The effects of a nucleoside-sparing antiretroviral regimen on the pharmacokinetics of ritonavir-boosted darunavir in HIV type-1-infected patients

Population pharmacokinetics and pharmacogenetics of ritonavir-boosted darunavir in the presence of raltegravir or tenofovir disoproxil fumarate/emtricitabine in HIV-infected adults and the relationship with virological response: a sub-study of the NEAT001/ANRS143 randomized trial

OBJECTIVES

NEAT001/ANRS143 demonstrated non-inferiority of once-daily darunavir/ritonavir (800/100 mg) + twice-daily raltegravir (400 mg) versus darunavir/ritonavir + tenofovir disoproxil fumarate/emtricitabine (245/200 mg once daily) in treatment-naive patients. We investigated the population pharmacokinetics of darunavir, ritonavir, tenofovir and emtricitabine and relationships with demographics, genetic polymorphisms and virological failure.

METHODS

Non-linear mixed-effects models (NONMEM v. 7.3) were applied to determine pharmacokinetic parameters and assess demographic covariates and relationships with SNPs (SLCO3A1, SLCO1B1, NR1I2, NR1I3, CYP3A5*3, CYP3A4*22, ABCC2, ABCC10, ABCG2 and SCL47A1). The relationship between model-predicted darunavir AUC0-24 and C24 with time to virological failure was evaluated by Cox regression.

RESULTS

Of 805 enrolled, 716, 720, 347 and 361 were included in the darunavir, ritonavir, tenofovir and emtricitabine models, respectively (11% female, 83% Caucasian). No significant effect of patient demographics or SNPs was observed for darunavir or tenofovir apparent oral clearance (CL/F); coadministration of raltegravir did not influence darunavir or ritonavir CL/F. Ritonavir CL/F decreased by 23% in NR1I2 63396C>T carriers and emtricitabine CL/F was linearly associated with creatinine clearance (P<0.001). No significant relationship was demonstrated between darunavir AUC0-24 or C24 and time to virological failure [HR (95% CI): 2.28 (0.53-9.80), P=0.269; and 1.82 (0.61-5.41), P=0.279, respectively].

CONCLUSIONS

Darunavir concentrations were unaltered in the presence of raltegravir and not associated with virological failure. Polymorphisms investigated had little impact on study-drug pharmacokinetics. Darunavir/ritonavir + raltegravir may be an appropriate option for patients experiencing NRTI-associated toxicity.

HIV treatment simplification to elvitegravir/cobicistat/emtricitabine/tenofovir disproxil fumarate (E/C/F/TDF) plus darunavir: a pharmacokinetic study

BACKGROUND

As a simplification strategy for treatment-experienced HIV-infected patients who have achieved virologic suppression on a multi-drug, multi-class antiretroviral regimen, the aim of this study was to evaluate the safety, efficacy, and pharmacokinetics of once-daily elvitegravir/cobicistat/emtricitabine/tenofovir disproxil fumarate (E/C/F/TDF) with darunavir.

METHODS

A single arm, open-label 48-week study was conducted of regimen simplification to E/C/F/TDF plus darunavir 800 mg daily from stable therapy including two nucleoside/nucleotide reverse transcriptase inhibitors, a ritonavir-boosted protease inhibitor, and an integrase inhibitor. Participants had plasma HIV viral load consistently < 200 copies/mL for ≥ 6 months, estimated glomerular filtration rate (eGFR) ≥ 60 mL/min, and no genotypic resistance to major components of the study regimen. Plasma viral load was measured at weeks 2 and 4, then every 4 weeks throughout the study. Safety laboratory assessments were conducted at baseline and at weeks 12, 24, 36, and 48. Antiretroviral drug concentrations were measured at baseline and once ≥ 2 weeks after the regimen change.

RESULTS

Ten HIV-infected adults (8 male and 2 female; median age 50.5 years) were enrolled. All maintained virologic suppression on the new regimen for 48 weeks. One subject experienced a decrease in eGFR from 62 mL/min at baseline to 52 mL/min at week 12; study medications were continued and his eGFR remained stable (50-59 mL/min) thereafter. No subjects discontinued study medications for renal function changes or other adverse events. Darunavir trough concentration were lower on the new regimen than on darunavir/ritonavir 800/100 mg (n = 5; p < 0.05).

