Cardiovascular Risk Management and Hepatitis C: Combining Drugs

Effect of carvedilol on pharmacokinetics of sofosbuvir and its metabolite GS-331007: role of P-glycoprotein

Sofosbuvir (SOF) is a P-glycoprotein (P-gp) substrate, and carvedilol (CAR) is an inhibitor of P-gp, suggesting that it may affect the oral pharmacokinetics and safety of SOF. The current study investigated the pharmacokinetic interaction of CAR with SOF and its metabolite, GS-331007, and the possible consequent toxicities in rats. To assess the pharmacokinetics of SOF and GS-331007, rats were divided into three groups; all received a single oral dose of SOF preceded with saline (SAL), verapamil (VER) as a standard P-gp inhibitor, or CAR, respectively. The serosal, plasma, and hepatic tissue contents of SOF and GS-331007 were assessed using LC-MS/MS. Renal and hepatic toxicities were assessed using biochemical and histopathological tests. Serosal and plasma concentrations of SOF and GS-331007 were increased in the presence of CAR, suggesting a significant inhibitory effect of CAR on intestinal P-gp. Simultaneously, the pharmacokinetic profile of SOF showed a significant increase in the Cmax, AUC(0-t), AUC (0-∞), t1/2, and a reduction in its apparent oral clearance. While the pharmacokinetic profile of GS-331007 was not significantly affected. However, this notable elevation in drug oral bioavailability was corroborated by a significant alteration in renal functions. Hence, further clinical investigations are recommended to ensure the safety and dosing of CAR/SOF combination.

Direct antiviral agents (DAAs) and their use in pregnant women with hepatitis C (HCV)

INTRODUCTION

Direct-Acting Antiviral Agents (DAAs) provide safer, efficacious, tolerable, and curative therapy for women with hepatitis C. Their preferred safety and efficacy profile make them potential therapies for the elimination of perinatal transmission of hepatitis C virus (HCV). However, DAAs are not currently recommended for use during pregnancy due to limited pharmacokinetic and safety data.

AREAS COVERED

This review covers the different DAA drug combinations, the available data on their pharmacodynamic and pharmacokinetic properties, how the physiology in pregnancy can potentially affect DAA drug disposition, known drug-drug interactions with DAAs, and available and planned epidemiological and pharmacokinetic studies on DAA use during pregnancy. Although no large randomized clinical trials or prospective cohort studies involving DAAs have been completed in pregnancy, the currently available studies demonstrate no significant changes in pharmacokinetics, and no major safety concerns in women with hepatitis C.

EXPERT OPINION

Initial pharmacokinetic and safety data suggest that DAAs have high efficacy and a low risk of adverse events during pregnancy. As more pharmacokinetic and epidemiologic data become available, DAAs could become a preferred option for treating HCV during pregnancy and elimination of perinatal transmission of hepatitis C virus.

Statins Increase the Bioavailability of Fixed-Dose Combination of Sofosbuvir/Ledipasvir by Inhibition of P-glycoprotein

BACKGROUND

Coadministration of statins and direct acting antiviral agents is frequently used. This study explored the effects of both atorvastatin and lovastatin on pharmacokinetics of a fixed-dose combination of sofosbuvir/ledipasvir "FDCSL".

METHODS

12 healthy volunteers participated in a randomized, three-phase crossover trial and were administered a single atorvastatin dose 80 mg plus tablet containing 400/90 mg FDCSL, a single lovastatin dose 40 mg plus tablet containing 400/90 mg FDCSL, or tablets containing 400/90 mg FDCSL alone. Liquid chromatography-tandem mass spectrometry was used to analyze plasma samples of sofosbuvir, ledipasvir and sofosbuvir metabolite "GS-331007" and their pharmacokinetic parameters were determined.

RESULTS

Atorvastatin caused a significant rise in sofosbuvir bioavailability as explained by increasing in AUC0-∞ and Cmax by 34.36% and 11.97%, respectively. In addition, AUC0-∞ and Cmax of GS-331007 were increased by 73.73% and 67.86%, respectively after atorvastatin intake. Similarly, co-administration of lovastatin with FDCSL increased the bioavailability of sofosbuvir, its metabolite (AUC0-∞ increase by 17.2%, 17.38%, respectively, and Cmax increase by 12.03%, 22.24%, respectively). However, neither atorvastatin nor lovastatin showed a change in ledipasvir bioavailability. Hepatic elimination was not affected after statin intake with FDCSL. Compared to lovastatin, atorvastatin showed significant increase in AUC0-∞ and Cmax of both sofosbuvir and its metabolite.

