Managing drug-drug interactions with new direct-acting antiviral agents in chronic hepatitis C

Effects of comorbid conditions and prescribed chronic medications on the treatment plan for chronic hepatitis C infection: A cross-sectional retrospective study

Background

Chronic hepatitis C (CHC) infection is a potentially life-threatening condition characterized by various complications, including end-stage liver disease and cirrhosis. The mortality rate associated with CHC has been increasing due to the presence of comorbidities and the use of chronic medications. Therefore, the objective of this study was to investigate the impact of these comorbidities and chronic medications on the treatment plan for CHC.

Methods

To achieve this objective, a cross-sectional retrospective study was conducted at a tertiary hospital in Jeddah, Saudi Arabia. The study population included patients aged 12 years and above who were diagnosed with CHC between 2016 and 2021. Patients below the age of 12 were excluded from the study. A total of 170 patients with CHC were included in the analysis. The study aimed to evaluate the relationship between CHC complications and the treatment approach.

Results

The mean age of the study participants was 66.78 years, with a higher proportion of female patients. The findings revealed a significant association between hypertension (p = 0.042) and cirrhosis (p = 0.007) with changes in the treatment plan for CHC. Moreover, the presence of diabetes mellitus (p = 0.045), renal diseases (p < 0.001), and hypothyroidism (p = 0.004) were significantly associated with HCV clearance after the initiation of therapy. Additionally, the use of proton pump inhibitors (p = 0.033) and levothyroxine (p = 0.025) was found to be associated with a higher rate of CHC clearance.

Conclusion

In conclusion, this study highlights the prevalence of comorbid conditions and the use of chronic medications among patients with CHC. The findings emphasize the importance of considering the effects of comorbidities and chronic medications when developing treatment plans for CHC infections. By taking these factors into account, healthcare professionals can optimize the management of CHC and improve patient outcomes.

Analysis of Patients' Characteristics and Treatment Profile of People Who Use Drugs (PWUDs) with and without a Co-Diagnosis of Viral Hepatitis C: A Real-World Retrospective Italian Analysis

PURPOSE

Hepatitis C virus (HCV) spreads from contact with blood of an infected person. HCV infections are common among people who use drugs (PWUDs), when sharing needles, syringes, or other equipment for injected drugs. The advent of pangenotypic direct-antiviral agents (DAA) in 2017 transformed the treatment landscape for HCV, but PWUDs remain a complex and hard-to-treat population with high risk of HCV reinfection. The aim of this real-world analysis was to characterize the demographic and clinical features of PWUDs in Italy, also focusing on comorbidity profile, treatment with DAAs, resource consumptions for the National Health System (NHS).

PATIENTS AND METHODS

During 01/2011-06/2020, administrative databases of Italian healthcare entities, covering 3,900,000 individuals, were browsed to identify PWUDs with or without HCV infection. Among HCV+ patients, a further stratification was made into treated and untreated with DAAs. The date of PWUD or HCV first diagnosis or DAA first prescription was considered as index-date. Patients were then followed-up for one year. Alcohol-dependency was also investigated.

RESULTS

Total 3690 PWUDs were included, of whom 1141 (30.9%) PWUD-HCV+ and 2549 (69.1%) PWUD-HCV-. HCV-positive were significantly older (43.6 vs 38.5 years, p < 0.001), had a worse comorbidity profile (Charlson-index: 0.8 vs 0.4, p < 0.001), and high rates of psychiatric, respiratory, dermatological, musculoskeletal diseases and genitourinary (sexually transmitted) infections. Moreover, they received more drug prescriptions (other than DAAs, like anti-acids, antiepileptics, psycholeptics) and had undergone more frequent hospitalization, predominantly for hepatobiliary, respiratory system and mental disorders. DDA-untreated had significantly higher Charlson-index than DAA-treated (0.9 vs 0.6, p = 0.003). Alcoholism was found in 436 (11.8%) cases.

CONCLUSION

This Italian real-world analysis suggests that PWUDs with HCV infection, especially those untreated with DAAs, show an elevated drug consumption due to their complex clinical profile. These findings could help to ameliorate the healthcare interventions on PWUDs with HCV infection.

Fitness-Dependent, Mild Mutagenic Activity of Sofosbuvir for Hepatitis C Virus

The concept of a mild mutagen was coined to describe a minor mutagenic activity exhibited by some nucleoside analogues that potentiated their efficacy as antiretroviral agents. In the present study, we report the mild mutagen activity of sofosbuvir (SOF) for hepatitis C virus (HCV). Serial passages of HCV in human hepatoma cells, in the presence of SOF at a concentration well below its cytotoxic concentration 50 (CC50) led to pre-extinction populations whose mutant spectra exhibited a significant increase of C→U transitions, relative to populations passaged in the absence of SOF. This was reflected in an increase in several diversity indices that were used to characterize viral quasispecies. The mild mutagenic activity of SOF was largely absent when it was tested with isogenic HCV populations that displayed high replicative fitness. Thus, SOF can act as a mild mutagen for HCV, depending on HCV fitness. Possible mechanisms by which the SOF mutagenic activity may contribute to its antiviral efficacy are discussed.

TASL, TADE, and DAROC consensus for the screening and management of hepatitis C in patients with diabetes

Diabetes mellitus (DM) and hepatitis C virus (HCV) infection are prevalent diseases globally and emerging evidence demonstrates the bidirectional association between the two diseases. Direct-acting antivirals (DAAs) for HCV have a high treatment success rate and can significantly reduce the risks of short and long-term complications of HCV infection. However, despite the evidence of the association between diabetes and HCV and the benefits of anti-HCV treatment, previously published guidelines did not focus on the universal HCV screening for patients with diabetes and their subsequent management once confirmed as having HCV viremia. Nonetheless, screening for HCV among patients with diabetes will contribute to the eradication of HCV infection. Thus, the three major Taiwan medical associations of diabetes and liver diseases endorsed a total of 14 experts in the fields of gastroenterology, hepatology, diabetology, and epidemiology to convene and formulate a consensus statement on HCV screening and management among patients with diabetes. Based on recent studies and guidelines as well as from real-world clinical experiences, the Taiwan experts reached a consensus that provides a straightforward approach to HCV screening, treatment, and monitoring of patients with diabetes.

Global treatment rate and barriers to direct-acting antiviral therapy: A systematic review and meta-analysis of 146 studies and 1 760 352 hepatitis C virus patients

BACKGROUND

Global data on the treatment rate with direct-acting antivirals (DAAs) for chronic hepatitis C (CHC) are sparse. We aimed to evaluate the CHC treatment rate and barriers to treatment in the DAA era.

METHODS

We searched PubMed, EMBASE and Cochrane from inception to 5 August 2021, for relevant articles. Patients treated with DAAs without interferon (IFN) therapy were categorized as IFN-free DAAs. Patients receiving DAA with IFN or unclear IFN status were categorized as DAA/IFN.

RESULTS

We identified and analysed data from 146 studies (1 760 352 CHC patients). DAA/IFN treatment rate was 16.0% (95% CI: 9.9-23.3, 49 studies, 886 535 patients). IFN-free DAA treatment rate was 52.3% (95% CI: 46.2-58.4, 123 studies, 1 276 754 patients): 45.4% in North America, 64.2% in South America (1 study), 90.4% in Africa (most data from Egypt), 54.4% in Europe, 60.7% in Australia and 60.5% in Asia, (p < .0001); 49% with hepatitis B co-infection and 32.3% with hepatocellular carcinoma (HCC). Treatment was not a priority in 22.8% of patients in Europe and 16.7% in Australia, compared to only 4.8% in North America and 2.1% in Asia (p < .0001). Poor adherence to clinical follow-up was the cause of no treatment in 74.7% of patients in Australia, 37.0% in North America, 7.9% in Europe and 14.3% in Asia (p < .0001).

