Evaluation of Drug-Drug Interactions Between Hepatitis C Antiviral Agents Ombitasvir, Paritaprevir/Ritonavir, and Dasabuvir and HIV-1 Protease Inhibitors

Pharmacokinetics, safety and tolerability of ravidasvir, with and without danoprevir/ritonavir, in healthy subjects

Ravidasvir (RDV) is a novel oral hepatitis C virus NS5A inhibitor. This study aimed to evaluate the pharmacokinetics and safety of RDV and the drug-drug interaction between RDV and ritonavir-boosted danoprevir (DNVr) in healthy adults. In 1^st study, healthy volunteers were administered oral single doses of 100, 200 and 300 mg RDV and 200 mg once daily for 7 days. The 2^nd study was randomized, double-blind and placebo-controlled sequential design (day 1 for 200 mg RDV alone, day 7 for 100 mg/100 mg DNVr, day 13 for 200 mg RDV plus 100mg/100mg DNVr, followed by RDV 200 mg once daily with DNVr 100mg/100mg twice daily for 10 days). The results showed that RDV exposure increased in a dose-proportional manner following a single dose with no evidence of accumulation with multiple doses. Co-administration with DNVr regimen (100 mg/100 mg, twice daily) resulted in a 2.92- and 1.99-fold increase in minimum plasma concentration at steady state (C_min,ss) and area under the concentration-time curve at steady state (AUC_τ) of RDV. With co-administration of RDV, maximum plasma concentration (C_max) and area under the concentration curve from zero to 12 h (AUC_0-12) of DNV increased 1.71-fold and 2.33-fold, respectively. We did not observe any significant changes in ritonavir exposure. Both single and multiple doses of RDV with or without DNVr were well tolerated. The favorable pharmacokinetic and safety results support ravidasvir's continued clinical development and treatment.

Impact of Therapeutic Drug Monitoring of Antiretroviral Drugs in Routine Clinical Management of People Living With HIV: A Narrative Review

BACKGROUND

The treatment of HIV infection has evolved significantly since the advent of highly active antiretroviral therapy. As a result, a response rate of 90%-95% now represents a realistically achievable target. Given this background, it is difficult to imagine the additional benefits that therapeutic drug monitoring (TDM) could provide in the management of HIV infection.

METHODS

This article is not intended to provide a systematic literature review on TDM of antiretroviral agents; rather, the authors aim to discuss the potential added value of TDM in the optimal management of people living with HIV (PLWH) in selected real-life clinical scenarios based on data collected over 10 years by their TDM service.

RESULTS

Some clinical situations, in which the selection of the optimal antiretroviral therapy is challenging, have been identified. These include poorly compliant patients, suboptimal antiretroviral therapies (in terms of both efficacy and toxicity), polypharmacy with a high risk of drug-drug interactions, and different patient populations, such as pregnant women.

CONCLUSIONS

The transformation of HIV infection from a near-universally fatal illness to a lifelong chronic disease has resulted in an HIV population that is growing and aging, placing new and increasing demands on public programs and health services. Increasingly, the management of comorbidities, polypharmacy, and drug-drug interaction, and their impact on antiretroviral therapy will have to be undertaken. These clinical settings represent some of the new frontiers for the use of TDM with the goal of achieving optimal prescription and outcome for PLWH.

Update on treatment and preventive interventions against COVID-19: an overview of potential pharmacological agents and vaccines

The outbreak of coronavirus disease 2019 (COVID-19) triggered by the new member of the coronaviridae family, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has created an unprecedented challenge for global health. In addition to mild to moderate clinical manifestations such as fever, cough, and fatigue, severe cases often developed lethal complications including acute respiratory distress syndrome (ARDS) and acute lung injury. Given the alarming rate of infection and increasing trend of mortality, the development of underlying therapeutic and preventive treatment, as well as the verification of its effectiveness, are the top priorities. Current research mainly referred to and evaluated the application of the empirical treatment based on two precedents, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), including antiviral drugs targeting different stages of virus replication, immunotherapy modulating the overactivated inflammation response, and other therapies such as herbal medicine and mesenchymal stem cells. Besides, the ongoing development of inventing prophylactic interventions such as various vaccines by companies and institutions worldwide is crucial to decline morbidity and mortality. This review mainly focused on promising candidates for the treatment of COVID-19 and collected recently updated evidence relevant to its feasibility in clinical practice in the near future.

Repurposing Antiviral Protease Inhibitors Using Extracellular Vesicles for Potential Therapy of COVID-19

