Lopinavir Plasma Concentrations Research Articles

Inadequate Lopinavir Concentrations With Modified 8-Hourly Lopinavir/Ritonavir 4:1 Dosing During Rifampicin-based Tuberculosis Treatment in Children Living With HIV.

Lopinavir/ritonavir plasma concentrations are profoundly reduced when co-administered with rifampicin. Super-boosting of lopinavir/ritonavir is limited by nonavailability of single-entity ritonavir, while double-dosing of co-formulated lopinavir/ritonavir given twice-daily produces suboptimal lopinavir concentrations in young children. We evaluated whether increased daily dosing with modified 8-hourly lopinavir/ritonavir 4:1 would maintain therapeutic plasma concentrations of lopinavir in children living with HIV receiving rifampicin-based antituberculosis treatment. Children with HIV/tuberculosis coinfection weighing 3.0 to 19.9 kg, on rifampicin-based antituberculosis treatment were commenced or switched to 8-hourly liquid lopinavir/ritonavir 4:1 with increased daily dosing using weight-band dosing approach. A standard twice-daily dosing of lopinavir/ritonavir was resumed 2 weeks after completing antituberculosis treatment. Plasma sampling was conducted during and 4 weeks after completing antituberculosis treatment. Of 20 children enrolled; 15, 1-7 years old, had pharmacokinetics sampling available for analysis. Lopinavir concentrations (median [range]) on 8-hourly lopinavir/ritonavir co-administered with rifampicin (n = 15; area under the curve 0-24 55.32 mg/h/L [0.30-398.7 mg/h/L]; C max 3.04 mg/L [0.03-18.6 mg/L]; C 8hr 0.90 mg/L [0.01-13.7 mg/L]) were lower than on standard dosing without rifampicin (n = 12; area under the curve 24 121.63 mg/h/L [2.56-487.3 mg/h/L]; C max 9.45 mg/L [0.39-26.4 mg/L]; C 12hr 3.03 mg/L [0.01-17.7 mg/L]). During and after rifampicin cotreatment, only 7 of 15 (44.7%) and 8 of 12 (66.7%) children, respectively, achieved targeted pre-dose lopinavir concentrations ≥1mg/L. Modified 8-hourly dosing of lopinavir/ritonavir failed to achieve adequate lopinavir concentrations with concurrent antituberculosis treatment. The subtherapeutic lopinavir exposures on standard dosing after antituberculosis treatment are of concern and requires further evaluation.

Pharmacokinetics, Safety, and Bioequivalence of 2 Lopinavir/Ritonavir (200/50mg) Tablets in Healthy Chinese Volunteers: Effect of Food on Absorption.

Lopinavir/ritonavir is an important protease inhibitor for treating HIV-1 infection in patients aged >2 years in combination with other antiretrovirals. The antiviral activity of lopinavir/ritonavir in vivo is mainly derived from lopinavir, while ritonavir improves the bioavailability of lopinavir. This study compared the bioequivalence and safety of 2 lopinavir/ritonavir (200/50mg) formulations under fasted and fed conditions in healthy Chinese volunteers and compared the pharmacokinetic parameters of lopinavir and ritonavir. A randomized, open-label, single-dose, 4-period, crossover bioequivalence was conducted in 72 subjects under fasted and fed conditions. Lopinavir and ritonavir plasma concentrations were analyzed using validated liquid chromatography with tandem mass spectrometry. Noncompartmental analysis was used to evaluate pharmacokinetic parameters. The 90% confidence intervals of test/reference geometric mean ratio for lopinavir and ritonavir area under the plasma concentration-time curve and maximum drug concentration meets the bioequivalence criteria based on the average bioequivalence method. A high-fat meal delayed the time to the maximum concentration of lopinavir and ritonavir. Therefore, these formulations were bioequivalent in healthy Chinese volunteers under fasting and fed conditions. Moreover, adverse events were more frequent in the fed state, but all were mild.