CONCLUSION

Though a marked improvement from IFN/DAA, the treatment rate with IFN-free DAA remains suboptimal (52.3% overall, 32.3% in HCC patients). Non-adherence to clinical follow-up and lack of disease awareness were treatment barriers.

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.

Drug-drug interactions between direct-acting antivirals and co-medications: a territory-wide cohort study

BACKGROUND

The increasing number of direct-acting antiviral (DAA) regimens along with limited number of subjects and co-medications involved in clinical trials results in drug-drug interactions (DDIs) with DAAs is to be determined. We aimed to examine the prevalence and degree of DDIs between DAAs and other co-medications in a territory-wide cohort of chronic hepatitis C virus (HCV) patients.

METHODS

DDIs were assigned to three risk categories: Category 1-no clinically significant DDI; category 2-potential clinically significant interaction (monitoring and caution required); category 3-contraindicated (should not be co-administered).

RESULTS

Of 2981 patients (mean age 59.3 ± 12.3 years; male 60.6%), 810 (48.8%) had genotype 1 and 552 (33.2%) genotype 6 HCV among the 1661 patients with HCV genotype tested; 769 (25.8%) received sofosbuvir/velpatasvir, 510 (17.1%) sofosbuvir/ledipasvir, and 865 (29.0%) glecaprevir/pibrentasvir. More than one-fourth (26.3%) of the patients have polypharmacy (≥ 3 co-medications) in all patients, 27.0% in patients received sofosbuvir/velpatasvir, 25.1% in elbasvir/grazoprevir, and 21.2% in glecaprevir/pibrentasvir. 2037 (68.3%) patient experienced DDI (Category 2: 53.1%; Category 3: 15.2%). The commonest drugs leading to DDIs were calcium channel blockers (31.5%) and proton pump inhibitors (23.0%) in category 2; statins (10.2%), antiplatelet/anticoagulants (3.0%) and antipsychotics (2.9%) in category 3. Changing medication was the most common response from physicians in both category 2 and 3 DDIs.

CONCLUSION

The commonest co-medications leading to contraindication during DAA treatment were statins and antipsychotics. Category 2 and 3 DDIs are often managed by appropriate dose adjustments or temporary discontinuation of relevant co-medications. Careful assessment for potential DDI before DAA use is mandatory to avoid potential harmful effects.

Evaluation of the Potency of Anti-HIV and Anti-HCV Drugs to Inhibit P-Glycoprotein Mediated Efflux of Digoxin in Caco-2 Cell Line and Human Precision-Cut Intestinal Slices

The inhibition of P-glycoprotein (ABCB1) could lead to increased drug plasma concentrations and hence increase drug toxicity. The evaluation of a drug’s ability to inhibit ABCB1 is complicated by the presence of several transport-competent sites within the ABCB1 binding pocket, making it difficult to select appropriate substrates. Here, we investigate the capacity of antiretrovirals and direct-acting antivirals to inhibit the ABCB1-mediated intestinal efflux of [³H]-digoxin and compare it with our previous rhodamine123 study. At concentrations of up to 100 µM, asunaprevir, atazanavir, daclatasvir, darunavir, elbasvir, etravirine, grazoprevir, ledipasvir, lopinavir, rilpivirine, ritonavir, saquinavir, and velpatasvir inhibited [³H]-digoxin transport in Caco-2 cells and/or in precision-cut intestinal slices prepared from the human jejunum (hPCIS). However, abacavir, dolutegravir, maraviroc, sofosbuvir, tenofovir disoproxil fumarate, and zidovudine had no inhibitory effect. We thus found that most of the tested antivirals have a high potential to cause drug–drug interactions on intestinal ABCB1. Comparing the Caco-2 and hPCIS experimental models, we conclude that the Caco-2 transport assay is more sensitive, but the results obtained using hPCIS agree better with reported in vivo observations. More inhibitors were identified when using digoxin as the ABCB1 probe substrate than when using rhodamine123. However, both approaches had limitations, indicating that inhibitory potency should be tested with at least these two ABCB1 probes.

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.

Understanding effect site pharmacology of uprifosbuvir, a hepatitis C virus nucleoside inhibitor: Case study of a multidisciplinary modeling approach in drug development

Uprifosbuvir is a uridine nucleoside monophosphate prodrug inhibitor of the hepatitis C virus NS5B RNA polymerase. To quantitatively elucidate key metabolic pathways, assess the link between unmeasurable effect site concentrations and viral load reduction, and evaluate the influence of intrinsic and extrinsic factors on pharmacokinetics and pharmacodynamics, a model‐informed drug development (MIDD) framework was initiated at an early stage. Originally scoped as a modeling effort focused on minimal physiologically based pharmacokinetic and covariate analyses, this project turned into a collaborative effort focused on gaining a deeper understanding of the data from drug metabolism, biopharmaceutics, pharmacometrics, and clinical pharmacology perspectives. This article presents an example of the practical execution of a MIDD‐based, cooperative multidisciplinary modeling approach, creating a model that grows along with the team's integrated knowledge. Insights gained from this process could be used in forming optimal collaborations between disciplines in drug development for other investigative compounds.

Potential interactions between pangenotypic direct-acting antivirals and concomitant cardiovascular therapies in patients with chronic hepatitis C virus infection

OBJECTIVE

To identify potential drug interactions (DIs) between pangenotypic direct-acting antivirals (pDAAs) and concomitant cardiovascular (CV) therapies in patients with chronic hepatitis C (CHC).

METHODS

A retrospective observational study was carried out. Patients ≥18 years of age diagnosed with CHC and treated with pDAAs during 2017 were included. Information was collected on concomitant CV therapies and potential DIs [www.hep-druginteractions.org]. The pDAAs analyzed were sofosbuvir/velpatasvir (SOF/VEL), glecaprevir/pibrentasvir (GLE/PIB) and sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX). An analysis including lipid-lowering drugs was also performed.

RESULTS

In total, 1286 patients (mean age 64.9 years, 56.6% men) were recruited. The percentages of potential DIs with CV drugs were 1.9% contraindications, 38.1% clinically significant and 2.4% weak. When lipid-lowering drugs were included, the percentages of potential DIs with CV drugs were 10.3% contraindications, 46.3% clinically significant and 3.2% weak. Potential DIs associated with each pDAA were as follows (contraindications; clinically significant; weak): SOF/VEL (1.4%; 23.0%; 0.9%), GLE/PIB (12.8%; 60.8%; 4.7%) and SOF/VEL/VOX (16.6%; 55.1%; 4.9%).

CONCLUSIONS

Approximately on third of patients with CHC are concomitantly treated with CV drugs. SOF/VEL may have fewer DIs with CV drugs than other pDAAs.

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.