In January 2020, Chinese health agencies reported an outbreak of a novel coronavirus-2 (CoV-2) which can lead to severe acute respiratory syndrome (SARS). The virus, which belongs to the coronavirus family (SARS-CoV-2), was named coronavirus disease 2019 (COVID-19) and declared a pandemic by the World Health Organization (WHO). Full-length genome sequences of SARS-CoV-2 showed 79.6% sequence identity to SARS-CoV, with 96% identity to a bat coronavirus at the whole-genome level. COVID-19 has caused over 133,000 deaths and there are over 2 million total confirmed cases as of April 15th, 2020. Current treatment plans are still under investigation due to a lack of understanding of COVID-19. One potential mechanism to slow disease progression is the use of antiviral drugs to either block the entry of the virus or interfere with viral replication and maturation. Currently, antiviral drugs, including chloroquine/hydroxychloroquine, remdesivir, and lopinavir/ritonavir, have shown effective inhibition of SARS-CoV-2 in vitro. Due to the high dose needed and narrow therapeutic window, many patients are experiencing severe side effects with the above drugs. Hence, repurposing these drugs with a proper formulation is needed to improve the safety and efficacy for COVID-19 treatment. Extracellular vesicles (EVs) are a family of natural carriers in the human body. They play a critical role in cell-to-cell communications. EVs can be used as unique drug carriers to deliver protease inhibitors to treat COVID-19. EVs may provide targeted delivery of protease inhibitors, with fewer systemic side effects. More importantly, EVs are eligible for major aseptic processing and can be upscaled for mass production. Currently, the FDA is facilitating applications to treat COVID-19, which provides a very good chance to use EVs to contribute in this combat.

Pharmacokinetic Interactions between the Hepatitis C Virus Inhibitors Elbasvir and Grazoprevir and HIV Protease Inhibitors Ritonavir, Atazanavir, Lopinavir, and Darunavir in Healthy Volunteers

The combination of the hepatitis C virus (HCV) nonstructural protein 5A (NS5A) inhibitor elbasvir and the NS3/4A protease inhibitor grazoprevir is a potent, once-daily therapy indicated for the treatment of chronic HCV infection in individuals coinfected with human immunodeficiency virus (HIV). We explored the pharmacokinetic interactions of elbasvir and grazoprevir with ritonavir and ritonavir-boosted HIV protease inhibitors in three phase 1 trials. Drug-drug interaction trials with healthy participants were conducted to evaluate the effect of ritonavir on the pharmacokinetics of grazoprevir (n = 10) and the potential two-way pharmacokinetic interactions of elbasvir (n = 30) or grazoprevir (n = 39) when coadministered with ritonavir-boosted atazanavir, lopinavir, or darunavir. Coadministration of ritonavir with grazoprevir increased grazoprevir exposure; the geometric mean ratio (GMR) for grazoprevir plus ritonavir versus grazoprevir alone area under the concentration-time curve from 0 to 24 h (AUC_0-24) was 1.91 (90% confidence interval [CI]; 1.31 to 2.79). Grazoprevir exposure was markedly increased with coadministration of atazanavir-ritonavir, lopinavir-ritonavir, and darunavir-ritonavir, with GMRs for grazoprevir AUC_0-24 of 10.58 (90% CI, 7.78 to 14.39), 12.86 (90% CI, 10.25 to 16.13), and 7.50 (90% CI, 5.92 to 9.51), respectively. Elbasvir exposure was increased with coadministration of atazanavir-ritonavir, lopinavir-ritonavir, and darunavir-ritonavir, with GMRs for elbasvir AUC_0-24 of 4.76 (90% CI, 4.07 to 5.56), 3.71 (90% CI, 3.05 to 4.53), and 1.66 (90% CI, 1.35 to 2.05), respectively. Grazoprevir and elbasvir had little effect on atazanavir, lopinavir, and darunavir pharmacokinetics. Coadministration of elbasvir-grazoprevir with atazanavir-ritonavir, lopinavir-ritonavir, or darunavir-ritonavir is contraindicated, owing to an increase in grazoprevir exposure. Therefore, HIV treatment regimens without HIV protease inhibitors should be considered for HCV/HIV-coinfected individuals who are being treated with elbasvir-grazoprevir.

Pharmacokinetics of Ombitasvir, Paritaprevir, Ritonavir, and Dasabuvir in Healthy Chinese Subjects and HCV GT1b-Infected Chinese, South Korean and Taiwanese Patients

BACKGROUND/PURPOSE

The 3 direct-acting antiviral (3D) regimen of ombitasvir/paritaprevir/ritonavir plus dasabuvir has recently been approved in several Asian geographic regions for the treatment of hepatitis C virus (HCV) genotype (GT) 1 infection. The pharmacokinetics of the components of the 3D regimen with or without ribavirin were evaluated in healthy Chinese subjects and HCV GT1b-infected Chinese, South Korean, and Taiwanese patients, with or without cirrhosis, to determine how the drug exposures in Asian populations compare with historical data in Western populations.

METHODS

Participants received ombitasvir/paritaprevir/ritonavir 25/150/100 mg once daily plus dasabuvir 250 mg twice daily for 14 days (healthy subjects, n = 36) or 12 weeks (HCV patients, n = 754). Patients with compensated cirrhosis also received ribavirin 1000 or 1200 mg divided twice daily, per the local label. Intensive or sparse pharmacokinetic sampling was performed for assessments of plasma drug concentrations.

RESULTS

The exposures [maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC)] of the components of the 3D regimen were comparable (< 20% difference) in healthy Chinese subjects residing in China or the United States. In addition, the trough plasma concentrations (C_trough) in HCV GT1b-infected Asian patients were either similar to (ombitasvir) or within 75% of (paritaprevir and dasabuvir) those in Western patients without cirrhosis, or similar to (ombitasvir and paritaprevir) or within 100% of (dasabuvir) those in Western patients with cirrhosis, with widely overlapping ranges of individual values. Generally comparable drug exposures were observed among Chinese, South Korean, and Taiwanese ethnicities for noncirrhotic and cirrhotic patients.

