Assessment of drug-drug interactions between daclatasvir and methadone or buprenorphine-naloxone

Reported adverse events related to use of hepatitis C virus direct-acting antivirals with opioids: 2017-2021

INTRODUCTION

Due to concerns over potential interactions between some hepatitis C direct-acting antivirals (DAAs) and opioids, we describe adverse event (AE) reports of concomitant use of opioids and DAAs.

METHODS

AEs reported (July 28, 2017-December 31, 2021) with the administration of the DAAs glecaprevir/pibrentasvir, sofosbuvir/velpatasvir, ledipasvir/sofosbuvir, sofosbuvir/velpatasvir/voxilaprevir, and elbasvir/grazoprevir as suspect products were downloaded from the US Food and Drug Administration AE Reporting System Public Dashboard. The number of AE reports containing opioids (fentanyl, hydrocodone, oxycodone) as co-suspect products/concomitant products were counted and summarized by severity, reporting country and whether an outcome of death was reported. Overdose AEs were counted irrespective of opioid use, and changes over time were assessed.

RESULTS

In total, 40 AEs were reported for DAAs and concomitant fentanyl use, 25 (62.5%) were in the USA, 35 (87.5%) were considered serious, and 14 (35.0%) resulted in death; and 626 were reported with concomitant oxycodone/hydrocodone use, 596 (95.2%) were in the USA, 296 (47.3%) were considered serious, and 28 (4.5%) resulted in death. There were 196 overdose AEs (32 [16%] deaths) declining from 2018 (N = 56) to 2021 (N = 29).

CONCLUSIONS

Treating people with hepatitis C virus (HCV) infection who use drugs is key to achieving HCV elimination. Low numbers of DAA AE reports with opioids may provide reassurance to prioritize HCV treatment in this population. These data contribute to evidence supporting the continued scale-up of DAA treatment among people who use drugs to achieve HCV elimination goals.

In vitro-in silico-based prediction of inter-individual and inter-ethnic variations in the dose-dependent cardiotoxicity of R- and S-methadone in humans

New approach methodologies predicting human cardiotoxicity are of interest to support or even replace in vivo-based drug safety testing. The present study presents an in vitro–in silico approach to predict the effect of inter-individual and inter-ethnic kinetic variations in the cardiotoxicity of R- and S-methadone in the Caucasian and the Chinese population. In vitro cardiotoxicity data, and metabolic data obtained from two approaches, using either individual human liver microsomes or recombinant cytochrome P450 enzymes (rCYPs), were integrated with physiologically based kinetic (PBK) models and Monte Carlo simulations to predict inter-individual and inter-ethnic variations in methadone-induced cardiotoxicity. Chemical specific adjustment factors were defined and used to derive dose–response curves for the sensitive individuals. Our simulations indicated that Chinese are more sensitive towards methadone-induced cardiotoxicity with Margin of Safety values being generally two-fold lower than those for Caucasians for both methadone enantiomers. Individual PBK models using microsomes and PBK models using rCYPs combined with Monte Carlo simulations predicted similar inter-individual and inter-ethnic variations in methadone-induced cardiotoxicity. The present study illustrates how inter-individual and inter-ethnic variations in cardiotoxicity can be predicted by combining in vitro toxicity and metabolic data, PBK modelling and Monte Carlo simulations. The novel methodology can be used to enhance cardiac safety evaluations and risk assessment of chemicals.

Precision dosing of methadone during pregnancy: A pharmacokinetics virtual clinical trials study

BACKGROUND

Methadone use for the management of opioid dependency during pregnancy is commonplace. Methadone levels are altered during pregnancy due to changes in maternal physiology. Despite this, a paucity of data exist regarding the most appropriate optimal dosing regimens during pregnancy.

METHODS

This study applied a pharmacokinetic modeling approach to examine gestational changes in R- and S-methadone concentrations in maternal plasma and fetal (cord) blood. This study did so to derive a theoretical optimal dosing regimen during pregnancy, and to identify the impact of Cytochromes P450 (CYP) 2B6 and 2C19 polymorphisms on methadone maternal and fetal pharmacokinetics.