CONCLUSIONS

Despite low darunavir trough concentrations, treatment simplification to a two-pill, once-daily regimen of E/C/F/TDF plus darunavir was safe and effective for 48 weeks among 10 selected treatment-experienced HIV-infected patients. Trial registration The study protocol was registered with ClinicalTrials.gov (NCT02199613) on July 22, 2014.

The pharmacokinetic profile of raltegravir-containing antiretroviral therapy in HIV-infected individuals over 60 years of age

BACKGROUND

Antiretroviral safety and efficacy and may differ in older versus younger HIV-infected patients. The objective of this study was to assess the pharmacokinetic (PK) profile in older HIV-infected subjects (>60 years) switching combination antiretroviral therapy (cART) to a raltegravir (RAL) containing regimen.

METHODS

Nineteen HIV-infected patients over 60 years of age on effective cART (HIV-RNA < 50 copies/ml) were enrolled in this prospective 24-week study. On day 1, patients switched to tenofovir/emtricitabine (245/200 mg once daily) and RAL (400 mg twice daily). On day 28, intensive PK sampling was undertaken in a fasted state and RAL plasma concentrations determined. Neurocognitive function was assessed at baseline and week 24 using a neuropsychological battery. RAL PK parameters were compared to those of two younger historical HIV-infected control groups that received twice-daily RAL co-administered with darunavir/ritonavir (DRV/r) 800/100 once daily by nonlinear mixed effects modelling.

RESULTS

In HIV-infected subjects over the age of 60 (mean ± SD age: 66 ± 3.4 years, n = 19) switching to a RAL containing regimen, we observed no safety concerns, no plasma virological rebounds, and no differences in RAL apparent oral clearance when compared to younger HIV-infected populations (mean ± SD age: 41 ± 9.2 years, n = 38) based on population pharmacokinetic analysis. After 24 weeks of study therapy a decline in cognitive function was observed [change in (SD) global score of (0.91 (1.3), P = 0.018].

CONCLUSIONS

No significant changes in RAL exposure associated with age were observed.

Pharmacokinetic study of dual therapy with raltegravir 400 mg twice daily and Darunavir/Ritonavir 800/100 mg once daily in HIV-1-infected patients

BACKGROUND

Combinations of new classes of antiretroviral drugs are attractive options to avoid toxicity associated with nucleoside reverse transcriptase inhibitors (NRTIs) and to provide a full active regimen in patients with some degree of resistance to NRTIs. However, data on the pharmacokinetic (PK) profiles of these regimens are limited. We explore the plasma PK profile of raltegravir (RAL) at a dose of 400 mg twice a day plus darunavir/ritonavir (DRV/RTV) at a dose of 800/100 mg once a day in HIV-1-infected patients.

METHODS

This was a pilot, open-label, fixed-sequence, prospective, single-center single-arm PK study. The treating physician chose an NRTI-sparing regimen because of toxicity or resistance mutations to NRTIs, which included DRV/RTV 800/100 mg once daily plus RAL 400 mg twice daily. All patients were RAL and DRV naive and had no evidence of protease inhibitor mutations. After at least 15 days on therapy, patients were admitted for a 24-hour PK study. Laboratory tests to assess efficacy and safety were performed at all study visits.

RESULTS

Fifteen patients were included. The geometric mean values for DRV were AUC0-24 68,730 ng·h·mL [95% confidence interval (CI): 58,970-86,480], Ctrough 1330 ng/mL (95% CI: 1110-1760; IC-50 for wild-type and resistant HIV-1 strains was 55 and 550 ng/mL, respectively), Cmax 7630 ng/mL (95% CI: 6740-9000), and t1/2 10.9 hours (95% CI: 9.20-13.99). Geometric mean values for RAL were AUC0-12 3050 ng·h·mL (95% CI: 2530-5180); Ctrough 40 ng/mL (95% CI: 30-80), Cmax 970 ng/mL (95% CI: 840-2270), t1/2 2.68 hours (95% CI: 1.97-4.40). No adverse effects including rash or laboratory test abnormalities were noted. At week 24, the HIV-1 viral load was below 37 copies/mL in all patients.

CONCLUSIONS

Our data suggest that dual therapy with RAL 400 mg twice daily plus DRV/RTV 800/100 mg once daily had a favorable PK profile for both drugs and that short-term efficacy and tolerability of this combination were adequate.

