Maraviroc, tenofovir disoproxil fumarate and dapivirine, activate progesterone receptor B in the absence of progestogens.

Antiretroviral therapy has slowed the HIV/AIDS pandemic and is currently being used as a prophylactic measure for individuals at high risk of infection. However, concerns over adverse effects of long-term use need to be explored. We hypothesize that this may occur, at least in part, through off-target effects via select steroid receptors (SRs) that broadly regulate multiple physiological processes. We investigated the effects of maraviroc (MVC), tenofovir disoproxil fumarate (TDF), and dapivirine (DPV) on progesterone receptor B (PR-B) transcriptional activity. We found that MVC and TDF activate PR-B transcription in the absence of progestogens on a PR-regulated promoter reporter construct and on endogenous PR-regulated genes. MVC and TDF exhibited no direct binding to PR-B; however, increased PR-B phosphorylation was detected with TDF but not MVC. DPV transactivated gilz and ptgs2 in the absence of progestogens and exhibited PR-B binding while showing no effects on phosphorylation, suggesting that it may activate PR-B through a direct mechanism. Our study shows that potential off-target immunomodulatory effects of MVC, TDF and DPV occur in vitro and these are most likely mediated by different mechanisms of PR-B activation.

Translational Approach to Predicting the Efficacy of Maraviroc-Based Regimens as HIV Preexposure Prophylaxis.

Maraviroc-based regimens have been explored as preexposure prophylaxis (PrEP) against human immunodeficiency virus (HIV). In this study, we utilized mucosal tissue drug exposure data, combined with target concentrations generated in vitro, in a pharmacokinetic-pharmacodynamic analysis to predict the effects of drug combinations and adherence on PrEP efficacy. Mucosal tissue concentrations of maraviroc were measured in 24 healthy women. The 90% effective concentrations (EC90) of maraviroc (alone and combined with tenofovir and emtricitabine) for protection against HIV were identified in CD4+ T cells. Monte Carlo simulations were performed to identify dosing strategies to protect colorectal and female genital tract (FGT) tissues from HIV infection. Colorectal maraviroc concentrations were 350-fold higher than in the FGT. Under steady-state conditions, our model predicted that one 300-mg dose/week was sufficient to protect colorectal tissue from HIV in 99% of the population, while 300 mg daily would protect the FGT in only 63% of the population. FGT protection increased to >90% when maraviroc was used in combination with tenofovir (5 doses/week) or emtricitabine (3 doses/week). Poor adherence resulted in a drastic decrease in efficacy in the FGT but not colorectal tissue. However, greater forgiveness was seen when maraviroc was combined with tenofovir or emtricitabine, suggesting that maraviroc should not be used alone as PrEP.

A drug interaction study investigating the effect of Rifabutin on the pharmacokinetics of Maraviroc in healthy subjects.

Effects of steady-state rifabutin on the pharmacokinetics of steady-state maraviroc were investigated in fourteen healthy adult female and male volunteers. Maraviroc 300 mg twice daily (BID) was given orally with food for fifteen days. On day six, rifabutin 300 mg once daily (QD, P.O.) was added to the regimen. Formal pharmacokinetic (PK) sampling was performed on days five and fifteen. Individual plasma drug concentration-time data for maraviroc, and rifabutin on day fifteen, were obtained using validated High Performance Liquid Chromatography (HPLC) tandem Mass Spectrometry (MS/MS). Rifabutin steady state exposure was comparable to data in the literature. Maraviroc area under the curve (AUC) and minimum plasma concentration (Clast or Cmin) were reduced by 17% and 30% respectively when co-administered with rifabutin. No unexpected or serious adverse eventsoccurred. Based on the reduced exposure of maraviroc observed in this study, increasing the dose of maraviroc may be studied to normalize its moderately reduced exposure following rifabutin co-administration, a moderate inducer of CYP3A4.

Interactions between Maraviroc and the ABCB1, ABCG2, and ABCC2 Transporters: An Important Role in Transplacental Pharmacokinetics.