RESULTS

The study noted significant decreases in maternal R- and S-methadone plasma concentrations during gestation, with concomitant increases in fetal levels. At a dose of 90 mg once daily, 75% (R-) and 94% (S-) of maternal methadone trough levels were below the lower therapeutic window at term (week 40). The developed optimal dosing regimen escalated doses to 110 mg by week 5, followed by 10 mg increments every 5 weeks up to a maximum of 180 mg once daily near term. This increase resulted in 27% (R-) and 11% (S-) of subjects with trough levels below the lower therapeutic window at term. CYP2B6 poor metabolizers (PM) and either CYP2C19 extensive metabolizers (EM), PM, or ultra-rapid (UM) metabolizer phenotypes demonstrated statistically significant increases in concentrations when compared to their matched CYP2B6 EM counterparts.

CONCLUSIONS

Specific and gestation-dependent dose titrations are required during pregnancy to reduce the risks associated with illicit drug use and to maintain fetal safety.

Direct-acting antiviral interactions with opioids, alcohol or illicit drugs of abuse in HCV-infected patients

The hepatitis C virus (HCV) prevalence is extremely high in patients who consume and inject illicit drugs. Concerns about poor adherence and fear of interaction with drugs of abuse could constitute further disincentive for treatment initiation in these patients. We discussed the pharmacokinetics (PKs) and pharmacodynamics (PD) of currently prescribed direct antiviral agents (NSA5 inhibitors: daclatasvir, elbasvir, ledipasvir, pibrentasvir, velpatasvir; NS5B inhibitor: sofosbuvir; NS3/4A protease inhibitors: glecaprevir, grazoprevir, voxilaprevir) and most common substances of abuse (opioids: buprenorphine, fentanyl, heroin, methadone, morphine, oxycodone; stimulants: amphetamines, cathinones, cocaine; cannabinoids; ethanol). Overall, most direct-acting antivirals (DAAs) are substrates and inhibitors of the transmembrane transporter P-glycoprotein (P-gp), and several of them are metabolized by cytochrome P450 enzymes. Clinically relevant interactions are associated with P-gp and CYP3A modulators. Most substances of abuse are eliminated by Phase I and Phase II metabolizing enzymes, but none of them are either major inhibitors or inducers. PK studies did not show any relevant interactions between DAA and methadone or buprenorphine. Based on pharmacological considerations, neither efficacy loss nor adverse drug event associated with detrimental interaction are expected with opioids, stimulants, cannabinoids and ethanol. In summary, our literature review shows that the interaction potential of DAA with most opioids and illicit drugs is limited and should not be a hurdle to the initiate DAA.

Daclatasvir: A Review of Preclinical and Clinical Pharmacokinetics

Daclatasvir is a first-in-class, highly selective, hepatitis C virus, non-structural protein 5a polymerase replication complex inhibitor with picomolar potency and broad genotypic coverage in vitro. Daclatasvir undergoes rapid absorption, with a time to reach maximum plasma concentration of 1-2 h and an elimination half-life of ~ 10 to 14 h observed in single-ascending dose studies. Steady state was achieved by day 4 in multiple-ascending dose studies. Daclatasvir can be administered without regard to food or pH modifiers. Daclatasvir exposure is similar between healthy subjects and subjects infected with hepatitis C virus. Intrinsic factors such as age, race, or sex do not impact daclatasvir exposure. No dose adjustment is necessary for patients with any degree of hepatic or renal impairment. Daclatasvir has low-to-moderate clearance with the predominant route of elimination via cytochrome P450 3A4-mediated metabolism and P-glycoprotein excretion and intestinal secretion. Renal clearance is a minor route of elimination for daclatasvir. As a result, the dose of daclatasvir should be reduced from 60 to 30 mg once daily when co-administered with strong inhibitors of cytochrome P450 3A4. No dose adjustment is required when daclatasvir is co-administered with moderate inhibitors of cytochrome P450 3A4. The dose of daclatasvir should be increased from 60 to 90 mg once daily when co-administered with moderate inducers of cytochrome P450 3A4. Co-administration of daclatasvir with strong inducers of cytochrome P450 3A4 is contraindicated. Concurrent medications with inhibitory effects on P-glycoprotein without concurrent inhibition of cytochrome P450 3A4 are unlikely to cause marked changes in daclatasvir exposure, as the clearance of daclatasvir is through both cytochrome P450 3A4 and P-glycoprotein. The potential for daclatasvir to affect the pharmacokinetics of concomitantly administered drugs that are substrates of the cytochrome P450 enzyme system is low. In vitro, daclatasvir is a weak-to-moderate inhibitor of transporters including organic cation transporter 1, P-glycoprotein, organic transporting polypeptide 1B1, organic transporting polypeptide 1B3, and breast cancer resistance protein, although in clinical studies, daclatasvir has not altered the pharmacokinetics of concomitantly administered drugs that are substrates of these transporters to an appreciable degree, except for rosuvastatin. In summary, daclatasvir is a hepatitis C virus, non-structural protein 5a-selective inhibitor with a well-characterized pharmacokinetic profile that forms part of potent and well-tolerated all-oral treatment regimens for chronic hepatitis C virus infection.

