Total, Unbound, Renal, and Hepatic Clearances of Raltegravir and the Formation and Elimination Clearances of Raltegravir Glucuronide in Pregnant Women.

This work aimed to evaluate the total, unbound, renal, and hepatic clearances of raltegravir (RAL) and the formation and elimination clearances of raltegravir glucuronide (RAL GLU) in pregnant women living with HIV. The participants received RAL 400 mg twice daily during the third trimester (n = 15) of gestation, delivery (n = 15), and the postpartum period (n = 8). Pharmacokinetic parameter values were calculated on the basis of plasma and urine data using noncompartmental methods. RAL clearances for the third trimester of gestation were as follows: total clearance: geometric mean, 63.63 L/h (95% CI, 47.5-85.25); renal clearance: geometric mean, 2.56 L/h (95% CI, 1.96-3.34); hepatic clearance: geometric mean, 60.52 L/h (95% CI, 44.65-82.04); and unbound clearance: geometric mean, 281.14 L/h (95% CI, 203.68-388.05). RAL GLU formation and elimination clearances for the third trimester of gestation were 7.57 L/h (95% CI, 4.94-11.6) and 8.71 L/h (95% CI, 6.71-11.32), respectively. No differences were observed in RAL GLU pharmacokinetic parameters between the third trimester of gestation and the postpartum period, except for higher formation (7.57 vs 4.03 L/h) and elimination (8.71 vs 4.92 L/h) clearances during the third trimester. The findings based on plasma and urine data are consistent with an increase in the hepatic uridine 5' diphospho-glucuronosyltransferase isoenzymes activities involved in RAL metabolism during pregnancy, and the formation of RAL GLU is a minor route of RAL elimination. Compared to the postpartum period, in the third trimester of gestation, the similar RAL plasma exposure in pregnant women reinforces the maintenance of an RAL regimen including a 400-mg oral dose twice daily during pregnancy.

A population pharmacokinetics analysis assessing the exposure of raltegravir once-daily 1200 mg in pregnant women living with HIV.

Once-daily two 600 mg tablets (1200 mg q.d.) raltegravir offers an easier treatment option compared to the twice-daily regimen of one 400 mg tablet. No pharmacokinetic, efficacy, or safety data of the 1200 mg q.d. regimen have been reported in pregnant women to date as it is challenging to collect these clinical data. This study aimed to develop a population pharmacokinetic (PopPK) model to predict the pharmacokinetic profile of raltegravir 1200 mg q.d. in pregnant women and to discuss the expected pharmacodynamic properties of raltegravir 1200 mg q.d. during pregnancy based on previously reported concentration-effect relationships. Data from 11 pharmacokinetic studies were pooled (n = 221). A two-compartment model with first-order elimination and absorption through three sequential transit compartments best described the data. We assessed that the bio-availability of the 600 mg tablets was 21% higher as the 400 mg tablets, and the bio-availability in pregnant women was 49% lower. Monte-Carlo simulations were performed to predict the pharmacokinetic profile of 1200 mg q.d. in pregnant and nonpregnant women. The primary criteria for efficacy were that the lower bound of the 90% confidence interval (CI) of the concentration before next dose administration (Ctrough ) geometric mean ratio (GMR) of simulated pregnant/nonpregnant women had to be greater than 0.75. The simulated raltegravir Ctrough GMR (90% CI) was 0.51 (0.41-0.63), hence not meeting the primary target for efficacy. Clinical data from two pregnant women using 1200 mg q.d. raltegravir showed a similar Ctrough ratio pregnant/nonpregnant. Our pharmacokinetic results support the current recommendation of not using the raltegravir 1200 mg q.d. regimen during pregnancy until more data on the exposure-response relationship becomes available.

Impact of Low Birth Weight and Prematurity on Neonatal Raltegravir Pharmacokinetics: Impaact P1097.