Maraviroc is a chemokine receptor 5 (CCR5) inhibitor used in the treatment of human immunodeficiency virus (HIV) that also shows therapeutic potential for several autoimmune, cancer, and inflammatory diseases that can afflict pregnant women. However, only limited information exists on the mechanisms underlying the transplacental transfer of the drug. We aimed to expand the current knowledge base on how maraviroc interacts with several placental ATP-binding cassette (ABC) efflux transporters that have a recognized role in the protection of a developing fetus: P-glycoprotein (ABCB1), breast cancer resistance protein (ABCG2), and multidrug resistance protein 2 (ABCC2). We found that maraviroc does not inhibit any of the three studied ABC transporters and that its permeability is not affected by ABCG2 or ABCC2. However, our in vitro results revealed that maraviroc shows affinity for human ABCB1 and the endogenous canine P-glycoprotein (Abcb1) expressed in Madin-Darby canine kidney II (MDCKII) cells. Perfusion of rat term placenta showed accelerated transport of maraviroc in the fetal-to-maternal direction, which suggests that ABCB1/Abcb1 facilitates in situ maraviroc transport. This transplacental transport was saturable and significantly diminished after the addition of the ABCB1/Abcb1 inhibitors elacridar, zosuquidar, and ritonavir. Our results indicate that neither ABCG2 nor ABCC2 influence maraviroc pharmacokinetic but that ABCB1/Abcb1 may be partly responsible for the decreased transplacental permeability of maraviroc to the fetus. The strong affinity of maraviroc to Abcb1 found in our animal models necessitates studies in human tissue so that maraviroc pharmacokinetics in pregnant women can be fully understood. SIGNIFICANCE STATEMENT: Antiretroviral drug maraviroc shows low toxicity and is thus a good candidate for prevention of mother-to-child transmission of human immunodeficiency virus when failure of recommended therapy occurs. Using in vitro cell-based experiments and in situ dually perfused rat term placenta, we examined maraviroc interaction with the placental ABC drug transporters ABCB1, ABCG2, and ABCC2. We demonstrate for the first time that placental ABCB1 significantly reduces mother-to-fetus transport of maraviroc, which suggests that ABCB1 may be responsible for the low cord-blood/maternal-blood ratio observed in humans.

Improving maraviroc oral bioavailability by formation of solid drug nanoparticles.

Oral drug administration remains the preferred approach for treatment of HIV in most patients. Maraviroc (MVC) is the first in class co-receptor antagonist, which blocks HIV entry into host cells. MVC has an oral bioavailability of approximately 33%, which is limited by poor permeability as well as affinity for CYP3A and several drug transporters. While once-daily doses are now the favoured option for HIV therapy, dose-limiting postural hypotension has been of theoretical concern when administering doses high enough to achieve this for MVC (particularly during coadministration of enzyme inhibitors). To overcome low bioavailability and modify the pharmacokinetic profile, a series of 70 wt% MVC solid drug nanoparticle (SDN) formulations (containing 30 wt% of various polymer/surfactant excipients) were generated using emulsion templated freeze-drying. The lead formulation contained PVA and AOT excipients (MVCSDNPVA/AOT), and was demonstrated to be fully water-dispersible to release drug nanoparticles with z-average diameter of 728 nm and polydispersity index of 0.3. In vitro and in vivo studies of MVCSDNPVA/AOT showed increased apparent permeability of MVC, compared to a conventional MVC preparation, with in vivo studies in rats showing a 2.5-fold increase in AUC (145.33 vs. 58.71 ng h ml-1). MVC tissue distribution was similar or slightly increased in tissues examined compared to the conventional MVC preparation, with the exception of the liver, spleen and kidneys, which showed statistically significant increases in MVC for MVCSDNPVA/AOT. These data support a novel oral format with the potential for dose reduction while maintaining therapeutic MVC exposure and potentially enabling a once-daily fixed dose combination product.

No Clinical Impact of CYP3A5 Gene Polymorphisms on the Pharmacokinetics and/or Efficacy of Maraviroc in Healthy Volunteers and HIV-1-Infected Subjects.

