Glecaprevir/pibrentasvir for the treatment of chronic hepatitis C: design, development, and place in therapy

Phase 1 study of safety and tolerability of an oral contraceptive containing low-dose ethinyl oestradiol combined with glecaprevir/pibrentasvir treatment in healthy premenopausal women

Glecaprevir/pibrentasvir (GLE/PIB) is an approved guideline-recommended chronic hepatitis C virus infection treatment. GLE/PIB coadministration with ethinyl oestradiol (EE) is not recommended in current labels owing to a Phase 1 study observing Grade ≥2 alanine aminotransferase (ALT) elevation in 2 out of 12 healthy women cotreated for 11 days with GLE/PIB and oral contraceptive (OC) containing 35 μg/250 μg EE/norgestimate. No Grade ≥2 elevation was observed with low-dose (20 μg) EE (n = 14). This Phase 1 study examined safety/tolerability of GLE/PIB coadministered with an OC containing low-dose EE using a larger sample size and longer treatment duration. Healthy premenopausal women were treated with EE/levonorgestrel alone (20/100 μg, Cycles 1-2), followed by coadministration with GLE/PIB (300/120 mg; Cycles 3-4). A safety criterion of special interest was a confirmed Grade ≥2 ALT elevation (>3× upper normal limit). Adverse events (AEs) and study drugs concentrations were examined. Of 85 enrolled women, 72 initiated combined GLE/PIB + EE/levonorgestrel treatment, 66 completed the study and 19 discontinued prematurely (non-safety reason, n = 16; AE [deemed unelated to GLE/PIB], n = 3). No participant met the safety criterion of special interest of confirmed Grade ≥2 ALT elevation. No serious/Grade ≥3 AEs were reported. Study drug concentrations were within the expected ranges. GLE/PIB in combination with an OC containing low-dose EE was generally well tolerated with no confirmed Grade ≥2 ALT elevation and no evidence of drug-induced liver injury. No pattern to the reported AEs and no new safety issues were identified. This was a Phase 1 study of healthy volunteers, not a registered clinical trial.

Adherence in Hepatitis C Virus Treatment: What We Know

Although therapy with direct-acting antiviral (DAA) agents achieves high hepatitis C virus (HCV) cure rates and is forgiving of missed doses, certain patient populations, such as people who inject drugs (PWID), are often denied therapy because of a perceived high risk of nonadherence. However, a relationship between adherence to DAAs for various patient populations and efficacy has not been well defined. The lack of a standardized method for evaluating adherence complicates making comparisons between studies, making it difficult to develop and implement novel measures that may improve adherent behavior. Traditional methods for assessing adherence may overestimate medication adherence, while newer, technology-based methods may assist with accurately assessing and maintaining patient adherence to therapy. Data demonstrate that special populations of patients with HCV, such as PWID, can be successfully treated, with relatively high rates of sustained virologic response (SVR) despite less-than-optimal adherence. While rates of adherence, and subsequently SVR, can be improved, antiviral therapy should not be withheld because of fear of nonadherence. This article addresses medication adherence and forgiveness of DAA regimens, such as sofosbuvir/velpatasvir and glecaprevir/pibrentasvir, in different patient populations with HCV. Considerations in evaluating adherence in HCV therapy and available methods for assessing adherence are detailed.