BACKGROUND: HIV treatment of neonates requires identifying appropriate antiretroviral dosing regimens. Our aims were to characterize raltegravir elimination kinetics in low birth weight (LBW) neonates after maternal dosing and to develop a pharmacokinetic model to predict raltegravir plasma concentrations for term and preterm neonates. METHODS: Mothers living with HIV who received raltegravir during pregnancy and their LBW neonates participated in IMPAACT P1097 study. Up to 6 serial plasma samples were collected from each infant over the first 2 postnatal weeks to characterize raltegravir elimination. Safety laboratory evaluations were obtained, and infants were monitored for 6 weeks for signs of raltegravir toxicity. An integrated maternal-neonatal pharmacokinetic model was developed to predict neonatal raltegravir plasma concentrations. RESULTS: Sixteen mothers and their 18 LBW neonates were enrolled. The median (range) raltegravir elimination half-life was 24.4 (10.1-83) hours (N = 17 neonates). No adverse events related to raltegravir in utero exposure were observed. Pharmacokinetic modeling revealed that raltegravir clearance in full-term LBW neonates was well described by allometric scaling but clearance in preterm LBW neonates was better described using slower clearance maturation kinetics. Simulations suggest receipt of the current dosing recommendations in a 34-week gestation neonate would result in plasma concentrations up to 2.5-fold higher than those observed in full-term LBW infants. CONCLUSIONS: Modeling suggests that prematurity reduces raltegravir clearance and a modified raltegravir dosing regimen will be necessary to avoid elevated plasma raltegravir concentrations.

Comparative Clinical Pharmacokinetics and Pharmacodynamics of HIV-1 Integrase Strand Transfer Inhibitors: An Updated Review.

Bictegravir, cabotegravir, dolutegravir, elvitegravir, and raltegravir are members of the latest class of antiretrovirals available to treat human immunodeficiency virus (HIV) infection, the integrase strand transfer inhibitors. Integrase strand transfer inhibitors are potent inhibitors of the HIV integrase enzyme with IC90/95 values in the low nanogram per milliliter range and they retain antiviral activity against strains of HIV with acquired resistance to other classes of antiretrovirals. Each of the integrase strand transfer inhibitors have unique pharmacokinetic/pharmacodynamic properties, influencing their role in clinical use in specific subsets of patients. Cabotegravir, approved for use in Canada but not yet by the US Food and Drug Administration, is formulated in both oral and intramuscular formulations; the latter of which has shown efficacy as a long-acting extended-release formulation. Cabotegravir, raltegravir, and dolutegravir have minimal drug-drug interaction profiles, as their metabolism has minimal cytochrome P450 involvement. Conversely, elvitegravir metabolism occurs primarily via cytochrome P450 3A4 and requires pharmacokinetic boosting to achieve systemic exposures amenable to once-daily dosing. Bictegravir metabolism has similar contributions from both cytochrome P450 3A4 and uridine 5'-diphospho-glucuronosyltransferase 1A1. Bictegravir, dolutegravir, and raltegravir are recommended components of initial regimens for most people with HIV in the US adult and adolescent HIV treatment guidelines. This review summarizes and compares the pharmacokinetics and pharmacodynamics of the integrase strand transfer inhibitor agents, and describes specific pharmacokinetic considerations for persons with hepatic impairment, renal dysfunction, pregnancy, and co-infections.

Prediction of Maternal and Fetal Pharmacokinetics of Dolutegravir and Raltegravir Using Physiologically Based Pharmacokinetic Modeling.

BACKGROUND: Predicting drug pharmacokinetics in pregnant women including placental drug transfer remains challenging. This study aimed to develop and evaluate maternal-fetal physiologically based pharmacokinetic models for two antiretroviral drugs, dolutegravir and raltegravir.

Raltegravir (RAL) in Neonates: Dosing, Pharmacokinetics (PK), and Safety in HIV-1-Exposed Neonates at Risk of Infection (IMPAACT P1110).