CONCLUSION

Collectively, the results of these pharmacokinetic analyses support the use of the same dose of the 3D regimen for Asian and Western patients. CLINICALTRIALS.GOV: NCT02534870, NCT02517515, NCT02517528.

Real-World Clinical Efficacy and Tolerability of Direct-Acting Antivirals in Hepatitis C Monoinfection Compared to Hepatitis C/Human Immunodeficiency Virus Coinfection in a Community Care Setting

Background/Aims

Limited data exist comparing the safety and efficacy of direct-acting antivirals (DAAs) in hepatitis C virus (HCV) monoinfected and HCV/human immunodeficiency virus (HIV) coinfected patients in the real-world clinic practice setting.

Methods

All HCV monoinfected and HCV/HIV coinfected patients treated with DAAs between January 2014 and October 2017 in community clinic settings were retrospectively analyzed. Pretreatment baseline patient characteristics, treatment efficacy, factors affecting sustained virologic response at 12 weeks (SVR12) after treatment, and adverse reactions were compared between the groups.

Results

A total of 327 patients were included in the study, of which 253 were HCV monoinfected, and 74 were HCV/HIV coinfected. There was a statistically significant difference observed in SVR12 when comparing HCV monoinfection and HCV/HIV coinfection (94% and 84%, respectively, p=0.005). However, there were no significant factors identified as a predictor of a reduced response. The most common adverse effect was fatigue (27%). No significant drug interaction was observed between DAA and antiretroviral therapy. None of the patients discontinued the treatment due to adverse events.

Conclusions

In a real-world setting, DAA regimens have lower SVR12 in HCV/HIV coinfection than in HCV monoinfection. Further studies involving a higher number of HCV/HIV coinfected patients are needed to identify real predictors of a reduced response.

Plasma trough concentrations of antiretrovirals in HIV-infected persons treated with direct-acting antiviral agents for hepatitis C in the real world

Background

Possible drug-drug interactions (DDIs) between antiretrovirals (ARVs) and direct-acting antiviral agents (DAAs) are of some concern.

Objectives

To investigate ARV plasma trough concentrations (Ctrough) before and during DAAs in patients treated in the real world.

Methods

Single-centre, prospective, observational study including HIV/HCV coinfected persons undergoing DAA treatment. Self-reported adherence was assessed and ARVs Ctrough measured by HPLC-UV. Blood samples were collected before and after 2 months of DAA treatment.

Results

One-hundred and thirty-seven patients were included: 21.2% treated with ombitasvir/paritaprevir/ritonavir ± dasabuvir (2D/3D) and 78.8% with sofosbuvir-based regimens. Suboptimal Ctrough before and during DAA was found, respectively, in 3 (10.3%) and 3 (10.3%) cases treated with 2D/3D, and 16 (14.8%) and 11 (10.2%) with sofosbuvir-based regimens, even if self-reported ARV adherence was always ≥93%. In 2D/3D-treated patients, median darunavir Ctrough during DAAs was significantly lower than observed before DAAs [1125 ng/mL (IQR, 810-1616) versus 1903 ng/mL (IQR 1387-3983), respectively] (n = 5; P = 0.009), with a 40.9% decrease. In the same group, no differences in atazanavir or raltegravir concentrations were found. In patients treated with sofosbuvir-based regimens, Ctrough of all ARVs were similar before and during DAAs.

Conclusions

In the real world of HIV/HCV coinfected patients, ARV plasma concentrations during DAAs were generally not different from those found before anti-HCV treatment. Although assessed in a small number of patients, darunavir concentrations during 2D/3D showed a significant reduction when compared with those found before DAAs. ARV plasma concentrations measurement during anti-HCV treatment may give useful information for managing HIV/HCV coinfected persons receiving treatment for both infections.

Clinical Pharmacokinetics of Paritaprevir

Paritaprevir is a potent hepatitis C virus (HCV) nonstructural (NS) protein 3/4A protease inhibitor that is used in combination with other direct-acting antivirals (DAAs) for the treatment of chronic HCV infection. Paritaprevir is primarily metabolized by cytochrome P450 (CYP) 3A4 and is administered with a low dose of ritonavir to achieve drug concentrations suitable for once-daily dosing. Coadministration of paritaprevir with ritonavir increases the half-life of single-dose paritaprevir from approximately 3 h to 5-8 h, doubles the time to maximum plasma concentration (T _max) from 2.3 to 4.7 h, and increases exposures 30-fold for maximum observed plasma concentration (C _max), 50-fold for area under the plasma concentration-time curve (AUC), and >300-fold for trough concentration (C ₂₄). Paritaprevir displays highly variable, nonlinear pharmacokinetics, with C _max and AUC increasing in a greater than dose proportional manner when administered with or without ritonavir. In the presence of ritonavir, paritaprevir is excreted mostly unchanged in feces via biliary excretion. Paritaprevir exposures are higher in Japanese subjects compared with Caucasian subjects; however, no dose adjustment is needed for Japanese patients as the higher exposures are safe and well tolerated. The pharmacokinetic characteristics of paritaprevir are similar between healthy subjects and HCV-infected patients, and are not appreciably altered by mild or moderate hepatic impairment or mild, moderate, or severe renal impairment, including those on dialysis. Paritaprevir exposures are increased in patients with severe hepatic impairment. Although the presence of a low dose of ritonavir in paritaprevir-containing regimens increases the likelihood of drug-drug interactions, results from several drug interaction studies demonstrated that paritaprevir-containing regimens can be coadministered with many comedications that are commonly prescribed in HCV-infected patients.

