Population analysis of the pregnancy-related modifications in lopinavir pharmacokinetics and their possible consequences for dose adjustment

Therapeutic Drug Monitoring of HIV Antiretroviral Drugs in Pregnancy: A Narrative Review

To date, therapeutic drug monitoring (TDM) has played an important role in the management of pregnant HIV patients on highly active antiretroviral therapy. Historically, in pregnant women living with HIV, the third agent in triple therapy has been either non-nucleoside reverse transcriptase inhibitors or protease inhibitors (PIs). PIs have been the preferred agents because of their robustness from the perspective of viral resistance and the dominant drug class for the management of HIV during pregnancy for the previous decade. As with many drugs used during pregnancy, pharmacokinetic changes decrease exposure to these agents as the pregnancy progresses. This can lead to viral escape at the time of pregnancy and ultimately increase the risk of mother-to-child transmission (MTCT) of HIV. TDM has been well-established for this class of highly active antiretroviral therapy, and appropriate dose adjustment studies have been performed. At present, there is a shift from the traditional treatment paradigm in pregnancy to a new drug class, integrase strand transfer inhibitors (INSTIs). Although INSTIs are affected by pharmacokinetic changes during pregnancy, they do not harbor the same issues with viral escape as seen with PIs at birth and in general eliminate the need for boosting with additional agents like ritonavir (r) and cobicistat (c) [bar elvitegravir (EVG)] that can lead to interactions with treatment of other common infections in HIV, including tuberculosis. Furthermore, INSTIs are the most successful medication for rapidly reducing the viral load (VL) in HIV patients, a useful factor where VL may be unknown, or in late presenters. These merits make INSTIs the best choice in pregnancy, although their use has been hindered in recent years by a report of neural tube defects from a large African study with dolutegravir (DTG). New data from Botswana and Brazil indicate that this risk is less significant than previously reported, necessitating further data to shed light on this critical issue. Current international guidelines including DHHS, EACS, WHO, and BHIVA (for patients with VLs >100,000 copies/mL or late presenters) now recommend INSTIs as first-line agents. The role of TDM in INSTIs shifts to cases of insufficient viral suppression with standard adherence measures, cases of drug-drug interactions, or cases where EVG/c is continued throughout pregnancy, and thus remains an important aspect of HIV care in pregnancy.

Pharmacokinetic Enhancement of HIV Antiretroviral Therapy During Pregnancy

Pharmacokinetic boosting of antiretroviral (ARV) therapies with either ritonavir or cobicistat is used to achieve target drug exposure, lower pill burden, and provide simplified dosing schedules. Several ARVs require boosting, including the integrase inhibitor elvitegravir as well as protease inhibitors such as darunavir, atazanavir, and lopinavir. The use of boosted regimens in pregnant women living with HIV has been studied for a variety of ARVs; however, a recent recommendation by the US Food and Drug Administration advised against cobicistat-boosted regimens in pregnancy due to substantially lower drug exposures observed in clinical pharmacokinetic studies. The objectives of this article are to review pharmacokinetic enhancement of ARVs with ritonavir and cobicistat during pregnancy and postpartum, describe clinical implications, and provide recommendations for future research.

Assessment of lamivudine, zidovudine, lopinavir, and ritonavir plasma levels in HIV-positive pregnant women: Drug monitoring application to improve patient safety

