Population Pharmacokinetic Analysis of Darunavir and Tenofovir Alafenamide in HIV-1-Infected Patients on the Darunavir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Single-Tablet Regimen (AMBER and EMERALD Studies).

The single-tablet regimen darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg has undergone phase III studies AMBER (NCT02431247) and EMERALD (NCT02269917) in HIV-infected patients. An existing population pharmacokinetic (PopPK) model for cobicistat-boosted darunavir (DRV) was updated to describe DRV PK in AMBER and EMERALD. For TAF, a PopPK model was developed using richly sampled phase I/II data and updated with sparsely sampled AMBER data. Individual exposure metrics for DRV and TAF in patients receiving D/C/F/TAF were derived (AMBER, n=356; EMERALD, n=750). The DRV PopPK model is a two-compartment model with sequential zero-order, first-order input. TAF PK is described by a one-compartment model with dual parallel input for absorption (slow and fast pathway). DRV covariates were α1-acid-glycoprotein and body weight. TAF covariates were lean body weight and α1-acid-glycoprotein. DRV and TAF PK were unaffected by age, race, or gender. Estimated DRV mean (SD) C0h and AUC24h, respectively, were 1899 (759) ng/mL and 87,909 (20,232) ng*h/mL in AMBER; 1813 (859) ng/mL and 85,972 (22,413) ng*h/mL in EMERALD. Estimated TAF mean (SD) AUC24h was 132 (41) ng*h/mL. These PK parameters were in line with historical data. No apparent relationships of DRV or TAF exposure with efficacy (virologic response) or safety (metabolic, cardiac, liver, gastrointestinal, skin, bone, renal, pancreas, lipid events) parameters were seen. Additionally, our findings demonstrate that in patients with low plasma concentrations, there is no risk of decreased virologic response or virologic rebound. This supports the use of a once-daily, single-tablet regimen of D/C/F/TAF 800/150/200/10 mg for the treatment of HIV-1-infected subjects.

Etravirine in treatment-experienced HIV-1-infected children 1 year to less than 6 years of age.

OBJECTIVE: To describe the pharmacokinetics, safety, and efficacy of etravirine (ETR) in HIV-infected children 1 to less than 6 years of age. DESIGN: Phase I/II, open-label, multicenter, dose-finding study. METHODS: Antiretroviral therapy (ART)-experienced children in two age cohorts (I: 2 to <6 years; II: 1 to less than 2 years) received weight-based ETR, swallowed whole or dispersed in liquid, with optimized ART including a ritonavir-boosted protease inhibitor. Intensive pharmacokinetics occurred 7-18 days after starting ETR. Participants with ETR AUC12h less than 2350 ng h/ml had a dose increase and repeat pharmacokinetics. RESULTS: Twenty-six children enrolled and 21 (15 in cohort I and 6 in cohort II) had evaluable intensive pharmacokinetics sampling at the final weight-based dose. On the final dose, the geometric mean ETR AUC12h was 3823 ng h/ml for cohort I and 3328 ng h/ml for cohort II. Seven children (33.3%) on the final dose, all taking ETR dispersed, had an AUC12  h less than 2350 ng h/ml and underwent a dose increase. ETR AUC12  h was 3.8-fold higher when ETR was swallowed whole vs. dispersed, P less than 0.0001. On the final dose, 75 and 33.3% in cohorts I and II, respectively, had HIV-1 RNA 400 copies/ml or less or at least 2 log reductions from baseline at week 48. Three children (11.5%) experienced a grade at least 3 adverse event related to ETR but only 1 discontinued. CONCLUSION: ETR was well tolerated. Predefined pharmacokinetics targets were met but overall exposures were low vs. historical data in adults, particularly in young children taking dispersed tablets. A high rate of viral efficacy was observed among those aged 2 to more than 6 years but not in those less than 2 years.

Bioequivalence of the Once-Daily Single-Tablet Regimen of Darunavir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide Compared to Combined Intake of the Separate Agents and the Effect of Food on Bioavailability.