An open-label randomized controlled trial of the effect of lopinavir/ritonavir, lopinavir/ritonavir plus IFN-β-1a and hydroxychloroquine in hospitalized patients with COVID-19

ObjectivesWe evaluated the clinical, virological and safety outcomes of lopinavir/ritonavir, lopinavir/ritonavir–interferon (IFN)-β-1a, hydroxychloroquine or remdesivir in comparison to standard of care (control) in coronavirus 2019 disease (COVID-19) inpatients requiring oxygen and/or ventilatory support. MethodsWe conducted a phase III multicentre, open-label, randomized 1:1:1:1:1, adaptive, controlled trial (DisCoVeRy), an add-on to the Solidarity trial (NCT04315948, EudraCT2020-000936-23). The primary outcome was the clinical status at day 15, measured by the WHO seven-point ordinal scale. Secondary outcomes included quantification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in respiratory specimens and pharmacokinetic and safety analyses. We report the results for the lopinavir/ritonavir-containing arms and for the hydroxychloroquine arm, trials of which were stopped prematurely. ResultsThe intention-to-treat population included 583 participants—lopinavir/ritonavir (n = 145), lopinavir/ritonavir–IFN–β-1a (n = 145), hydroxychloroquine (n = 145), control (n = 148)—among whom 418 (71.7%) were male, the median age was 63 years (IQR 54–71), and 211 (36.2%) had a severe disease. The day-15 clinical status was not improved with the investigational treatments: lopinavir/ritonavir versus control, adjusted odds ratio (aOR) 0.83, (95% confidence interval (CI) 0.55–1.26, p 0.39), lopinavir/ritonavir–IFN–β-1a versus control, aOR 0.69 (95%CI 0.45–1.04, p 0.08), and hydroxychloroquine versus control, aOR 0.93 (95%CI 0.62–1.41, p 0.75). No significant effect of investigational treatment was observed on SARS-CoV-2 clearance. Trough plasma concentrations of lopinavir and ritonavir were higher than those expected, while those of hydroxychloroquine were those expected with the dosing regimen. The occurrence of serious adverse events was significantly higher in participants allocated to the lopinavir/ritonavir-containing arms. ConclusionIn adults hospitalized for COVID-19, lopinavir/ritonavir, lopinavir/ritonavir–IFN–β-1a and hydroxychloroquine improved neither the clinical status at day 15 nor SARS-CoV-2 clearance in respiratory tract specimens.

Neglecting Plasma Protein Binding in COVID-19 Patients Leads to a Wrong Interpretation of Lopinavir Overexposure.

Boffito et al. recalled the critical importance to correctly interpret protein binding. Changes of lopinavir pharmacokinetics in coronavirus disease 2019 (COVID‐19) are a perfect illustration. Indeed, several studies described that total lopinavir plasma concentrations were considerably higher in patients with severe COVID‐19 than those reported in patients with HIV. These findings have led to a reduction of the dose of lopinavir in some patients, hypothesizing an inhibitory effect of inflammation on lopinavir metabolism. Unfortunately, changes in plasma protein binding were never investigated. We performed a retrospective cohort study. Data were collected from the medical records of patients hospitalized for COVID‐19 treated with lopinavir/ritonavir in intensive care units or infectious disease departments of Toulouse University Hospital (France). Total and unbound concentrations of lopinavir, C reactive protein, albumin, and alpha‐1‐acid glycoprotein (AAG) levels were measured during routine care on the same samples. In patients with COVID‐19, increased total lopinavir concentration is the result of an increased AAG‐bound lopinavir concentration, whereas the unbound concentration remains constant, and insufficient to reduce the severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2) viral load. Although international guidelines have recently recommended against using lopinavir/ritonavir to treat severe COVID‐19, the description of lopinavir pharmacokinetics changes in COVID‐19 is a textbook case of the high risk of misinterpretation of a total drug exposure when changes in protein binding are not taken into consideration.

Plasma Concentrations and Safety of Lopinavir/Ritonavir in COVID-19 Patients.

