Focus on drug interactions: the challenge of treating hepatitis C virus infection with direct-acting antiviral drugs in the HIV-positive patient. Curr Opin Infect Dis. 2013;26:50-57. [PMID: 23242341 DOI: 10.1097/QCO.0b013e32835c2027]

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.

Dual antiviral therapy for HIV and hepatitis C - drug interactions and side effects

INTRODUCTION

Roughly 20% of HIV-positive persons worldwide are coinfected with hepatitis C virus (HCV). The recent advent of direct-acting antivirals (DAA) that cure most hepatitis C patients has attracted much attention. Knowledge on drug interactions between DAA and antiretrovirals (ARV) may allow maximizing antiviral efficacy while minimizing drug-related toxicities.

AREAS COVERED

We review the most frequent side effects and clinically significant drug interactions between DAA and ARV. We further discuss how they can be prevented and managed in HIV/HCV-coinfected patients.

EXPERT OPINION

The safety profile of current DAA and the most recently approved ARV is quite favorable. Interactions between DAA and ARV could be frequent in clinical practice. The most common drug interactions affect drug metabolism by inducing or inhibiting the cytochrome P450 system, leading to abnormal drug exposures. Throughout this mechanism HCV and HIV protease inhibitors interact, especially when co-formulated with ritonavir as a pharmacoenhancer, and non-nucleoside HCV and HIV polymerase inhibitors. In contrast, HIV and HCV nucleos(t)ide polymerase inhibitors, and most HCV NS5A inhibitors (i.e., ledipasvir) and HIV integrase inhibitors (i.e., dolutegravir), do not or only marginally affect CYP450, and therefore are free of significant drug interactions. Exposure to HIV and HCV nucleos(t)ide analogues (i.e., tenofovir and sofosbuvir, respectively) is subject to induction/inhibition of drug transporters (i.e., P-glycoprotein).

HIV and HCV Medications in End-Stage Renal Disease

Human immunodeficiency virus (HIV) infection and hepatitis C virus (HCV) infection affect populations worldwide. With the availability of over 35 Food and Drug Administration approved medications for treatment of HIV, the morbidity and mortality associated with HIV has greatly improved. On the other hand, treatment options for HCV have been limited until very recently. While the use of protease inhibitors (such as boceprevir and telaprevir) has become standard of care for treatment of hepatitis C in the general population, data for individuals with impaired kidney function, particularly those on dialysis, are extremely limited. Use of medications in dialysis patients can be challenging given the dose adjustments that must be made for renally cleared molecules, and potentially increased impact of adverse effects such as anemia. Recommendations for dosing of marketed therapies for HIV and HCV are reviewed.

Hepatitis C and HIV Coinfection for Social Workers in Public Health, Medical and Substance Use Treatment Settings

Hepatitis C virus (HCV) infection is a leading cause of liver disease and liver-related deaths among those living with human immunodeficiency virus (HIV) infection. Due to recent pharmacologic advancements with direct acting antivirals, if detected and treated, HCV antiviral therapy can prevent liver disease progression and permanently cure coinfected patients of HCV. The objectives of this article are to inform public health social workers and social workers in medical and substance use treatment settings of the public health burden of HCV/HIV coinfection and to highlight state-of-the art pharmacologic advancements in HCV antiviral therapy.

Drug interactions with new hepatitis C oral drugs

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has recently become a curable disease with antiviral therapy. The knowledge of drug interactions using direct-acting antivirals (DAA) may permit maximizing antiviral efficacy and avoiding drug-related toxicities. Ageing in the chronic hepatitis C population, along with added co-morbidities that require other medications, has increased the attention on drug interactions using DAA.

AREAS COVERED

This review provides an update of the most clinically significant pharmacokinetic and pharmacodynamic drug interactions occurring between currently available DAA and other medications. The review also revisits how drug interactions with DAA can be prevented and managed.

EXPERT OPINION

Interactions between DAA and other drugs are frequent in clinical practice. The most frequent drug interactions modify drug metabolism by inducing or inhibiting the cytochrome P450, leading to abnormal drug exposures. Through this mechanism HCV protease inhibitors, especially when co-formulated with ritonavir as pharmacoenhancer, and non-nucleoside HCV polymerase inhibitors interact with other medications. In contrast, NS5B nucleos(t)ide analog inhibitors (i.e., sofosbuvir) and some HCV NS5A inhibitors (i.e., ledipasvir), which do not or only marginally affect CYP450, are relatively free of significant pharmacokinetic interactions. However, exposure to HCV nucleos(t)ide analogs may be influenced by induction/inhibition of drug transporters (i.e., P-glycoprotein) as well as by pharmacodynamic interference with other nucleos(t)ide analogs used as antivirals or cancer drugs. Drug interactions for some NS5A inhibitors (i.e., daclatasvir) are generally moderate and can be managed with dose adjustments.

Prevalence and Predictors of Important Telaprevir Drug Interactions Among Patients Coinfected With Hepatitis C and Human Immunodeficiency Virus