The effect of food on the bioavailability of the components of the once-daily, single-tablet human immunodeficiency virus (HIV) type 1 regimen containing darunavir (DRV 800 mg), cobicistat (COBI 150 mg), emtricitabine (FTC 200 mg), and tenofovir alafenamide (TAF 10 mg) (D/C/F/TAF) (NCT02475135) and the bioequivalence of D/C/F/TAF versus combined intake of the separate agents (NCT02578550) were evaluated. These were 2 phase 1, open-label, randomized, 2-period crossover studies (7-day washout between treatments) in HIV-negative healthy volunteers. Twenty-four participants each received a single dose of D/C/F/TAF in fasted conditions (test) or after a standardized high-fat breakfast (reference). Ninety-six participants each received a single dose of D/C/F/TAF (test) or combined intake of a single DRV 800-mg tablet, a COBI 150-mg tablet, and an FTC/TAF 200/10-mg tablet (reference), both after a standardized regular-calorie, regular-fat breakfast. Pharmacokinetic profiles for all D/C/F/TAF components, safety, and tolerability were assessed. Following D/C/F/TAF in fasted conditions, DRV peak concentration, area under the concentration-time curve from time of administration until the last time point with a measurable concentration (AUC)last , and extrapolated to infinity (AUCinf ) were lower by 45%, 34%, and 30%, respectively, compared with fed conditions, with no clinically relevant differences in COBI, FTC, or TAF exposures between fed and fasted conditions. In the bioequivalence study 90% confidence intervals of the geometric mean ratios of all main pharmacokinetic parameters were within the 80.00% to 125.00% bioequivalence limits for DRV, COBI, FTC, and TAF. No grade 3/4 adverse events (AEs), serious AEs, deaths, or discontinuations due to AEs occurred. D/C/F/TAF is bioequivalent to combined administration of the separate agents. Consistent with other (co)formulations of DRV, DRV exposure was lower in fasted than in fed conditions as evaluated when taken with food, so D/C/F/TAF should be taken with food.

Pharmacokinetics, Antiviral Activity, and Safety of Rilpivirine in Pregnant Women with HIV-1 Infection: Results of a Phase 3b, Multicenter, Open-Label Study.

INTRODUCTION: Physiologic changes during pregnancy may impact the pharmacokinetics of drugs. In addition, efficacy and safety/tolerability concerns have been identified for some antiretroviral agents. METHODS: Human immunodeficiency virus (HIV)-1-infected pregnant women (18-26 weeks gestation) receiving the non-nucleoside reverse transcriptase inhibitor rilpivirine 25 mg once daily were enrolled in this phase 3b, open-label study examining the impact of pregnancy on the pharmacokinetics of rilpivirine when it is given in combination with other antiretroviral agents. Blood samples (collected over the 24-h dosing interval) to assess total and unbound rilpivirine plasma concentrations were obtained during the second and third trimesters (24-28 and 34-38 weeks gestation, respectively) and 6-12 weeks postpartum. Pharmacokinetic parameters were derived using noncompartmental analysis and compared (pregnancy versus postpartum) using linear mixed effects modeling. Antiviral and immunologic response and safety were assessed. RESULTS: Nineteen women were enrolled; 15 had evaluable pharmacokinetic results. Total rilpivirine exposure was 29-31% lower during pregnancy versus postpartum; differences were less pronounced for unbound (pharmacodynamically active) rilpivirine. At study entry, 12/19 (63.2%) women were virologically suppressed; 10/12 (83.3%) women were suppressed at the postpartum visit. Twelve infants were born to the 12 women who completed the study (7 discontinued); no perinatal viral transmission was observed among 10 infants with available data. Rilpivirine was generally safe and well tolerated in women and infants exposed in utero. CONCLUSION: Despite decreased rilpivirine exposure during pregnancy, treatment was effective in preventing mother-to-child transmission and suppressing HIV-1 RNA in pregnant women. Results suggest that rilpivirine 25 mg once daily, as part of individualized combination antiretroviral therapy, may be an appropriate option for HIV-1-infected pregnant women. TRIAL REGISTRATION: ClinicalTrials.gov Identifier, NCT00855335.