Background:Although the efficacy of lopinavir/ritonavir has not been proven, it has been proposed as an off-label treatment for COVID-19. Previously, it has been reported that the plasma concentrations of lopinavir significantly increase in inflammatory settings. As COVID-19 may be associated with major inflammation, assessing the plasma concentrations and safety of lopinavir in COVID-19 patients is essential.Methods:Real-world COVID-19 data based on a retrospective study.Results:Among the 31 COVID-19 patients treated with lopinavir/ritonavir between March 18, 2020 and April 1, 2020, higher lopinavir plasma concentrations were observed, which increased by 4.6-fold (interquartile range: 3.6–6.2), compared with the average plasma concentrations in HIV. Lopinavir concentrations in all except one patient were above the upper limit of the concentration range of HIV treatment. Approximately one to 5 patients prematurely stopped treatment mainly because of an ADR related to hepatic or gastrointestinal disorders.Conclusions:Lopinavir plasma concentrations in patients with moderate-to-severe COVID-19 were higher than expected, and they were associated with the occurrence of hepatic or gastrointestinal adverse drug reactions. However, a high plasma concentration may be required for in vivo antiviral activity against SARS-CoV-2, as suggested by previous studies. Therefore, in the absence of adverse drug reaction, lopinavir dosage should not be reduced. Caution is essential because off-label use can be associated with a new drug safety profile.

Effect of Systemic Inflammatory Response to SARS-CoV-2 on Lopinavir and Hydroxychloroquine Plasma Concentrations.

Coronavirus disease 2019 (COVID-19) leads to inflammatory cytokine release, which can downregulate the expression of metabolizing enzymes. This cascade affects drug concentrations in the plasma. We investigated the association between lopinavir (LPV) and hydroxychloroquine (HCQ) plasma concentrations and the levels of the acute-phase inflammation marker C-reactive protein (CRP). LPV plasma concentrations in 92 patients hospitalized at our institution were prospectively collected. Lopinavir-ritonavir was administered every 12 hours, 800/200 mg on day 1 and 400/100 mg on day 2 until day 5 or 7. HCQ was given at 800 mg, followed by 400 mg after 6, 24, and 48 h. Hematological, liver, kidney, and inflammation laboratory values were analyzed on the day of drug level determination. The median age of study participants was 59 (range, 24 to 85) years, and 71% were male. The median durations from symptom onset to hospitalization and treatment initiation were 7 days (interquartile range [IQR], 4 to 10) and 8 days (IQR, 5 to 10), respectively. The median LPV trough concentration on day 3 of treatment was 26.5 μg/ml (IQR, 18.9 to 31.5). LPV plasma concentrations positively correlated with CRP values (r = 0.37, P < 0.001) and were significantly lower when tocilizumab was preadministered. No correlation was found between HCQ concentrations and CRP values. High LPV plasma concentrations were observed in COVID-19 patients. The ratio of calculated unbound drug fraction to published SARS-CoV-2 50% effective concentrations (EC50) indicated insufficient LPV concentrations in the lung. CRP values significantly correlated with LPV but not HCQ plasma concentrations, implying inhibition of cytochrome P450 3A4 (CYP3A4) metabolism by inflammation.

Pharmacokinetics of lopinavir/ritonavir oral solution to treat COVID-19 in mechanically ventilated ICU patients.

