until week-48 (W48). After W48, all patients switched to the 4/7 strategy and were followed until W96. W0 measured concentrations were comparable in both groups, except for raltegravir, concentrations of which were higher in the 4/7 group, and were all above the values usually recommended to be effective in therapeutic drug monitoring. Comparison of ON-period median concentrations between the two groups showed a statistical difference for rilpivirine [88 ng/mL (interquartile range (IQR) = 64-112) for 4/7 arm versus 130 ng/mL (82-160) for 7/7 arm, P < 0.001] and tenofovir [tenofovir disoproxil fumarate: 93 ng/mL (73-135) for 4/7 arm versus 117 ng/mL (83-160) for 7/7 arm, P < 0.001; tenofovir alafenamide: 11 ng/mL (7-15) for 4/7 arm versus 14 ng/mL (11-18) for 7/7 arm, P = 0.001]. Median OFF concentrations were significantly lower (P < 0.001) at the 48 week analysis for all medications except for raltegravir (P = 0.493) and atazanavir (P = 0.105), for which the numbers of patients were very small. The 4/7-day treatment option led to antiretroviral blood levels close to continuous treatment after the four consecutive days of medication, and to low levels at the end of the non-treatment period.

A validated method for simultaneous quantification of four antiretrovirals in dried blood spot and plasma using LC-MS/MS: Application to efavirenz therapeutic drug monitoring in pregnant patients

IntroductionThe specific physiological background induced by pregnancy leads to significant changes in maternal pharmacokinetics, suggesting potential variability in plasma concentrations of antiretrovirals. Pregnant HIV patients exposed to subtherapeutic doses, particularly in the last trimester of the pregnancy, have higher chances to transmit the infection to their children. Therefore, the therapeutic drug monitoring of antiretrovirals in HIV pregnant patients would be of great value. ObjectivesThis study aimed to develop and validate a sensitive liquid chromatograph tandem mass spectrometry (LC-MS/MS) method for simultaneous quantification of efavirenz, raltegravir, atazanavir, and ritonavir in dried blood spots (DBS) and plasma. Design and MethodsThe analytes were extracted from the DBS punch and plasma with a mixture of methanol:zinc sulfate 200 mM (50:50, v/v) and 100 % methanol, respectively. For the chromatographic separation a Shim-pack® C18, 4.6 mm × 150 mm, 5 μm column was used. Detection was performed in a 3200-QTRAP® mass spectrometer, with a run time of 6 min. ResultsThe assay was linear in the range of 15–1,000 ng/mL for raltegravir, 50–10,000 ng/mL for both atazanavir and ritonavir, 50–5,000 ng/mL for efavirenz. Precision and accuracy at these concentrations were less than 15 % for all analytes. Raltegravir, atazanavir, and ritonavir were stable for seven days at 23 °C and 40 °C, whereas efavirenz was stable for twenty-four hours at the same conditions. ConclusionsThe method was successfully applied to quantify efavirenz in DBS samples obtained from HIV-1 infected pregnant volunteers under antiretroviral therapy. The concentrations of efavirenz in DBS and plasma were comparable according to Passing-Bablok regression and Bland-Altman analysis.

Outcomes of Bariatric Surgery in People With Human Immunodeficiency Virus: A Retrospective Analysis From the ATHENA Cohort.

The implications of bariatric surgery (BS) on virologic and metabolic outcomes in people with human immunodeficiency virus (HIV; PWH) on antiretroviral therapy (ART) are unknown. Here, we report a retrospective analysis up to 18 months post-BS in PWH from the AIDS Therapy evaluation in The Netherlands (ATHENA) cohort with data from all dutch HIV treating Centers. Primary end points were a confirmed virologic failure (2 consecutive HIV-RNA measurements >200 copies/mL) and the percentage of patients who achieved >20% total body weight loss up to 18 months post-BS. Switches from baseline ART and trough plasma concentrations of antiretrovirals were also reported post-BS. Metabolic parameters and medication usage were compared pre- and post-BS. Fifty-one patients were included. One case of confirmed virologic failure and 3 cases with viral blips were detected in this cohort up to 18 months post-BS. Eighty-five percent of patients achieved >20% total body weight loss at 18 months post-BS, with a mean difference from baseline (95% confidence interval) of -33.5% (-37.7% to -29.3%). Trough plasma concentrations of measured antiretroviral agents were all above minimum effective concentrations, except for 1 sample of darunavir. Lipid profiles, but not serum creatinine and blood pressure, improved significantly (P < .01) post-BS. Total medications and obesity-related comedications declined from 203 to 103 and from 62 to 25, respectively, at 18 months post-BS. BS was an effective intervention for weight loss and lipid control in PWH using ART in this cohort with no clear link to poor virologic outcomes.