Pharmacokinetics of Total and Unbound Etravirine in HIV-1-Infected Pregnant Women.

BACKGROUND: Treatment of HIV-1-infected women during pregnancy protects maternal health and reduces the risk of perinatal transmission of HIV-1. However, physiologic changes that occur during pregnancy may affect drug pharmacokinetics. This phase IIIb, open-label study evaluated the effects of pregnancy on the pharmacokinetics of the nonnucleoside reverse transcriptase inhibitor etravirine. METHODS: Eligible HIV-1-infected pregnant women (18-26 weeks gestation) on an individualized, highly active antiretroviral therapy regimen including etravirine 200 mg twice daily were enrolled. Blood samples to assess the pharmacokinetics of total and unbound etravirine were obtained at clinic visits during the second and third trimesters (24- to 28-weeks and 34- to 38-weeks gestation, respectively) and 6-12 weeks postpartum. At each time point, plasma concentrations were measured over 12 hours (12-hour time point was obtained before the second daily dose of etravirine); pharmacokinetic parameters were derived using noncompartmental analysis and were compared between pregnancy and postpartum using general linear models. Antiviral and immunologic response and safety were assessed at each visit. RESULTS: Etravirine pharmacokinetic profiles were available for 13 of 15 enrolled women. Exposure to total etravirine was generally higher during pregnancy compared with 6-12 weeks postpartum (1.2- to 1.4-fold); the differences were less pronounced for unbound (pharmacodynamically active) etravirine. Virologic response was generally preserved throughout the study, and no perinatal transmission was observed. Etravirine was generally safe and well tolerated. CONCLUSIONS: Etravirine 200 mg twice daily, as part of individualized combination antiretroviral therapy, may be a treatment option for HIV-1-infected pregnant women.

Formulation and pharmacology of long-acting rilpivirine.

PURPOSE OF REVIEW: Rilpivirine (RPV), a nonnucleoside reverse transcriptase inhibitor, is a potent antiretroviral (ARV) effective for HIV treatment at 25 mg daily oral dose. Its physio-chemical and pharmacological properties enable formulation of RPV as a long-acting injectable nanosuspension. This review summarizes these properties supporting the potential of intermittent parenteral administration of rilpivirine long acting (RPV LA) in both treatment and prevention of HIV-1 infection. RECENT FINDINGS: RPV is unusual among ARVs in that its stability and solubility enable aqueous suspensions with high drug loading, so that injection volumes can be minimized. Such innovative nanosuspensions are well tolerated in animals and humans after intramuscular injection and provide sustained drug concentrations in systemic circulation. The pharmacological findings support further investigations of RPV LA injections every 4 or 8 weeks, both as a single agent for potential preexposure prophylaxis and as two-drug all-injectable maintenance therapy with cabotegravir long acting. SUMMARY: By building on expertise with long-acting injectable antipsychotic agents, RPV has been formulated as an agent for infrequent intramuscular dosing, in addition to its conventional oral tablet forms. The advantages of adherence to a regimen of intermittent injections may be significant.

The effect of rilpivirine on the pharmacokinetics of methadone in HIV-negative volunteers.

Antiretrovirals may influence methadone exposure in HIV-1-infected patients receiving methadone for opiate addiction. Rilpivirine is a non-nucleoside reverse transcriptase inhibitor for treating HIV-1 infection. In this open-label trial (NCT00744770), 13 HIV-negative volunteers continued on their regular stable methadone therapy (60 to 100 mg once daily; Days -14 to 12), with rilpivirine coadministration (Days 1 to 11). Methadone and rilpivirine pharmacokinetics and opiate withdrawal symptoms (Short Opiate Withdrawal Scale, Desires for Drugs Questionnaire, pupillometry) were evaluated. Rilpivirine decreased methadone minimum and maximum plasma concentrations (Cmin ; Cmax ) and area under the plasma concentration-time curve versus methadone alone (least-square mean ratio; 90% confidence interval) by 22% (0.78; 0.67, 0.91), 14% (0.86; 0.78, 0.95), and 16% (0.84; 0.74, 0.95), respectively (R-methadone), and 21% (0.79; 0.67, 0.92), 13% (0.87; 0.78, 0.97), and 16% (0.84; 0.74, 0.96), respectively (S-methadone). Rilpivirine pharmacokinetics with methadone were consistent with historic data. No clinically relevant opiate withdrawal symptoms were reported. Methadone and rilpivirine coadministration was generally well tolerated. No grade 3/4 adverse events (AEs), serious AEs, or discontinuations due to AEs were seen. No methadone dose adjustment is prompted by rilpivirine coadministration. Clinical monitoring for opiate withdrawal is recommended, as some patients may require adjustment of methadone maintenance therapy.