Simultaneous therapeutic drug monitoring (TDM) of combination antiretroviral therapy (cART) is critical during pregnancy in order to improve clinical follow-up, monitor viral load, and patient adherence to treatment.A modified simple and fast ultra-high performance liquid chromatography coupled with tandem mass spectrometry and electrospray ionization (UPLC-ESI-MS/MS) method was developed and validated according to national and international guidelines for the simultaneous determination of lamivudine (LMV), zidovudine (ZDV), lopinavir (LPV), and ritonavir (RTV) concentrations in 100-μL plasma sample of Human Immunodeficiency Virus (HIV)-positive pregnant women. Protein precipitation using 0.1% formic acid in cold acetonitrile was used for sample preparation. The chromatographic separation was achieved with a run-time of 3.0 minutes and 3-μL injection on an ethylene bridged hybrid C18 column (2.1 μm × 50 mm, 1.7 μm), under gradient conditions using acetonitrile and formic acid (0.1%).The chromatographic method was used to analyze 10 plasma samples from 8 HIV pregnant women as a clinical patient routinely follow-up by applying TDM criteria.The protonated precursor/product ion transitions for LMV (230.18/112.08), ZDV (268.22/127.10), LPV (629.55/447.35), and RTV (721.50/296.20) were recorded in multiple-reaction-monitoring (MRM) mode. The calibration curve was linear in the range of 50-3,000, 75-4,500, 250-15,000, and 25-1,500-ng/mL for LMV, ZDV, LPV, and RTV, respectively. The range of accuracy was 97.2% to 100.1% and precision 3.4% to 12.7%. The method showed specificity and matrix effect values of < 15%. Minimum absolute recovery percentages (%CV) were 90.5 (5.4), 90.8 (5.0), 95.4 (3.5), and 93.7 (6.9), for LMV, ZDV, LPV, and RTV, respectively. Drug concentrations in patient samples had high inter-individual variability with %CV of 91.98%, 77.54%, 53.80%, and 92.16% for ZDV, LMV, LPV, and RTV, respectively. Two of the 8 patients showed no adherence due to the absence of Protease Inhibitors (PIs) levels in plasma.This technique demonstrated to be effective in therapeutic drug monitoring and is intended to be used in population pharmacokinetics specifically for HIV-positive pregnant women.

Pregnancy-Associated Changes in Pharmacokinetics: A Systematic Review

BACKGROUND

Women are commonly prescribed a variety of medications during pregnancy. As most organ systems are affected by the substantial anatomical and physiological changes that occur during pregnancy, it is expected that pharmacokinetics (PK) (absorption, distribution, metabolism, and excretion of drugs) would also be affected in ways that may necessitate changes in dosing schedules. The objective of this study was to systematically identify existing clinically relevant evidence on PK changes during pregnancy.

METHODS AND FINDINGS

Systematic searches were conducted in MEDLINE (Ovid), Embase (Ovid), Cochrane Central Register of Controlled Trials (Ovid), and Web of Science (Thomson Reuters), from database inception to August 31, 2015. An update of the search from September 1, 2015, to May 20, 2016, was performed, and relevant data were added to the present review. No language or date restrictions were applied. All publications of clinical PK studies involving a group of pregnant women with a comparison to nonpregnant participants or nonpregnant population data were eligible to be included in this review. A total of 198 studies involving 121 different medications fulfilled the inclusion criteria. In these studies, commonly investigated drug classes included antiretrovirals (54 studies), antiepileptic drugs (27 studies), antibiotics (23 studies), antimalarial drugs (22 studies), and cardiovascular drugs (17 studies). Overall, pregnancy-associated changes in PK parameters were often observed as consistent findings among many studies, particularly enhanced drug elimination and decreased exposure to total drugs (bound and unbound to plasma proteins) at a given dose. However, associated alterations in clinical responses and outcomes, or lack thereof, remain largely unknown.

CONCLUSION

This systematic review of pregnancy-associated PK changes identifies a significant gap between the accumulating knowledge of PK changes in pregnant women and our understanding of their clinical impact for both mother and fetus. It is essential for clinicians to be aware of these unique pregnancy-related changes in PK, and to critically examine their clinical implications.

CYP3A4 polymorphism and lopinavir toxicity in an HIV-infected pregnant woman

Cytochrome P450 (CYP) 3A4 has been considered to be the most important enzyme system for metabolism of lopinavir/ritonavir (LPV/r), a widely used HIV protease inhibitor (PI) recommended during pregnancy. Herein we present a clinical case of a pregnant HIV-infected woman who was taking standard doses of LPV/r, 400/100 mg twice daily. The trough plasma concentrations for LPV were fourfold above that recommended for PI-pretreated patients and toxicity associated with LPV/r and PI regimens was observed. These high concentrations continued after delivery in spite of a dosage reduction. The pharmacogenetic analysis revealed a genetic polymorphism in the CYP3A4 gene that encodes a non-functional protein. The pharmacokinetic study could indicate the occurrence of a phenomenon of non-linear pharmacokinetics which would justify why dosage reduction after pregnancy did not proportionally affect the patient's degree of exposure to the drug. In addition, an increment in CYP3A activity during pregnancy could explain lower LPV/r exposure during this period compared to postpartum, despite the impaired activity of CYP3A4 caused by the polymorphism.