Emerging paradigms of viral diseases and paramount role of natural resources as antiviral agents

In the current scenario, the increasing prevalence of diverse microbial infections as well as emergence and re-emergence of viral epidemics with high morbidity and mortality rates are major public health threat. Despite the persistent production of antiviral drugs and vaccines in the global market, viruses still remain as one of the leading causes of deadly human diseases. Effective control of viral diseases, particularly Zika virus disease, Nipah virus disease, Severe acute respiratory syndrome, Coronavirus disease, Herpes simplex virus infection, Acquired immunodeficiency syndrome, and Ebola virus disease remain promising goal amidst the mutating viral strains. Current trends in the development of antiviral drugs focus solely on testing novel drugs or repurposing drugs against potential targets of the viruses. Compared to synthetic drugs, medicines from natural resources offer less side-effect to humans and are often cost-effective in the productivity approaches. This review intends not only to emphasize on the major viral disease outbreaks in the past few decades and but also explores the potentialities of natural substances as antiviral traits to combat viral pathogens. Here, we spotlighted a comprehensive overview of antiviral components present in varied natural sources, including plants, fungi, and microorganisms in order to identify potent antiviral agents for developing alternative therapy in future.

Asymmetric profiles of infection and innate immunological responses in human iPS cell-derived small intestinal epithelial-like cell monolayers following infection with mammalian reovirus

The intestinal mucosa plays an important role as an immune barrier due to its continual exposure to invading pathogens, including viruses. It is thus highly important to evaluate virus infection profiles in the intestinal mucosa for prevention of virus infection and development of antivirus medicines; however, only a few enterocyte lines are available as in vitro intestinal models for the evaluation of virus infection. In this study, we evaluated profiles of infection and innate immune responses following infection with a mammalian orthoreovirus (hereafter reovirus), which has often been used as a tractable model for studies of viral pathogenesis, in human iPS cell-derived small intestinal epithelial-like cell (hiPS-SIEC) monolayers and cells of a human colon adenocarcinoma cell line, Caco-2. The levels of reovirus infection were similar between hiPS-SIEC and Caco-2 cell monolayers, which are often used as an intestinal model, after apical and basolateral infection. In hiPS-SIEC monolayers, more efficient replication of the virus genome was observed following basolateral infection than apical infection, while apical infection resulted in higher levels of virus protein expression and progeny virus production than basolateral infection. Reovirus significantly induced innate immune responses, including expression of type I and III interferons (IFNs), in hiPS-SIEC monolayers more efficiently than Caco-2 cells. Higher levels of type I and III interferon (IFN) expression were found in hiPS-SIEC monolayers following apical infection than basolateral infection. These results suggested that hiPS-SIECs are a promising in vitro model for the evaluation of virus infection.

Drug-Drug Interactions of Newly Approved Direct-Acting Antiviral Agents in Patients with Hepatitis C

Hepatitis C is a major health problem worldwide, frequently resulting in cirrhosis and increasing the risk of hepatocellular carcinoma significantly. In recent years, the advent of direct-acting antivirals (DAAs) has dramatically improved the therapeutic outcomes in hepatitis C patients. In the last two years, several new DAA combinations have been approved for the treatment of the hepatitis C virus (HCV) infection, including elbasvir/grazoprevir, sofosbuvir/velpatasvir, sofosbuvir/velpatasvir/voxilaprevir, and glecaprevir/pibrentasvir. The newly approved DAA regimens may be prescribed with other drugs simultaneously, increasing the potential of pharmacokinetic interactions. Therefore, the knowledge and management of drug-drug interactions (DDIs) with DAAs should be considered a key issue in HCV therapy. This review summarizes researches of DDIs focusing on newly approved DAAs (elbasvir, grazoprevir, velpatasvir, voxilaprevir, glecaprevir, pibrentasvir) for patients undergoing HCV treatment to provide clinical consideration for comedication. With respect to DDIs, newly approved DAA regimens, including elbasvir/grazoprevir, sofosbuvir/velpatasvir, sofosbuvir/velpatasvir/voxilaprevir, and glecaprevir/pibrentasvir, are safely applicable.

Influence of drug-drug interactions on effectiveness and safety of direct-acting antivirals against hepatitis C virus

OBJECTIVES

Direct-acting antivirals are the recommended treatment for hepatitis C-infected patients. Drug-drug interactions with concomitant treatments can cause lack of effectiveness and/or safety. The objective of this study is to characterise drug-drug interactions of direct-acting antivirals and to analyse their influence both on the effectiveness of antiviral treatment and on the overall safety of pharmacological treatment in hepatitis C-infected patients.

METHODS

Observational and prospective cohort study for 3 years in the pharmaceutical care outpatient consultation of a general hospital, undertaking detection, evaluation and management of drug-drug interactions by clinical pharmacists and physicians. The main outcome measures were sustained virologic response at week 12 for effectiveness and serious drug-related adverse events for safety. Multivariate statistical analysis applied to: (a) patient basal characteristics related to presence of drug-drug interactions; (b) previous antiviral treatments, viral genotype, cirrhosis, decompensations and presence of drug-drug interactions related to the effectiveness of direct-acting antivirals.

RESULTS

Of a total of 1092 patients, the majority of them were men, around 60 years old and HCV-genotype 1 mono-infected, with a high basal viral load, naive to antiviral treatment, treated with ledipasvir/sofosbuvir and without cirrhosis. 24.5% had drug-drug interactions. Proton pump inhibitors were the concomitant drugs that caused the most drug-drug interactions. Age ≥65 years and direct-acting antivirals based on protease inhibitors were independently related to the presence of drug-drug interactions (p≤0.012). All (100%) of the therapeutic recommendations based on detected drug-drug interactions were implemented; 97.7% of patients with interactions versus 99.0% without them reached sustained virologic failure (p=0.109). The serious adverse events rates were 1.5% and 1.3% in patients with and without drug-drug interactions, respectively (p=0.841).

CONCLUSIONS

Drug-drug interactions are frequent among hepatitis C-infected patients receiving treatment with direct-acting antivirals. However, the collaboration between physicians and clinical pharmacists makes it possible to detect, evaluate, avoid or clinically manage these drug-drug interactions, in order to maintain whole treatment therapeutic safety and the effectiveness of direct-acting antivirals.

Drug-Drug Interactions between Direct Oral Anticoagulants and Hepatitis C Direct-Acting Antiviral Agents: Looking for Evidence Through a Systematic Review

Background

Direct oral anticoagulants (DOACs), as substrates of cytochrome P450 (CYP) 3A4 and/or P-glycoprotein, are susceptible to drug–drug interactions (DDIs). Hepatitis C direct-acting antiviral agents (DAAs), via P-glycoprotein or CYP3A4 inhibition, may increase DOAC exposure with relevant bleeding risk. We performed a systematic review on DDIs between DOACs and DAAs.

Methods

Two reviewers independently identified studies through electronic databases, until 7 July 2020, supplementing the search by reviewing conference abstracts and the ClinicalTrials.gov website.

Results

Of 1386 identified references, four articles were finally included after applying the exclusion criteria. Three phase I clinical studies in healthy volunteers assessed interactions between dabigatran and glecaprevir/pibrentasvir, odalasvir/simeprevir, or sofosbuvir/velpatasvir/voxilaprevir, showing an increase in the dabigatran area under the concentration–time curve (AUC) by 138%, 103%, and 161%, respectively.

Conclusions

DOACs and DAAs are under-investigated for DDI risk. Real-world studies are needed to assess the clinical relevance of the pharmacokinetic interactions with dabigatran and describe the actual spectrum of possible DDIs between DAAs and other DOACs.

Tuberculosis and pharmacological interactions: A narrative review

Even if major improvements in therapeutic regimens and treatment outcomes have been progressively achieved, tuberculosis (TB) remains the leading cause of death from a single infectious microorganism. To improve TB treatment success as well as patients' quality of life, drug-drug-interactions (DDIs) need to be wisely managed. Comprehensive knowledge of anti-TB drugs, pharmacokinetics and pharmacodynamic (PK/PD) parameters, potential patients' changes in absorption and distribution, possible side effects and interactions, is mandatory to built effective anti-TB regimens. Optimization of treatments and adherence to international guidelines can help bend the curve of TB-related mortality and, ultimately, decrease the likelihood of treatment failure and drop-out during anti-TB treatment. Aim of this paper is to describe the most relevant DDIs between anti-TB and other drugs used in daily clinical practice, providing an updated and "easy-to-use" guide to minimize adverse effects, drop-outs and, in the long run, increase treatment success.