Pharmacokinetic interaction between etravirine or rilpivirine and telaprevir in healthy volunteers: A randomized, two-way crossover trial.

Coinfection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) may require treatment with an HIV non-nucleoside reverse transcriptase inhibitor (NNRTI), for example, rilpivirine or etravirine, and an HCV direct-acting antiviral drug such as telaprevir. In a two-panel, two-way, crossover study, healthy volunteers were randomized to receive etravirine 200 mg twice daily ± telaprevir 750 mg every 8 hours or rilpivirine 25 mg once daily ± telaprevir 750 mg every 8 hours. Pharmacokinetic assessments were conducted for each drug at steady-state when given alone and when coadministered; statistical analyses were least-square means with 90% confidence intervals. Telaprevir minimum plasma concentration (Cmin), maximum plasma concentration (Cmax), and area under the concentration-time curve (AUC) decreased 25%, 10%, and 16%, respectively, when coadministered with etravirine and 11%, 3%, and 5%, respectively, when coadministered with rilpivirine. Telaprevir did not affect etravirine pharmacokinetics, but increased rilpivirine Cmin, Cmax, and AUC by 93%, 49%, and 78%, respectively. Both combinations were generally well tolerated. The small decrease in telaprevir exposure when coadministered with etravirine is unlikely to be clinically relevant. The interaction between telaprevir and rilpivirine is not likely to be clinically relevant under most circumstances. No dose adjustments are deemed necessary when they are coadministered.

Lack of an effect of rilpivirine on the pharmacokinetics of ethinylestradiol and norethindrone in healthy volunteers.

UNLABELLED: Rilpivirine is a human immunodeficiency virus Type 1 (HIV-1) non-nucleoside reverse transcriptase inhibitor. OBJECTIVE: Rilpivirine metabolism involves cytochrome P450 3A4 (CYP3A4). This trial (ClinicalTrials. gov number: NCT00739622) evaluated the interaction between rilpivirine and ethinylestradiol/norethindrone (combination oral contraceptives), which are metabolized by multiple pathways, including CYP3A4. METHODS: During three consecutive 28-day cycles, 18 HIV-negative females received once-daily ethinylestradiol (35 µg)/norethindrone (1 mg) (Days 1 - 21); Days 22 - 28 were pill-free. Only in Cycle 3 was once-daily rilpivirine (25 mg) co-administered (Days 1 - 15). Minimum and maximum plasma concentrations (Cmin; Cmax) and area under the plasma concentration-time curve over 24 hours (AUC24h) of ethinylestradiol/norethindrone (Day 15, Cycles 2 and 3) and rilpivirine (Day 15, Cycle 3) were evaluated. RESULTS: Rilpivirine coadministration had no effect on (least square mean ratio, 90% confidence interval) ethinylestradiol Cmin (1.09, 1.03 - 1.16) or AUC24h (1.14, 1.10 - 1.19), but increased Cmax by 17% (1.17, 1.06 - 1.30), which is unlikely to affect ethinylestradiol pharmacodynamics. Norethindrone pharmacokinetics were unaffected by rilpivirine (AUC24h: 0.89, 0.84 - 0.94; Cmin: 0.99, 0.90 - 1.08; Cmax: 0.94, 0.83 - 1.06). Steady-state rilpivirine pharmacokinetics with ethinylestradiol/norethindrone was comparable with historical data for rilpivirine alone. Rilpivirine with ethinylestradiol/norethindrone was generally well tolerated. No new safety events were identified. CONCLUSIONS: Co-administration of rilpivirine, at the therapeutic dosing regimen, with ethinylestradiol/norethindrone does not affect hormone pharmacokinetics, and is, therefore, unlikely to affect the efficacy or safety of this oral hormonal contraceptive. Rilpivirine pharmacokinetics was not affected by ethinylestradiol/norethindrone. Rilpivirine (25 mg once daily) can be co-administered with ethinylestradiol/norethindrone-based contraceptives without dose modification.