Methadone and buprenorphine pharmacokinetics and pharmacodynamics when coadministered with fostemsavir to opioid-dependent, human immunodeficiency virus seronegative participants

AIMS

Regional human immunodeficiency virus (HIV) prevalence rates are high in people with history of injection drug use, including those managed with maintenance opioids. Fostemsavir (FTR) is an oral prodrug of temsavir, a first-in-class attachment inhibitor that binds HIV-1 gp120, preventing initial HIV attachment and entry into host immune cells. Here we determine the impact of FTR on the pharmacokinetics of opioids methadone (MET: R-, S- and total) or buprenorphine and norbuprenorphine (BUP and norBUP) when coadministered.

METHODS

Study 206216 (NCT02666001) was a Phase I, open-label study, assessing the effect of FTR 600 mg (extended-release formulation) twice daily on pharmacokinetics of MET or BUP and norBUP, in non-HIV-infected participants on stable maintenance therapy with MET (40-120 mg; n = 16) or BUP plus naloxone (8-24 mg plus 2-6 mg; n = 16); pharmacodynamic response was assessed using standard opioid rating scales.

RESULTS

Following coadministration with FTR, dose-normalized MET (R-, S- and total) exposures (maximum concentration in plasma, area under the plasma concentration-time curve over the dosing interval and concentration in plasma at 24 hours) increased 9-15% and BUP and norBUP exposures increased 24-39%. The 90% confidence interval ranges for MET (1.01-1.21) and BUP and norBUP (1.03-1.69) were within respective no-effect ranges (0.7-1.43 and 0.5-2.0). Opioid pharmacodynamic scores were similar with and without MET/BUP with no symptoms of withdrawal/overdose; no new safety signal for FTR when combined with a stable opioid regimen.

CONCLUSIONS

FTR did not impact MET and had no clinically significant impact on BUP pharmacokinetics. Standardized assessments of opioid pharmacodynamics were unchanged throughout FTR administration with MET or BUP. FTR can be administered with MET or BUP without dose adjustment.

The optimization of methadone dosing whilst treating with rifampicin: A pharmacokinetic modeling study

BACKGROUND

The use of oral methadone in opioid substitution treatment (OST) for the management of opioid use disorder is established clinical practice. Confounding treatment is the increased risks of contracting Mycobacterium tuberculosis, the mainstay treatment of which incorporates the potent CYP 2B6 inducer rifampicin.

METHODS

This study applied pharmacokinetic modelling using virtual clinical trials, to pharmacokinetically quantify the extent and impact of rifampicin-mediated drug-drug interactions (DDI) on methadone plasma concentrations. An R-methadone model was developed and validated against 11 retrospective clinical studies prior to use in all subsequent studies. The aims were to investigate: (i) the impact of the DDI on daily methadone doses of 60 mg, 90 mg and 120 mg; (ii) dose escalation during rifampicin and (iii) dose reduction following rifampicin cessation.