BackgroundThe combination lopinavir/ritonavir is recommended to treat HIV-infected patients at the dose regimen of 400/100 mg q12h, oral route. The usual lopinavir trough plasma concentrations are 3000–8000 ng/mL. A trend towards a 28 day mortality reduction was observed in COVID-19-infected patients treated with lopinavir/ritonavir.ObjectivesTo assess the plasma concentrations of lopinavir and ritonavir in patients with severe COVID-19 infection and receiving lopinavir/ritonavir.Patients and methodsMechanically ventilated patients with COVID-19 infection included in the French COVID-19 cohort and treated with lopinavir/ritonavir were included. Lopinavir/ritonavir combination was administered using the usual adult HIV dose regimen (400/100 mg q12h, oral solution through a nasogastric tube). A half-dose reduction to 400/100 mg q24h was proposed if lopinavir Ctrough was >8000 ng/mL, the upper limit considered as toxic and reported in HIV-infected patients. Lopinavir and ritonavir pharmacokinetic parameters were determined after an intensive pharmacokinetic analysis. Biological markers of inflammation and liver/kidney function were monitored.ResultsPlasma concentrations of lopinavir and ritonavir were first assessed in eight patients treated with lopinavir/ritonavir. Median (IQR) lopinavir Ctrough reached 27 908 ng/mL (15 928–32 627). After the dose reduction to 400/100 mg q24h, lopinavir/ritonavir pharmacokinetic parameters were assessed in nine patients. Lopinavir Ctrough decreased to 22 974 ng/mL (21 394–32 735).ConclusionsIn mechanically ventilated patients with severe COVID-19 infections, the oral administration of lopinavir/ritonavir elicited plasma exposure of lopinavir more than 6-fold the upper usual expected range. However, it remains difficult to safely recommend its dose reduction without compromising the benefit of the antiviral strategy, and careful pharmacokinetic and toxicity monitoring are needed.

Relationship between untimed plasma lopinavir concentrations and virological outcome on second-line antiretroviral therapy: Erratum.

Relationship between untimed plasma lopinavir concentrations and virological outcome on second-line antiretroviral therapy: Erratum.

Relationship between untimed plasma lopinavir concentrations and virological outcome on second-line antiretroviral therapy.

Resource constraints in low and middle-income countries necessitate practical approaches to optimizing antiretroviral therapy outcomes. We hypothesised that an untimed plasma lopinavir concentration (UPLC) at week 12 would predict loss of virological response in those taking lopinavir as part of a second-line antiretroviral regimen. We measured plasma lopinavir concentration at week 12 on stored samples from the SECOND-LINE study. We characterized UPLC as: detectable and optimal (≥1000 μg/l); detectable but suboptimal (≥25 to < 1000 μg/l); and undetectable (<25 μg/l). We used Cox regression to explore the relationship between UPLC and loss of virological response over 48 weeks and backwards stepwise logistic regression to explore the relationship between UPLC and other predictors of virological failure at week 48. At week 48, we observed virological failure in 15/32 (47%) and 53/485 (11%) of patients with undetectable and detectable UPLC, respectively, P < 0.001. Both suboptimal [adjusted hazard ratio (HR) 2.94; 95% confidence interval (CI) 1.54-5.62; P = 0.001], and undetectable (adjusted HR 3.55; 95% CI 1.89-6.64; P < 0.001) UPLC were associated with higher rates of loss of virological response over 48 weeks. In multivariate analysis, an independent association with virological failure at week 48 and undetectable UPLC was observed after adjustment (odds ratio 5.48; 95% CI 2.23-13.42; P < 0.01). In low and middle-income countries implementing a public health approach to antiretroviral therapy treatment, an untimed plasma drug concentration may provide a practical method for early identification of patients with inadequate medication adherence and facilitate timely corrective interventions to prevent virological failure.

Effect of Lopinavir and Nevirapine Concentrations on Viral Outcomes in Protease Inhibitor-experienced HIV-infected Children.