Drug-Drug Interactions in People Living With HIV at Risk of Hepatic and Renal Impairment: Current Status and Future Perspectives.

Despite the advancement of antiretroviral therapy (ART) for the treatment of human immunodeficiency virus (HIV), drug–drug interactions (DDIs) remain a relevant clinical issue for people living with HIV receiving ART. Antiretroviral (ARV) drugs can be victims and perpetrators of DDIs, and a detailed investigation during drug discovery and development is required to determine whether dose adjustments are necessary or coadministrations are contraindicated. Maintaining therapeutic ARV plasma concentrations is essential for successful ART, and changes resulting from potential DDIs could lead to toxicity, treatment failure, or the emergence of ARV‐resistant HIV. The challenges surrounding DDI management are complex in special populations of people living with HIV, and often lack evidence‐based guidance as a result of their underrepresentation in clinical investigations. Specifically, the prevalence of hepatic and renal impairment in people living with HIV are between five and 10 times greater than in people who are HIV‐negative, with each condition constituting approximately 15% of non‐AIDS‐related mortality. Therapeutic strategies tend to revolve around the treatment of risk factors that lead to hepatic and renal impairment, such as hepatitis C, hepatitis B, hypertension, hyperlipidemia, and diabetes. These strategies result in a diverse range of potential DDIs with ART. The purpose of this review was 2‐fold. First, to summarize current pharmacokinetic DDIs and their mechanisms between ARVs and co‐medications used for the prevention and treatment of hepatic and renal impairment in people living with HIV. Second, to identify existing knowledge gaps surrounding DDIs related to these special populations and suggest areas and techniques to focus upon in future research efforts.

Persistent low-level viraemia in antiretroviral treatment-experienced patients is not linked to viral resistance or inadequate drug concentrations.

To assess genotypic sensitivity scores (GSSs), plasma antiretroviral concentrations (PACs) and immunovirological outcomes at Week 96 (W96) in patients with persistent low-level viraemia (LLV). On 1 January 2017, we analysed data from patients on three-drug regimens with persistent LLV defined as at least two consecutive plasma viral loads (pVLs) between 21 and 200 copies/mL (including one pVL of ≥50 copies/mL), at the Pitié-Salpêtrière Hospital. Outcomes were: GSS, PACs and HIV-DNA load at study entry; and virological status and proportion of patients with resistance-associated mutations (RAMs) at W96. Fifty-seven patients were included, with median age of 52.6 years (IQR 45.2-57.9), last CD4 count of 658 cells/mm3 (IQR 462-909) and total ART duration of 10.2 years (IQR 5.7-15.2). LLV duration was 14.0 months (IQR 5.5-22.3). GSS was 3 in 46/57 (81%) patients and PACs were adequate in 53/57 (93%) patients. Median total HIV-DNA was 2.65 log10 copies/106 cells (IQR 2.44-2.86). During follow-up, 26/57 (46%) had experienced ART modifications. At W96, 38/57 (67%) patients remained with LLV, 15/60 (26%) had achieved confirmed pVL of <20 copies/mL and 4/57 (7%) had virological failure. The four virological failures were due to three ART interruptions and one incomplete adherence (selection of Y181C RAM). No factors (patient characteristics at study entry, GSS, PACs, total HIV-DNA load and ART modification) were associated with W96 viral outcome, except for time from HIV diagnosis and the LLV duration at study entry. A substantial number of patients harbouring LLV had no resistance to ART and adequate PACs. Two-thirds of these patients remained with this LLV status.

Ritonavir and cobicistat as pharmacokinetic enhancers in pregnant women

Ritonavir and cobicistat are commonly used as pharmacokinetic enhancers to boost plasma concentrations of antiretrovirals used to treat HIV infection, including the protease inhibitors atazanavir, ...