RESULTS

A dose increase to 160 mg daily during rifampicin treatment phases was required to maintain peak methadone plasma concentrations within a derived therapeutic window of 80-700 ng/mL. Dose escalation prior to rifampicin initiation was not required and resulted in an increase in subjects with supra-therapeutic concentrations. However, during rifampicin cessation, a dose reduction of 10 mg every 2 days commencing prior to rifampicin cessation, ensured that most patients possessed a peak methadone plasma concentration within an optimal therapeutic window.

IMPLICATIONS

Rifampicin significantly alters methadone plasma concentrations and necessitates dose adjustments. Daily doses of almost double those used perhaps more commonly in clinical practice are required for optimal plasma concentration and careful consideration of dose reduction strategies would be required during the deinduction phase.

The pharmacological interactions between direct-acting antivirals for the treatment of chronic hepatitis c and psychotropic drugs

INTRODUCTION

Most direct-acting antivirals (DAAs) and psychotropic drugs are metabolized by or induct/inhibit CYP enzymes and drug transporters. Although they are frequently coadministered, the drug-drug interactions (DDIs) have been little studied. Therefore, the aim of this review is to describe the interactions between the approved DAA or combination regimens and the main psychoactive substances, including legal and illegal drugs of abuse. Areas covered: We performed a literature search on PubMed database on drug interactions with the currently available antivirals for hepatitis C and a review of the information on pharmacokinetics, metabolism, and drug interactions from www.hep-druginteractions.org and from all the Summary of Product Characteristics (SmPC). This review covers the DDI between the DAA regimens approved, such as simeprevir and sofosbuvir, paritaprevir, glecaprevir, voxilaprevir, ombitasvir, ledipasvir, daclatasvir and sofosbuvir, elbasvir and grazoprevir, sofosbuvir and velpatasvir, glecaprevir/pibrentasvir, sofosbuvir and velpatasvir, and main psychotropic agents. Expert Commentary: DAA regimens based on sofosbuvir combination usually have less DDI than protease inhibitor-based regimens. Among protease inhibitors regimens, new combinations, such as glecaprevir/elbasvir and grazoprevir/elbasvir, seemed to have less DDI than the combination POrD (paritaprevir/ombitasvir/ritonavir/dasabuvir). However, the analysis of each interaction is theoretical and further interaction studies would be necessary to confirm actual effect.

Methadone Metabolism and Drug-Drug Interactions: In Vitro and In Vivo Literature Review

Methadone is utilized for the treatment of individuals with opiate dependence. Methadone undergoes N-demethylation by multiple cytochrome P450 (CYP) enzymes including CYP3A4, CYP2B6, CYP2C19, CYP2D6, CYP2C9, and CYP2C8. In vivo, polymorphism effects on methadone systemic exposure have been noted for CYP2B6, CYP3A4, and CYP2D6. Clinical drug interaction studies with antiviral drugs in methadone maintenance treatment patients yield varying results on methadone pharmacokinetics and pharmacodynamics. In general, CYP inhibitors altered methadone exposure with no adverse effects. CYP inducers generally decreased methadone exposure with some reports of withdrawal symptoms in the subjects. Interaction studies with antiviral drug combinations yielding differing results depend on the enzyme(s) affected. For certain antiviral medicines which are dual inhibitor(s) and inducer(s) for CYP enzymes, their effect on methadone pharmacokinetics can change with time since the effect of induction is usually delayed compared to the effect of inhibition.

Population Pharmacokinetic Analysis of Daclatasvir in Subjects with Chronic Hepatitis C Virus Infection

BACKGROUND AND OBJECTIVE

Daclatasvir is a potent, pangenotypic once-daily hepatitis C virus (HCV) NS5A inhibitor that is approved for the treatment of chronic HCV infection. The objective of this analysis was to characterize the pharmacokinetics of daclatasvir in subjects with chronic HCV infection.