Adequate exposure to antiretroviral drugs is necessary to achieve and sustain viral suppression. However, the target antiretroviral concentrations associated with long-term viral suppression have not been adequately defined in children. We assessed the relationship between plasma lopinavir or nevirapine concentrations and the risk of subsequent viremia in children initially suppressed on antiretroviral therapy. After an induction phase of antiretroviral treatment, 195 children with viral suppression (viral load ≤400 copies/mL) were randomized to continue a lopinavir/ritonavir-based regimen or to switch to a nevirapine-based regimen (together with lamivudine and stavudine). Viral load and lopinavir or nevirapine concentrations were measured at clinic visits 4, 8, 12, 16, 20, 24, 36, 52, 64 and 76 weeks post randomization. Cox multiple failure event models were used to estimate the effects of drug concentrations on the hazard of viremia (viral load >50 copies/mL) RESULTS:: At randomization, the median (interquartile range) age, CD4 T-Lymphocyte percentage, weight-for-age and weight-for-height z scores were 19 (16-24) months, 29% (23-37), -0.6 (-1.3 to 0.2) and -3.2 (-4.1 to -2.1), respectively. The proportion of children with viral load 51-400 copies/mL at randomization was 43%. The hazard of subsequent viremia during follow-up was increased for lopinavir concentrations <1 versus ≥1 mg/L [adjusted hazard ratio 0.62 (95% confidence interval, 0.40-0.94)] and for children with viral loads 51-400 copies/mL at randomization. Nevirapine concentrations were not significantly associated with subsequent viremia. Plasma lopinavir concentrations predicted viral outcomes in children receiving lopinavir-based antiretroviral therapy. Our findings support a minimum target concentration of ≥1 mg/L of lopinavir to ensure sustained viral suppression.

Random lopinavir concentrations predict resistance on lopinavir-based antiretroviral therapy

Considering that most patients who experience virological failure (VF) on lopinavir-based antiretroviral therapy (ART) fail due to poor adherence rather than resistance, an objective adherence measure could limit costs by rationalising the use of genotype antiretroviral resistance testing (GART) in countries with access to third-line ART. A cross-sectional study was conducted in a resource-limited setting at two large clinics in Kwazulu-Natal, South Africa, in patients experiencing VF (HIV-RNA > 1000 copies/mL) on lopinavir-based ART who had undergone GART. Associations between major protease inhibitor (PI) resistance mutations and random plasma lopinavir concentrations were explored. A total of 134 patients, including 31 children, were included in the analysis. The prevalence of patients with major PI resistance mutations was 20.9% (n = 28). A random lopinavir concentration above the recommended minimum trough of 1 µg/mL [adjusted odds ratio (aOR) = 5.81, 95% confidence interval (CI) 2.04–16.50; P = 0.001] and male sex (aOR = 3.19, 95% CI 1.22–8.33; P = 0.018) were predictive of the presence of at least one major PI resistance mutation. Random lopinavir concentrations of <1 µg/mL had a negative predictive value of 91% for major PI resistance mutations. Random lopinavir concentrations are strongly associated with the presence of major PI resistance mutations. Access to costly GART in patients experiencing VF on second-line ART could be restricted to patients with lopinavir concentrations above the recommended minimum trough of 1 µg/mL or, in areas where GART is unavailable, could be used as a criterion to empirically switch to third-line ART.

Differences in genetic variants in lopinavir disposition among HIV-infected Bantu Africans.

Variability in lopinavir (LPV) plasma concentration among patients could be due to genetic polymorphisms. This study set to evaluate significance of variants in CYP3A4/5, SLCO1B1 and ABCC2 on LPV plasma concentration among African HIV-positive patients. Eighty-six HIV-positive participants on ritonavir (LPV/r) were genetically characterized and LPV plasma concentration determined. LPV plasma concentrations differed >188-fold (range 0.0206-38.6 µg/ml). Both CYP3A4*22 and SLCO1B1 rs4149056G (c.521C) were not observed in this cohort. CYP3A4*1B, CYP3A5*3, CYP3A5*6 and ABCC2 c.1249G>A which have been associated with LPV plasma concentration, showed no significant association. These findings highlight the need to include African groups in genomics research to identify variants of pharmacogenomics significance.

Polyinosinic/Polycytidylic Acid-mediated changes in maternal and fetal disposition of lopinavir in rats.