Maraviroc is a C-C chemokine receptor type-5 antagonist approved for the treatment of HIV-1. Previous studies show that cytochrome P450 3A5 (CYP3A5) plays a role in maraviroc metabolism. CYP3A5 is subject to a genetic polymorphism. The presence of 2 functional alleles (CYP3A5*1/*1) confers the extensive metabolism phenotype, which is rare in whites but common in blacks. The effect of CYP3A5 genotype on maraviroc and/or metabolite pharmacokinetics was evaluated in 2 clinical studies: a post hoc analysis from a phase 2b/3 study (NCT00098293) conducted in 494 HIV-1-infected subjects (study 1) in which the impact on maraviroc efficacy in 303 subjects was also assessed, and a study conducted in 47 healthy volunteers (study 2). In study 2 (NCT02625207), extensive metabolizers had 26% to 37% lower mean area under the concentration-time curve compared with poor metabolizers (no CYP3A5*1 alleles). This effect diminished to 17% in the presence of potent CYP3A inhibition. The effect of CYP3A5 genotype was greatest in the formation of the metabolite (1S,2S)-2-hydroxymaraviroc. In study 1, the CYP3A5*1/*1 genotype unexpectedly had higher maraviroc area under the curve predictions (20%) compared with those with no CYP3A5*1 alleles. The reason for this disparity remains unclear. The proportions of subjects with viral loads <50 and <400 copies/mL for maraviroc were comparable among all 3 CYP3A5 genotypes. In both studies maraviroc exposures were in the range of near-maximal viral inhibition in the majority of subjects. These results demonstrate that although CYP3A5 contributes to the metabolism of maraviroc, CYP3A5 genotype does not affect the clinical response to maraviroc in combination treatment of HIV-1 infection at approved doses.

The pharmacokinetics, pharmacodynamics, and mucosal responses to maraviroc-containing pre-exposure prophylaxis regimens in MSM.

OBJECTIVE: HIV Prevention Trials Network 069/AIDS Clinical Trials Group A5305 was a study of 48-week oral pre-exposure prophylaxis (PrEP) regimens in MSM and transgender women. A rectal substudy was included to evaluate drug concentrations in rectal compartment vs. blood, gut-associated lymphoid tissue (GALT) responses to four antiretroviral PrEP regimens [maraviroc (MVC), MVC + emtricitabine (FTC), MVC + tenofovir (TFV) disoproxil fumarate, and TFV disoproxil fumarate + FTC], and to determine whether ARV exposure was associated with ex-vivo suppression of HIV infection in colorectal explants. METHODS: C-C chemokine receptor type 5 (CCR5) genotype was characterized using PCR. At baseline and at Weeks 24, 48, and 49, GALT phenotype was characterized by flow cytometry, rectal biopsies were challenged with HIV-1BaL, and tissue and plasma pharmacokinetics were measured via mass spectrometry. RESULTS: Exposure to MVC was not associated with increased expression of CD4+/CCR5+ HIV target T cells. Significant ex-vivo viral suppression compared with baseline was seen at Weeks 24 and 48, ranging from 1.4 to 1.8 log10 for all study regimens except the MVC-alone arm which did not show statistically significant viral suppression at Week 48. Tissue concentrations of TFV, TFV-diphosphate, and FTC were correlated with viral suppression. CONCLUSION: MVC-containing HIV PrEP regimens did not increase GALT CD4+ T-cell activation or the CD4+/CCR5+ phenotype. No virologic suppression was seen with MVC-alone at Week 48 compared with combination regimens, suggesting MVC monotherapy might be less effective than combination antiretroviral PrEP regimens.

Evaluation of Digital Image Recognition Methods for Mass Spectrometry Imaging Data Analysis.

Analyzing mass spectrometry imaging data can be laborious and time consuming, and as the size and complexity of datasets grow, so does the need for robust automated processing methods. We here present a method for comprehensive, semi-targeted discovery of molecular distributions of interest from mass spectrometry imaging data, using widely available image similarity scoring algorithms to rank images by spatial correlation. A fast and powerful batch search method using a MATLAB implementation of structural similarity (SSIM) index scoring with a pre-selected reference distribution is demonstrated for two sample imaging datasets, a plant metabolite study using Artemisia annua leaf, and a drug distribution study using maraviroc-dosed macaque tissue. Graphical Abstract ᅟ.

Safety and pharmacokinetics of single, dual, and triple antiretroviral drug formulations delivered by pod-intravaginal rings designed for HIV-1 prevention: A Phase I trial.