Cheminformatics-Based Study Identifies Potential Ebola VP40 Inhibitors

The Ebola virus (EBOV) is still highly infectious and causes severe hemorrhagic fevers in primates. However, there are no regulatorily approved drugs against the Ebola virus disease (EVD). The highly virulent and lethal nature of EVD highlights the need to develop therapeutic agents. Viral protein 40 kDa (VP40), the most abundantly expressed protein during infection, coordinates the assembly, budding, and release of viral particles into the host cell. It also regulates viral transcription and RNA replication. This study sought to identify small molecules that could potentially inhibit the VP40 protein by targeting the N-terminal domain using an in silico approach. The statistical quality of AutoDock Vina’s capacity to discriminate between inhibitors and decoys was determined, and an area under the curve of the receiver operating characteristic (AUC-ROC) curve of 0.791 was obtained. A total of 29,519 natural-product-derived compounds from Chinese and African sources as well as 2738 approved drugs were successfully screened against VP40. Using a threshold of −8 kcal/mol, a total of 7, 11, 163, and 30 compounds from the AfroDb, Northern African Natural Products Database (NANPDB), traditional Chinese medicine (TCM), and approved drugs libraries, respectively, were obtained after molecular docking. A biological activity prediction of the lead compounds suggested their potential antiviral properties. In addition, random-forest- and support-vector-machine-based algorithms predicted the compounds to be anti-Ebola with IC50 values in the micromolar range (less than 25 μM). A total of 42 natural-product-derived compounds were identified as potential EBOV inhibitors with desirable ADMET profiles, comprising 1, 2, and 39 compounds from NANPDB (2-hydroxyseneganolide), AfroDb (ZINC000034518176 and ZINC000095485942), and TCM, respectively. A total of 23 approved drugs, including doramectin, glecaprevir, velpatasvir, ledipasvir, avermectin B1, nafarelin acetate, danoprevir, eltrombopag, lanatoside C, and glycyrrhizin, among others, were also predicted to have potential anti-EBOV activity and can be further explored so that they may be repurposed for EVD treatment. Molecular dynamics simulations coupled with molecular mechanics Poisson–Boltzmann surface area calculations corroborated the stability and good binding affinities of the complexes (−46.97 to −118.9 kJ/mol). The potential lead compounds may have the potential to be developed as anti-EBOV drugs after experimental testing.

Prevalence and predictors of abnormal alanine aminotransferase in patients with HCV who have achieved SVR

Chronic hepatitis C virus (HCV) is common. Treatment with direct acting antivirals (DAA) result in high sustained virologic response (SVR) associated with normalization of alanine aminotransferase (ALT). However, abnormal ALT after SVR has been observed. Since fatty liver disease can co-exist with HCV, its impact on abnormal ALT after SVR is unknown. This was a retrospective case-control analysis evaluating those with SVR and baseline fatty liver disease by transient elastography defined by controlled attenuated parameter (CAP) was performed. Abnormal ALT was defined as >1.5 ULN. The primary analysis compared abnormal ALT at SVR-12 and beyond in those with and without fatty liver disease. Six-hundred and ninety-three patients with SVR-12 were evaluated. Abnormal ALT at SVR-12 was present in 8.2% and was similar in those with and without fatty liver disease. Abnormal ALT at SVR-12 was associated with atrial fibrillation (p = .02), CAP (p = .047), age (p = .08), baseline ALT (p = .008), BMI (p = .002) and obesity (p = .02). On multivariate analysis, only BMI was associated with abnormal ALT at SVR-12 (p = .017). ALT at follow-up after SVR-12 was available in 264 patients. In those with initial normal ALT (n = 244), 11.5% had a delayed abnormal ALT and in those with initial abnormal ALT (n = 20), 47% remained abnormal while 53% normalized. Abnormal ALT after SVR following treatment with DAA is uncommon and related to increased BMI, but not related to underlying fatty liver disease assessed by CAP. The pattern of ALT can vary, and long-term follow-up is needed to assess the clinical impact of abnormal ALT after SVR.

Safety analysis of glecaprevir/pibrentasvir in patients with markers of advanced liver disease in clinical and real-world cohorts