BACKGROUND: Adequate pharmacokinetic and safety data in neonates are lacking for most antiretroviral agents. Raltegravir is a selective HIV-1 integrase strand transfer inhibitor available in a granule formulation suitable for use in neonates and young infants as prophylaxis or treatment of HIV infection. METHODS: IMPAACT P1110 is a phase 1, multicenter, noncomparative dose-finding study of raltegravir in infants exposed to HIV-1 infection. A 2-cohort adaptive design was utilized where pharmacokinetic data from infants in cohort 1 who received 2 single doses of raltegravir 3 mg/kg were included in population modeling and simulations to guide selection of a daily dose for infants in cohort 2. RESULTS: A total of 52 infants enrolled in IMPAACT 1110: cohort 1 (N = 16) and cohort 2 (N = 36). Using simulations based on population PK modeling incorporating cohort 1 data, the following daily dosing regimen was selected for study: 1.5 mg/kg daily from birth through day 7; 3 mg/kg twice daily from days 8-28 of life; and 6 mg/kg twice daily after 4 weeks of age through 6 weeks of age. The geometric mean protocol exposure targets for AUC, Ctrough, and Cmax were met or slightly exceeded in all infants. The chosen neonatal raltegravir dosing regimen was safe and well tolerated in full-term neonates during treatment over the first 6 weeks of life and follow-up to age 24 weeks. CONCLUSIONS: Raltegravir can be safely administered to full-term infants using the daily dosing regimen studied. This regimen is not recommended for use in premature infants in a new version of P1110.

Determination of raltegravir and raltegravir glucuronide in human plasma and urine by LC-MS/MS with application in a maternal-fetal pharmacokinetic study.

Raltegravir (RAL) is a HIV-integrase inhibitor recommended for treatment of HIV type 1 infection during pregnancy. The elimination of RAL to RAL glucuronide (RAL GLU) is mediated primarily by UDP glucuronosyltransferase 1A1 (UGT1A1). The present study shows the development and validation of 4 different methods for the analysis of RAL and RAL GLU in plasma and in urine samples. The methods were applied to evaluate the maternal-fetal pharmacokinetics of RAL and RAL GLU in a HIV-infected pregnant woman receiving RAL 400 mg twice daily. The sample preparation for RAL and RAL GLU analysis in 25 µL plasma and 100 µL diluted urine (10-fold with water containing 0.1% formic acid) were carried out by protein precipitation procedure. RAL and RAL GLU generate similar product mass fragments and require separation in the chromatographic system, so a suitable resolution was achieved for unchanged RAL and RAL GLU employing Ascentis Express C18 (75 × 4.6 mm, 2.7 µm) for both plasma and urine samples. The methods showed linearities at the ranges of 0.1-13.5 µg/mL RAL and 0.15-19.5 µg/mL RAL GLU in urine and 10-2000 ng/mL RAL and 2.5-800 RAL GLU in plasma. Precise and accurate evaluation showed coefficients of variation and relative errors ≤ 15%. The methods have been successfully applied in a maternal-fetal pharmacokinetic study.

Pharmacokinetics and safety of a raltegravir-containing regimen in HIV-infected children aged 2-12 years on rifampicin for tuberculosis.

OBJECTIVES: Drug-drug interactions limit current antiretroviral treatment options for HIV-infected children with tuberculosis (TB). Rifampicin (RIF) induces UDP-glucuronosyltransferase activity, accelerating the clearance of raltegravir (RAL). We sought to establish an optimal and well tolerated dose of RAL when administered with RIF to HIV and TB co-infected children. DESIGN: P1101 is a phase I/II open-label dose-finding study of RAL with RIF for children 2 to less than 12 years of age beginning treatment for HIV and active TB. SETTING: Four sites in South Africa. METHODS: Chewable RAL was given at 12 mg/kg per dose twice daily (twice the usual pediatric dose) with two nucleoside reverse transcriptase inhibitors. Intensive RAL pharmacokinetic sampling was conducted 5 to 8 days after antiretroviral therapy was initiated; a fourth antiretroviral agent was then added. RESULTS: Children were recruited into two age-defined groups: cohort 1 (2 to <6 years old) and cohort 2 (6 to <12 years old). Pharmacological targets [geometric mean (GM) AUC12 h of 14-45 µmol/l h and GM C12 h ≥75 nmol/l) were reached in both cohort 1 (28.8 µmol/l h and 229 nmol/l) and cohort 2 (38.8 µmol/l h and 228 nmol/l). The RAL-based ART was well tolerated by most participants: one participant discontinued treatment because of grade 4 hepatitis that was possibly treatment-related. At week 8, 22 of 24 participants (92%) had HIV RNA concentrations below 400 copies/ml; 19 of 24 (79%) were below 50 copies/ml. CONCLUSION: Giving 12 mg/kg twice daily of the chewable RAL formulation achieved pharmacokinetic targets safely in HIV-infected children receiving RIF for TB.