BACKGROUND: Intravaginal rings (IVRs) for HIV pre-exposure prophylaxis (PrEP) theoretically overcome some adherence concerns associated with frequent dosing that can occur with oral or vaginal film/gel regimens. An innovative pod-IVR, composed of an elastomer scaffold that can hold up to 10 polymer-coated drug cores (or "pods"), is distinct from other IVR designs as drug release from each pod can be controlled independently. A pod-IVR has been developed for the delivery of tenofovir (TFV) disoproxil fumarate (TDF) in combination with emtricitabine (FTC), as daily oral TDF-FTC is the only Food and Drug Administration (FDA)-approved regimen for HIV PrEP. A triple combination IVR building on this platform and delivering TDF-FTC along with the antiretroviral (ARV) agent maraviroc (MVC) also is under development. METHODOLOGY AND FINDINGS: This pilot Phase I trial conducted between June 23, 2015, and July 15, 2016, evaluated the safety, pharmacokinetics (PKs), and acceptability of pod-IVRs delivering 3 different ARV regimens: 1) TDF only, 2) TDF-FTC, and 3) TDF-FTC-MVC over 7 d. The crossover, open-label portion of the trial (N = 6) consisted of 7 d of continuous TDF pod-IVR use, a wash-out phase, and 7 d of continuous TDF-FTC pod-IVR use. After a 3-mo pause to evaluate safety and PK of the TDF and TDF-FTC pod-IVRs, TDF-FTC-MVC pod-IVRs (N = 6) were evaluated over 7 d of continuous use. Safety was assessed by adverse events (AEs), colposcopy, and culture-independent analysis of the vaginal microbiome (VMB). Drug and drug metabolite concentrations in plasma, cervicovaginal fluids (CVFs), cervicovaginal lavages (CVLs), and vaginal tissue (VT) biopsies were determined via liquid chromatographic-tandem mass spectrometry (LC-MS/MS). Perceptibility and acceptability were assessed by surveys and interviews. Median participant age was as follows: TDF/TDF-FTC group, 26 y (range 24-35 y), 2 White, 2 Hispanic, and 2 African American; TDF-FTC-MVC group, 24.5 y (range 21-41 y), 3 White, 1 Hispanic, and 2 African American. Reported acceptability was high for all 3 products, and pod-IVR use was confirmed by residual drug levels in used IVRs. There were no serious adverse events (SAEs) during the study. There were 26 AEs reported during TDF/TDF-FTC IVR use (itching, discharge, discomfort), with no differences between TDF alone or in combination with FTC observed. In the TDF-FTC-MVC IVR group, there were 12 AEs (itching, discharge, discomfort) during IVR use regardless of attribution to study product. No epithelial disruption/thinning was seen by colposcopy, and no systematic VMB shifts were observed. Median (IQR) tenofovir diphosphate (TFV-DP) tissue concentrations of 303 (277-938) fmol/10(6) cells (TDF), 289 (110-603) fmol/10(6) cells (TDF-FTC), and 302 (177.1-823.8) fmol/10(6) cells (TDF-FTC-MVC) were sustained for 7 d, exceeding theoretical target concentrations for vaginal HIV prevention. The study's main limitations include the small sample size, short duration (7 d versus 28 d), and the lack of FTC triphosphate measurements in VT biopsies. CONCLUSIONS: An innovative pod-IVR delivery device with 3 different formulations delivering different regimens of ARV drugs vaginally appeared to be safe and acceptable and provided drug concentrations in CVFs and tissues exceeding concentrations achieved by highly protective oral dosing, suggesting that efficacy for vaginal HIV PrEP is achievable. These results show that an alternate, more adherence-independent, longer-acting prevention device based on the only FDA-approved PrEP combination regimen can be advanced to safety and efficacy testing. TRIAL REGISTRATION: ClinicalTrials.gov NCT02431273.