Population approach to analyze the pharmacokinetics of free and total lopinavir in HIV-infected pregnant women and consequences for dose adjustment

The aims of this study were to describe the unbound and total lopinavir (LPV) pharmacokinetics in pregnant women in order to evaluate if a dosing adjustment is necessary during pregnancy. Lopinavir placental transfer is described, and several genetic covariates were tested to explain its variability. A total of 400 maternal, 79 cord blood, and 48 amniotic fluid samples were collected from 208 women for LPV concentration determinations and pharmacokinetics analysis. Among the maternal LPV concentrations, 79 samples were also used to measure the unbound LPV concentrations. Population pharmacokinetics models were developed by using NONMEM software. Two models were developed to describe (i) unbound and total LPV pharmacokinetics and (ii) LPV placental transfer. The pharmacokinetics was best described by a one-compartment model with first-order absorption and elimination. A pregnancy effect was found on maternal clearance (39% increase), whereas the treatment group (monotherapy versus triple therapy) or the genetic polymorphisms did not explain the pharmacokinetics or placental transfer of LPV. Efficient unbound LPV concentrations in nonpregnant women were similar to those measured during the third trimester of pregnancy. Our study showed a 39% increase of maternal total LPV clearance during pregnancy, whereas unbound LPV concentrations were similar to those simulated in nonpregnant women. The genetic polymorphisms selected did not influence the LPV pharmacokinetics or placental transfer. Thus, we suggest that the LPV dosage should not be increased during pregnancy.

Therapeutic drug monitoring in HIV-infected pregnant women with a focus on protease inhibitors

The goals of HIV therapy in pregnant patients are to ensure health of mother and to prevent mother to child transmission of HIV to the unborn child. Pregnancy is a time of significant physiological alterations that affect all pharmacological aspects of the antiretroviral (ARV) drugs. Studies point toward lower levels of ARVs in maternal blood especially during late stages of pregnancy. Therapeutic drug monitoring is a strategy to ensure that maternal blood contains adequate level of ARVs to achieve these targets. Pharmacokinetics and therapeutic drug monitoring studies of protease inhibitors are reviewed in this article with emphasis on darunavir which is a newer protease inhibitor gaining popularity as a therapeutic choice in pregnant patients.

Basic obstetric pharmacology

Pregnancy is associated with a variety of physiological changes that can alter the pharmacokinetics and pharmacodynamics of several drugs. However, limited data exists on the pharmacokinetics and pharmacodynamics of the majority of the medications used in pregnancy. In this article, we first describe basic concepts (drug absorption, bioavailability, distribution, metabolism, elimination, and transport) in pharmacokinetics. Then, we discuss several physiological changes that occur during pregnancy that theoretically affect absorption, distribution, metabolism, and elimination. Further, we provide a brief review of the literature on the clinical pharmacokinetic studies performed in pregnant women in recent years. In general, pregnancy increases the clearance of several drugs and correspondingly decreases drug exposure during pregnancy. Based on current drug exposure measurements during pregnancy, alterations in the dose or dosing regimen of certain drugs are essential during pregnancy. More pharmacological studies in pregnant women are needed to optimize drug therapy in pregnancy.

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

OBJECTIVES

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.

PATIENTS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Integrated population pharmacokinetic/viral dynamic modelling of lopinavir/ritonavir in HIV-1 treatment-naïve patients

BACKGROUND

Lopinavir (LPV)/ritonavir (RTV) co-formulation (LPV/RTV) is a widely used protease inhibitor (PI)-based regimen to treat HIV-infection. As with all PIs, the trough concentration (C trough) is a primary determinant of response, but the optimum exposure remains poorly defined. The primary objective was to develop an integrated LPV population pharmacokinetic model to investigate the influence of α-1-acid glycoprotein and link total and free LPV exposure to pharmacodynamic changes in HIV-1 RNA and assess viral dynamic and drug efficacy parameters.