Sustained Virologic Response of Patients Hospitalized Compared With Those Not Hospitalized During Treatment for Hepatitis C Virus With Direct-Acting Antivirals

BACKGROUND

Direct-acting antivirals (DAAs) for treatment of hepatitis C virus (HCV) have resulted in great success through high attainment of sustained virologic response (SVR). Risk factors for DAA treatment failure are important to identify because of worsened outcomes with failure and high treatment cost.

OBJECTIVE

We sought to identify whether hospitalization during treatment affects SVR. The primary outcome was the difference in SVR at 12 weeks after treatment.

METHODS

This multicenter, single health system retrospective cohort review compared achievement of SVR between patients hospitalized during DAA treatment for HCV with those not hospitalized during treatment.

RESULTS

Patients in the hospitalized cohort (n = 94) had more severe disease at baseline than nonhospitalized patients (n = 167) as indicated through higher Model for End-Stage Liver Disease (MELD) scores, Fibrosis-4 scores, and imaging-suggested or biopsy-confirmed cirrhosis. Patients hospitalized during treatment had lower SVR rates compared with those not hospitalized (87.2% vs 95.2%; P = 0.043) but failed to reach significance when inpatient mortality was excluded on secondary analysis (91.1% vs 95.2%; P = 0.195). Patients who were hospitalized and did not achieve SVR had higher MELD scores, were more likely to have intensive care unit stay, and had longer hospital stay compared with those who achieved SVR. Of 94 patients, 93 provided home supply of DAAs during hospitalization.

CONCLUSION AND RELEVANCE

Patients hospitalized during DAA treatment for HCV had reduced rates of SVR. This reduced SVR rate may be driven by inpatient mortality and severity of liver disease. Patient education to bring home supply of medication for use during admission is an effective intervention.

Development and Validation of a New LC-MS/MS Analytical Method for Direct-Acting Antivirals and Its Application in End-Stage Renal Disease Patients

BACKGROUND AND OBJECTIVE

The effectiveness of direct-acting antivirals (DAAs) is not well established in end-stage renal disease (ESRD) patients. Assessment of the plasma concentrations may support understanding of their therapeutic outcomes in this population. The aim of this study is to develop a direct, yet matrix-effect tolerant, analytical method for determining DAAs in the plasma of ESRD patients while maintaining a moderate cost per sample and with an improved analyte extraction recovery.

METHODS

In this study, a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the analysis of ombitasvir (OMB), paritaprevir (PRT) and ritonavir (RIT) in plasma. Sample preparation was performed using the liquid-liquid extraction (LLE) method. Isocratic separation was performed using a mixture of methanol and 10 mM ammonium acetate (79:21, v/v) followed by MS/MS detection. The method was validated and applied to determine DAAs in the plasma of ESRD patients (n = 7).

RESULTS

The developed method was linear (r²> 0.995), accurate (89.4 ± 7.8 to 108.3 ± 3.0) and precise (% CV 0.9-15.0) and showed improved recovery (> 80) over previously published ones in the range 5-250, 30-1,500, 20-1,000 ng/mL for OMB, PRT and RIT, respectively. Relative matrix effect was absent, and the method accurately determined the three DAAs in real-life samples (n = 7).

CONCLUSIONS

An efficient analytical method for the determination of DAAs is presented. The method overcomes the potential analytical response fluctuation in ESRD. The developed method show improved extraction recoveries and is suitable for routine application in developing economies where hepatitis C virus is most prevalent.

Impact of the COVID-19 Outbreak on the Management of Patients with Cancer

The coronavirus SARS-CoV-2 (COVID-19) outbreak is having a profound impact on the management of patients with cancer. In this review, we comprehensively investigate the various aspects of cancer care during the pandemic, taking advantage of data generated in Asia and Europe at the frontline of the COVID-19 pandemic spread. Cancer wards have been subjected to several modifications to protect patients and healthcare professionals from COVID-19 infection, while attempting to maintain cancer diagnosis, therapy, and research. In this setting, the management of COVID-19 infected patients with cancer is particularly challenging. We also discuss the direct and potential remote impacts of the global pandemic on the mortality of patients with cancer. As such, the indirect impact of the pandemic on the global economy and the potential consequences in terms of cancer mortality are discussed. As the infection is spreading worldwide, we are obtaining more knowledge on the COVID-19 pandemic consequences that are currently impacting and may continue to further challenge cancer care in several countries.

2020 Taiwan consensus statement on the management of hepatitis C: part (I) general population

Hepatitis C virus (HCV) infection remains a major public health issue with high prevalence in Taiwan. Recently, the advent of direct-acting antiviral (DAA) agents, with higher efficacy, excellent safety profile, and truncated treatment duration, has revolutionized the paradigm of hepatitis C treatment and made HCV elimination possible. To provide timely guidance for optimal hepatitis C management, the Taiwan Association for the Study of the Liver (TASL) established an expert panel to publish a 2-part consensus statement on the management of hepatitis C in the DAA era. After comprehensive literature review and a consensus meeting, patient-oriented, genotype-guided recommendations on hepatitis C treatment for the general and special populations have been provided based on the latest indications and scientific evidence. In the first part of this consensus, we present the epidemiology and treatment situation of hepatitis C in Taiwan, the development of DAA, pre-treatment evaluation, post sustained virologic response (SVR) monitoring, and most importantly the treatment recommendations for the general population with compensated liver disease. The second part will focus on the treatment recommendations for the special populations.

Development and validation of UPLC-MS/MS method for studying the pharmacokinetic interaction of dasabuvir and tamoxifen, 4-hydroxytamoxifen in Wistar rats

Hepatitis C virus (HCV) is the main cause of chronic hepatitis and probably liver cirrhosis. Dasabuvir (DSV) is a direct-acting antiviral agent with efficiency in managing HCV. The anti-viral activity of the anti-estrogen drug tamoxifen (TAM) suggested the synergistic effect of DSV and TAM for blocking the replication of HCV. However, being substrates and inhibitors of efflux transporters (TAM inhibits P-gp, DSV inhibits P-gp and BCRP), there is a possibility for a pharmacokinetic (PK) drug-drug interaction. In this work, a new UPLC-MS/MS method was developed and validated for the simultaneous determination of TAM, its active metabolite 4-hydroxy tamoxifen (TOH), and DSV in rat plasma. The method was applied to investigate the PK interaction between DSV and TAM/TOH following the co-administration of DSV and TAM to Wistar rats. Chromatographic analysis was performed on Waters BEH^TM C18 column using a mobile phase of acetonitrile/water containing 0.1% formic acid (80: 20, v/v). The method allowed the determination of concentration ranges 20–1000, 0.1–500, 0.5–500 ng/mL for DSV, TAM, and TOH, respectively. Unexpectedly, results revealed the absence of PK interactions between DSV and TAM/TOH, compared with their single administration, suggesting the safety of co-administering DSV/TAM as an anti-viral combination without the need of dosage adjustment.

PK/PD and antiviral activity of anti-HCV therapy: is there still a role in the choice of treatment?