Use of Modeling and Simulations to Determine Raltegravir Dosing in Neonates: A Model for Safely and Efficiently Determining Appropriate Neonatal Dosing Regimens: IMPAACT P1110.

BACKGROUND: Population modeling and simulations can be used to facilitate the conduct of phase I studies to develop safe and effective dosing regimens in neonates. SETTING: P1110 is an international, multicenter trial to determine safe and effective raltegravir doses in neonates at risk for HIV infection. METHODS: P1110 used a 2-cohort adaptive design incorporating population pharmacokinetic modeling and simulations. An initial cohort of neonates received 2 single oral doses of raltegravir with standard-of-care therapy for prevention of perinatal transmission-one within 48 hours of birth and a second at 7-10 days of life. Raltegravir concentration data after administration of these doses were combined with data from a previous study of infants aged 4 weeks to 2 years. The combined database was used for population pharmacokinetic modeling and simulations to select a daily dosing regimen for investigation in a second cohort of neonates. RESULTS: Raltegravir concentration data from 6 neonates were combined with data from infants aged 4 weeks to 2 years receiving raltegravir twice daily. The combined data set allowed for successful development of a population pharmacokinetic model with reasonable precision of parameter estimates. Monte Carlo simulations were run to evaluate potential daily dosing regimens from birth to 6 weeks of age, allowing for selection of a regimen to be evaluated in a subsequent cohort of neonates receiving chronic raltegravir dosing. CONCLUSIONS: An adaptive design incorporating population pharmacokinetic modeling and simulations was used to select a developmentally appropriate neonatal raltegravir dosing regimen in the first 6 weeks of life.

Maternal-Neonatal Raltegravir Population Pharmacokinetics Modeling: Implications for Initial Neonatal Dosing.

Raltegravir readily crosses the placenta to the fetus with maternal use during pregnancy. After birth, neonatal raltegravir elimination is highly variable and often extremely prolonged, with some neonates demonstrating rising profiles after birth despite removal from the source of extrinsic raltegravir. To establish an appropriate dosing regimen, an integrated maternal-neonatal pharmacokinetics model was built to predict raltegravir plasma concentrations in neonates with in utero raltegravir exposure. Postnatal age and body weight were used as structural covariates. The model predicted rising or decreasing neonatal elimination profiles based on the time of maternal drug administration relative to time of birth and degree of in utero drug disposition into the central and peripheral compartments. Based on this model, it is recommended to delay the first oral dose of raltegravir until 1-2 days of age in those neonates born to mothers who received raltegravir during pregnancy, labor, and delivery.

Lack of a Clinically Significant Pharmacokinetic Interaction between Etravirine and Raltegravir Using an Original Approach Based on Drug Metabolism, Protein Binding, and Penetration in Seminal Fluid: A Pharmacokinetic Substudy of the ANRS-163 ETRAL Study.