Effects of age on antiretroviral plasma drug concentration in HIV-infected subjects undergoing routine therapeutic drug monitoring

OBJECTIVES

The pharmacokinetic and pharmacodynamic effects of antiretroviral therapy may differ in older compared with younger subjects with HIV infection. We aimed to assess factors associated with plasma antiretroviral drug exposure, including age, within a large HIV-infected cohort undergoing therapeutic drug monitoring (TDM).

METHODS

Data from the Liverpool TDM Registry were linked with the UK Collaborative HIV Cohort (CHIC) Study. All TDM of protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) was included and in order to account for different antiretroviral drugs the plasma concentrations were standardized by group measurements according to drug, dosing and timing of TDM. Regression modelling was used to evaluate associations of drug exposure with age and clinical parameters, including hepatic transaminase results and time to antiretroviral treatment modification.

RESULTS

Data from 3589 TDM samples were available from 2447 subjects. The greatest numbers of plasma concentrations were assessed for lopinavir (22.4%), efavirenz (18.5%), atazanavir (17.0%) and saquinavir (11.6%). As age increased, median standardized NNRTI concentrations remained constant, whereas PI concentrations increased (correlation coefficient 0.04, P = 0.033). In a regression analysis stratified by antiretroviral drug class, standardized plasma concentrations were significantly associated with age for PIs (0.05 increase in standard deviation of drug concentration with each 10 year increase in age, P = 0.044), but not for NNRTIs or other clinical parameters, including hepatic transaminase results or time to antiretroviral treatment modification.

CONCLUSIONS

With increasing age, statistically significant rises in plasma PI exposure, but not NNRTI exposure, were observed. The clinical relevance of this observation merits further investigation.

Pharmacokinetic profile and safety of 150 mg of maraviroc dosed with 800/100 mg of darunavir/ritonavir all once daily, with and without nucleoside analogues, in HIV-infected subjects

BACKGROUND

Once-daily nucleoside-sparing combination antiretroviral therapy regimens are attractive options for the treatment of HIV infection. However, the pharmacokinetic profiles of such regimens are often not established.

METHODS

HIV-infected subjects receiving 245/200 mg of tenofovir/emtricitabine plus 800/100 mg of darunavir/ritonavir once daily with plasma HIV RNA <50 copies/mL were eligible. On day 1 (period 1), 150 mg of maraviroc daily was added and on day 11 (period 2), tenofovir/emtricitabine discontinued. At steady-state (days 10 and 20), intensive pharmacokinetic sampling was undertaken. We assessed (i) the number of subjects with trough (C(trough)) and average (C(avg)) maraviroc concentrations <25 and <75 ng/mL, respectively; (ii) geometric mean (GM) ratios for pharmacokinetic parameters for period 2 versus period 1; and (iii) factors associated with total maraviroc exposure.

RESULTS

Eleven subjects completed the study procedures (mean age 49 years; range 35-59 years). In three subjects, maraviroc C(trough) and C(avg) were <25 and <75 ng/mL, respectively (C(avg), 68 ng/mL and C(trough), 14 and 21 ng/mL). Although not statistically significant, a trend was observed towards lower maraviroc, darunavir and ritonavir concentrations in period 2 versus period 1; total maraviroc exposure was 3579 ng· h/mL (95% CI: 2983-4294) and 2996 ng· h/mL (95% CI: 2374-3782) in periods 1 and 2, respectively, and the GM ratio was 0.84 (95% CI: 0.67-1.05). Only total ritonavir exposure was significantly associated with total maraviroc exposure (P=0.049; 95% CI: 0.01-0.91). No clinical safety concerns were observed.

CONCLUSIONS

Within this novel nucleoside-sparing regimen, maraviroc exposure is dependent on ritonavir exposure, which was slightly reduced in the absence of tenofovir/emtricitabine.

Effect of efavirenz, nevirapine, etravirine, and raltegravir administration on the pharmacokinetics of ritonavir-boosted darunavir in a population of HIV-infected patients

Abstract The influence of efavirenz, etravirine, raltegravir, and nevirapine administration on the pharmacokinetics of ritonavir-boosted darunavir was investigated using population pharmacokinetics analysis. The population was composed of 142 patients infected with HIV: darunavir plus nucleoside/nucleotide reverse transcriptase inhibitors (NRTI), 54 patients (group A); darunavir plus efavirenz±NRTI, 4 patients (group B); darunavir plus etravirine±NRTI, 5 patients (group C); darunavir plus nevirapine±NRTI, 21 patients (group D); darunavir plus raltegravir±NRTI, 38 patients (group E); and darunavir plus raltegravir and etravirine±NRTI, 20 patients (group F). A significant increase in darunavir clearance in combination with nevirapine (+66%) and efavirenz (+235%) was observed. A significant decrease (p<0.05) in trough plasma concentration was observed in groups B and D compared with the other groups. Our study indicates that the combination of ritonavir-boosted darunavir and etravirine or raltegravir has no significant influence on the pharmacokinetics of darunavir in contrast to the combination of ritonavir-boosted darunavir and nevirapine or efavirenz, which involves an increase in darunavir clearance and a decrease in the plasma concentration of darunavir.