Impact of food and different meal types on the pharmacokinetics of rilpivirine.

The objective of the study was to determine the impact of food and different meal types on the pharmacokinetics of rilpivirine, a nonnucleoside reverse transcriptase inhibitor. In this open-label, randomized, crossover study, healthy volunteers received a single, oral 75 mg dose of rilpivirine either with a normal-fat breakfast (reference), under fasting conditions, with a high-fat breakfast, or with a protein-rich nutritional drink. Pharmacokinetic parameters were determined by non-compartmental methods and analyzed using a linear mixed-effects model. Safety was assessed throughout. The least-squares mean ratio for area under the plasma concentration-time curve to last timepoint was 0.57 (90% confidence interval [CI]: 0.46-0.72) under fasting conditions compared to dosing with a normal-fat breakfast. With a high-fat breakfast or only a protein-rich nutritional drink, the corresponding values were 0.92 (90% CI: 0.80-1.07) and 0.50 (90% CI: 0.41-0.61), respectively, compared to dosing with a normal-fat breakfast. Under all conditions, rilpivirine was generally safe and well tolerated. Administration of rilpivirine under fasting conditions or with only a protein-rich nutritional drink substantially lowered the oral bioavailability when compared to administration with a normal-fat breakfast. Rilpivirine bioavailability was similar when administered with a high-fat or normal-fat breakfast. Rilpivirine should always be taken with a meal to ensure adequate bioavailability.

Transcription profiles of aortic smooth muscle cells from atherosclerosis-prone and -resistant regions in young apolipoprotein E-deficient mice before plaque development.

BACKGROUND/AIMS: Site-specific atherosclerosis is generally attributed to differential gene expression in endothelial cells. We investigated whether the transcriptome of smooth muscle cells is different between atherosclerosis-prone and atherosclerosis-resistant regions in apolipoprotein E-deficient (apoE-/-) mice before plaque development, and in C57Bl/6 mice. METHODS: De-endothelialized aortas (both strains: 3 males, 3 females, age 4 months) were divided into atherosclerosis-prone (AA: ascending aorta, aortic arch and proximal 2 mm of thoracic aorta) and -resistant (CTA: central thoracic aorta, i.e. 6 mm distal from the proximal 2 mm) regions. The transcriptome of these two regions was compared using whole-genome mouse microarrays. RESULTS: Microarray analysis revealed differential expression (>2-fold difference) of 70 and 244 genes in C57Bl/6 and apoE-/- mice. This was confirmed for 6 genes using the real-time quantitative polymerase chain reaction. Up- or downregulation in the AA was observed for 33 and 37 genes in C57Bl/6, and for 186 and 58 genes in apoE-/- mice, respectively. The 201 genes that showed exclusively differential expression in apoE-/- mice were related to atherosclerotic processes, such as cell adhesion, proliferation, differentiation, motility, cell death, lipid metabolism and immune responses. CONCLUSION: Our findings indicate that smooth muscle cells display an altered transcriptome at atherosclerosis-prone locations before actual lesion development.

Pharmacological characterization of nucleotide P2Y receptors on endothelial cells of the mouse aorta.