STUDY OBJECTIVE: The ANRS163-ETRAL study showed that etravirine 200 mg/raltegravir 400 mg twice-daily dual therapy was highly effective in the treatment of human immunodeficiency virus (HIV)-infected patients older than 45 years, with virologic and therapeutic success rates at week 48 of 99.4% and 94.5%, respectively. The objective of this study was to determine whether a clinically significant pharmacokinetic interaction between etravirine and raltegravir exists by assessing steady-state total and unbound etravirine, raltegravir, and inactive raltegravir-glucuronide concentrations 12 hours after last intake (C12h ) in blood plasma (BP) and seminal plasma (SP). DESIGN: Pharmacokinetic analysis of data from the ANRS163-ETRAL study. PATIENTS: One hundred forty-six HIV-1-infected patients (of the 165 patients included in the ANRS-163 ETRAL study) who were receiving etravirine 200 mg and raltegravir 400 mg twice daily. MEASUREMENTS AND MAIN RESULTS: Blood was collected from all 146 patients at weeks 2-4, 12, 24, and 48, and semen was collected from 21 patients at week 48. The extent of BP and SP protein binding was determined by using ultrafiltration assay. Total and unbound etravirine, raltegravir, and raltegravir-glucuronide C12h were determined by ultra high performance liquid chromatography coupled with tandem mass spectrometry and interpreted by using the in vitro calculated protein-bound 95% inhibitory concentration (PBIC95 ) for wild-type (WT) HIV: etravirine (116 ng/ml) and raltegravir (15 ng/ml). Median (interquartile range [IQR]) total BP etravirine C12h (536 ng/ml [376-719]) and raltegravir (278 ng/ml [97-690]) were adequate in 99% and 96% of patients, respectively. Median (IQR) SP:BP C12h ratio and BP unbound fraction were etravirine 0.3 (0.2-0.5) and < 1%, respectively, raltegravir 1.8 (1.3-3.3) and 12%, respectively, and raltegravir-glucuronide 12.0 (6.5-17.7) and > 99%, respectively. The BP raltegravir metabolic ratio (raltegravir glucuronide:raltegravir ratio) was 1.7, suggesting only weak induction of raltegravir glucuronidation by etravirine. Only three patients had etravirine and raltegravir C12h < PBIC95 simultaneously. CONCLUSION: No clinically significant pharmacokinetic interaction between etravirine and raltegravir was detected. Total etravirine and raltegravir BP concentrations were adequate in most patients, favoring virologic efficacy and confirming good treatment adherence (> 95%), despite twice-daily administration. The long half-life of etravirine and higher unbound fraction SP of raltegravir (57%) ensured adequate concentrations of dual therapy in genital compartments. Our results indicate that etravirine and raltegravir have good, complementary pharmacokinetic profiles, suggesting that they could be used in a dual-treatment strategy.

Pharmacokinetics of HIV-Integrase Inhibitors During Pregnancy: Mechanisms, Clinical Implications and Knowledge Gaps.

Prevention of mother-to-child transmission of HIV and optimal maternal treatment are the most important goals of antiretroviral therapy in pregnant women with HIV. These goals may be at risk due to possible reduced exposure during pregnancy caused by physiological changes. Limited information is available on the impact of these physiological changes. This is especially true for HIV-integrase inhibitors, a relatively new class of drugs, recommended first-line agents and hence used by a large proportion of HIV-infected patients. Therefore, the objective of this review is to provide a detailed overview of the pharmacokinetics of HIV-integrase inhibitors in pregnancy. Second, this review defines potential causes for the change in pharmacokinetics of HIV-integrase inhibitors during pregnancy. Despite increased clearance, for raltegravir 400 mg twice daily and dolutegravir 50 mg once daily, exposure during pregnancy seems adequate; however, for elvitegravir, the proposed minimal effective concentration is not reached during pregnancy. Lower exposure to these drugs may be caused by increased hormone levels and, subsequently, enhanced drug metabolism during pregnancy. The pharmacokinetics of bictegravir and cabotegravir, which are under development, have not yet been evaluated in pregnant women. New studies need to prospectively assess whether adequate exposure is reached in pregnant women using these new HIV-integrase inhibitors. To further optimize antiretroviral treatment in pregnant women, studies need to unravel the underlying mechanisms behind the changes in the pharmacokinetics of HIV-integrase inhibitors during pregnancy. More knowledge on altered pharmacokinetics during pregnancy and the underlying mechanisms contribute to the development of effective and safe antiretroviral therapy for HIV-infected pregnant women.

Safety and efficacy at 240 weeks of different raltegravir formulations in children with HIV-1: a phase 1/2 open label, non-randomised, multicentre trial.