CONCLUSIONS

Both atorvastatin and lovastatin increased AUC of sofosbuvir and its metabolite after concurrent administration with FDCSL. Statins' P-glycoprotein inhibition is the attributed mechanism of interaction. The increase in sofosbuvir bioavailability was more pronounced after atorvastatin intake. Close monitoring is needed after co-administration of atorvastatin and FDCSL.

The Use of Hepatitis C Virus-Positive Organs in Hepatitis C Virus-Negative Recipients

The use of hepatitis C virus (HCV) -positive organs in HCV-negative recipients with posttransplant antiviral treatment has increasingly been studied since the introduction of new direct-acting antivirals. This article reviews existing experience in liver and kidney transplant. Fifteen studies with 218 HCV D+/R- liver transplants, with 182 from viremic donors, show a sustained viral response for 12 weeks (SVR12) rate of 99.5%. Nine studies involving 204 HCV donor-positive recipient-negative kidney transplant recipients had an SVR12 rate of 99.5%. Complications are infrequent. Preemptive treatment in kidney transplant of for only 4 weeks or even 4 days showed surprising success rates.

Drug-Drug Interactions in Italian Patients with Chronic Hepatitis C Treated with Pangenotypic Direct Acting Agents: Insights from a Real-World Study

This Italian observational real-world study aims to assess in chronic hepatitis C virus (HCV) patients treated with pangenotypic direct acting agents (pDAAs) glecaprevir/pibrentasvir (GLE/PIB) or sofosbuvir/velpatasvir (SOF/VEL) the potential drug-drug interactions (DDIs) with concomitant medications prescribed, with a focus on cardiovascular and system nervous (CNS) co-medications. Data were collected from administrative databases covering 6.9 million health-assisted individuals. All patients prescribed SOF/VEL or GLE/PIB between 11/2017 and 12/2018 were included. Patients were analyzed while on DAA. DDIs were identified according to the Liverpool University tool. Overall, 3181 HCV patients were included: 1619 in the GLE/PIB cohort and 1562 in the SOF/VEL cohort. SOF/VEL patients were generally older than GLE/PIB ones (mean age 58.4 vs. 53.1, p < 0.001) and had more cardiovascular and CNS comorbidities (58% vs. 42%, p < 0.001 and 33% vs. 28%, p = 0.002, respectively). Contraindications due to DDIs in the GLE/PIB cohort affected 9.3% and 3.2% of patients before and on DAA, respectively, while the percentages in the SOF/VEL cohort were 3.2% before and 0.4% after pDAAs initiation. Among GLE/PIB patients, 2.7% had cardiovascular drugs (all statins) contraindicated while on DAA. The potential DDIs between cardiovascular drugs and SOF/VEL were mainly with statins (5%). SOF/VEL was prescribed in patients with older age and with more cardiovascular and CNS comorbidities. Despite this, a proportion of contraindicated drugs lower than that of GLE/PIB was registered.

Comorbidities and Prescribed Medications in Korean Patients with Chronic Hepatitis C: A Nationwide, Population-Based Study

Background/Aims

Extrahepatic comorbidities and comedication are important to consider in the treatment of chronic hepatitis C (CHC) patients with direct-acting antivirals (DAAs) due to the risk of drug-drug interaction (DDI) and the effect of comorbidities on clinical outcomes. This study aimed to investigate the detailed profiles of comorbidities and comedication among Korean CHC patients.

Methods

All adult patients (≥18 years old) with a primary diagnostic code of CHC in 2013 were selected from the National Health Insurance claims database. For each patient, all ICD-10 codes listed as primary or secondary diagnoses and all prescribed medications were collected.

Results

Among 47,104 CHC patients (median age, 57 years; male, 49.3%), 84.8% had at least one comorbidity for a mean number of 2.4, which increased with age. The most prevalent comorbidities were hypertension, esophagitis, dyslipidemia, diabetes mellitus, and peptic ulcer. Overall, 96.8% of the patients took at least one prescribed medication, with a mean of 8.1 medications/ year, and the three most common drug types were analgesics, gastrointestinal agents, and antibacterials. Use of at least one drug with a DDI risk category of "contraindicated medication" or "required dose-reduction/additional monitoring" was observed in 97% of the overall patients. The proportion of prescribed medications that were contraindicated with DAAs varied from 2.0% to 38.9% depending on the hepatitis C virus regimen.