METHODS

Data from 35 treatment-naïve HIV-infected patients initiating therapy with LPV/RTV 400/100 mg orally twice daily across two studies were used for model development and simulations using ADAPT. Total LPV (LPVt) and RTV concentrations were measured by high-performance liquid chromatography with ultraviolet (UV) detection. Free LPV (LPVf) concentrations were measured using equilibrium dialysis and mass spectrometry.

RESULTS

The LPVt typical value of clearance (CLLPVt/F) was 4.73 L/h and the distribution volume (VLPVt/F) was 55.7 L. The clearance (CLLPVf/F) and distribution volume (Vf/F) for LPVf were 596 L/h and 6,370 L, respectively. The virion clearance rate was 0.0350 h(-1). The simulated LPVLPVt C trough values at 90% (EC90) and 95% (EC95) of the maximum response were 316 and 726 ng/mL, respectively.

CONCLUSIONS

The pharmacokinetic-pharmacodynamic model provides a useful tool to quantitatively describe the relationship between LPV/RTV exposure and viral response. This comprehensive modelling and simulation approach could be used as a surrogate assessment of antiretroviral (ARV) activity where adequate early-phase dose-ranging studies are lacking in order to define target trough concentrations and possibly refine dosing recommendations.

Pharmacokinetics of lopinavir/ritonavir and efavirenz in food insecure HIV-infected pregnant and breastfeeding women in Tororo, Uganda

Pregnancy and food insecurity may impact antiretroviral (ART) pharmacokinetics (PK), adherence and response. We sought to quantify and characterize the PK of lopinavir/ritonavir (LPV/r) and efavirenz (EFV) by pregnancy and nutritional status among HIV-infected women in Tororo, Uganda. In 2011, 62/225 ante-partum/post-partum single dried blood spot samples DBS and 43 post-partum hair samples for LPV/r were derived from 116 women, 51/194 ante-/post-partum DBS and 53 post-partum hair samples for EFV from 105 women. Eighty percent of Ugandan participants were severely food insecure, 26% lost weight ante-partum, and median BMI post-partum was only 20.2 kg/m(2) . Rich PK-data of normally nourished (pregnant) women and healthy Ugandans established prior information. Overall, drug exposure was reduced (LPV -33%, EFV -15%, ritonavir -17%) compared to well-nourished controls (P < 0.001), attributable to decreased bioavailability. Pregnancy increased LPV/r clearance 68% (P < 0.001), whereas EFV clearance remained unchanged. Hair concentrations correlated with plasma-exposure (P < 0.001), explaining 29% PK-variability. In conclusion, pregnancy and food insecurity were associated with lower ART exposures in this cohort of predominantly underweight women, compared to well-nourished women. Much variability in plasma-exposure was quantified using hair concentrations. Addressing malnutrition as well as ART-PK in this setting should be a priority.

HIV protease inhibitors in pregnancy : pharmacology and clinical use

The impact of antiretroviral therapy (ART) on the natural history of HIV-1 infection has resulted in dramatic reductions in disease-associated morbidity and mortality. Additionally, the epidemiology of HIV-1 infection worldwide is changing, as women now represent a substantial proportion of infected adults. As more highly effective and tolerable antiretroviral regimens become available, and as the prevention of mother-to-child transmission becomes an attainable goal in the management of HIV-infected individuals, more and more HIV-positive women are choosing to become pregnant and have children. Consequently, it is important to consider the efficacy and safety of antiretroviral agents in pregnancy. Protease inhibitors are a common class of medication used in the treatment of HIV-1 infection and are increasingly being used in pregnancy. However, several studies have raised concerns regarding pharmacokinetic alterations in pregnancy, particularly in the third trimester, which results in suboptimal drug concentrations and a theoretically higher risk of virologic failure and perinatal transmission. Drug level reductions have been observed with each individual protease inhibitor and dose adjustments in pregnancy are suggested for certain agents. Furthermore, studies have also raised concerns regarding the safety of protease inhibitors in pregnancy, particularly as they may increase the risk of pre-term birth and metabolic disturbances. Overall, protease inhibitors are safe and effective for the treatment of HIV-infected pregnant women. Specifically, ritonavir-boosted lopinavir- and atazanavir-based regimens are preferred in pregnancy, while ritonavir-boosted darunavir- and saquinavir-based therapies are reasonable alternatives. This paper reviews the use of protease inhibitors in pregnancy, focusing on pharmacokinetic and safety considerations, and outlines the recommendations for use of this class of medication in the HIV-1-infected pregnant woman.