Clinical Pharmacokinetics of Dasabuvir

Dasabuvir is a nonstructural (NS) 5B non-nucleoside inhibitor of the hepatitis C virus (HCV) used in combination with ombitasvir/paritaprevir/ritonavir for the treatment of chronic HCV infection. It is primarily metabolized by cytochrome P450 (CYP) 2C8, with a minor contribution from CYP3A. Biotransformation of dasabuvir forms the M1 metabolite, which retains antiviral activity. Dasabuvir exhibits linear pharmacokinetics with a terminal half-life of approximately 5-8 h, allowing for twice-daily dosing. The M1 metabolite of dasabuvir is the major metabolite in plasma and has a half-life similar to that of dasabuvir. Dasabuvir exposures in Asian subjects are comparable with Caucasian subjects. The pharmacokinetic characteristics of dasabuvir are similar between healthy subjects and HCV-infected patients, and are not appreciably altered by mild, moderate, or severe renal impairment or dialysis. Dasabuvir pharmacokinetic parameters were not significantly altered in subjects with mild or moderate hepatic impairment; however, exposures were significantly increased in subjects with severe hepatic impairment. Dasabuvir should be administered with food to maximize absorption. Coadministration of dasabuvir with a strong CYP2C8 inhibitor increased dasabuvir exposures by greater than tenfold, whereas coadministration with strong CYP3A inhibitors increased dasabuvir exposures by less than 50%. Furthermore, coadministration of dasabuvir with a CYP3A inducer decreased dasabuvir exposures by 55-70%. Coadministration of dasabuvir with strong CYP2C8 inhibitors or strong CYP3A/CYP2C8 inducers is contraindicated. Results from several drug interaction studies demonstrated that dasabuvir in combination with ombitasvir/paritaprevir/ritonavir can be coadministered with most comedications that are commonly prescribed in HCV-infected patients.

Clinical Pharmacokinetics of Ombitasvir

Ombitasvir is a potent, nonstructural protein 5A inhibitor of the hepatitis C virus (HCV) that is used in combination with other direct-acting antivirals for the treatment of chronic HCV infection. Ombitasvir is predominantly metabolized by amide hydrolysis followed by oxidative metabolism and is a substrate of P-glycoprotein. Ombitasvir displays linear pharmacokinetics with minimal accumulation and is eliminated via metabolism and biliary excretion. A negligible amount of unchanged drug is excreted in urine. Exposures are comparable across Chinese, Japanese, and non-Asian subjects. The pharmacokinetic characteristics of ombitasvir are similar in healthy subjects and HCV-infected patients, and are not appreciably altered by hepatic or renal impairment. Results from several drug interaction studies demonstrated that ombitasvir has a low potential for drug interactions.

Paritaprevir/ritonavir/ombitasvir plus dasabuvir in HIV/HCV-coinfected patients with genotype 1 in real-life practice

Background Data on the efficacy, safety, and concomitant use with other drugs of the combination ritonavir-boosted paritaprevir/ombitasvir plus dasabuvir (PrOD) in HIV/HCV-coinfected patients in real life are limited. The objectives of this study were to analyze these topics in HIV/HCV-coinfected subjects bearing HCV genotype 1 (GT1). Methods One hundred and eighty-two HIV/HCV-coinfected patients with GT1 (87 1a, 71 1b, 23 other) treated with PrOD, plus ribavirin (RBV) in 119 cases, in routine clinical practice were analyzed. The main variable of efficacy was sustained virological response (SVR) 12 weeks after completing therapy in an intention-to-treat (ITT) analysis and that of safety treatment discontinuation because of adverse effects. Factors associated with SVR were analyzed with a modified ITT (mITT) strategy. Results One hundred and seventy-two (94%) patients attained SVR, 3 (2%) experienced a relapse and two (1%) discontinued therapy due to adverse events. The rates of SVR in subjects with GT 1a and 1b by mITT were, respectively, 97% and 98%. Sixty-five (98%) out of 66 patients with cirrhosis and 107 (98%) out of 110 (p = 1) non-cirrhotics achieved SVR. Fifty-five (95%) patients on concomitant darunavir therapy developed SVR vs. 117 (99%) (p = 0.105) of those without DRV. RBV dose was reduced in 13 (11%) patients and permanently discontinued in 2 (2%), with no impact on SVR. Conclusions PrOD is highly effective and well tolerated in HIV/HCV-coinfected patients with GT1 in routine clinical practice. RBV is often required. However, RBV dose reduction or discontinuation is uncommonly needed and do not impair the SVR rate.