METHODS

A population pharmacokinetic (PPK) model was developed to evaluate effects of covariates on daclatasvir pharmacokinetics in subjects with chronic HCV infection (n = 2149 from 11 studies). All significant demographic, laboratory, prognostic and treatment covariates (p < 0.05) from univariate screening were included in the full model. The final model was reached by backward elimination (p < 0.001) and simulations were performed to further evaluate the effects of covariates on daclatasvir exposures. The plasma pharmacokinetics of daclatasvir was described by a two-compartment model with linear elimination. Absorption was modeled as a zero-order release followed by a first-order absorption into the central compartment.

RESULTS

The typical value of apparent clearance (CL/F) was 5.7 L/h (1.58% relative standard error [RSE]) and of apparent volume of the central compartment (V _c/F) was 58.6 L (2.00% RSE). Modest inter-individual variability was estimated for CL/F (35.1%) and V _c/F (29.5%). Statistically significant covariates in the final model were sex, race, virus genotype, baseline creatinine clearance, and alanine aminotransferase (ALT) on CL/F and sex, race, and body weight on V _c/F. Covariate effects demonstrated a 30% higher area under the plasma concentration-time curve at steady state (AUC_ss) in female subjects; effects of all other covariates were <16%.

CONCLUSIONS

The model adequately described the daclatasvir pharmacokinetics and estimated relatively small covariate effects. Considering the exposure range for the therapeutic dose of daclatasvir 60 mg once daily and the favorable safety profile, the small difference in exposures due to these covariates is not considered clinically relevant.

Hepatitis C virus prevention and care for drug injectors: the French approach

After France removed hepatitis C treatment reimbursement restrictions on 25 May 2016, an expert report presented recommendations, which focused on vulnerable groups including people who inject drugs (PWID). This commentary presents the key points of the chapter with a particular focus on policy. Thanks to the official lifting of restrictions based on disease stage and to the excellent efficacy and tolerance of the new DAA (Direct-Acting Antivirals) among PWID, the main issue is to improve the HCV care cascade. In France, many HCV-infected PWID, especially active/current PWID, remain undiagnosed and unlinked to care. Our challenge is to improve HCV screening by point of care testing (POCT), outreach methods with mobile teams, rapid tests, FibroScan, etc. and to provide PWID with appropriate services in all the settings they attend, such as drug treatment or harm reduction services, social services, prisons, etc. Another important issue is the prevention of reinfection through comprehensive and long-term follow-up. The report recommends a new national policy: testing and treating PWID as a priority, since this is the best way to eliminate HCV infection. It requires a global strategy consisting of combined and long-term interventions: prevention, outreach, screening, DAA, drug treatment programs including opiate substitution treatment (OST) and various harm reduction programs, including needle exchange programs (NEP). Ideally, these services should be delivered in the same place with an integrated approach. This should lead to meeting the national objective set by the government of eliminating hepatitis C by 2025.

Treatment of Chronic Hepatitis C in Patients Receiving Opioid Agonist Therapy: A Review of Best Practice

Injection drug use is the most common transmission route for hepatitis C. High rates of infection are observed among individuals on opioid agonist therapy. Although people who inject drugs carry the highest burden, few have initiated treatment. We present a comprehensive review of the evidence on the efficacy of HCV medications, drug-drug interactions, and barriers to and models of care. Studies have demonstrated comparable efficacy for individuals who are on opioid agonist therapy compared with those who are not. We propose that a strategy of treatment and cure-as-prevention is imperative in this population to curb the hepatitis C epidemic.

No Clinically Relevant Drug-Drug Interactions between Methadone or Buprenorphine-Naloxone and Antiviral Combination Glecaprevir and Pibrentasvir