Introduction: Despite the high rate of response, the treatment of special populations, the management of patients with previous failure to direct-acting antiviral (DAA) regimens, and the development of drug resistance are still a challenge. Moreover, the FDA suggested stopping research on new DAA because of the high efficacy of those already available.Areas covered: Understanding pharmacokinetic/pharmacodynamic parameters could be a simple and effective way to improve the management of anti-hepatitis C virus (HCV) treatment. The aim of this review is to provide an overview of this aspect in order to offer a new insight into treatment choice.Expert opinion: Clinicians should offer an adequate strategy for HCV treatment taking into consideration patient-related factors and by improving their knowledge of the antiviral activity and pharmaceutical 'forgiveness' of each DAA.

Transplantation of kidneys from hepatitis C-infected donors to hepatitis C-negative recipients: Single center experience

Our aim was to evaluate the safety of transplanting kidneys from HCV-infected donors in HCV-uninfected recipients. Data collected from 53 recipients in a single center, observational study included donor and recipient characteristics, liver and kidney graft function, new infections and de novo donor-specific antibodies and renal histology. Treatment with a direct-acting antiviral regimen was initiated when HCV RNA was detected. The mean ± SD age of recipients was 53 ± 11 years, 34% were female, 19% and 79% of recipients were white and African American, respectively. The median and interquartile range (IQR) time between transplant and treatment initiation was 76 (IQR: 68-88) days. All 53 recipients became viremic (genotype: 1a [N = 34], 1b [N = 1], 2 [N = 3], and 3 [N = 15]). The majority (81%) of recipients did not experience clinically significant increases (>3 times higher than upper limit of the normal value) in aminotransferase levels and their HCV RNA levels were in the 5 to 6 log range. One patient developed fibrosing cholestatic hepatitis with complete resolution. All recipients completed antiviral treatment and 100% were HCV RNA-negative and achieved 12-week sustained virologic response. The estimated GFRs at end of treatment and 12-week posttreatment were 67 ± 21 mL/min/1.73 m² and 67 ± 17 mL/min/1.73 m² , respectively. Four recipients developed acute rejection. Kidney transplantation from HCV-infected donors to HCV-negative recipients should be considered in all eligible patients.

Effects of sofosbuvir-based hepatitis C treatment on the pharmacokinetics of tenofovir in HIV/HCV-coinfected individuals receiving tenofovir disoproxil fumarate

Background

The nucleotide analogues tenofovir and sofosbuvir are considered to have low potential for drug interactions.

Objectives

To determine the effect of sofosbuvir-based HCV treatment on plasma concentrations of tenofovir and cellular concentrations of tenofovir diphosphate.

Methods

HIV-infected participants with acute HCV were treated for 12 weeks with sofosbuvir + ribavirin in Cohort 1 or 8 weeks with ledipasvir/sofosbuvir in Cohort 2 of AIDS Clinical Trials Group study 5327. Only participants taking tenofovir disoproxil fumarate were included in this analysis. Tenofovir in plasma, tenofovir diphosphate in dried blood spots and tenofovir diphosphate in PBMCs were measured pre-HCV therapy and longitudinally during the study using validated LC/MS-MS.

Results

Fifteen and 22 men completed Cohorts 1 and 2, respectively. In Cohort 1, tenofovir diphosphate was 4.3-fold higher (95% CI geometric mean ratio 2.46-7.67; P = 0.0001) in dried blood spots and 2.3-fold higher (95% CI 1.09-4.92; P = 0.03) in PBMCs following 12 weeks of sofosbuvir + ribavirin versus study entry. Tenofovir in the plasma was unchanged. In Cohort 2, tenofovir diphosphate was 17.8-fold higher (95% CI 12.77-24.86; P < 0.0001) in dried blood spots after 8 weeks of ledipasvir/sofosbuvir versus study entry. Tenofovir plasma concentrations were 2.1-fold higher (95% CI 1.44-2.91; P = 0.0005). Despite the increase in cellular tenofovir diphosphate concentrations, only a small decline in CLCR (6%-7%) was observed in both cohorts between study entry and end of treatment.

Conclusions

These data indicate an unexpected drug interaction with tenofovir disoproxil fumarate and sofosbuvir at the cellular level. Additional studies are needed to determine the mechanism and clinical significance.

Efficacy and safety of the new antiviral agents for the treatment of hepatitis C virus infection in Egyptian renal transplant recipients

PURPOSE

Hepatitis C virus (HCV) infection in kidney transplant recipients (KTRs) is common and can impact on patient and graft survival rates. The efficacy and safety of direct-acting antivirals (DAAs) to treat genotype-4 HCV-infected KTRs have not been fully established.

METHODS

A prospective, single-arm, single-center study was conducted at Mansoura Urology/Nephrology Center (Mansoura University, Egypt). 114 HCV RNA(+) genotype 4 KTRs were enrolled in this study after a hepatology consultation and consented to start treatment with interferon-free DAAs. A sofosbuvir-based regimen was given to 109 recipients that had creatinine clearance (Crcl) of > 30 mL/min/1.73 m². Ritonavir-boosted paritaprevir/ombitasvir was prescribed to five recipients with Crcl < 30 mL/min/1.73 m².

RESULTS

The mean age of the cohort was 45.2 ± 11.2 years; most were male. The mean duration with a transplant was 14.2 ± 3.5 years, with different immunosuppressive regimens, mostly based on calcineurin inhibitors. A rapid virological response (RVR), i.e., clearance of viral load, was achieved in 100% at 4 weeks after starting treatment. All patients had a sustained virological response (SVR) at 12 and 24 weeks posttreatment, with one exception. During DAA therapy serum creatinine increased in 12 patients. In three, this was concomitant with elevated calcineurin inhibitor and sirolimus trough levels. Graft biopsies were performed in 8 of these 12 patients: these revealed an acute rejection in 4 cases (acute cellular rejection grade-1A: n = 2, and grade-1B: n = 2). The rejection episodes occurred at 4-6 weeks after starting treatment.

CONCLUSION

DAAs were highly efficacious and safely treated genotype-4 HCV-infected KTRs and had no significant adverse effects on graft function/survival.

Prevalence of the potential drug-drug interactions between pangenotypic direct-acting antivirals and the concomitant medications associated with patients with chronic hepatitis C virus infection in Spain

OBJECTIVE

To determine the comorbidity and potential for drug-drug interactions (DDIs) among pangenotypic direct-acting-antivirals (pDAAs) and the concomitant medications associated with chronic hepatitis C (CHC) patients in routine clinical practice in Spain.

METHODS

Retrospective observational study. Included patients were ≥18 years, diagnosed with CHC, on antiviral treatment and required medical attention during 2017. Two groups were differentiated according to age ranges (<50 and ≥50 years). The variables collected were: age, gender, general/specific comorbidity, concomitant medication and potential DDIs (www.hep-druginteractions.org). The pDAAs analysed were: a) Sofosbuvir/Velpatasvir (SOF/VEL), b) Glecaprevir/Pibrentasvir (GLE/PIB) and c) Sofosbuvir/Velpatasvir/Voxilaprevir (SOF/VEL/VOX). Bivariate statistical analysis, P<.05.