Similar effectiveness of direct-acting antiviral against hepatitis C virus in patients with and without HIV infection

OBJECTIVE

We compared the baseline characteristics, effectiveness, and tolerance of direct-acting antiviral drug (DAA)-based regimens taken by hepatitis C virus (HCV)-monoinfected and HCV/HIV-coinfected individuals in clinical practice.

DESIGN

We performed a prospective observational study in two tertiary centres in Madrid, Spain, which included all HCV-monoinfected and HCV/HIV-coinfected patients undergoing HCV treatment with all-oral DAA regimens in a routine clinical setting, from April 2015 to November 2015. We evaluated sustained virological response 12 weeks after the end of therapy (SVR12), adverse events, and baseline and treatment characteristics.

RESULTS

The study population comprised 1634 patients: 1152 HCV-monoinfected patients (70%) and 482 HCV/HIV-coinfected patients (30%). Fifty percent had cirrhosis, and 47% were peginterferon/ribavirin-experienced. HCV/HIV-coinfected patients were younger [median age (interquartile range) 51 (48-54) years vs. 59 (50-68) years; P < 0.001), more frequently male (76 vs. 54%; P < 0.001), and infected with genotypes 1a (37 vs. 17%; P < 0.001), 3 (15 vs. 7%; P < 0.001), and 4 (23 vs. 4%; P < 0.001). One of every three patients took ribavirin. SVR12 was 94% (95% confidence interval 91.7-96%) and 97% (95% confidence interval 95.7-99.4%) in coinfected and monoinfected patients, respectively, with no significant differences between the groups after adjustment for cirrhosis, genotype, and DAA combination. DAA-based regimens were well tolerated, and only 1% of patients had severe adverse events, with no differences between the populations.

CONCLUSIONS

HCV/HIV-infected patients treated with all-oral DAA combinations achieved high rates of SVR12 that were similar to those of HCV-monoinfected patients under real-life conditions. Safety and tolerance were excellent, even in patients with end-stage liver disease.

TURQUOISE-I Part 1b: Ombitasvir/Paritaprevir/Ritonavir and Dasabuvir with Ribavirin for Hepatitis C Virus Infection in HIV-1 Coinfected Patients on Darunavir

Background

Ombitasvir/paritaprevir/ritonavir with dasabuvir (OBV/PTV/r + DSV) ± ribavirin (RBV) is approved for hepatitis C virus (HCV) genotype 1 (GT1) treatment in HIV-1 coinfected patients. In healthy controls, coadministration of OBV/PTV/r + DSV + darunavir (DRV) lowered DRV trough concentration (Ctrough) levels. To assess the clinical significance of this change, TURQUOISE-I, Part 1b, evaluated the efficacy and safety of OBV/PTV/r + DSV + RBV in coinfected patients on stable, DRV-containing antiretroviral therapy (ART).

Methods

Patients were HCV treatment-naive or interferon-experienced, had CD4+ lymphocyte count ≥200 cells/µL or ≥14%, and plasma HIV-1 RNA suppression on once-daily (QD) DRV-containing ART at screening. Patients were randomized to maintain DRV 800 mg QD or switch to twice-daily (BID) DRV 600 mg; all received OBV/PTV/r + DSV + RBV for 12 weeks.

Results

Twenty-two patients were enrolled and achieved SVR12. No adverse events led to discontinuation. Coadministration had minimal impact on DRV maximum observed plasma concentration and area under the curve; DRV Ctrough levels were slightly lower with DRV QD and BID. No patient experienced plasma HIV-1 RNA >200 copies/mL during treatment.

Conclusions

HCV GT1/HIV-1 coinfected patients on stable DRV-containing ART achieved 100% SVR12 while maintaining plasma HIV-1 RNA suppression. Despite DRV exposure changes, episodes of intermittent HIV-1 viremia were infrequent.

Mechanisms and Predictions of Drug-Drug Interactions of the Hepatitis C Virus Three Direct-Acting Antiviral Regimen: Paritaprevir/Ritonavir, Ombitasvir, and Dasabuvir

To assess drug-drug interaction (DDI) potential for the three direct-acting antiviral (3D) regimen of ombitasvir, dasabuvir, and paritaprevir, in vitro studies profiled drug-metabolizing enzyme and transporter interactions. Using mechanistic static and dynamic models, DDI potential was predicted for CYP3A, CYP2C8, UDP-glucuronosyltransferase (UGT) 1A1, organic anion-transporting polypeptide (OATP) 1B1/1B3, breast cancer resistance protein (BCRP), and P-glycoprotein (P-gp). Perpetrator static model DDI predictions for metabolizing enzymes were within 2-fold of the clinical observations, but additional physiologically based pharmacokinetic modeling was necessary to achieve the same for drug transporters. When perpetrator interactions were assessed, ritonavir was responsible for the strong increase in exposure of sensitive CYP3A substrates, whereas paritaprevir (an OATP1B1/1B3 inhibitor) greatly increased the exposure of sensitive OATP1B1/1B3 substrates. The 3D regimen drugs are UGT1A1 inhibitors and are predicted to moderately increase plasma exposure of sensitive UGT1A1 substrates. Paritaprevir, ritonavir, and dasabuvir are BCRP inhibitors. Victim DDI predictions were qualitatively in line with the clinical observations. Plasma exposures of the 3D regimen were reduced by strong CYP3A inducers (paritaprevir and ritonavir; major CYP3A substrates) but were not affected by strong CYP3A4 inhibitors, since ritonavir (a CYP3A inhibitor) is already present in the regimen. Strong CYP2C8 inhibitors increased plasma exposure of dasabuvir (a major CYP2C8 substrate), OATP1B1/1B3 inhibitors increased plasma exposure of paritaprevir (an OATP1B1/1B3 substrate), and P-gp or BCRP inhibitors (all compounds are substrates of P-gp and/or BCRP) increased plasma exposure of the 3D regimen. Overall, the comprehensive mechanistic assessment of compound disposition along with mechanistic and PBPK approaches to predict victim and perpetrator DDI liability may enable better clinical management of nonstudied drug combinations with the 3D regimen.