The combination of glecaprevir (formerly ABT-493), a nonstructural protein 3/4A (NS3/4A) protease inhibitor, and pibrentasvir (formerly ABT-530), an NS5A protein inhibitor, is being developed as treatment for HCV genotype 1 to 6 infection. The pharmacokinetics, pharmacodynamics, safety, and tolerability of methadone or buprenorphine-naloxone when coadministered with the glecaprevir-pibrentasvir combination in HCV-negative subjects on stable opioid maintenance therapy were investigated in a phase 1, single-center, two-arm, multiple-dose, open-label sequential study. Subjects received methadone (arm 1) or buprenorphine-naloxone (arm 2) once daily (QD) per their existing individual prescriptions alone (days 1 to 9) and then in combination with glecaprevir at 300 mg QD and pibrentasvir at 120 mg QD (days 10 to 16) each morning. Dose-normalized exposures were similar with and without glecaprevir and pibrentasvir for (R)- and (S)-methadone (≤5% difference) and for buprenorphine and naloxone (≤24% difference); the norbuprenorphine area under the curve was 30% higher with glecaprevir and pibrentasvir, consistent with maximum and trough plasma concentrations that increased by 21% to 25%. No changes in pupil response, short opiate withdrawal scale score, or desire for drugs questionnaire were observed when glecaprevir and pibrentasvir were added to methadone or buprenorphine-naloxone therapy. No dose adjustment is required when glecaprevir and pibrentasvir are coadministered with methadone or buprenorphine-naloxone.

An insight into the molecular characteristics of hepatitis C virus for clinicians

Hepatitis C virus (HCV) consists of envelope proteins, core proteins, and genome RNA. The structural genes and non-structural genes in the open reading frame of its genome encode functional proteins essential to viral life cycles, ranging from virus attachment to progeny virus secretion. After infection, the host cells suffer damage from virus-induced oxidative stress, steatosis, and activation of proto-oncogenes. Every process during the viral life cycle can be considered as targets for direct acting antivirals. However, protective immunity cannot be easily acquired for the volatility in HCV antigenic epitopes. Understanding its molecular characteristics, especially pathogenesis and targets the drugs act on, not only helps professionals to make optimal therapeutic decisions, but also helps clinicians who do not specialize in infectious diseases/hepatology to provide better management for patients. This review serves to provide an insight for clinicians and this might provide a possible solution for any possible collision.

Belgian experience with direct acting antivirals in people who inject drugs

BACKGROUND AND AIM

Hepatitis C viral infection (HCV) has become a curable disease due to the development of direct acting antivirals (DAA). The WHO has set a target to eliminate HCV completely. Therefore, people who inject drugs (PWID) also need to be treated. In this study, we compared the real-life uptake and outcome of DAA treatment for HCV in PWID and non-PWID.

METHODS

We performed a nation-wide, retrospective cohort study in 15 hospitals. All patients who were treated with simeprevir-sofosbuvir, daclatasvir-sofosbuvir, or ombitasvir/paritaprevir ritonavir-dasabuvir between December 2013 and November 2015 were included.

RESULTS

The study population consisted of 579 patients: 115 PWID (19.9%) and 464 non-PWID (80.1%). Of the PWID 18 were active PWID (15.6%), 35 still received opiate substitution therapy (OST) (30.4%) and 62 were former PWID without OST (53.9%). PWID were more infected with genotype 1a and 3 (p=0.001). There were equal rates of side-effects (44.7% vs. 46.6%; p=0.847), similar rates of treatment completion (95.7% vs 98.1%; p=0.244) and SVR (93.0% vs 94.8%; p=0.430) between PWID and non-PWID, respectively.

CONCLUSION

PWID, especially active users, are underserved for DAA treatment in real life in Belgium. Reimbursement criteria based on fibrosis stage make it difficult to treat PWID. Treatment adherence is similar in PWID and the general population, even in patients with active abuse. DAA were safe and effective in PWID despite the higher prevalence of difficult-to-treat genotypes. Based on these data more efforts to treat PWID are needed and policy changes are necessary to reach the WHO targets.

Real-World Efficacy of Daclatasvir and Sofosbuvir, With and Without Ribavirin, in HIV/HCV Coinfected Patients With Advanced Liver Disease in a French Early Access Cohort

Supplemental Digital Content is Available in the Text.