The relationship between zidovudine, lamivudine and nevirapine plasma drug levels and antiretroviral treatment outcomes in Nigeria children living with HIV

Plasma concentrations of antiretrovirals are significant and important determinants of treatment failure and toxicity. The relationship between antiretroviral pharmacokinetic exposures and immunovirological outcomes has not been extensively studied in our setting. The aim of this study was to investigate the relationship between antiretroviral plasma concentrations and virological and immunological treatment outcomes in children living with human immunodeficiency virus (HIV) A retrospective collection of demographic, clinical , laboratory data and a prospective determination of plasma drug concentrations in 120 children aged 2-14 years after two years of receiving fixed dose zidovudine, lamivudine and nevirapine tablets using a simple, rapid, sensitive and validated method of high performance liquid chromatography with UV detection for simultaneous quantification of zidovudine, lamivudine and nevirapine in human plasma. All analyses were performed using graph pad prism version 5.0. A perfect agreement (p 100 cells/mm3). At 2 years zidovudine, lamivudine and nevirapine therapeutic levels, zidovudine supra therapeutic levels ,and nevirapine subtherapeutic levels were respectively significantly associated with immunologic success (CD4%>15 %). Low nevirapine levels can be used to identify those that require adherence counseling. Despite good virological and immunological outcomes, plasma concentrations of zidovudine, lamivudine and nevirapine were not significantly associated with virological and immunological outcomes (Absolute CD4 counts) but was significantly associated with immunological outcomes (CD4%). Plasma drug levels may be good surrogates of adherence but not of treatment outcomes. Monitoring CD4% remains important to optimize paediatric HIV treatment.Keywords: Antiretroviral treatment, children, therapeutic drug monitoring, treatment outcomes, immune-virological outcomes, plasma concentrations, zidovudine, lamivudine and nevirapine

Drug interactions between hormonal contraceptives and antiretrovirals

Objective:To summarize published evidence on drug interactions between hormonal contraceptives and antiretrovirals.Design:Systematic review of the published literature.Methods:We searched PubMed, POPLINE, and EMBASE for peer-reviewed publications of studies (in any language) from inception to 21 September 2015. We included studies of women using hormonal contraceptives and antiretrovirals concurrently. Outcomes of interest were effectiveness of either therapy, toxicity, or pharmacokinetics. We used standard abstraction forms to summarize and assess strengths and weaknesses.Results:Fifty reports from 46 studies were included. Most antiretrovirals whether used for therapy or prevention, have limited interactions with hormonal contraceptive methods, with the exception of efavirenz. Although depot medroxyprogesterone acetate is not affected, limited data on implants and combined oral contraceptive pills suggest that efavirenz-containing combination antiretroviral therapy may compromise contraceptive effectiveness of these methods. However, implants remain very effective despite such drug interactions. Antiretroviral plasma concentrations and effectiveness are generally not affected by hormonal contraceptives.Conclusion:Women taking antiretrovirals, for treatment or prevention, should not be denied access to the full range of hormonal contraceptive options, but should be counseled on the expected rates of unplanned pregnancy associated with all contraceptive methods, in order to make their own informed choices.

Gender Differences in Adherence and Response to Antiretroviral Treatment in the Stratall Trial in Rural District Hospitals in Cameroon.

Evidence of gender differences in antiretroviral treatment (ART) outcomes in sub-Saharan Africa is conflicting. Our objective was to assess gender differences in (1) adherence to ART and (2) virologic failure, immune reconstitution, mortality, and disease progression adjusting for adherence. Cohort study among 459 ART-naive patients followed up 24 months after initiation in 2006-2010 in 9 rural district hospitals. Adherence to ART was assessed using (1) a validated tool based on multiple patient self-reports and (2) antiretroviral plasma concentrations. The associations between gender and the outcomes were assessed using multivariate mixed models or accelerated time failure models. One hundred thirty-five patients (29.4%) were men. At baseline, men were older, had higher body mass index and hemoglobin level, and received more frequently efavirenz than women. Gender was not associated with self-reported adherence (P = 0.872, 0.169, and 0.867 for moderate adherence, low adherence, and treatment interruption, respectively) or with antiretroviral plasma concentrations (P = 0.549 for nevirapine/efavirenz). In contrast, male gender was associated with virologic failure [odds ratio: 2.18, 95% confidence interval (CI): 1.31 to 3.62, P = 0.003], lower immunologic reconstitution (coefficient: -58.7 at month 24, 95% CI: -100.8 to -16.6, P = 0.006), and faster progression to death (time ratio: 0.30, 95% CI: 0.12 to 0.78, P = 0.014) and/or to World Health Organization stage 4 event (time ratio: 0.27, 95% CI: 0.09 to 0.79, P = 0.017). Our study provides important evidence that African men are more vulnerable to ART failure than women and that the male vulnerability extends beyond adherence issues. Additional studies are needed to determine the causes for this vulnerability to optimize HIV care. However, personalized adherence support remains crucial.