Update on raltegravir and the development of new integrase strand transfer inhibitors

Raltegravir (RAL) is the first antiretroviral in the integrase strand transfer inhibitors (INSTI) class. The use of RAL has expanded since its approval in October 2007 for multidrug-resistant human immunodeficiency virus type 1 infection in adults. RAL is now a guideline-preferred treatment option for antiretroviral-naïve patients, indicated for treatment in adolescents, and is being studied as an integral part of nucleoside sparing regimens. The development of resistance and the need for a once-daily dosing option has led to the development of new INSTIs, including elvitegravir and dolutegravir. Elvitegravir is being studied in a promising once-daily single-tablet regimen with tenofovir, emtricitabine, and the investigational pharmacoenhancer cobicistat. The development of cobicistat and the new once-daily INSTIs may revolutionize the treatment of human immunodeficiency virus type 1 infection. This article reviews the current literature on raltegravir and new developments in the INSTI class.

Role of raltegravir in HIV-1 management

OBJECTIVE

To review the literature concerning the role of raltegravir in the treatment of HIV-1 in antiretroviral (ARV)-experienced and ARV-naïve patients.

DATA SOURCES

A PubMed search was conducted for published data through March 2012 using the search terms raltegravir, MK-0518, and integrase strand transfer inhibitor. An additional search of International Pharmaceutical Abstracts for unpublished data, including data from the Infectious Diseases Society of America, the Conference on Retroviruses and Opportunistic Infections, the International AIDS Society, and the Interscience Conference on Antimicrobial Agents and Chemotherapy, was conducted using similar search terms.

STUDY SELECTION AND DATA EXTRACTION

In vitro and in vivo Phase 2, Phase 3, and postmarketing studies available in English, evaluating antiretroviral regimens that contain raltegravir for the treatment of HIV-1 infection in both ARV-naïve and ARV-experienced patients, were evaluated. Studies assessing raltegravir pharmacokinetics and pharmacodynamics were included for review.

DATA SYNTHESIS

The nucleoside-based regimen of raltegravir with tenofovir/emtricitabine provides an effective first-line treatment option. However, nucleoside-sparing regimens appear unfavorable in ARV-naïve subjects and should be reserved for patients with limited treatment options. Raltegravir used with optimized background therapy provides an alternative regimen for ARV-experienced patients. This review describes the available in vitro and in vivo data on raltegravir potency, defined as the ability to achieve undetectable viral load, and safety profile, as well as comparison to standard HIV-1 therapies.

CONCLUSIONS

Raltegravir has demonstrated potent antiretroviral activity against HIV-1 in both ARV-naïve and ARV-experienced subjects, with the benefits of a favorable adverse effect profile and minimal drug interactions. Raltegravir must be dosed twice daily, as once daily raltegravir displays decreased virologic efficacy compared to twice daily dosing. However, the ongoing development of new integrase strand transfer inhibitors may provide potent once daily regimens.

Plasma and intracellular pharmacokinetics of darunavir/ritonavir once daily and raltegravir once and twice daily in HIV-infected individuals

OBJECTIVES

To investigate the pharmacokinetics of darunavir/ritonavir and raltegravir, in HIV-infected subjects, in both plasma and at the intracellular (IC) site of action.

METHODS

HIV-infected patients on antiretroviral therapy received raltegravir 400 mg twice daily for 21 days (period 1); darunavir/ritonavir 800/100 mg once daily was added for 14 days (period 2), and patients were randomized to continue raltegravir twice daily (group 1) or to switch to 800 mg once daily (group 2), then they all stopped raltegravir intake and continued darunavir/ritonavir once daily for 14 days (period 3). Drug concentrations in plasma and cells (peripheral blood mononuclear cell) were measured, and differences in geometric mean ratios (GMR) and 90% confidence intervals (CI) between period 2 versus period 3 and period 2 versus period 1 were assessed.