RESULTS

3,430 patients with a mean age of 56.9 years and 60.3% males were enrolled. The average Charlson index was 0.8. Age range distribution: 18-49 years (28.9%) and ≥50 years (71.1%). The average number of medications per patient/year was 3.1 (SD 2.6). The total percentage of potential DDIs was: 8.6% minor DDIs, 40.5% clinically significant DDIs and 10.0% contraindicated medication. These DDIs were greater in patients ≥50 years (8.6%, 43.8% and 12.4%, respectively, P<.001). For all ages, SOF/VEL showed a lower percentage of: minor interactions (1.3% vs. 6.6% and 5.9%, P<.001); clinically significant interactions (53.4%, vs. 77.4% and 66.3%, P<.001) and contraindicated medication (1.7% vs. 8.3% and 10.7%, P<.001) compared to GLE/PIB and SOF/VEL/VOX, respectively.

CONCLUSIONS

Patients with CHC present high comorbidity and concomitant medication use, particularly elderly patients, thus implying a greater exposure to potential DDIs. Although the DDI rate was considerable with the three combinations analysed, SOF/VEL showed a lower number of clinically significant interactions.

Comparison of the effect of direct-acting antiviral with and without ribavirin on cyclosporine and tacrolimus clearance values: results from the ANRS CO23 CUPILT cohort

PURPOSE

Direct-acting antiviral agents have demonstrated their efficacy in treating HCV recurrence after liver transplantation and particularly the sofosbuvir/daclatasvir combination. Pharmacokinetic data on both calcineurin inhibitors and direct-acting antiviral exposure in liver transplant recipients remain sparse.

METHODS

Patients were enrolled from the ANRS CO23 CUPILT cohort. All patients treated with sofosbuvir/daclatasvir with or without ribavirin were included in this study when blood samples were available to estimate the clearance of immunosuppressive therapy before direct-acting antiviral initiation and during follow-up. Apparent tacrolimus and cyclosporine clearances were estimated from trough concentrations measured using validated quality control assays.

RESULTS

Sixty-seven mainly male patients (79%) were included, with a mean age of 57 years and mean MELD score of 8.2; 50 were on tacrolimus, 17 on cyclosporine. Ribavirin was combined with sofosbuvir/daclatasvir in 52% of patients. Cyclosporine clearance remained unchanged as well as tacrolimus clearance under the ribavirin-free regimen. Tacrolimus clearance increased 4 weeks after direct-acting antivirals and ribavirin initiation versus baseline (geometric mean ratio 1.81; 90% CI 1.30-2.52). Patients under ribavirin had a significantly higher fibrosis stage (> 2) (p = 0.02) and lower haemoglobin during direct-acting antiviral treatment (p = 0.02) which impacted tacrolimus measurements. Direct-acting antiviral exposure was within the expected range.

CONCLUSION

Our study demonstrated that liver transplant patients with a recurrence of hepatitis C who are initiating ribavirin combined with a sofosbuvir-daclatasvir direct-acting antiviral regimen may be at risk of lower tacrolimus concentrations because of probable ribavirin-induced anaemia and higher fibrosis score, although there are no effects on cyclosporine levels.

TRIAL REGISTRATION

NCT01944527.

Long-term follow-up of HCV infected kidney transplant recipients receiving direct-acting antiviral agents: a single-center experience in China

Background

Long-term outcome of DAAs therapy in kidney transplant recipients was unknown. Thus, we aimed to evaluate it in a Chinese cohort of HCV-infected kidney transplant recipients.

Methods

Single-center and retrospective study of HCV-infected kidney transplant recipients initiating an DAAs regimen between January 2015 and December 2017 was conducted. Totally 26 KTX recipients were divided into three groups, including KTX-HD Group, DAA-KTX Group and KTX-DAA Group. On-treatment response was defined as target not detected within 12 weeks. SVR 48, 96 were defined as HCV-RNA negativity 48, 96 weeks after treatment cessation, respectively.

Results

HCV genotype was predominantly 1b (80.8%), followed by 2a. All (100%) patients achieved on-treatment response. Time to first TnD was 1.9 ± 0.6 weeks, with no significant difference among the three groups. All patients achieved SVR, with an SVR rate of 100.0% (26/26) among the patients who were followed up over 48 weeks after treatment cessation, and the same SVR rate (24/24) among the patients who were followed up over 96 weeks. Trough levels of Tac remained stable under DAAs therapy, without any dose adjustment. Two patients with abnormal GFR before treatment experienced serum creatinine elevation. Other adverse events included nausea, diarrhea, acid regurgitation, bilirubin elevation and edema of lower limbs. All patients recovered after treatment cessation without reductions in dose, or withdrawal of DAAs or immunosuppressive agents.

Conclusions

HCV genotype 1b and 2a are the only genotypes and 1b is predominant in our center. Antiviral treatment with DAAs in HCV-infected kidney transplant recipients is persistently effective and well tolerated during long-term follow-up. A regular monitoring of renal function in patients who receive DAAs regimens with preexisting impaired renal function is strongly recommended. Furthermore, the trough CNIs levels were recommended to be frequently monitored.

The benefits of a public pharmacist service in chronic hepattis C treatment: The real-life results of sofosbuvir-based therapy

BACKGROUND

In Brazil, the sofosbuvir-based therapy was introduced in the public health system (SUS) in 2015 to treat Chronic Hepatitis C (CHC). This drug and other direct-acting antiviral agents (DAAs) represent a major advance in the HCV-infection treatment due to their high effectiveness and tolerability. However, the drug safety profile is limited by significant drug interactions and its use is restricted for their high cost. Pharmacists have the opportunity to improve patient care by monitoring the therapy, recommending strategies to guarantee treatment adherence, effectiveness and safety, preventing complications of the disease, and drug-related problems, thus reducing the cost for patients and payers.

OBJECTIVE

This study aimed to assess the results of the one of the first patient group treated with sofosbuvir in Brazil and their opinions about the benefits of clinical pharmacist services in the achievement of the cure for CHC and in the management of their therapy difficulties.

METHODS

This cohort study (November 2015-January 2017) enrolled 240 patients followed up by the clinical pharmacists at the University Pharmacy (UPh) of the Federal University of Santa Catarina, Brazil, during the CHC treatment. The therapeutic schemes used were sofosbuvir + daclatasvir or + simeprevir associated or not with ribavirin. At the end of the therapy, the patients provided qualitative feedback about the clinical pharmacist services.

RESULTS

The study demonstrated high levels of treatment adherence (99.2% of completion rates) and effectiveness rates (Sustained Virological Response rates) (92.1%). Patients reported high levels of satisfaction with the care provided on account of the good rapport built with their pharmacist, the counseling and education on HCV-infection and on sofosbuvir-based therapy utilization, motivation for adherence, and convenient access to the pharmacist.

CONCLUSIONS

The clinical pharmacist services provided by the UPh was beneficial to patients treated for CHC with the sofosbuvir-based therapy.

Pharmacokinetics of Daclatasvir, Sofosbuvir, and GS-331007 in a Prospective Cohort of Hepatitis C Virus-Positive Kidney Transplant Recipients

BACKGROUND

Limited data exist on the pharmacokinetic profile of novel direct-acting antivirals in kidney transplant recipients. Daclatasvir is primarily eliminated through the biliary route and sofosbuvir through the renal route; here, we report the pharmacokinetic profile of combined treatment with these compounds in a prospective study of hepatitis C virus (HCV)-positive kidney transplant recipients (EudraCT: 2014-004551-32).

METHODS

In this study, plasma samples of 16 HCV-positive kidney transplant recipients receiving daclatasvir and sofosbuvir were collected at 4 time points at days 1, 7, 14, 21, 56, and 84 after start of treatment. Inclusion criteria were stable graft function and an estimated glomerular filtration rate (eGFR) >30 mL/min/1.73 m. Daclatasvir, sofosbuvir, and GS-331007 (inactive metabolite of sofosbuvir) plasma concentrations were determined using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry.