Update in HIV-hepatitis C virus coinfection in the direct acting antiviral era

PURPOSE OF REVIEW

Availability of direct acting antivirals (DAAs) that demonstrate remarkable clinical efficacy and safety has revolutionized the ability to treat chronic infection with hepatitis C virus (HCV). An equal measure of clinical success has now been achieved in persons coinfected with HCV and the HIV, a historically harder to cure cohort with interferon-based therapy. Global goals include identifying all HIV-HCV-infected persons, gaining access to DAA therapy, preventing de novo and reinfection, and managing the sequelae of chronic infection. This review will discuss advances in the field of HIV-HCV coinfection reported during the last 18 months, and will suggest areas for future investigation.

RECENT FINDINGS

An expanding body of literature has enhanced our understanding of the clinical and epidemiologic issues surrounding HIV-HCV coinfection. DAA therapy for HCV is highly efficacious in HIV-HCV-coinfected persons if drug-drug interactions are appropriately considered.

SUMMARY

Eradicating HCV infection in persons with HIV coinfection can be achieved safely and effectively with available DAAs. Economic and social approaches to enable access and delivery of curative HCV therapy to HIV-infected persons require continued research and resource allocation.

Population pharmacokinetics of paritaprevir, ombitasvir, dasabuvir, ritonavir and ribavirin in hepatitis C virus genotype 1 infection: analysis of six phase III trials

AIM

The aim of the current study was to characterize the population pharmacokinetics of a triple direct-acting antiviral (DAA) regimen (3D) (ombitasvir, paritaprevir-ritonavir and dasabuvir) and adjunctive ribavirin, and estimate covariate effects in a broad spectrum of subjects with hepatitis C virus (HCV) genotype 1 infection.

METHODS

Pharmacokinetic data from six phase III studies and one phase II study in subjects receiving the currently approved doses of the 3D ± ribavirin regimen for treating HCV genotype 1 infection for 12 weeks or 24 weeks were characterized using separate population pharmacokinetic models, built using each component of the regimen from nonlinear mixed-effects methodology in NONMEM 7.3. In the models, demographic and clinical covariates were tested. Models were assessed via goodness-of-fit plots, visual predictive checks and bootstrap evaluations.

RESULTS

The population pharmacokinetic models for each component of the 3D ± ribavirin regimen (DAAs and ritonavir, n = 2348) and ribavirin (n = 1841) adequately described their respective plasma concentration-time data. Model parameter estimates were precise and robust, and all models showed good predictive ability. Significant covariate effects associated with apparent clearance and volume of distribution included age, body weight, gender, cirrhosis, HCV subtype, opioid or antidiabetic agent use, and creatinine clearance.

CONCLUSION

The population pharmacokinetics of the 3D ± ribavirin regimen components in HCV-infected patients were characterized using phase II and III HCV clinical trial data. Although several statistically significant covariates were identified, their effects were modest and not clinically meaningful to necessitate dose adjustments for any component of the 3D regimen.

Progress in eradication of HCV in HIV positive patients with significant liver fibrosis in Vienna

Aim

We aimed to investigate the efficacy of interferon and ribavirin-free sofosbuvir/ledipasvir (SOF/LDV) and ritonavir boosted paritaprevir/ombitasvir with or without dasabuvir (2D/3D) regimens in a real-life cohort of human immunodeficiency virus/hepatitis C virus (HIV/HCV) coinfected patients. The study focused on efficacy, need for changes in antiretroviral therapy (ART) due to drug-drug interaction (DDI), and treatment-associated changes in liver stiffness.

Methods

In this study 36 patients (n = 21 SOF/LDV and n = 15 2D/3D) were retrospectively analyzed. Depending on the genotype the following treatment regimens were used: HCV genotype (GT)-1: either SOF/LDV or 3D, no patient with HCV-GT2 was included, HCV-GT3: SOF/LDV, HCV-GT4: 2D.

Results

Approximately one third (35.3%) of patients were treatment-experienced and 13.9% had cirrhosis. Antiretroviral therapy had to be changed in 38.1% of SOF/LDV and 60% of 2D/3D patients prior to anti-HCV treatment due to expected DDIs. We observed sustained virologic response (SVR) rates of 100% in patients treated with SOF/LDV (19/19) and 2D/3D (14/14). One 2D/3D patient was lost to follow-up, while two SOF/LDV patients died during therapy from non-treatment-related causes. They were excluded from the analysis. Between baseline and follow-up liver stiffness decreased from 11.4 to 8.3 kPa (p = 0.008) and from 8.1 to 5.7 kPa (p = 0.001) in SOF/LDV and 2D/3D patients, respectively.