HIV and noncommunicable diseases: the Asian perspective.

Asia is seeing a rise in noncommunicable diseases in their general population and among people living with HIV. Many Asians have low body weight, which can lead to higher plasma concentrations of antiretrovirals and, as a result, their toxicities. Examples are metabolic complications from protease inhibitors, chronic kidney disease from tenofovir, and hepatotoxicity from nevirapine. Asia has not only the highest burden of hepatitis B viral infection than any other continent but also a predominance of genotypes B and C, the latter associated with higher risk for hepatocellular carcinoma. HIV-associated neurocognitive disorders are equally common among Asians as other populations. Diastolic dysfunction and asymptomatic myocardial ischemia are not infrequent. Non-Hodgkin lymphoma is the most common AIDS-related cancer, whereas Kaposi sarcoma is relatively infrequent. Emerging data show high prevalence of human papillomavirus-associated anal dysplasia in men who have sex with men. Resource-limited countries in Asia suffer from lack of resources for national screening programs of noncommunicable diseases, which, in turn, limits the epidemiologic data that exist to guide the use of national health resources.

Genotypic resistance profiles of HIV-2-treated patients in West Africa

To assess the virological response, genotypic resistance profiles, and antiretroviral plasma concentrations in HIV-2 antiretroviral-treated (antiretroviral therapy, ART) patients in Côte d'Ivoire. A cross-sectional survey was conducted among HIV-2 patients receiving ART. Plasma HIV-2 viral load was performed using the Agence Nationale de Recherche sur le SIDA et les hépatites virales (ANRS) assay. Protease and reverse transcriptase sequencing was performed using in-house methods and antiretroviral plasma concentrations were assessed using ultra performance liquid chromatography combined with tandem mass spectrometry. One hundred and forty-five HIV-2-treated patients were enrolled with a median CD4 cell count of 360 cells/μl (interquartile range, IQR = 215-528). Median duration of ART was 4 years (IQR = 2-7) and 74% of patients displayed viral load less than 50 copies/ml. Median plasma HIV-2 RNA among patients with viral load more than 50 copies/ml was 3016 copies/ml (IQR = 436-5156). Most patients (84%) received a lopinavir/ritonavir-based regimen. HIV-2 resistance mutations to nucleoside reverse transcriptase inhibitors and protease inhibitors were detected in 21 of 25 (84%) and 20 of 29 (69%) samples, respectively. The most prevalent nucleoside reverse transcriptase inhibitor resistance mutations were M184I/V (90%), Q151M (24%), and S215F/Y (24%). The most prevalent protease inhibitor resistance mutations were V47A (60%) and I54M (30%). Median CD4 cell counts were 434 cells/μl (292-573) and 204 cells/μl (122-281) in patients with viral load less than 50 copies/ml and those exhibiting virological failure (P < 0.0001), respectively. The proportions of patients with adequate antiretroviral plasma concentrations were 81 and 93% in patients displaying virological failure and in those with viral load less than 50 copies/ml, respectively (P = 0.046), suggesting good treatment adherence. We observed adequate drug plasma concentrations and virological suppression in a high proportion of HIV-2-infected patients. However, in cases of virological failure, the limited HIV-2 therapeutic arsenal and cross-resistance dramatically reduced treatment options.

Therapeutic drug monitoring of atazanavir/ritonavir in pregnancy.