Chronic hepatitis C virus (HCV) infection has the greatest health impact in patients with advanced liver disease. The direct-acting antiviral (DAA) regimen glecaprevir/pibrentasvir (G/P) is approved for treatment of HCV-infected patients without cirrhosis and with compensated cirrhosis. However, events of liver decompensation/failure have been reported in patients treated with protease-inhibitor-containing DAA regimens, often in patients with advanced liver disease. This study examines the safety of on-label G/P treatment in patients with compensated cirrhosis (F4 at baseline) with markers of advanced liver disease. Patients with cirrhosis were categorized into 4 subgroups, based on different noninvasive markers of advanced liver disease identified using laboratory measures: platelet count < or ≥ 100 × 10⁹ /L, and Child-Pugh score 5 or 6. Separate analyses were performed using pooled data from clinical trials and from real-world post-marketing observational studies. G/P was well tolerated in patients with platelet count ≥100 × 10⁹ /L (n = 800), platelet count <100 × 10⁹ /L (n = 215), a Child-Pugh score of 5 (n = 915) and a Child-Pugh score of 6 (n = 95). In the clinical trial and real-world cohorts two patients and no patients experienced a serious adverse event (AE) possibly related to study drug, respectively; three patients and no patients experienced an AE of special interest for hepatic decompensation and hepatic failure. This analysis reaffirms G/P's safety profile in indicated patients with compensated cirrhosis, including those with markers of more advanced liver disease. Increasing the number of patients treated with short-duration G/P therapy may contribute to meeting HCV elimination targets.

Viral proteases as therapeutic targets

Some medically important viruses-including retroviruses, flaviviruses, coronaviruses, and herpesviruses-code for a protease, which is indispensable for viral maturation and pathogenesis. Viral protease inhibitors have become an important class of antiviral drugs. Development of the first-in-class viral protease inhibitor saquinavir, which targets HIV protease, started a new era in the treatment of chronic viral diseases. Combining several drugs that target different steps of the viral life cycle enables use of lower doses of individual drugs (and thereby reduction of potential side effects, which frequently occur during long term therapy) and reduces drug-resistance development. Currently, several HIV and HCV protease inhibitors are routinely used in clinical practice. In addition, a drug including an inhibitor of SARS-CoV-2 main protease, nirmatrelvir (co-administered with a pharmacokinetic booster ritonavir as Paxlovid®), was recently authorized for emergency use. This review summarizes the basic features of the proteases of human immunodeficiency virus (HIV), hepatitis C virus (HCV), and SARS-CoV-2 and discusses the properties of their inhibitors in clinical use, as well as development of compounds in the pipeline.

A Pilot Trial for Prevention of Hepatitis C Virus Transmission From Donor to Organ Transplant Recipient With Short-Course Glecaprevir/Pibrentasvir

A 7-day course of glecaprevir/pibrentasvir started in the preoperative period prevented transmission of hepatitis C virus (HCV) from viremic donors to 10 HCV-negative recipients (2 heart, 1 lung, 6 kidney, 1 heart/kidney) with 100% sustained virological response at 12 weeks.

Challenges of Treating an Acute Hepatitis C Virus Infection With Concurrent Seizure Treatment in a Free Clinic

Currently, there is limited data evaluating the coadministration of first-generation anticonvulsants for epilepsy treatment and direct-acting antivirals (DAAs) for the treatment of hepatitis C virus (HCV) infection. There is a potential risk of suboptimal DAA serum concentrations that could potentially lead to HCV treatment failure. In this report, we describe the case of an uninsured, non-Hispanic Black male in his mid-40s with a history of generalized epilepsy that was managed with phenytoin 100mg twice a day and divalproex 500mg extended-release once daily. He was diagnosed with an acute hepatitis C viral infection with a genotype of 1a. Due to the viral genotype, treatment naivety, and lack of cirrhosis, the recommended treatment is to start glecaprevir/pibrentasvir, but the concomitant use of phenytoin and glecaprevir/pibrentasvir is not recommended due to a drug-drug interaction that could lead to subtherapeutic DAA levels and possible treatment failure. Through shared decision-making and close follow-up, we slowly weaned the patient off phenytoin, replaced it with levetiracetam, and started glecaprevir/pibrentasvir. We successfully eradicated the patient’s HCV infection, and no breakthrough seizures were reported. Although an unprecedented case and with the limited data evaluating the coadministration of DAAs and treatment of acute HCV infection, we were able to successfully treat and achieve full remission of the HCV infection. By virtue of this case report, we hope to encourage others to report similar cases and spread awareness regarding the difficulties in management.