Conclusions

We confirmed the excellent HCV eradication rates >95% in a real-life cohort of HIV/HCV coinfected patients treated with SOF/LDV and 2D/3D. We observed no HCV relapse or breakthrough. More patients treated with 2D/3D required a change in ART than patients treated with SOF/LDV. Additionally, HCV eradication led to a rapid decline in liver stiffness.

Pharmacokinetic Evaluation of Darunavir Administered Once or Twice Daily in Combination with Ritonavir or the Three-Direct-Acting Antiviral Regimen of Ombitasvir/Paritaprevir/Ritonavir and Dasabuvir in Adults Coinfected with Hepatitis C and Human Immunodeficiency Viruses

The three-direct-acting antiviral (3D) regimen containing ombitasvir, paritaprevir, ritonavir, and dasabuvir with or without ribavirin (RBV) is approved for treatment of hepatitis C virus (HCV) genotype 1 (GT1)/human immunodeficiency virus type 1 (HIV-1) coinfection. Results of a pharmacokinetic substudy of 3D and darunavir are presented. HCV/HIV-1-coinfected subjects were randomized to maintain an antiretroviral regimen with darunavir at 800 mg once daily (QD) or switched to a regimen with darunavir at 600 mg twice daily (BID). On study day 1, subjects received 3D and RBV plus darunavir for 12 weeks. Pharmacokinetic parameters were compared for darunavir and ritonavir with and without 3D (week 4 and day -1). Pharmacokinetic parameters of 3D were compared to historical data. Ten subjects received darunavir QD, and 12 subjects received darunavir BID. The central value ratios (90% confidence interval [CI]) for maximum concentrations (C_max), area under the plasma concentration-time curve between 0 and 24 h postdose (AUC₂₄), and trough plasma concentration at 24 h postdose (C₂₄) of darunavir administered QD with 3D versus administration of darunavir alone were 0.92 (0.72, 1.18), 0.83 (0.71, 0.98), and 0.64 (0.44, 0.93), respectively. The ratios (90% CI) for darunavir C_max, AUC₁₂, and C₁₂ administered BID with 3D were 0.92 (0.76, 1.12), 0.88 (0.73, 1.05), and 0.73 (0.58, 0.92), respectively. Exposures of 3D were similar to or slightly lower than those in historical data. All darunavir trough concentrations (C_trough) associated with an HIV-1 RNA level of >40 copies/ml were above the darunavir 50% effective concentration (EC₅₀) of 550 ng/ml for resistant virus. In conclusion, the 3D regimen with darunavir QD or BID did not affect darunavir C_max and AUC, whereas the darunavir C_trough decreased. Changes in pharmacokinetic parameters of 3D were not considered clinically significant. Episodes of intermittent HIV-1 viremia were infrequent and were not associated with darunavir C_trough values below 550 ng/ml. (This study has been registered at ClinicalTrials.gov under identifier NCT01939197.).

HIV/HCV Antiviral Drug Interactions in the Era of Direct-acting Antivirals

Therapy for human immunodeficiency virus (HIV) and chronic hepatitis C has evolved over the past decade, resulting in better control of infection and clinical outcomes; however, drug-drug interactions remain a significant hazard. Joint recommendations from the American Association for the Study of Liver Diseases and the Infectious Diseases Society of America regarding drug-drug interactions between HIV antiretroviral agents and direct-acting antiviral agents for treatment of hepatitis C virus (HCV) infection are reviewed here. This review is oriented to facilitate appropriate selection of an antiviral therapy regimen for HCV infection based on the choice of antiretroviral therapy being administered and, if necessary, switching antiretroviral regimens.

Drug-Drug Interaction between the Direct-Acting Antiviral Regimen of Ombitasvir-Paritaprevir-Ritonavir plus Dasabuvir and the HIV Antiretroviral Agent Dolutegravir or Abacavir plus Lamivudine

The direct-acting antiviral regimen of 25 mg ombitasvir-150 mg paritaprevir-100 mg ritonavir once daily (QD) plus 250 mg dasabuvir twice daily (BID) is approved for the treatment of hepatitis C virus genotype 1 infection, including patients coinfected with human immunodeficiency virus. This study was performed to evaluate the pharmacokinetic, safety, and tolerability effects of coadministering the regimen of 3 direct-acting antivirals with two antiretroviral therapies (dolutegravir or abacavir plus lamivudine). Healthy volunteers (n = 24) enrolled in this phase I, single-center, open-label, multiple-dose study received 50 mg dolutegravir QD for 7 days or 300 mg abacavir plus 300 mg lamivudine QD for 4 days, the 3-direct-acting-antiviral regimen for 14 days, followed by the 3-direct-acting-antiviral regimen with dolutegravir or abacavir plus lamivudine for 10 days. Pharmacokinetic parameters were calculated to compare combination therapy with 3-direct-acting-antiviral or antiretroviral therapy alone, and safety/tolerability were assessed throughout the study. Coadministration of the 3-direct-acting-antiviral regimen increased the geometric mean maximum plasma concentration (Cmax) and the area under the curve (AUC) of dolutegravir by 22% (central value ratio [90% confidence intervals], 1.219 [1.153, 1.288]) and 38% (1.380 [1.295, 1.469]), respectively. Abacavir geometric mean Cmax and AUC values decreased by 13% (0.873 [0.777, 0.979]) and 6% (0.943 [0.901, 0.986]), while those for lamivudine decreased by 22% (0.778 [0.719, 0.842]) and 12% (0.876 [0.821, 0.934]). For the 3-direct-acting-antiviral regimen, geometric mean Cmax and AUC during coadministration were within 18% of measurements made during administration of the 3-direct-acting-antiviral regimen alone, although trough concentrations for paritaprevir were 34% (0.664 [0.585, 0.754]) and 27% (0.729 [0.627, 0.847]) lower with dolutegravir and abacavir-lamivudine, respectively. All study treatments were generally well tolerated, with no evidence of increased rates of adverse events during combination administration. These data indicate that the 3-direct-acting-antiviral regimen can be administered with dolutegravir or abacavir plus lamivudine without dose adjustment.