Pregnant women experience physiological changes during pregnancy that can have a significant impact on antiretroviral pharmacokinetics. Ensuring optimal plasma concentrations of antiretrovirals is essential for maternal health and to minimize the risk of vertical transmission. Here we describe atazanavir/ritonavir (ATV/r) plasma concentrations in a cohort of pregnant women undergoing routine therapeutic drug monitoring (TDM). Pregnant HIV-positive women received ATV/r as part of their routine pre-natal care. Demographic and clinical data were collected. ATV plasma concentrations ([ATV]) were determined in the first (T1), second (T2) and third (T3) trimesters and at postpartum (PP) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). From January 2007, 44 women (37 black African) were enrolled in the study. All received ATV/r at a dose of 300/100 mg once a day. Twenty-four had received antiretroviral therapy (ART) prior to pregnancy, and 20 initiated ATV/r in pregnancy. At the time nearest to delivery, 36 patients had undetectable plasma viral loads. [ATV] values were determined in 11 (T1), 25 (T2), 34 (T3) and 28 (PP) patients. [ATV] at 24 hours post-dose (C24) values significantly lower at T2/T3 relative to PP. This study was carried out in one of the larger cohorts of women undergoing TDM for ATV in pregnancy. Lower [ATV] values were seen in T2/T3 compared with T1/PP. However, [ATV] were not associated with a lack of virologic suppression at delivery. Nonetheless, careful monitoring of women in pregnancy is required, and dose adjustment of ATV to 400 mg may be an option.

Free and Total Plasma Levels of Lopinavir during Pregnancy, at Delivery and Postpartum: Implications for Dosage Adjustments in Pregnant Women

Physiological changes associated with pregnancy may alter antiretroviral plasma concentrations and might jeopardize prevention of mother-to-child HIV transmission. Lopinavir is one of the protease inhibitors more frequently prescribed during pregnancy in Europe. We described the free and total pharmacokinetics of lopinavir in HIV-infected pregnant and non-pregnant women, and evaluated whether significant alterations in its disposition and protein binding warrant systematic dosage adjustment. Plasma samples were collected at first, second and third trimester of pregnancy, at delivery, in umbilical cord and postpartum. Lopinavir free and total plasma concentrations were measured by HPLC-MS/MS. Bayesian calculations were used to extrapolate total concentrations to trough (Cmin). A total of 42 HIV-positive pregnant women and 37 non-pregnant women on lopinavir/ritonavir were included in the study. Compared to postpartum and control values, total lopinavir Cmin was decreased moderately (31-39%) during pregnancy, and free Cmin minimally, showing significant alteration only at delivery (-35%). However, total and free Cmin remained in all patients above the target concentrations for wild-type virus of 1,000 ng/ml, and above the unbound IC50(WT) of 0.64-0.77 ng/ml of lopinavir, respectively. Lopinavir free fractions remained higher during pregnancy compared to postpartum and controls, and were influenced by α-1-acid-glycoprotein and albumin decrease. Free cord-to-mother ratio (0.43) was 2.7-fold higher than total cord-to-mother ratio (0.16), suggesting higher fetal exposure. The moderate decrease of total lopinavir concentrations during pregnancy is not associated with proportional decrease in free concentrations. Both reach a nadir at delivery, albeit not to an extent that would put treatment-naive women at risk of insufficient exposure to the free, pharmacologically active concentrations of lopinavir. No dosage adjustment is therefore needed during pregnancy as it is unlikely to further enhance treatment efficacy but could potentially increase the risk of maternal and fetal toxicity. Nonetheless, in case of viral resistance in treatment-experienced pregnant women, loss of virological control or questionable adherence, it is justified to consider lopinavir dosage adjustment based on total plasma concentration measurement.