Conclusions

The majority of CHC patients had comorbidities; almost all patients took multiple prescribed medications, the number of which increased with age, and significant DDI risk was present in 97% of this Korean patient cohort. Comorbidities and comedication profiles should be considered during DAA therapy.

Metabolism of Direct-acting Antiviral Agents (DAAs) in Hepatitis C Therapy: A Review of the Literature

BACKGROUND

Hepatitis C virus (HCV) infection is still one of the leading causes of chronic liver disease, with chronically infected making up approximately 1% of the global population. Of those infected, 70% (55-85%) will develop chronic HCV infection. Chronic HCV infection causes substantial morbidity and mortality, with complications including cirrhosis, end-stage liver disease, hepatocellular carcinoma, and eventually death.

OBJECTIVE

Therapeutic options for chronic HCV infection have evolved dramatically since 2014, with a translation from pegylated interferon and ribavirin (associated with suboptimal cure and high treatment-related toxicity) to oral direct-acting antiviral treatment. There are four classes of direct-acting antivirals which differ by their mechanism of action and therapeutic target. They are all pointed to proteins that form the cytoplasmic viral replication complex. Multiple studies have demonstrated that direct-acting antiviral therapy is extremely well tolerated, highly efficacious, with few side effects.

METHODS

We performed an indexed MEDLINE search with keywords regarding specific direct-acting antiviral regimes and their pharmacokinetics, drug-drug interactions, and metabolism in specific settings of pregnancy, lactation, liver cirrhosis, liver transplantation and HCC risk, kidney failure and kidney transplantation.

RESULTS

We present a comprehensive overview of specific direct-acting antiviral metabolism and drug-drug interaction issues in different settings.

CONCLUSION

Despite its complex pharmacokinetics and the possibility of drug-drug interactions, direct-acting antivirals are highly efficacious in providing viral clearance, which is an obvious advantage compared to possible interactions or side effects. They should be administered cautiously in patients with other comorbidities, and with tight control of immunosuppressive therapy.

New Antiviral Agents for Treatment of Hepatitis C

Between 70 and 170 million people worldwide are infected with hepatitis C virus (HCV) which frequently causes chronic liver disease and cirrhosis. There are several genotypes and many subtypes of HCV. Direct-acting antiviral agents are effective at eradicating HCV in the vast majority of patients, producing much higher cure rates than were seen with interferon and ribavirin regimens only a few years ago. The chapter reviews the epidemiology and virology of HCV infection. Treatment regimens are complex but a straightforward approach to selection of patients, choice of direct-acting antiviral agents and follow-up is presented.

Hepatitis C and Treatment in Patients with Chronic Kidney Disease

Hepatitis C virus (HCV) is associated with increased mortality and morbidity in patients with chronic kidney disease (CKD). The early detection and treatment of Hepatitis C associated with kidney disease is paramount to preventing the progressive loss of kidney function. HCV treatment until the advent of direct acting anti-viral agents (DAAs) was limited to interferon and ribavirin. Interferon and ribavirin treatment resulted in only modest success but with frequent adverse events and poor tolerability. Furthermore, interferon and ribavirin could not be used in certain patient populations including those with advanced CKD, were on dialysis, or those who have received a kidney transplant. DAAs have now made treatment possible in these sub-groups with a sustained viral response (SVR) of 90-100% and minimal side effects. DAAs have helped increase transplant rates by allowing for the use of HCV positive kidneys in recipients who are HCV negative. Although the choice of DAAs should be carefully considered and based on patient characteristics, concomitant medications, and HCV genotype.

Drug-drug interactions between direct-acting antivirals and statins in the treatment of chronic hepatitis C

As the first line of treatment for hepatitis C virus (HCV) infection, direct-acting antivirals (DAAs) have greater efficacy and fewer adverse effects than other treatments; however, drug-drug interactions (DDIs) must be avoided when used in combination with other medications, such as statins. HCV patients are mostly in the need for polypharmacy, particularly the comedication of DAAs and cardiovascular drugs such as statins. This poses a risk of pharmacokinetic interactions between the two classes of drugs that may lead to severe myopathy or even rhabdomyolysis. Therefore, evaluating the severity of the DDIs and managing them is important. A multidisciplinary team-based model of care for HCV patients receiving DAAs can review the pharmacology profiles of other drugs for relevant DDIs with the DAAs, before prescription. Such a model can also follow the patients through the therapeutic cycle to make sure that their medical regimen is safe and effective. This article reviews the comedication rate and DDI-prevalence in HCV patients receiving statins along with the DAAs, details the mechanisms involved, gives recommendations for management, and shares our experience with a multidisciplinary team-based care program for the treatment of HCV patients.