RESULTS

Twenty-four patients completed the study. Group 1 GMR (90% CI) of darunavir area under the curve (AUC) with and without raltegravir was 1.24 (1.13 to 1.45) for plasma and 1.24 (1.07 to 1.73) for cells and for group 2 was 1.14 (1.07 to 1.24) and 1.03 (0.94 to 1.16). GMR (90% CI) of raltegravir AUC without and with darunavir/ritonavir (plasma and cells) for group 1 was 0.90 (0.73 to 1.44) and 1.02 (0.81 to 1.67) and for group 2 was 1.21 (1.03 to 1.77) and 1.27 (1.07 to 1.94). Geometric mean IC to plasma AUC ratios were 5.3 and 4.9 for darunavir in groups 1 and 2 when darunavir/ritonavir was given alone and 4.9 and 5.6 for raltegravir when given alone. These ratios were not altered by the coadministered drug.

CONCLUSIONS

No remarkable interactions between darunavir/ritonavir and raltegravir in plasma or cells were seen. Raltegravir IC concentrations are higher than previously reported; the difference being due to modified cell isolation procedures that reduced drug loss caused by washing.

Co-administration of raltegravir reduces daily darunavir exposure in HIV-1 infected patients

The potential drug-to-drug interaction between darunavir and raltegravir in the setting of HIV infection is a highly debated issue still unresolved. In the present study we have evaluated the pharmacokinetics of darunavir and ritonavir in 53 HIV-1 infected patients with or without concomitant raltegravir administration. The assessment of trough plasma drug concentrations was carried out in all subjects and the potential influence of raltegravir on darunavir and ritonavir disposition, assessed by specific pharmacokinetic evaluations in a subgroup of 25 patients. No significant differences on darunavir and ritonavir plasma trough levels were observed between patients receiving or not raltegravir. Co-administration of raltegravir was, however, associated with a 40% reduction in darunavir C(max) and estimated AUC(0-24), as well a 60% increase in the estimated darunavir clearance compared with values measured in patients not given raltegravir. Notably, this interaction was independent of the dosage of darunavir and not due to effects of raltegravir on the pharmacokinetics of ritonavir. These results should be taken into account when darunavir-based regimens are implemented in the setting of HIV, especially considering that this drug is usually administered at fixed daily dose and no therapeutic drug monitoring is performed in most centres.

Nephrotoxicity of HAART

Highly active antiretroviral therapy (HAART) and other medical therapies for HIV-related infections have been associated with toxicities. Antiretroviral therapy can contribute to renal dysfunction directly by inducing acute tubular necrosis, acute interstitial nephritis, crystal nephropathy, and renal tubular disorders or indirectly via drug interactions. With the increase in HAART use, clinicians must screen patients for the development of kidney disease especially if the regimen employed increases risk of kidney injury. It is also important that patients with chronic kidney disease (CKD) are not denied the best combinations, especially since most drugs can be adjusted based on the estimated GFR. Early detection of risk factors, systematic screening for chronic causes of CKD, and appropriate referrals for kidney disease management should be advocated for improved patient care. The interaction between immunosuppressive therapy and HAART in patients with kidney transplants and the recent endorsement of tenofovir/emtricitabine by the Centers for Disease Control (CDC) for preexposure prophylaxis bring a new dimension for nephrotoxicity vigilance. This paper summarizes the common antiretroviral drugs associated with nephrotoxicity with particular emphasis on tenofovir and protease inhibitors, their risk factors, and management as well as prevention strategies.

Switch from enfuvirtide to raltegravir lowers plasma concentrations of darunavir and tipranavir: a pharmacokinetic substudy of the EASIER-ANRS 138 trial

We compared tipranavir and darunavir concentrations measured at steady state in 20 human immunodeficiency virus (HIV)-infected patients enrolled in the EASIER-ANRS 138 clinical trial who switched from enfuvirtide to raltegravir while maintaining the same background regimen. The geometric mean ratios of the observed predose concentration (C(trough)), maximum concentration of drug observed in plasma (C(max)), and area under the plasma concentration-time curve (AUC) before (day 0) and after (week 24) the switch were 0.49, 0.76, and 0.67 and 0.82, 0.68, and 0.64 for tipranavir and darunavir, respectively. The virologic consequences of these drug interactions have yet to be determined.