AIDS Diarrhea and Antiretroviral Drug Concentrations: A Matched-Pair Cohort Study in Port au Prince, Haiti

Diarrhea in patients with acquired immunodeficiency syndrome (AIDS) may cause malabsorption of medications and failure of antiretroviral therapy (ART). We prospectively evaluated human immunodeficiency virus-1 (HIV-1)-infected patients with and without chronic diarrhea initiating ART in Haiti. We report mean plasma antiretroviral concentrations at 2 and 4 weeks. We measured plasma HIV-1 RNA levels at four points. Fifty-two HIV-1-infected patients (26 matched pairs) were enrolled. No differences in antiretroviral concentrations were detected. At week 24, 18/25 (72%) cases and 16/24 (68%) controls had undetectable plasma HIV-1 RNA levels (P = 0.69). Patients with plasma HIV-1 RNA levels > 50 copies/mL at week 24 had lower early efavirenz concentrations than patients with undetectable HIV-1 RNA (2,621 ng/mL versus 5,278 ng/mL; P = 0.02). Diarrhea at ART initiation does not influence plasma concentrations of the medications evaluated. Virologic outcome at Week 24 does correlate with efavirenz concentrations early in therapy but not with the presence of chronic diarrhea.

Severe insomnia related to high concentrations of raltegravir

Severe insomnia related to high concentrations of raltegravir

Impact of hepatitis C and liver fibrosis on antiretroviral plasma drug concentrations in HIV-HCV co-infected patients: the HEPADOSE study

To compare plasma antiretroviral concentrations in HIV-HCV co-infected and in matched HIV mono-infected patients. This was a cross-sectional, observational study. Antiretroviral trough concentrations (C(min)) in plasma were measured in HIV-HCV co-infected patients with liver disease documented by liver biopsy, matched with HIV mono-infected patients according to gender and antiretroviral treatment. C(min) values in serum were measured using an HPLC method. Statistical analysis was performed using the Wilcoxon test. Seventy-three HIV-HCV co-infected patients and 66 HIV-infected patients were enrolled; 70% of patients were receiving a protease inhibitor (PI)- and 30% a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimen. Among the 73 co-infected patients, 27 had a fibrosis score (Fibrotest(®)) of F4. Abacavir was the only nucleoside reverse transcriptase inhibitor whose trough concentrations differed between the co-infected and mono-infected groups. PI median plasma C(min) values were not different in the two groups, except for lopinavir, with a lower C(min) in the co-infected group than in the HIV-infected group (median 3673 versus 5990 ng/mL, P=0.04), and nelfinavir, with significantly higher concentrations in the co-infected group. Seventy-five percent of co-infected patients scoring F4, 33% of those scoring F0-F3 and 12% of HIV-infected patients were underdosed (P=0.02). Co-infected patients receiving an NNRTI had a higher plasma C(min) than HIV-infected patients; median C(min) was 3583 versus 1494 ng/mL (P=0.025) and 5331 versus 3954 ng/mL (P=0.10) for efavirenz and nevirapine, respectively. Overall, there was a greater proportion of co-infected patients with high concentrations of both NNRTIs (15/23) compared with HIV mono-infected patients (5/21) (P=0.008), especially in co-infected patients with an advanced liver fibrosis stage. Median plasma C(min) values differed significantly between HIV and HIV-HCV co-infected patients for abacavir, lopinavir and efavirenz. NNRTIs were strongly overdosed in HIV-HCV co-infected patients.

Validation of a rapid and sensitive high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) assay for the simultaneous determination of existing and new antiretroviral compounds

Clinical pharmacokinetic studies of antiretrovirals require accurate and precise measurement of plasma drug concentrations. Here we describe a simple, fast and sensitive HPLC–MS/MS method for determination of the commonly used protease inhibitors (PI) amprenavir, atazanavir, darunavir, lopinavir, ritonavir, saquinavir and the non-nucleoside reverse transcriptase inhibitor (NNRTI) nevirapine, as well as the more recent antiretrovirals, the CCR5 antagonist maraviroc and the “second generation” NNRTI etravirine and rilpivirine. An internal standard (quinoxalone; QX) was added to plasma aliquots (100 μl) prior to protein precipitation with acetonitrile (500 μl) followed by centrifugation and addition of 0.05% formic acid (200 μl) to the supernatant. Chromatographic separation was achieved using a gradient (acetonitrile and 0.05% formic acid) mobile phase on a reverse-phase C 18 column. Detection was via selective reaction monitoring (SRM) operating in positive ionization mode on a triple-quadrupole mass spectrometer. All compounds eluted within a 5 min run time. Calibration curves were validated over concentration ranges reflecting therapeutic concentrations observed in HIV-infected patients from pharmacokinetic data reported in the literature. Correlation coefficients ( r 2) exceeded 0.998. Inter- and intra-assay variation ranged between 1% and 10% and % recovery exceeded 90% for all analytes. The method described is being successfully applied to measure plasma antiretroviral concentrations from samples obtained from clinical pharmacokinetic studies.