Maintenance of optimal lopinavir (LPV) concentration is essential for effective antiretroviral therapy and prevention of mother-to-child transmission of human immunodeficiency virus. However, little is known about the effects of inflammation on the pharmacokinetics of this protease inhibitor and drug transporter substrate, particularly during gestation. Our objective was to study the effect of polyinosinic/polycytidylic acid [poly(I:C)], a viral mimetic, on key maternal drug transporters, and to examine the effect on maternal and fetal disposition of LPV in rats. Poly(I:C) (5.0 mg/kg i.p.) or saline vehicle was administered to pregnant Sprague-Dawley rats on gestational days 17-18. At 24 hours postinjection, all rats were administered LPV (10 mg/kg i.v.), and plasma and tissues were collected at 5-120 minutes postadministration. Plasma interferon-γ (IFN-γ) levels were measured by enzyme-linked immunosorbent assay, and transporter expression was measured via real-time polymerase chain reaction. Maternal plasma, hepatic, placental, and fetal LPV concentrations were determined by liquid chromatography-tandem mass spectrometry. Administration of poly(I:C) induced IFN-γ plasma levels and downregulated the expression of several important ATP-binding cassette (ABC) drug efflux transporters in the placenta and liver of pregnant rats, compared with controls (P < 0.05). Maternal LPV plasma concentration and area under the concentration-versus-time curve were significantly increased in the poly(I:C) group. Plasma protein binding was also significantly higher in poly(I:C)-treated rats. Pronounced increases in hepatic, placental, and fetal LPV tissue:unbound plasma concentrations were seen in the poly(I:C) group; however, absolute tissue concentrations were not changed. Since the majority of commonly used and clinically important antiretroviral drugs are known to be ABC transporter substrates, inflammation-mediated changes in transporter expression could affect their maternal disposition and fetal exposure.

CSF LPV concentrations and viral load in viral suppressed patients on LPV/r monotherapy given once daily.

Introduction Plasma trough concentrations of lopinavir (LPV) given as LPV/r 800/200 mg once daily (OD) are reduced in comparison with 400/100 mg twice daily (BID). While OD dosage of LPV/r is sufficient to achieve viral suppression in plasma, data about drug penetration and viral suppression in central nervous system (CNS) is needed, mainly if LPVr is used as maintenance monotherapy strategy in selected patients. The objective of this study was to evaluate CSF HIV-1 RNA and CSF LPV concentrations in patients receiving LPV/r monotherapy OD (LPVrMOD).Material and Methods This is a cross-sectional sub-study within a prospective, open-label pilot simplification study to evaluate the efficacy and safety of LPV/rMOD in virologically suppressed patients previously receiving a BID LPV/r monotherapy regimen (LPV/rMBID), the “Kmon study” (NCT01581853). To assess LPV concentrations and HIV-1 RNA in CSF, a lumbar puncture (LP) was performed in a subgroup of patients after at least one month of LPVrMOD treatment. Plasma-paired samples of all patients were also obtained. HIV-1 RNA was determined by real-time PCR (limit of detection 40 copies/mL). Liquid chromatography-tandem mass spectrometry (Tandem labs, NJ) was used to determine CSF and blood plasma LPV concentrations.Results Nine patients were included. Median (range) age was 48 (34–56) years, median CD4 cell count 672 (252–1,408) cells/mL, median nadir CD4 count 125 (35–537) cells/mL and 40% of subjects were HCV-positive. Before starting LPV/rMOD median time on a LPV/r-containing regimen and on LPV/rMBID were 9 (4–11) years and 15 (7–24) months respectively, median time with undetectable HIV viral load was 5 (3–12) years and 2 patients had a previous documented blip. LP was performed a median of 24 (8–36) weeks after starting LPV/rMOD and 24 (11–28) hours after the last LPV/rMOD dose CSF and plasma HIV RNA was 40 copies/mL in all patients. Median LPV CSF concentration was 9.78 (1.93–78.3) ng/mL, median LPV plasma concentration 1,103 (377–16,700) ng/mL and median LPV CSF/plasma ratio 0.3% (0.1–1.2).Conclusions No CSF viral escape was detected and LPV concentrations were above the IC50 for wtHIV-1 (1.9 ng/mL). However, as concentrations were close to IC50 in some patients, a careful clinical follow up of patients receiving this regimen would be advisable. Larger longitudinal studies will be helpful for a better understanding of the CNS antiviral activity of LPVr monotherapy.