Hepatitis C virus infection and tight junction proteins: The ties that bind

The hepatitis C virus (HCV) is a major cause of liver diseases ranging from liver inflammation to advanced liver diseases like cirrhosis and hepatocellular carcinoma (HCC). HCV infection is restricted to the liver, and more specifically to hepatocytes, which represent around 80% of liver cells. The mechanism of HCV entry in human hepatocytes has been extensively investigated since the discovery of the virus 30 years ago. The entry mechanism is a multi-step process relying on several host factors including heparan sulfate proteoglycan (HSPG), low density lipoprotein receptor (LDLR), tetraspanin CD81, Scavenger Receptor class B type I (SR-BI), Epidermal Growth Factor Receptor (EGFR) and Niemann-Pick C1-like 1 (NPC1L1). Moreover, in order to establish a persistent infection, HCV entry is dependent on the presence of tight junction (TJ) proteins Claudin-1 (CLDN1) and Occludin (OCLN). In the liver, tight junction proteins play a role in architecture and homeostasis including sealing the apical pole of adjacent cells to form bile canaliculi and separating the basolateral domain drained by sinusoidal blood flow. In this review, we will highlight the role of liver tight junction proteins in HCV infection, and we will discuss the potential targeted therapeutic approaches to improve virus eradication.

Viral Hepatitis C Therapy: Pharmacokinetic and Pharmacodynamic Considerations: A 2019 Update

It has been estimated by the World Health Organization (WHO) that over 71 million people were infected with the hepatitis C virus (HCV) in 2015. Since then, a number of highly effective direct-acting antiviral (DAA) regimens have been licensed for the treatment of chronic HCV infection: sofosbuvir/daclatasvir, sofosbuvir/ledipasvir, elbasvir/grazoprevir, sofosbuvir/velpatasvir, glecaprevir/pibrentasvir, and sofosbuvir/velpatasvir/voxilaprevir. With these treatment regimens, almost all chronic HCV-infected patients, even including prior DAA failures, can be treated effectively and safely. It is therefore likely that further development of DAAs will be limited. In this descriptive review we provide an overview of the clinical pharmacokinetic characteristics of currently available DAAs by describing their absorption, distribution, metabolism, and excretion. Potential drug-drug interactions with the DAAs are briefly discussed. Furthermore, we summarize what is known about the pharmacodynamics of the DAAs in terms of efficacy and safety. We briefly discuss the relationship between the pharmacokinetics of the DAAs and efficacy or toxicity in special populations, such as hard to cure patients and patients with liver cirrhosis, liver transplantation, renal impairment, hepatitis B virus or HIV co-infection, bleeding disorders, and children. The aim of this overview is to educate/update prescribers and pharmacists so that they are able to safely and effectively treat HCV-infected patients even in the presence of underlying co-infections or co-morbidities.

Treatment of Chronic Hepatitis C: Efficacy, Side Effects and Complications

Background

Chronic hepatitis C virus (HCV) infection can lead to liver cirrhosis and its complications. Viral eradication is essential to prevent disease progression and reduces liver-related mortality and morbidity. Since the availability of direct-acting antivirals (DAA), HCV treatment has changed significantly. Current treatment strategies for different groups of patients as well as potential risks and caveats will be discussed in this review.

Summary

Interferon-free (IFN-free) treatment not only shortens treatment duration, but also achieves high rates of viral clearance and is overall well tolerated. Genotype-restricted but also pangenotypic combinations are available. Usually two DAA of different drug classes are combined. For the majority of the patients, treatment duration ranges from 8 to 12 weeks. Liver and kidney function as well as prior treatment experience and potential drug-drug interactions influence substance choices and treatment duration. However, modern IFN-free treatment is not only safer, but also overall far more simplified and effective. Global HCV eradication might be an ambitious but not completely unrealistic goal to pursue.

Key Messages

IFN-free antiviral treatment is safe and well tolerated. Patients can be treated almost independently of liver function or concomitant disease. Viral eradication is associated with reduced morbidity and mortality and better quality of life.