Comparison of levels of antiretroviral drugs with efficacy in children with HIV infection

To determine the prevalence of low and high antiretroviral (ARV) plasma levels and to analyze correlation between ARV concentrations and the appearance of therapeutic failure and toxicity. The authors present here a study evaluating antiretroviral plasma concentrations in HIV infected children on nonnucleoside reverse transcriptase inhibitors and protease inhibitors based therapy. The authors carried out a multicentre, cross-sectional study, including HIV-infected children from five large Hospitals in Madrid, Spain. Clinical, haematological, biochemical and immuno-virological parameters were assessed. Antiretroviral plasma trough levels were performed using a validated high performance liquid chromatography method. Between April 2006 and April 2008, 129 children were enrolled in the present study, with median treatment duration of 39.2 months. 25.5% of the non-nucleoside reverse transcriptase inhibitors levels were low and 17.6%, high. 27.9% percent of the protease inhibitors levels were low and 12.5%, high. A correlation was found among adequate or high levels of antiretrovirals and normal CD4 percentage and low viral load. Lopinavir/ritonavir plasma levels were correlated with an increase in lipodystrophy. Patients with Tanner stage 1 presented the lowest ARV plasma levels. Full adherence was reported for all the participants by a questionnaire. Many HIV-infected children show ARV plasma levels out of the therapeutic range which demands a child-adjusted approach. However, larger studies are urgently needed in pediatric populations to define optimal reference values.

Niveles plasmáticos de antirretrovirales en niños con infección por el virus de la inmunodeficiencia humana. Influencia del género y de la edad

Pharmacologic studies have shown a relationship between plasma antiretroviral levels and toxicity/viral activity. Nevertheless, pharmacokinetic and pharmacodynamic data are inconsistent and limited in HIV-infected children. An analysis was performed of plasma antiretroviral concentrations in clinical practice and their influence on therapy efficacy in HIV-infected children. Observational, prospective, multicenter study, including HIV-infected children followed up at 5 reference hospitals between March 2006 and June 2008. Pre-dose plasma antiretroviral levels were determined and the relationships with various clinical and analytical variables were investigated. A total of 129 patients were included, and 41.3% had antiretroviral plasma levels outside the established range. No differences were found between sexes. Children younger than 1 year had a higher rate of suboptimal levels and higher viral load than the remaining children. Antiretroviral plasma concentrations are more frequently suboptimal in children younger than 1 year. This finding is related with greater viral failure and implies a considerable challenge in this population, which requires very long-term treatment.

Risk factors for virological failure and subtherapeutic antiretroviral drug concentrations in HIV-positive adults treated in rural northwestern Uganda

BackgroundLittle is known about immunovirological treatment outcomes and adherence in HIV/AIDS patients on antiretroviral therapy (ART) treated using a simplified management approach in rural areas of developing countries, or about the main factors influencing those outcomes in clinical practice.MethodsCross-sectional immunovirological, pharmacological, and adherence outcomes were evaluated in all patients alive and on fixed-dose ART combinations for 24 months, and in a random sample of those treated for 12 months. Risk factors for virological failure (>1,000 copies/ml) and subtherapeutic antiretroviral (ARV) concentrations were investigated with multiple logistic regression.ResultsAt 12 and 24 months of ART, 72% (n = 701) and 70% (n = 369) of patients, respectively, were alive and in care. About 8% and 38% of patients, respectively, were diagnosed with immunological failure; and 75% and 72% of patients, respectively, had undetectable HIV RNA (<400 copies/ml). Risk factors for virological failure (>1,000 copies/ml) were poor adherence, tuberculosis diagnosed after ART initiation, subtherapeutic NNRTI concentrations, general clinical symptoms, and lower weight than at baseline. About 14% of patients had low ARV plasma concentrations. Digestive symptoms and poor adherence to ART were risk factors for low ARV plasma concentrations.ConclusionEfforts to improve both access to care and patient management to achieve better immunological and virological outcomes on ART are necessary to maximize the duration of first-line therapy.