RESULTS

All patients showed a rapid virological response with HCV RNA below the detection limit 21 days after the start of therapy (medium time to viral clearance). No difference of the areas under the concentration-time curve (AUC) of daclatasvir, sofosbuvir, and GS-331007 was observed between patients with an eGFR below or ≥60 mL/min. For GS-331007, no relevant changes of trough levels were observed over time. Mean GS-331007 trough levels were 339.5 ± 174.9 ng/mL in patients with an eGFR ≥60 mL/min and 404.3 ± 226 ng/mL in patients with an eGFR <60 mL/min at day 7 (P = 0.52). At day 84, GS-331007 trough levels were 357.8 ± 200.8 and 404.2 ± 70.2 ng/mL in patients with an eGFR ≥60 mL/min and in patients with an eGFR <60 mL/min, respectively (P = 0.51). The accumulation ratios of renally eliminated GS-331007 for AUC and Cmax did not significantly differ between the 2 eGFR groups at day 7.

CONCLUSIONS

An impaired eGFR (30-60 mL/min) does not lead to a dose accumulation of daclatasvir, sofosbuvir, and GS-331007. This study provides the rationale for future studies investigating the pharmacokinetic profile of sofosbuvir-based HCV treatment in kidney transplant recipients with an eGFR <30 mL/min.

Treatment With Grazoprevir/Elbasvir for Renal Transplant Recipients With Chronic Hepatitis C Virus Infection and Impaired Allograft Function

BACKGROUND

Direct-acing antiviral agents are highly efficient treatment options for chronic hepatitis C virus (HCV) infection after renal allograft transplantation. Treatment options for patients with impaired graft function remain limited. Therefore, we assessed the effectiveness and safety of grazoprevir/elbasvir therapy for patients with chronic HCV infection and impaired renal allograft function.

METHODS

Eleven renal allograft recipients with therapy-naïve HCV genotype (GT) 1a, 1b, or 4 were treated with the fixed-dose combination of elbasvir/grazoprevir without ribavirin for 12 weeks. All recipients exhibited impaired graft function with an average glomerular filtration rate lower than 30 mL/min per 1.73 m2. Clinical data were retrospectively reviewed for renal and liver function parameters. Patients were closely monitored for trough levels of immunosuppressive agents, viral load, laboratory values, and potential adverse effects.

RESULTS

Seven (64%) patients exhibited a rapid virologic response within 4 weeks (HCV GT1a, n = 2; HCV GT1b, n = 5). The other 4 patients exhibited a virologic response within 8 weeks (HCV GT1b, n = 3; HCV GT 4, n = 1). All patients exhibited a sustained virologic response at week 12 after the end of treatment. Clinical measures of liver function improved substantially for all patients. Few adverse effects were reported. Impaired renal allograft function and proteinuria remained stable. For most patients, only moderate adjustments to the tacrolimus dosage were necessary for maintaining sufficient trough levels.

CONCLUSIONS

This treatment appears to be safe and effective for renal transplant recipients with impaired allograft function and is a promising treatment option for eradicating HCV infection in this patient population.

Drug-Drug Interactions Potential of Direct-Acting Antivirals for the treatment of Chronic Hepatitis C Virus infection

The advent of direct-acting antiviral agents (DAAs) has transformed the hepatitis C virus (HCV) therapeutic landscape in terms of efficacy and safety, with a cure rate of more than 90%. However, an important potential for drug-drug interactions (DDIs) is expected with these combinations, particularly in patients with other comorbidities (e.g. HIV co-infection, cardiovascular diseases). Each DAA can be a substrate, an inhibitor and/or an inducer of metabolic enzymes and drug efflux transporters. DAAs can act as both victims and perpetrators of DDIs and can sometimes increase the risk and/or intensity of side effects or limit the efficacy of treatment. Therefore, knowledge and management of DDIs with DAAs should be considered a key issue of HCV therapy. This review describes the pharmacokinetic profile of currently used and recommended DAA regimens and summarizes available data regarding DDIs to optimize HCV treatment in clinical practice.

Era of direct acting anti-viral agents for the treatment of hepatitis C

Hepatitis C infection is universal and the most common indication of liver transplantation in the United States. The period of less effective interferon therapy with intolerable side effects has gone. Now we have stepped into the era of direct acting anti-viral agents (DAAs) against hepatitis C virus. Treatment of hepatitis C is now extremely effective, tolerable and requires a short duration of intake of oral agents. Less monitoring is required with the current therapy and drug-drug interactions are less than the previous regimen. The current treatment options of chronic hepatitis C with various DAAs are discussed in this article.

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.

Safety of Direct-Acting Antiviral Therapy Regarding Renal Function in Post-Liver Transplant Patients Infected with Hepatitis C Virus and a 100% 12-Week Sustained Virologic Response-A Single-Center Study

BACKGROUND

Patients after liver transplantation (LT) with hepatitis C virus (HCV) infection often suffer from renal or hepatic impairment. Treating patients after LT with direct-acting antivirals (DAA) might result in decreasing renal function due to interaction of DAA and immunosuppressive therapy. In this single-center study we analyzed clinical parameters of 18 HCV-infected patients treated with DAA therapy after LT.

METHODS

The primary end points were change of renal function (glomerular filtration rate) and sustained virologic response 12 weeks after therapy (SVR12). For secondary end points, we investigated the influence of DAA therapy on transaminases, bilirubin, international normalized ratio, noninvasive fibrosis measurement, and Model for End-Stage Liver Disease (MELD) score.

RESULTS

Five out of 18 patients treated with DAA suffered from renal impairment stage 2, and 7 patients of renal impairment stage 3. Renal function at SVR12 was not influenced by preexisting renal impairment (P > .5), type of immunosuppressant (P > .5), or type of DAA regimen (P > .5). All patients reached SVR12. The levels of transaminases and bilirubin declined rapidly, as expected. Ten out of 18 patients already suffered from cirrhosis or liver fibrosis >F3 according to noninvasive measurement before initiation of treatment. Single-point acoustic radiation force impulse imaging improved in 9 patients (P = .012). In 7 patients, MELD score improved owing to the decrease of bilirubin levels. In 6 patients it worsened.

CONCLUSIONS

DAA therapy in LT patients was effective and safe in this single-center real-life cohort. Renal function was not influenced by the administered drug combinations, even in patients with preexisting renal impairment.

Glycyrrhizin has a high likelihood to be a victim of drug-drug interactions mediated by hepatic organic anion-transporting polypeptide 1B1/1B3

BACKGROUND AND PURPOSE

Intravenous glycyrrhizin, having anti-inflammatory and hepatoprotective properties, is incorporated into the management of liver diseases in China. This investigation was designed to elucidate the molecular mechanism underlying hepatobiliary excretion of glycyrrhizin and to investigate its potential for drug-drug interactions on organic anion-transporting polypeptide (OATP)1B.

EXPERIMENTAL APPROACH

Human transporters mediating hepatobiliary excretion of glycyrrhizin were characterized at the cellular and vesicular levels and compared with rat hepatic transporters. The role of Oatp1b2 in glycyrrhizin's elimination and pharmacokinetics was evaluated in rats using the inhibitor rifampin. A physiologically based pharmacokinetic (PBPK) model for glycyrrhizin, incorporating transporter-mediated hepatobiliary excretion, was established and applied to predict potential drug-drug interactions related to glycyrrhizin in humans.