BACKGROUND: Raltegravir is an integrase inhibitor approved for use in adults and children with HIV-1 infection, but there are no data on the long-term use of this medication in children. We aimed to assess the long-term safety, tolerability, pharmacokinetics, and efficacy of multiple raltegravir formulations in children aged 4 weeks to 18 years with HIV-1 infection. METHODS: In this phase 1/2 open-label multicentre trial (IMPAACT P1066), done in 43 IMPAACT network sites in the USA, South Africa, Brazil, Botswana, and Argentina, eligible participants were children aged 4 weeks to 18 years with HIV-1 infection who had previously received antiretroviral therapy (ART), had HIV-1 RNA higher than 1000 copies per mL, and no exposure to integrase inhibitors. Participants were separated into five age groups and enrolled in six cohorts. Three formulations of open-label raltegravir-adult tablets, chewable tablets, and granules for oral suspension-were added to individualised optimised background therapy, according to the age and weight of participants. The primary outcome at 48 weeks has been previously reported. In the 240-week follow-up, outcomes of interest included graded clinical and laboratory safety of raltegravir formulations during the study and virological efficacy (with virological success defined as HIV-1 RNA reduction of >1 log10 from baseline or HIV-1 RNA <400 copies per mL) at week 240. The primary analysis group for safety and efficacy comprised patients treated only with the final selected dose of raltegravir. This trial is registered with ClinicalTrials.gov, number NCT00485264. FINDINGS: Between August, 2007, and December, 2012, 220 patients were assessed for eligibility, and 153 were enrolled and treated. Of these patients, 122 received only the final selected dose of raltegravir (63 received adult tablets, 33 chewable tablets, and 26 oral granules), and one was not treated. There were few serious clinical or laboratory safety events noted, with two patients having a drug-related adverse event (skin rash), which led one patient to discontinue the study treatment. The addition of raltegravir to an individually optimised ART regimen resulted in virological success at week 240 in 19 (44·2%, 95% CI 29·1-60·1) of 43 patients receiving 400 mg tablets, 24 (77·4%, 58·9-90·4) of 31 patients receiving the chewable tablets, and 13 (86·7%, 59·5-98·3) of 15 patients receiving oral granules. Among patients with virological failure, raltegravir resistance was noted in 19 (38%) of 50 patients who had virological rebound after initial suppression and had samples at virological failure available for testing. INTERPRETATION: Our study suggests that raltegravir can be used for the treatment of HIV-1 infection in children as young as 4 weeks, with the expectation of long-term safety and efficacy, but should be used with caution among older children who had previous extensive antiretroviral therapy. FUNDING: National Institute of Allergy and Infectious Diseases, National Institute of Child Health and Human Development, National Institute of Mental Health, and Merck.

Decreased darunavir concentrations during once-daily co-administration with maraviroc and raltegravir: OPTIPRIM-ANRS 147 trial.

Background: The OPTIPRIM-ANRS 147 trial compared intensive combination ART (darunavir/ritonavir, tenofovir disoproxil fumarate/emtricitabine, raltegravir and maraviroc) started early during primary HIV-1 infection with standard tritherapy with darunavir/ritonavir, tenofovir disoproxil fumarate and emtricitabine. From month 6 to 18, the percentage of viral load values <50 copies/mL was lower in the pentatherapy arm than in the tritherapy arm. Here we compared antiretroviral drug concentrations between the two arms. Methods: Plasma samples were collected from 50 patients at various times after drug administration. A Bayesian approach based on published population pharmacokinetic models was used to estimate residual drug concentrations (Ctrough) and exposures (AUC) in each patient. A mixed linear regression model was then used to compare the AUC and Ctrough values of each drug used in both groups. Results: Published models adequately described our data and could be used to predict Ctrough and AUC. No significant difference in tenofovir disoproxil fumarate, emtricitabine and ritonavir parameters was found between the two arms. However, darunavir Ctrough and AUC were significantly lower in the pentatherapy arm than in the tritherapy arm (P = 0.03 and P = 0.04, respectively). Conclusions: Adding maraviroc and raltegravir to darunavir-based tritherapy decreased darunavir concentrations. Compliance issues, maraviroc-darunavir interaction and raltegravir-darunavir interaction were suspected and may affect the kinetics of viral decay during pentatherapy. A specific pharmacokinetic interaction study is needed to explore the interactions between darunavir and maraviroc and raltegravir.

Single- and Multiple-Dose Pharmacokinetics of Once-Daily Formulations of Raltegravir.