Impact of body weight and missed doses on lopinavir concentrations with standard and increased lopinavir/ritonavir doses during late pregnancy

To assess the influence of body weight and missed doses on lopinavir pharmacokinetics with standard and increased doses of lopinavir/ritonavir melt extrusion tablets during late pregnancy. Lopinavir concentration data during the third trimester of pregnancy were pooled from clinical trials in Thailand (NCT00409591) and the USA (NCT00042289). A total of 154 HIV-infected pregnant women receiving either 400/100 mg (standard) or 600/150 mg (increased) twice daily had lopinavir plasma concentration data available. Population parameters were estimated using non-linear mixed-effects regression models. Monte Carlo simulations were performed to estimate the probability of achieving target lopinavir trough concentrations (>1.0 mg/L) with standard and increased doses of lopinavir/ritonavir during pregnancy. The median (range) age, weight and gestational age were 28 years (18-43), 62 kg (45-123) and 33 weeks (29-38), respectively. Body weight influenced lopinavir oral clearance (CL/F) and volume of distribution (V/F). Population estimates of lopinavir CL/F and V/F were 6.21 L/h/70 kg and 52.6 L/70 kg, respectively. Based on simulations, the highest risk of subtherapeutic trough concentrations was for women weighing >100 kg using the standard dose (∼ 7%), while the risk was <2% with the 600/150 mg dose for women weighing 40-130 kg. After a missed dose, 61% of women have lopinavir concentrations below target prior to the next dose with the standard dose compared with 42% with the increased dose. Standard dosing provides adequate lopinavir trough concentrations for the majority of pregnant women but increased doses may be preferable for women weighing >100 kg and with a history of lopinavir/ritonavir use and/or adherence issues.

CYP3A4*22 (c.522-191 C>T; rs35599367) is associated with lopinavir pharmacokinetics in HIV-positive adults.

The CYP3A4*22 (c.522-191 C>T; rs35599367) single nucleotide polymorphism has been associated with lower CYP3A4 mRNA expression and activity. We investigated the association of CYP3A4*22 with the pharmacokinetics of lopinavir through a population pharmacokinetic approach. The minor allele frequency for CYP3A4*22 was 0.035, and seven of 375 patients had a combination of CYP3A4*22 and SLCO1B1 521T>C alleles. Lack of information on the ethnicity in this cohort should be considered as a limitation. However, in the final model, the population clearance was 5.9 l/h and patients with CYP3A4*22/*22 had 53% (P=0.023) lower clearance compared with noncarriers. In addition, the combined effect of CYP3A4*22 with SLCO1B1 521T>C (previously shown to be associated with lopinavir plasma concentration) was analysed. We observed a 2.3-fold higher lopinavir trough concentration (Ctrough) in individuals with CYP3A4*22/*22, a 1.8-fold higher Ctrough with SLCO1B1 521CC and a 9.7-fold higher Ctrough in individuals homozygous for both single nucleotide polymorphisms, compared with noncarriers. A simulated dose-reduction scenario showed that 200/100 mg lopinavir/ritonavir was adequate to achieve therapeutic concentration in individuals with CYP3A4*22/*22 alone or in combination with SLCO1B1 521CC. These data further our understanding of the genetic basis for variability in the pharmacokinetics of lopinavir.

Plasma and Intracellular Antiretroviral Concentrations in HIV-Infected Patients under Short Cycles of Antiretroviral Therapy.

Study of plasma and intracellular concentrations of atazanavir, lopinavir, nevirapine, and efavirenz was conducted on 48 patients under short cycles of antiretroviral therapy. Intracellular concentrations (IC) were still measurable for all drugs after 85 h or 110 h drug intake despite the absence of drug in plasma for atazanavir and lopinavir. A linear relationship between plasma and intracellular efavirenz was observed. Further studies to fully understand the impact of IC in the intermittent antiviral treatment are required.