Background:

Efficacious, well-tolerated, direct antiviral agents have drastically changed the prognosis of hepatitis C virus (HCV) disease, but real-world data for oral treatments are limited in key populations such as HIV/HCV coinfection with advanced liver disease. Daclatasvir (DCV) efficacy and safety was assessed in the French “Autorisation Temporaire d'Utilisation” (ATU) program, providing DCV ahead of market authorization to patients with advanced HCV disease without other treatment options.

Methods:

This was a subanalysis of HIV/HCV coinfected ATU patients treated with DCV plus sofosbuvir (SOF). Recommended duration was 24 weeks; addition of ribavirin (RBV) and/or shorter treatment was at the physician's discretion. The primary efficacy analysis was sustained virologic response at posttreatment week 12 (SVR12; modified intention-to-treat). Safety was assessed by spontaneous adverse event reporting.

Results:

The efficacy population (N = 407) was mostly cirrhotic (72%, of whom 18% were decompensated), HCV treatment–experienced (82%), and infected with genotypes 1 (69%), 3 (12%), or 4 (19%). Median CD4 was 555 cells/mm³; 95% had HIV RNA <50 copies/mL. Most (74%) were treated for 24 weeks; 14% received RBV. SVR12 was 92% overall (95% confidence interval: 88.6% to 94.0%); 90% (86.4% to 93.2%) in patients with cirrhosis; 95% (88.9% to 97.5%) in patients without cirrhosis. SVR12 was consistent across HCV genotypes and antiretroviral regimens. Among 617 patients with safety data, 7 discontinued for an adverse event and 10 died.

Conclusions:

DCV+SOF±RBV achieved high SVR12 and was well tolerated in this large real-world cohort of HIV/HCV coinfected patients with advanced liver disease.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Daclatasvir plus sofosbuvir, with or without ribavirin, in real-world patients with HIV-HCV coinfection and advanced liver disease

BACKGROUND

HIV-HCV-coinfected patients respond just as well to modern direct-acting antiviral HCV therapy as HCV-monoinfected patients. However, clinical data for all-oral HCV treatments are sparse in HIV-HCV-coinfected patients with an advanced stage of liver cirrhosis.

METHODS

A subanalysis of efficacy and safety for a daclatasvir (DCV) and sofosbuvir (SOF) regimen, with or without ribavirin (RBV), was undertaken in HIV-HCV-coinfected patients with advanced liver disease and no other treatment options enrolled into a European DCV compassionate use programme.

RESULTS

Fifty five HIV-HCV (mostly genotypes 1, 3, 4) coinfected patients were treated with DCV+SOF with (n=16) or without RBV (n=39), mostly for 24 weeks. Patients were predominantly (95%) cirrhotic (50% were Child-Pugh class B or C) and were receiving a wide range of antiretrovirals; 40% were injection drug users and 25% were receiving oral opioid substitution. Sustained virological response at post-treatment week 12 (SVR12) by modified intention-to-treat analysis (n=52) was 92% overall (95% CI 81.5, 97.9), and was similar with (94% [95% CI 69.8, 99.8]) or without RBV (92% [95% CI 77.5, 98.2]). Only one patient relapsed (Child-Pugh class B). The overall SVR12 rate after excluding non-virological failures (n=49) was 98% (95% CI 89.1, 99.9). Four patients discontinued treatment for adverse events and one died during treatment (not treatment-related). No patient lost opioid maintenance or required a change of antiretrovirals due to drug-drug interactions.

CONCLUSIONS

DCV+SOF, with or without RBV, showed high SVR12 rates and was well tolerated in this real-world cohort of HIV-HCV-coinfected patients with very advanced liver disease. ClinicalTrials.gov ID NCT02097966 (Study AI444-237).