Nucleotides regulate various effects including vascular tone. This study was aimed to characterize P2Y receptors on endothelial cells of the aorta of C57BL6 mice. Five adjacent segments (width 2 mm) of the thoracic aorta were mounted in organ baths to measure isometric force development. Nucleotides evoked complete (adenosine 5' triphosphate (ATP), uridine 5' triphosphate (UTP), uridine 5' diphosphate (UDP); >90%) or partial (adenosine 5' diphosphate (ADP)) relaxation of phenylephrine precontracted thoracic aortic rings of C57BL6 mice. Relaxation was abolished by removal of the endothelium and was strongly suppressed (>90%) by inhibitors of nitric oxide synthesis. The rank order of potency was: UDP approximately UTP approximately ADP>adenosine 5'-[gamma-thio] triphosphate (ATPgammaS)>ATP, with respective pD2 values of 6.31, 6.24, 6.22, 5.82 and 5.40. These results are compatible with the presence of P2Y1 (ADP>ATP), P2Y2 or P2Y4 (ATP and UTP) and P2Y6 (UDP) receptors. P2Y4 receptors were not involved, since P2Y4-deficient mice displayed unaltered responses to ATP and UTP. The purinergic receptor antagonist suramin exerted surmountable antagonism for all agonists. Its apparent pKb for ATP (4.53+/-0.07) was compatible with literature, but the pKb for UTP (5.19+/-0.03) was significantly higher. This discrepancy suggests that UTP activates supplementary non-P2Y2 receptor subtype(s). Further, pyridoxal-phosphate-6-azophenyl-2'-4'-disulphonic acid (PPADS) showed surmountable (UTP, UDP), nonsurmountable (ADP) or no antagonism (ATP). Finally, 2'-deoxy-N6-methyladenosine3',5'-bisphosphate (MRS2179) inhibited ADP-evoked relaxation only. Taken together, these results point to the presence of functional P2Y1 (ADP), P2Y2 (ATP, UTP) and P2Y6 (UDP) receptors on murine aorta endothelial cells. The identity of the receptor(s) mediating the action of UTP is not fully clear and other P2Y subtypes might be involved in UTP-evoked vasodilatation.

Plaque-associated endothelial dysfunction in apolipoprotein E-deficient mice on a regular diet. Effect of human apolipoprotein AI.

OBJECTIVE: Apolipoprotein E-deficient mice (apoE(-/-)) on a regular diet become hypercholesterolemic and develop atherosclerosis, but endothelium-dependent relaxation remains undisturbed for up to 6 months. We investigated whether vasomotor dysfunction develops in aged apoE(-/-), whether the defect was systemic (hypercholesterolemia-dependent) or focal (plaque-related), and the effect of human apolipoprotein AI transgenesis (apoAI/E(-/-)). METHODS: Arteries of apoE(-/-) (n=5), apoAI/E(-/-) (n=6) and C57Bl/6J (WT, n=4) mice (18 months) were systematically dissected for isometric tension recording and subsequent morphometry. RESULTS: Acetylcholine (ACh)-induced relaxation was impaired (P<0.01) in atherosclerotic segments of apoE(-/-) (26+/-14%) as compared to WT mice (93+/-2%). Similar reduced (P<0.01) responses to adenosine 5'-triphosphate (apoE(-/-) 38+/-14, WT 94+/-3%) and the calcium ionophore A23187 (apoE(-/-) 19+/-6%, WT 97+/-2%) pointed to a post-receptor defect. Indeed, responses to exogenous nitric oxide were impaired in atherosclerotic segments as well (apoE(-/-) 71+/-7%, WT 92+/-1%, P<0.05). Furthermore, relaxations inversely correlated with plaque size (ACh r(s)=-0.74, P<0.01). In adjacent plaque-free segments however, responses to ACh (apoE(-/-) 92+/-3%, WT 97+/-1%) and all other agents were preserved, despite the prolonged hypercholesterolemia. ApoAI improved vasomotor responses in atherosclerotic segments. However, negative correlations between maximal relaxation and plaque area remained in apoAI/E(-/-) mice (ACh r(s)=-0.67, P<0.01). Indeed, covariate analysis of variance did not point to direct protection of vasomotor function by apoAI when the smaller lesions were taken into account. CONCLUSIONS: Endothelial dysfunction in apoE(-/-) mice is not affected by hypercholesterolemia alone, but is strictly associated with plaque formation. Human apoAI transgenesis-known to raise HDL-attenuated atherogenesis, thereby indirectly improving relaxation responses in apoE(-/-) mice.