Photoinduced, Copper-Catalyzed Enantioconvergent Alkylations of Anilines by Racemic Tertiary Electrophiles: Synthesis and Mechanism

Transition-metal catalysis of substitution reactions of alkyl electrophiles by nitrogen nucleophiles is beginning to emerge as a powerful strategy for synthesizing higher-order amines, as well as controlling their stereochemistry. Herein, we report that a readily accessible chiral copper catalyst (commercially available components) can achieve the photoinduced, enantioconvergent coupling of a variety of racemic tertiary alkyl electrophiles with aniline nucleophiles to generate a new C-N bond with good ee at the fully substituted stereocenter of the product; whereas this photoinduced, copper-catalyzed coupling proceeds at -78 °C, in the absence of light and catalyst, virtually no C-N bond formation is observed even upon heating to 80 °C. The mechanism of this new catalytic enantioconvergent substitution process has been interrogated with the aid of a wide array of tools, including the independent synthesis of proposed intermediates and reactivity studies, spectroscopic investigations featuring photophysical and EPR data, and DFT calculations. These studies led to the identification of three copper-based intermediates in the proposed catalytic cycle, including a chiral three-coordinate formally copper(II)-anilido (DFT analysis points to its formulation as a copper(I)-anilidyl radical) complex that serves as a persistent radical that couples with a tertiary organic radical to generate the desired C-N bond with good enantioselectivity.

Treatment-Resistant Hepatitis C Viral Infection: A Case Report and Literature Review

Hepatitis C virus (HCV) is an ongoing global public health threat affecting millions worldwide. Increasing recognition of its impact and recent advances towards HCV prevention and cure have provided incentive for the World Health Organization to call for global elimination by 2030. The goal of therapy is to achieve a sustained virologic response (SVR-12), defined as undetectable HCV-RNA within 12 weeks after treatment completion. In 2011, approval was given for the first direct-acting antiviral agents (DAAs). More recently, in 2013, more effective DAAs, with pan-genomic properties, have been introduced, and these regimens boast increasing rates of SVR. The ultimate goal is that the history of HCV ends with the pan-genotypic efficacy of multiple, easy-to-use and tolerate, combination regimens. These regimens have already demonstrated the ability to cure previously challenging patient groups. However, limitations exist in the current portfolio of agents, with suboptimal outcomes for patients with HCV genotype 3. In addition to this, access to DAAs remains an obstacle for many patients. We present this case of a 61-year-old male with HCV genotype 3 who has had several treatment failures with standard HCV therapy who was eventually approved for compassionate use of a 16-week course of glecaprevir (GLE)/pibrentasvir (PIB), sofosbuvir (SOF), and ribavirin (RBV) which ultimately led to SVR-12.

Non-nucleoside structured compounds with antiviral activity—past 10 years (2010–2020)

Nucleosides and their derivatives are a well-known and well-described class of compounds with antiviral activity. Currently, in the era of the COVID-19 pandemic, scientists are also looking for compounds not related to nucleosides with antiviral properties. This review aims to provide an overview of selected synthetic antiviral agents not associated to nucleosides developed against human viruses and introduced to preclinical and clinical trials as well as drugs approved for antiviral therapy over the last 10 years. The article describes for the first time the wide classification of such antiviral drugs and drug candidates and briefly summarizes the biological target and clinical applications of the compounds. The described compounds are arranged according to the antiviral mechanism of action. Knowledge of the drug's activity toward specific molecular targets may be the key to researching new antiviral compounds and repositioning drugs already approved for clinical use. The paper also briefly discusses the future directions of antiviral therapy. The described examples of antiviral compounds can be helpful for further drug development.

Regulatory Role of Phospholipids in Hepatitis C Virus Replication and Protein Function

Positive-strand RNA viruses such as hepatitis C virus (HCV) hijack key factors of lipid metabolism of infected cells and extensively modify intracellular membranes to support the viral lifecycle. While lipid metabolism plays key roles in viral particle assembly and maturation, viral RNA synthesis is closely linked to the remodeling of intracellular membranes. The formation of viral replication factories requires a number of interactions between virus proteins and host factors including lipids. The structure-function relationship of those proteins is influenced by their lipid environments and lipids that selectively modulate protein function. Here, we review our current understanding on the roles of phospholipids in HCV replication and of lipid-protein interactions in the structure-function relationship of the NS5A protein. NS5A is a key factor in membrane remodeling in HCV-infected cells and is known to recruit phosphatidylinositol 4-kinase III alpha to generate phosphatidylinositol 4-phosphate at the sites of replication. The dynamic interplay between lipids and viral proteins within intracellular membranes is likely key towards understanding basic mechanisms in the pathobiology of virus diseases, the mode of action of specific antiviral agents and related drug resistance mechanisms.