Background: Among patients with HIV and hepatitis C (HCV) coinfection, drug-drug interactions involving nonstructural protein 3/4 (NS3/4A) serine protease inhibitors for HCV infection are an important concern because these drugs affect cytochrome P450 metabolism and p-glycoprotein transporters. Objectives: The primary objective was to determine the prevalence of clinically significant drug-drug interactions (CSDDIs) in HIV/HCV coinfected patients if telaprevir-based HCV therapy is added to patients' medication regimens. Secondary objectives were to identify antiretroviral therapy (ART) regimens associated with the lowest risk of CSDDI and determine the clinical risk factors. Methods: A cross-sectional study was performed among adult HIV/HCV coinfected patients. Demographics, comorbidities, social history, and medication lists were extracted from medical records. For each patient, CSDDIs were identified by entering all medications and pegylated interferon, ribavirin, and telaprevir into Lexi-Interact drug interaction software. The number and nature of CSDDIs were recorded before and after addition of telaprevir-based therapy. Results: There were 335 patients included. Prior to the addition of telaprevir-based HCV therapy, there was a high frequency (82.1%) of any CSDDI. After the addition of telaprevir-based HCV therapy, the frequency of any CSDDI increased to 97% (P < .001). Contraindicated interactions rose from 20.0% to 38.2% of patients after addition of telaprevir-based therapy. Use of ≥10 non-HIV medications, dyslipidemia, and HIV protease inhibitors were independently associated with the occurrence of a contraindicated interaction. Conclusions: Clinicians considering initiating telaprevir in HIV/HCV coinfected patients should be vigilant of drug-drug interactions, particularly among patients with dyslipidemia, those using ≥10 non-HIV medications, and those using HIV protease inhibitors.

Using patient-reported outcomes to improve the management of co-infection with HIV and HCV: the ANRS CO13 HEPAVIH cohort

The management of co-infection with HIV and hepatitis C virus (HCV) is complicated by viral and drug-drug interactions, treatment-related side effects, and the poor response to therapy of certain HCV genotypes. Current or past drug use may also have a negative impact. HEPAVIH (ANRS CO13) is an ongoing French cohort study of co-infected individuals which combines medical and socio-behavioral follow-up. This cohort study aims at analyzing the course of HCV infection and access to HCV treatment in HIV-HCV co-infected patients, using both clinical and patient-reported outcomes. This article documents the main lessons learned to date from the HEPAVIH data and published literature, while describing research prospects and needs requiring further investigation in the field of patient-reported outcomes.

Outcomes and management of viral hepatitis and human immunodeficiency virus co-infection in liver transplantation

Liver transplantation for human immunodeficiency virus (HIV) positive patients with viral hepatitis co-infection is increasingly offered in many North American and European liver transplant centers. Prior studies have demonstrated acceptable post-transplant outcomes and no increased risk of HIV complications in patients co-infected with hepatitis B virus (HBV). However, liver transplantation in HIV positive patients with hepatitis C virus (HCV) has poorer outcomes overall, requiring careful selection of candidates. This review aims to summarize the published literature on outcomes after transplant in HIV patients with HBV or HCV related end-stage liver disease and recommendations for management. In particular the pre-transplant factors impacting outcomes in HCV/HIV co-infected candidates and importance of multidisciplinary management will be discussed.

Transmission and evolution of hepatitis C virus in HCV seroconverters in HIV infected subjects

HIV/HCV co-infection provides a model to determine the role of immunity on HCV transmission and evolution. In this study HCV transmission and evolution were evaluated in 6 HCV seroconverters in HIV-infected subjects with a wide range of CD4 cell count. The HCV envelope E1/E2 sequences were analyzed for transmission bottleneck, viral diversity/divergence, immune pressure, and mutations of HLA class I/II restricted epitopes. HCV infection started with transmission bottleneck in all HIV-infected individuals. During the 1.0-2.0 years of infection there was a shift of viral quasispecies in majority of the subjects from one to next visit. However, HCV diversity, divergence, mutations in HLA class I/II restricted and virus neutralizing epitopes were similar in all subjects regardless of CD4 cell count at the time of HCV infection. Our results suggest that HCV transmission and evolution in HIV-infected subjects may not be influenced by host CD4 cell count at the time of infection.

Treatment of genotype 1 HCV infection in the HIV coinfected patient in 2014

Hepatitis C (HCV) coinfection is the leading cause of liver-related morbidity and is a leading cause of mortality in human immunodeficiency virus (HIV)-infected individuals in the antiretroviral therapy era. Direct-acting antiviral (DAA) therapies are transforming how HCV is treated with significant improvements in efficacy and tolerability. In this article, DAA agents expected to be available in 2014 are reviewed, including telaprevir, boceprevir, sofosbuvir, simeprevir, faldaprevir, and daclatasvir. Available data regarding clinical efficacy, adverse effects, and drug interactions in HIV-HCV coinfection are discussed. The management of adverse effects of HCV therapy and treatment considerations in patients with cirrhosis are also reviewed.

The importance of drug-drug interactions in the DAA era

With the licensing of the direct acting antivirals telaprevir and boceprevir the topic of drug-drug interactions has come to the forefront. These first generation hepatitis C virus protease inhibitors are metabolized by and inhibit the key drug metabolizing enzyme CYP3A4, which means that knowledge of drug-drug interactions has become an essential component of the evaluation of a patient starting triple therapy. The number of potential co-medications means that many drugs will be used in hepatitis C virus patients where there are no pharmacokinetic study data. Here we have to use the data that are available and seek to extrapolate to unstudied drugs using key principles of clinical pharmacology (disposition characteristics, concentration-effect relationships, therapeutic window) in order to give some guidance for management of patients. This is a rapidly moving area in hepatitis C therapy, both in terms of understanding the drug interaction profile of telaprevir and boceprevir, interaction mechanisms that sometimes appear counterintuitive and that may involve enzymes other than CYP3A4 or transporters, but then seeking to understand the interaction potential of the next wave of drugs that will soon be with us.

Hepatitis C virus infection: looking for interferon free regimens

Recent developments of new drugs' combinations are changing the treatment paradigm in hepatitis C virus infection. Due to the side effect profile of pegylated interferons, interferon-sparing regimens have become the main target in chronic hepatitis C treatment research. Recent proofs of concept studies have suggested that cure of chronic hepatitis C can be achieved without interferon. The purpose of this paper is to provide an overview of the clinical results recently reported for the treatment of hepatitis C virus infection with interferon-free regimens, focusing on the most promising new compounds and combinations.