A new once-daily formulation of raltegravir, an integrase strand transfer inhibitor indicated in combination with other antiretroviral drugs for the treatment of human immunodeficiency virus-1 infection, is under development. Single-dose and steady-state pharmacokinetics of 1200 mg for 2 formulations of raltegravir were characterized in 2 open-label phase 1 studies in healthy male and female subjects aged 18 to 55 years. The new raltegravir 600-mg formulation had a higher relative bioavailability compared with the 400-mg tablets. Once absorbed, both 3 × 400-mg and 2 × 600-mg dosage forms of raltegravir exhibited similar systemic pharmacokinetics; in dictating bioavailability, differences were from increased absorption that was the result of improved in vivo disintegration/dissolution. Food had a smaller effect on the pharmacokinetics of raltegravir when given as 2 × 600-mg formulation (42% vs 73% decrease in AUC0-last ). Steady state was generally reached in 2 days, with little to no accumulation with multiple-dose administration. Raltegravir 1200 mg was found to exhibit pharmacokinetic properties amenable for once-daily dosing and was generally well tolerated in healthy subjects after single and multiple doses. The new formulation improved the bioavailability of this Biopharmaceutics Classification System class II compound.

Penetration and antiviral efficacy of total and unbound maraviroc, raltegravir and rilpivirine in both female and male genital fluids from HIV-positive patients receiving regimens containing these antiretrovirals.

BACKGROUND: Sub-optimal penetration of antiretroviral drugs in genital compartments might promote local HIV persistence and increase the risk of HIV transmission. OBJECTIVES: To describe the penetration of maraviroc, raltegravir, raltegravir glucuronide and rilpivirine in seminal plasma and cervico-vaginal secretions (CVS) and to assess local antiretroviral efficacy in HIV-1-positive patients. METHODS: This was a prospective, multicentre study. Inclusion criteria were HIV-1 positive, age >18 years, receiving regimens containing maraviroc and/or raltegravir and/or rilpivirine for >1 month, and good self-reported adherence. Paired blood and genital samples were collected 12 h (raltegravir and maraviroc) or 24 h (rilpivirine) post-dose. These concentrations were determined (UPLC-MS/MS) in blood and seminal plasma (total and unbound) and CVS (total, dried spots) and HIV-RNA was quantified in paired blood and genital samples. RESULTS: Among the 54 enrolled patients, 15 received maraviroc (6 men), 27 received raltegravir (14 men) and 20 received rilpivirine (10 men), corresponding to 54 total and 52 unbound plasma concentrations, 29 total CVS samples and 23 total and 18 unbound seminal plasma samples. Maraviroc and raltegravir displayed a ratio of genital fluids/plasma concentrations >0.5 in both male and female genital tracts. Conversely, rilpivirine displayed a low ratio. Antiretroviral free fractions were consistent with historical data. Nine patients had blood plasma HIV-RNA >50 copies/mL (2/9 had sub-optimal antiretroviral blood plasma exposure) and two other patients had detectable HIV-RNA in genital fluids. CONCLUSIONS: Maraviroc and raltegravir demonstrated good penetration in genital compartments, yielding good local virological response in genital compartments, whereas rilpivirine presented a low penetration profile but good local response.

Raltegravir 1200 mg once daily versus raltegravir 400 mg twice daily, with tenofovir disoproxil fumarate and emtricitabine, for previously untreated HIV-1 infection: a randomised, double-blind, parallel-group, phase 3, non-inferiority trial.