The management of HIV-infected pregnant women

PURPOSE OF REVIEW

The purpose of this article is to update the current practice in the management of HIV-infected pregnant women and present evidence-based recommendations for the reduction of mother-to-child transmission.

RECENT FINDINGS

Early and sustained control of HIV viral replication is associated with decreasing residual risk of transmission and favors initiating antiretroviral drugs sufficiently early in naive women to suppress viral replication by the third trimester; however, this potential benefit must be balanced against the unknown long-term outcome of first-trimester drug exposure. Efavirenz should whenever possible be avoided in the first trimester of gestation, but its use seems well tolerated for 39 days after last menstrual period when the neural tube closes. Raltegravir may be considered in special circumstances in pregnancy.

SUMMARY

The HIV viral load and the risk factors for prematurity must be considered when deciding when to start antiretroviral treatment in each individual pregnant woman. A ritonavir-boosted protease inhibitor combined with two nucleoside reverse transcriptase inhibitors is currently the most widely used regimen. Among protease inhibitors, lopinavir combined with ritonavir is the most frequently used; however, atazanavir combined with ritonavir is a good alternative. Elective cesarean section is the best delivery mode for pregnant women with viral loads more than 50  copies/ml.

Therapeutic levels of lopinavir in late pregnancy and abacavir passage into breast milk in the Mma Bana Study, Botswana

BACKGROUND

Pharmacokinetic data for lopinavir in late pregnancy and in breastfeeding are limited, and no data for abacavir in breast milk are available.

METHODS

Women in the Mma Bana Study initiated HAART from 18 to 34 weeks of gestation. We determined trough plasma and whole breast milk concentrations of lopinavir (LPV), abacavir (ABC), nevirapine (NVP), lamivudine (3TC) and zidovudine (ZDV) among separate subsets of pregnant and breastfeeding women, and in plasma of exposed infants. Lopinavir was measured 1 month after starting HAART or 1 month postpartum, and other drugs were measured 1 month postpartum.

RESULTS

Sampling occurred a median of 14 h (range 11-17) from last maternal drug ingestion. Although 50% higher median LPV levels were seen in postpartum than antepartum plasma (8.29 μg/ml versus 5.51 μg/ml; P = 0.02), antepartum levels with standard LPV dosing were therapeutic for all women (> 1.0 μg/ml). Very low LPV levels (< 0.25 μg/ml) were detected in breast milk. Median ABC levels in breast milk were 85% of those in plasma (0.057 μg/ml versus 0.067 μg/ml). Breast milk concentrations of NVP and 3TC were 27% and 74% of plasma levels, respectively. At these trough maternal time points, only NVP was detectable in potentially inhibitory levels in breastfeeding infants, and most infants had non-detectable levels of LPV, ABC, ZDV and 3TC via maternal breast milk.

CONCLUSIONS

Standard LPV dosing achieved therapeutic levels in pregnancy and no appreciable concentrations in breast milk. ABC is detectable in breast milk at similar concentrations to plasma, but does not result in appreciable infant exposure.

Free and total plasma levels of lopinavir during pregnancy, at delivery and postpartum: implications for dosage adjustments in pregnant women

BACKGROUND

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

Assessment of lopinavir pharmacokinetics with respect to developmental changes in infants and the impact on weight band-based dosing

Improved antiretroviral therapies are needed for the treatment of HIV-infected infants, given the rapid progression of the disease and drug resistance resulting from perinatal exposure to antiretrovirals. We examined longitudinal pharmacokinetics (PK) data from a clinical trial of lopinavir/ritonavir (LPV/r) in HIV-infected infants in whom therapy was initiated at less than 6 months of age. A population PK analysis was performed using NONMEM to characterize changes in lopinavir (LPV) PK relating to maturational changes in infants, and to assess dosing requirements in this population. We also investigated the relationship between LPV PK and viral dynamic response. Age and ritonavir concentrations were the only covariates found to be significant. Population PK of LPV was characterized by high apparent clearance (CL/F) in young infants, which decreased with increasing age. Although younger infants had lower LPV concentrations, the viral dynamics did not correlate with initial LPV exposure. Monte Carlo simulations demonstrated that WHO weight band-based dosing recommendations predicted therapeutic LPV concentrations and provided drug exposure levels comparable to those resulting from US Food and Drug Administration (FDA)-suggested dosing regimens.