Effect of co-medications on paritaprevir, ritonavir, ombitasvir, dasabuvir and ribavirin pharmacokinetics: analysis of data from seven Phase II/III trials

BACKGROUND

The three drug direct-acting antiviral regimen (3D regimen) of ombitasvir, paritaprevir/ritonavir and dasabuvir, with and without ribavirin, was evaluated in one Phase II trial and six Phase III trials in over 2,300 HCV genotype-1-infected patients. Patients continued taking their protocol-permitted co-medications while receiving the 3D ± ribavirin regimen. The effects of the co-medications on exposures of the 3D regimen and ribavirin were examined.

METHODS

Population pharmacokinetic model-predicted steady-state area under the curve (AUC_24,ss) values were evaluated in the presence/absence of the co-medications. Interactions resulting in a greater than 50% reduction or 100% increase in an AUC_24,ss value were examined as covariates for an effect on apparent clearance (CL/F).

RESULTS

More than 1,200 co-medications belonging to 15 drug classes and/or 19 enzyme and transporter inhibitor and/or inducer categories were used concomitantly with the 3D regimen in the trials. Approximately 1,500 patients (65%) in Phase III trials received two or more co-medications from multiple drug classes or categories. No co-medication class/category decreased or increased ombitasvir, dasabuvir, ritonavir or ribavirin AUC_24,ss by more than half or twofold, respectively. Opioids, antipsychotics, anti-epileptics, antidiabetics and non-ethinyl estradiol-containing hormone replacement therapies appeared to have an effect (AUC_24,ss ratio ≤0.5 or ≥2.0) on paritaprevir exposures. However, when these classes were included in the paritaprevir population pharmacokinetic model, only opioids and antidiabetics had a statistically significant effect on CL/F, but with no clinically meaningful increase in exposures (≤55%).

CONCLUSIONS

No dose adjustment is necessary for the 3D ± ribavirin regimen when used with the co-medications included in this analysis as there were no clinically meaningful effects on exposures of the DAAs.

Antiretroviral Use in the CEASE Cohort Study and Implications for Direct-Acting Antiviral Therapy in Human Immunodeficiency Virus/Hepatitis C Virus Coinfection

Background.  Interferon-free direct-acting antiviral (DAA) regimens for hepatitis C virus (HCV) provide a major advance in clinical management, including in human immunodeficiency virus (HIV)/HCV coinfection. Drug-drug interactions (DDIs) with combination antiretroviral therapy (cART) require consideration. This study aimed to characterize the cART regimens in HIV/HCV-coinfected individuals and assess the clinical significance of DDIs with DAAs in a real-world cohort. Methods.  This analysis included participants enrolled in CEASE-D, a prospective cohort of HIV/HCV-coinfected individuals in Sydney, Australia, between July 2014 and December 2015. A simulation of potential DDIs between participants' cART and interferon-free DAA regimens was performed using www.hep-druginteractions.org and relevant prescribing information. Results.  In individuals on cART with HCV genotype (GT) 1 and 4 (n = 128), category 3 DDIs (contraindicated or not recommended) were noted in 0% with sofosbuvir/ledipasvir, 0% with sofosbuvir plus daclatasvir, 17% with sofosbuvir/velpatasvir, 36% with ombitasvir/paritaprevir/ritonavir ± dasabuvir, 51% with grazoprevir/elbasvir, and 51% with sofosbuvir plus simeprevir; current cART regimens were suitable for coadministration in 100%, 100%, 73%, 64%, 49%, and 49%, respectively. In individuals with HCV GT 2 or 3 (n = 53), category 3 DDIs were evident in 0% with sofosbuvir plus daclatasvir, 0% with sofosbuvir and ribavirin, and 13% with sofosbuvir/velpatasvir; current cART regimens were suitable in 100%, 100%, and 81%, respectively. Conclusions.  Potential DDIs are expected and will impact on DAA prescribing in HIV/HCV coinfection. Sofosbuvir in combination with an NS5A inhibitor or ribavirin appeared to be the most suitable regimens in this cohort. Evaluation of potential DDIs is required to prevent adverse events or treatment failure.