Pharmacokinetics, safety and efficacy of maraviroc in treatment-experienced pediatric patients Infected with CCR5-tropic HIV-1

BACKGROUND: Maraviroc is a CC-chemokine receptor 5 antagonist approved to treat adults infected with CC-chemokine receptor 5-tropic (R5) HIV-1. Study A4001031 was conducted to evaluate the pharmacokinetics, safety and efficacy of maraviroc in combination with optimized background therapy in treatment-experienced pediatric patients infected with R5 HIV-1 and support registration of maraviroc for pediatric use. METHODS: This is an open-label, 2-stage, age-stratified, noncomparative multicenter study. One-hundred and three participants were enrolled into 4 age/formulation cohorts and dosed twice daily. Initial doses were determined by body surface area and optimized background therapy, based on drug interactions with maraviroc in adults. Dose adjustment and pharmacokinetic reevaluation occurred if the average concentrations (Cavg) at Week 2 were <100 ng/mL (Stage 1-dose finding). RESULTS: Data from the Week 48 analysis demonstrated that 49/50 Stage 1 participants rolling over into Stage 2 (safety and efficacy) achieved Cavg ≥100 ng/mL. Doses were identified that achieved similar concentration ranges to those seen in adults. The majority (90/103) received optimized background therapy containing potent cytochrome P450 3A inhibitors. Maraviroc was well tolerated and the safety and efficacy were comparable to those of adults. All cohorts had a mean decrease from baseline in HIV-1 RNA of >1 log10. Increases from baseline in the median CD4+ cell count and percentage were seen for all age groups. CONCLUSIONS: The maraviroc dosing strategy resulted in participants achieving the target Cavg, with exposure ranges similar to those observed in adults on approved doses. The safety and efficacy of maraviroc in this pediatric population were comparable to those seen in adults

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.

Pharmacodynamic Monitoring Predicts Outcomes of CCR5 Blockade as Graft-versus-Host Disease Prophylaxis.

Blocking lymphocyte trafficking after allogeneic hematopoietic stem cell transplantation is a promising strategy to prevent graft-versus-host disease (GVHD) while preserving the graft-versus-tumor response. Maraviroc, a CCR5 antagonist, has shown promise in clinical trials, presumably by disrupting the migration of effector cells to GVHD target organs. We describe a phosphoflow assay to quantify CCR5 blockade during treatment with maraviroc and used it to evaluate 28 patients in a phase II study. We found that insufficient blockade of CCR5 was associated with significantly worse overall survival (HR, 10.6; 95% CI, 2.2 to 52.0; P = .004) and higher rates of nonrelapse mortality (HR, 146; 95% CI, 1.0 to 20,600; P = .04) and severe acute GVHD (HR, 12; 95% CI, 1.9 to 76.6; P = .009). In addition, we found that pretransplant high surface expression of CCR5 on recipient T cells predicted higher nonrelapse mortality and worse GVHD- and relapse-free survival. Our results demonstrate that pharmacodynamic monitoring of CCR5 blockade unravels interpatient variability in the response to therapy and may serve as a clinically informative biomarker.

Pharmacokinetics, Safety and Efficacy of Maraviroc in Treatment-experienced Pediatric Patients Infected With CCR5-Tropic HIV-1.

BACKGROUND: Maraviroc is a CC-chemokine receptor 5 antagonist approved to treat adults infected with CC-chemokine receptor 5-tropic (R5) HIV-1. Study A4001031 was conducted to evaluate the pharmacokinetics, safety and efficacy of maraviroc in combination with optimized background therapy in treatment-experienced pediatric patients infected with R5 HIV-1 and support registration of maraviroc for pediatric use. METHODS: This is an open-label, 2-stage, age-stratified, noncomparative multicenter study. One-hundred and three participants were enrolled into 4 age/formulation cohorts and dosed twice daily. Initial doses were determined by body surface area and optimized background therapy, based on drug interactions with maraviroc in adults. Dose adjustment and pharmacokinetic reevaluation occurred if the average concentrations (Cavg) at Week 2 were <100 ng/mL (Stage 1-dose finding). RESULTS: Data from the Week 48 analysis demonstrated that 49/50 Stage 1 participants rolling over into Stage 2 (safety and efficacy) achieved Cavg ≥100 ng/mL. Doses were identified that achieved similar concentration ranges to those seen in adults. The majority (90/103) received optimized background therapy containing potent cytochrome P450 3A inhibitors. Maraviroc was well tolerated and the safety and efficacy were comparable to those of adults. All cohorts had a mean decrease from baseline in HIV-1 RNA of >1 log10. Increases from baseline in the median CD4+ cell count and percentage were seen for all age groups. CONCLUSIONS: The maraviroc dosing strategy resulted in participants achieving the target Cavg, with exposure ranges similar to those observed in adults on approved doses. The safety and efficacy of maraviroc in this pediatric population were comparable to those seen in adults.