A Review of Daclatasvir Drug-Drug Interactions

The treatment of hepatitis C virus (HCV) infection has been revolutionized in recent years by the development of direct-acting antiviral regimens that do not contain peginterferon (pegIFN) and/or ribavirin (RBV). While direct-acting antiviral-based regimens have been shown to be greatly superior to pegIFN/RBV-based regimens in terms of efficacy and safety, they have a greater susceptibility to drug-drug interactions (DDIs). Daclatasvir (DCV)-the benchmark pangenotypic nonstructural protein 5A inhibitor-has been shown to be efficacious and generally well tolerated in partnership with other HCV direct-acting antivirals, including sofosbuvir, asunaprevir (ASV), and ASV plus beclabuvir. DCV may be the object of a DDI via the induction or inhibition of cytochrome P450 (CYP) 3A4 and/or P-glycoprotein (P-gp) by the concomitant medication, or the precipitant of a DDI via DCV-based induction/inhibition of CYP 3A4 or inhibition of P-gp, organic anion transporting polypeptide 1B1/B3, and/or breast cancer resistance protein. This article presents an overview of the drug interaction studies conducted during the clinical development of DCV, the findings of these studies that led to the guidance on concomitant medication use and dosage along with any required DCV dose modifications, and the use of the known metabolic pathway of DCV to guide concomitant dosing where direct drug-drug studies have not been conducted. The robust characterization of the DCV clinical pharmacology program has demonstrated that DCV has few or no clinically relevant DDIs with medications with which it is likely to be co-administered, and the majority of DDIs that do occur can be predicted and easily managed.

FUNDING

Bristol-Myers Squibb.

No clinically significant pharmacokinetic interactions between dolutegravir and daclatasvir in healthy adult subjects

Background

Daclatasvir (DCV) is an NS5A replication complex inhibitor recently approved for chronic hepatitis C virus treatment.

Methods

To assess drug interactions between the HIV integrase strand transfer inhibitor dolutegravir (DTG) and DCV, subjects were randomized into 1 of 2 sequences in an open-label, 3-period, crossover study. Subjects received either DTG 50 mg once daily or DCV 60 mg once daily for 5 days in periods 1 and 2 and DTG 50 mg plus DCV 60 mg once daily for 5 days in period 3, with no washout between periods 2 and 3. Between periods 1 and 2, there was a washout period of at least 7 days.

Results

The geometric least-squares mean ratios (90 % confidence intervals) of DCV area under the concentration-time curve over a dosing interval (AUC_0-τ), maximum observed concentration (C_max), and concentration at the end of the dosing interval (C_τ) were 0.978 (0.831–1.15), 1.03 (0.843–1.25), and 1.06 (0.876–1.29), respectively, when DCV was administered with DTG compared with DCV alone. Compared with DTG alone, coadministration of DTG with DCV increased DTG AUC_0-τ, C_max, and C_τ by approximately 33, 29, and 45 %, respectively.

Conclusions

DCV plasma exposure was not meaningfully affected by DTG. Coadministration of DTG with DCV resulted in slight increases in DTG AUC_0-τ, C_max, and C_τ. Accumulated safety and tolerability data in humans receiving DTG to date suggests this effect is not considered clinically significant. DTG and DCV can be coadministered without dose adjustment.

Trial registration

Registered on March 6, 2014 with ClinicalTrials.gov; registration number: NCT02082808 and as Study ID: 201102 on the ViiV Clinical Study Registry.

Safety and efficacy of daclatasvir in the management of patients with chronic hepatitis C

Daclatasvir (Daklinza™), a new oral direct-acting antiviral, is an inhibitor of hepatitis C virus NS5A protein and has recently been approved in the United States, Europe and Japan in chronic hepatitis C. It shows potent pangenotypic activity and moderately high genetic barrier to resistance improving the sustained virological response (SVR) rates. In COMMAND phase 2 trials, daclatasvir demonstrated high SVR rates in HCV genotype 1-4 chronically infected patients treated with peginterferon-a (pegIFNα) plus ribavirin (RBV). Furthermore, it produced even higher response rates in all-oral combination with sofosbuvir, an interferon-free regimen, with or without ribavirin, in patients with advanced liver disease, HCV/HIV coinfection, liver transplantation in ALLY studies and other real-world studies. This narrative review provides information on the pharmacological properties, role, efficacy and safety of daclatasvir-containing regimens in chronic hepatitis C patients. Daclatasvir administered once-daily in combination with sofosbuvir is an effective 12-week treatment in adult patients with chronic hepatitis C and is generally safe and well tolerated.