Pharmacokinetics of Lopinavir Determined with an ELISA Test in Youths with Perinatally Acquired HIV

To investigate the plasma levels of lopinavir by enzyme-linked immunosorbent assay (ELISA) in a cohort of patients who were vertically infected with human immunodeficiency virus 1 (HIV). Plasma levels of lopinavir (Cmin) were determined by ELISA test in patients treated with lopinavir/ritonavir-based combined antiretroviral therapy who had achieved virological response after 4 wk of therapy. Reference lopinavir concentrations were Cmin 1-8 μg/mL. Correlation between lopinavir plasma concentration and continuous variables was evaluated by mean of Pearson correlation coefficient. Differences in lopinavir (LPV) concentration for binary categorical variables were assessed by Mann-Whitney test, while for variables with more than two categories Kruskal-Wallis test was used. Thirty-four patients were enrolled; median age was 133 mo (15-265). The median lopinavir dose tested was 383.5 mg/kg (IQR: 266.6-400 mg/kg), with a median plasma concentration of 8.8 μg/mL (IQR: 5-14 μg/mL). Lopinavir Cmin was <1 μg/mL in only one sample (2.9 %), while 14 samples had Cmin between 1 and 8 μg/mL (41.2 %) and 19 (55.9 %) > 8 μg/mL. No significant correlations were found between plasma concentrations of lopinavir and the continuous variables considered in the study. A negative but, not completely significant, correlation was found between plasma drug concentration and body mass index (r = -0.29; p = 0.09). The use of a simple and relatively cost-effective methodology might render therapeutic drug monitoring (TDM) appeal in the daily clinical practice.

Recurrence of another hepatitis B virus escape mutant comes back in a patient infected with HIV and low CD4+ count

The case of an HIV-positive patient who cleared formerly acute HBV infection and experienced HBV exacerbation before starting antiretroviral therapy (ART) followed by a severe elevation of liver enzymes one month after the introduction of ART is reported. Laboratory tests revealed the presence of a subgenotype A2 carrying at least seven different mutations within the S protein and high lopinavir plasma concentrations. Irrespectively of the many possible mechanisms of HBV reactivation in patients infected with HIV (escape mutants selection, host immune deficiency progression, antiretroviral-related immune reconstitution, glucocorticosteroids, chemotherapy), the message is that HIV patients should be monitored strictly not only by serological and virological assays to recognize early HBV reactivation, but also for drug over-exposure.

Lopinavir Plasma Concentrations and Virological Outcome with Lopinavir-Ritonavir Monotherapy in HIV-1-Infected Patients

There is significant intra- and intersubject variability in lopinavir (LPV) plasma concentrations after standard dosing; thus, this prospective study was conducted to determine whether low plasma LPV concentrations could be associated with virological outcome throughout lopinavir-ritonavir maintenance monotherapy (mtLPVr) in the clinical practice setting. If this hypothesis would be confirmed, LPV drug monitoring could improve the efficacy of mtLPVr regimens. Patients with previous virological failure (VF) on protease inhibitor-based regimens were also included if the genotypic resistance tests showed no major resistance mutation associated with reduced susceptibility to lopinavir-ritonavir. VF was defined as 2 consecutive determinations of HIV RNA levels of >200 copies/ml. Efficacy was analyzed by per-protocol analysis. Plasma LPV trough concentrations were measured by high-performance liquid chromatography using a UV detector. A total of 127 patients were included (22% with previous failure on protease inhibitors). After 96 weeks, the efficacy rate was 82.3% (95% confidence interval [CI(95)], 75.3 to 89.3%). Virological efficacy was independent of LPV plasma concentrations even when LPVr was given once daily. An adherence of <90% (HR, 4.4 [CI(95), 1.78 to 10.8; P = 0.001]) and the presence of blips in the preceding 12 months (HR, 3.06 [CI(95), 1.17 to 8.01; P = 0.022]) were the only variables independently associated with time to VF. These findings suggest that the LPV concentrations achieved with the standard doses of LPVr are sufficient to maintain virological control during monotherapy and that measurement of LPV concentrations is not useful for predicting virological outcome. Tight control of viral replication in the previous months and strict adherence throughout the mtLPVr regimen could improve the virological efficacy of this maintenance regimen.