Lopinavir tablet pharmacokinetics with an increased dose during pregnancy

OBJECTIVE

Reduced lopinavir concentrations have been demonstrated with use of the capsule formulation during the third trimester of pregnancy. This study determined lopinavir exposure with an increased dose of the new tablet formulation during the third trimester.

DESIGN

International Maternal Pediatric Adolescent AIDS Clinical Trials 1026s is a prospective nonblinded pharmacokinetic study in HIV-infected pregnant women, including a cohort receiving 2 lopinavir/ritonavir tablets (400 mg/100 mg) twice daily during the second trimester, 3 tablets (600 mg/150 mg) twice daily during the third trimester, and 2 tablets (400 mg/100 mg) twice daily post delivery through 2 weeks postpartum.

METHODS

Steady-state 12-hour pharmacokinetic profiles were performed during pregnancy and at 2 weeks postpartum. Lopinavir and ritonavir were measured by reverse-phase high-performance liquid chromatography (detection limit, 0.09 mcg/mL).

RESULTS

Thirty-three women were studied. Median lopinavir AUC for the second trimester (n = 11), third trimester (n = 33), and postpartum (n = 27) were 72, 96, and 133 mcg x hr/mL, respectively. Median minimum lopinavir concentrations were 3.4, 4.9, and 6.9 mcg/mL.

CONCLUSIONS

The higher lopinavir/ritonavir tablet dose (600 mg/150 mg) provided exposure during the third trimester similar to the average AUC (98 mcg x hr x mL(-1) in nonpregnant adults taking 400 mg/100 mg twice daily. The higher dose should be used during the second and third trimesters of pregnancy. Postpartum dosing can be reduced to standard dosing before 2 weeks postpartum.

Antiretroviral regimens in pregnancy and breast-feeding in Botswana

BACKGROUND

The most effective highly active antiretroviral therapy (HAART) to prevent mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1) in pregnancy and its efficacy during breast-feeding are unknown.

METHODS

We randomly assigned 560 HIV-1-infected pregnant women (CD4+ count, > or = 200 cells per cubic millimeter) to receive coformulated abacavir, zidovudine, and lamivudine (the nucleoside reverse-transcriptase inhibitor [NRTI] group) or lopinavir-ritonavir plus zidovudine-lamivudine (the protease-inhibitor group) from 26 to 34 weeks' gestation through planned weaning by 6 months post partum. A total of 170 women with CD4+ counts of less than 200 cells per cubic millimeter received nevirapine plus zidovudine-lamivudine (the observational group). Infants received single-dose nevirapine and 4 weeks of zidovudine.

RESULTS

The rate of virologic suppression to less than 400 copies per milliliter was high and did not differ significantly among the three groups at delivery (96% in the NRTI group, 93% in the protease-inhibitor group, and 94% in the observational group) or throughout the breast-feeding period (92% in the NRTI group, 93% in the protease-inhibitor group, and 95% in the observational group). By 6 months of age, 8 of 709 live-born infants (1.1%) were infected (95% confidence interval [CI], 0.5 to 2.2): 6 were infected in utero (4 in the NRTI group, 1 in the protease-inhibitor group, and 1 in the observational group), and 2 were infected during the breast-feeding period (in the NRTI group). Treatment-limiting adverse events occurred in 2% of women in the NRTI group, 2% of women in the protease-inhibitor group, and 11% of women in the observational group.

CONCLUSIONS

All regimens of HAART from pregnancy through 6 months post partum resulted in high rates of virologic suppression, with an overall rate of mother-to-child transmission of 1.1%. (ClinicalTrials.gov number, NCT00270296.)