BACKGROUND: Once daily regimens are preferred for HIV-1 treatment, to facilitate adherence and improve quality of life. We compared a new once daily formulation of raltegravir to the currently marketed twice daily formulation. METHODS: In this randomised, double-blind, parallel-group, phase 3, non-inferiority study, we enrolled participants aged 18 years or older with HIV-1 RNA of 1000 or more copies per mL and no previous antiretroviral treatment at 139 sites worldwide. We randomly assigned participants (2:1) via an interactive voice and web response system to raltegravir 1200 mg (two 600 mg tablets) orally once daily or raltegravir 400 mg (one tablet) orally twice daily, each with tenofovir disoproxil fumarate and emtricitabine orally once daily, for up to 96 weeks. A computer-generated allocation schedule stratified randomisation by screening HIV-1 RNA value and co-infection with hepatitis B or C. Participants, sponsor personnel, investigators, and study site personnel involved in the treatment or evaluation of the participants were unaware of the treatment group assignments. The primary endpoint was the proportion of participants with HIV-1 RNA less than 40 copies per mL at week 48 assessed with the US Food and Drug Administration Snapshot algorithm. Non-inferiority was concluded if the lower bound of the two-sided 95% CI was greater than -10%. We assessed efficacy and safety in all participants who received one dose or more of study treatment. This study is registered with ClinicalTrials.gov, number NCT02131233. FINDINGS: Between May 26, 2014, and Dec 5, 2014, 802 participants were enrolled and randomly assigned, 533 to once daily treatment and 269 to twice daily; 797 received study therapy, 531 once daily and 266 twice daily. At week 48, 472 (89%) of 531 once daily recipients and 235 (88%) of 266 twice daily recipients achieved HIV-1 RNA less than 40 copies per mL (treatment difference 0·5%, 95% CI -4·2 to 5·2). Drug-related adverse events occurred in 130 (24%) of 531 participants in the once daily group (one of which was serious; none led to treatment discontinuation) and 68 (26%) of 266 participants in the twice daily group (two of which were serious; two led to treatment discontinuation). The most common drug-related adverse events were nausea (39 [7%] vs 18 [7%]), headache (16 [3%] vs 12 [5%]), and dizziness (12 [2%] vs eight [3%]). No treatment-related deaths were reported. INTERPRETATION: A once daily raltegravir 1200 mg regimen was non-inferior compared with raltegravir 400 mg twice daily for initial treatment of HIV-1 infection. These results support the use of raltegravir 1200 mg once daily for first-line therapy. FUNDING: Merck & Co, Inc.

Plasma and saliva concentrations of abacavir, tenofovir, darunavir, and raltegravir in HIV-1-infected patients
.

OBJECTIVE: We studied the relationships between plasma and saliva concentrations of antiretroviral drugs to explore whether saliva can be used for therapeutic drug monitoring (TDM). METHODS: Abacavir (ABC), tenofovir (TFV), darunavir (DRV), and raltegravir (RAL) in plasma and saliva from 30 HIV-1-infected patients were quantified using liquid chromatography-tandem mass spectrometry. RESULTS: Mean saliva-to-plasma concentration ratios were 0.623 (ABC), 0.024 (TFV), 0.065 (DRV), and 0.0135 (RAL), which agree with the plasma protein binding rates except TFV. Significant correlations were evident between saliva and plasma concentrations of ABC, DRV, and RAL. CONCLUSIONS: This study suggests that plasma concentrations of ABC, DRV, and RAL can be estimated from their saliva concentrations and that the saliva concentration of some antiretroviral drugs reflects the unbound drug concentration in plasma.
.

Therapeutic drug monitoring guided raltegravir dosing for prevention of vertical transmission in a premature neonate born to a woman living with perinatally acquired HIV.

We report a case of therapeutic drug monitoring guided raltegravir use for the prevention of vertical HIV transmission in a premature neonate born to a woman living with perinatally acquired HIV and documented resistance to multiple HIV drugs. Maternal viral load was above 1,000 copies/ml at delivery. This case demonstrates delayed raltegravir elimination in a neonate born at 33 weeks gestational age and a need for less frequent raltegravir dosing than is used in older infants and children.

Pregnancy-related changes of antiretroviral pharmacokinetics: an argument for therapeutic drug monitoring.

Here we describe a case of an HIV-infected young woman with extensive drug-resistant virus, who was successfully switched from a raltegravir-based regimen to a dolutegravir-based intensified antiretroviral regimen a few days before scheduled caesarean section because of the still detectable viral load. The trough concentrations of all antiretroviral drugs before and after delivery are also described. Our case underlines both the difficult management of young women, HIV-infected at young age with very limited treatment options and the great variability in the pregnancy-related physiological changes affecting the pharmacokinetics of antiretrovirals.