KEY RESULTS

Hepatobiliary excretion of glycyrrhizin involved human OATP1B1/1B3 (Oatp1b2 in rats)-mediated hepatic uptake from blood and human multidrug resistance-associated protein (MRP)2/breast cancer resistance protein (ABCP)/bile salt export pump (BSEP)/multidrug resistance protein 1 (Mrp2/Abcp/Bsep in rats)-mediated hepatic efflux into bile. In rats, rifampin impaired hepatic uptake of glycyrrhizin significantly increasing its systemic exposure. Glomerular-filtration-based renal excretion of glycyrrhizin was slow due to extensive protein binding in plasma. Quantitative analysis using the PBPK model demonstrated that OATP1B1/1B3 have critical roles in the pharmacokinetics of glycyrrhizin, which is highly likely to be a victim of drug-drug interactions when co-administered with potent dual inhibitors of these transporters.

CONCLUSIONS AND IMPLICATIONS

Transporter-mediated hepatobiliary excretion governs glycyrrhizin's elimination and pharmacokinetics. Understanding glycyrrhizin's potential drug-drug interactions on OATP1B1/1B3 should enhance the therapeutic outcome of glycyrrhizin-containing drug combinations on liver diseases.

Pharmacokinetics, safety, and tolerability of the 2- and 3-direct-acting antiviral combination of AL-335, odalasvir, and simeprevir in healthy subjects

This Phase I, open-label, two-group, fixed-sequence study evaluated the pharmacokinetics and safety of AL-335, odalasvir, and simeprevir in healthy subjects. Group 1 (n = 16) received AL-335 800 mg once daily (QD) (days 1-3, 11-13, and 21-23), simeprevir 150 mg QD (days 4-23), and odalasvir 150 mg (day 14) followed by 50 mg QD (days 15-23). Group 2 (n = 16) received the same AL-335 regimen as in Group 1 plus odalasvir 150 mg (day 4) followed by 50 mg QD (days 5-23) and simeprevir 150 mg QD (days 14-23). Blood samples were collected to determine plasma concentrations of AL-335 (prodrug) and its metabolites, ALS-022399 (monophosphate precursor) and ALS-022227 (parent nucleoside), odalasvir, and simeprevir. Thirty-two subjects were enrolled. Odalasvir and simeprevir given alone, or in combination, increased AL-335 area under plasma concentration-time curve over 24 hours (AUC 0-24 h) 3-, 4-, and 7- to 8-fold, respectively; ALS-022399 AUC 0-24 h increased 2-, 2-, and 3-fold, respectively. Simeprevir had no effect on ALS-022227 AUC 0-24 h, whereas odalasvir with/without simeprevir increased ALS-022227 AUC 0-24 h 1.5-fold. AL-335 had no effect on odalasvir or simeprevir pharmacokinetics. Odalasvir and simeprevir AUC 0-24 h increased 1.5- to 2-fold for both drugs when coadministered irrespective of AL-335 coadministration. Study medications were well tolerated with no serious adverse events. One subject prematurely discontinued study drugs (unrelated event). This study defined the preliminary pharmacokinetic and safety profiles of the combination of AL-335, odalasvir, and simeprevir in healthy subjects. These data support the further evaluation of this combination for the treatment of chronic hepatitis C virus infection.

Potential drug-drug interactions of OMBITASVIR, PARITAPREVIR/ritonavir ± DASABUVIR ± ribavirin in clinical practice

BACKGROUND & AIMS

Drug-drug interactions (DDIs) with ombitasvir/paritaprevir/ritonavir with or without dasabuvir and with or without ribavirin (OBV/PTV/r ± DSV ± RBV) are common in clinical trials. Our aim was to analyze the prevalence and management of potential DDIs and adverse events (AEs) related to DDIs in patients with chronic hepatitis C (CHC) receiving OBV/PTV/r ± DSV ± RBV in clinical practice.

METHODS

177 CHC patients started OBV/PTV/r ± DSV ± RBV in 4 Spanish hospitals and were screened for potential DDIs using the University of Liverpool database. Patients were classified according to the most serious potential DDIs at baseline and AEs during therapy.

RESULTS

At least one potential DDI was found in 110 (62.1%) patients: 100 (56.5%) had at least one manageable potential DDI and 10 (5.6%) at least one contraindicated. Patients with potential DDIs were receiving a higher number of concomitant drugs (4 vs. 2, P < 0.001). Routine medication was modified at baseline due to potential DDIs in 49 (27.7%) patients. During antiviral treatment, 67 (37.9%) patients presented at least one AE. In 9 (4.5%) patients, a DDI was suspected between OBV/PTV/r ± DSV ± RBV and the concomitant drug, requiring antiviral discontinuation in 4 patients.

CONCLUSIONS

Potential DDIs are frequent with OBV/PTV/r ± DSV ± RBV, although a change in baseline medication is made in only one-quarter of patients. More than half of potential DDIs were only followed, and only 5% of patients developed AEs in which the implication of DDIs could not be excluded.

Highlights of the Structure-Activity Relationships of Benzimidazole Linked Pyrrolidines Leading to the Discovery of the Hepatitis C Virus NS5A Inhibitor Pibrentasvir (ABT-530)

Curative interferon and ribavirin sparing treatments for hepatitis C virus (HCV)-infected patients require a combination of mechanistically orthogonal direct acting antivirals. A shared component of these treatments is usually an HCV NS5A inhibitor. First generation FDA approved treatments, including the component NS5A inhibitors, do not exhibit equivalent efficacy against HCV virus genotypes 1-6. In particular, these first generation NS5A inhibitors tend to select for viral drug resistance. Ombitasvir is a first generation HCV NS5A inhibitor included as a key component of Viekira Pak for the treatment of patients with HCV genotype 1 infection. Since the launch of next generation HCV treatments, functional cure for genotype 1-6 HCV infections has been achieved, as well as shortened treatment duration across a wider spectrum of genotypes. In this paper, we show how we have modified the anchor, linker, and end-cap architecture of our NS5A inhibitor design template to discover a next generation NS5A inhibitor pibrentasvir (ABT-530), which exhibits potent inhibition of the replication of wild-type genotype 1-6 HCV replicons, as well as improved activity against replicon variants demonstrating resistance against first generation NS5A inhibitors.

Prevalence of HCV Infection in Adults with Congenital Heart Disease and Treatment with Direct Antiviral Agents

OBJECTIVES

Hepatitis C virus (HCV) infection affects >3% of the US population, which over time can lead to cirrhosis and hepatocellular carcinoma. The lack of a reliable screening method for HCV before 1992 resulted in a higher prevalence of the virus in adults with congenital heart disease who underwent corrective surgery that required blood transfusions. Direct-acting antiviral agents such as sofosbuvir/ledipasvir have significantly increased the efficacy of HCV therapy, although use of these medications in adults with congenital heart disease has not been described.

METHODS

Ours was a retrospective study of 188 adults with congenital heart conditions who had cardiac surgery before 1992. These patients were screened for HCV using HCV antibody followed by HCV RNA if the screening test was positive.

RESULTS

Of the 188 adults, 116 (43% male patients, 24-70 years) were screened for the HCV antibody, demonstrating that 104 individuals were negative and 12 subjects were positive for the virus. Subsequently, further testing for the presence of HCV demonstrated 11 of 12 were infected, with an overall prevalence of 9.5%. Five individuals chose to be treated with sofosbuvir/ledipasvir and 5 of 5 have successfully cleared the virus and are considered cured.

CONCLUSIONS

Adults with congenital heart disease who underwent cardiac surgery before 1992 warrant being screened for HCV, and, if testing positive, may be considered for therapy using direct-acting antiviral agents with close monitoring for cardiac complications.