SARS-CoV-2 vaccine development

SARS-CoV-2 is a well-known viral strain that causes COVID-19. The disease became a pandemic in early 2020 and infected millions of people and killed hundreds of thousands of people worldwide. Vaccine development against the disease was accelerated with multiple collaborations among research institutions in order to shorten the duration that vaccine development normally takes. Prior coronavirus vaccines present a basis on which vaccines against the current strain can be developed with much speed and relative ease. Among the patented coronavirus vaccines, DNA-based vaccine had the most patents registered which must have clues to guide the efforts in the current works. This work presents some progress on COVID-19 vaccine development and also possible animal venom protein sources that can potentially be used in the pipeline. The future of COVID-19 vaccine is bright with the heightened collaborative efforts and data sharing opportunities that the pandemic has brought among researchers.

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.

Is an 8-week regimen of glecaprevir/pibrentasvir sufficient for all hepatitis C virus infected patients in the real-world experience?

BACKGROUND AND AIMS

The revolution of the antiviral treatment of hepatitis C virus (HCV) infection resulting in higher effectiveness came with the introduction of direct-acting antivirals with pangenotypic regimens as a final touch. Among them, the combination of glecaprevir (GLE) and pibrentasvir (PIB) provides the opportunity for shortening therapy to 8 weeks in the majority of patients. Because of still insufficient evaluation of this regimen in the real-world experience, our study aimed to assess the efficacy and safety of 8-week GLE/PIB in chronic hepatitis C patients depending on liver fibrosis and genotype (GT).

METHODS

The analysis included patients who received GLE/PIB for 8 weeks selected from the EpiTer-2 database, large retrospective national real-world study evaluating antiviral treatment in 12 584 individuals in 22 Polish hepatology centers.

RESULTS

A total of 1034 patients with female predominance (52%) were enrolled in the analysis. The majority of them were treatment naïve (94%), presented liver fibrosis (F) of F0-F3 (92%), with the most common GT1b, followed by GT3. The overall sustained virologic response after exclusion of nonvirologic failures was achieved in 95.8% and 98%, respectively (P = 0.19). In multivariate logistic regression HCV GT-3 (beta = 0.07, P = 0.02) and HIV infection (beta = -0.14, P < 0.001) were independent predictors of nonresponse.

CONCLUSIONS

We demonstrated high effectiveness of 8-week GLE/PIB treatment in a non-GT3 population irrespective of liver fibrosis stage. Comparable efficacy was achieved in non-cirrhotic patients regardless of the genotype, including GT3 HCV.

Identification of multipotent drugs for COVID-19 therapeutics with the evaluation of their SARS-CoV2 inhibitory activity

The SARS-CoV2 is a highly contagious pathogen that causes COVID-19 disease. It has affected millions of people globally with an average lethality of ~3%. There is an urgent need of drugs for the treatment of COVID-19. In the current studies, we have used bioinformatics techniques to screen the FDA approved drugs against nine SARS-CoV2 proteins to identify drugs for repurposing. Additionally, we analyzed if the identified molecules can also affect the human proteins whose expression in lung changed during SARS-CoV2 infection. Targeting such genes may also be a beneficial strategy to curb disease manifestation. We have identified 74 molecules that can bind to various SARS-CoV2 and human host proteins. We experimentally validated our in-silico predictions using vero E6 cells infected with SARS-CoV2 virus. Interestingly, many of our predicted molecules viz. capreomycin, celecoxib, mefloquine, montelukast, and nebivolol showed good activity (IC50) against SARS-CoV2. We hope that these studies may help in the development of new therapeutic options for the treatment of COVID-19.

Danoprevir for the Treatment of Hepatitis C Virus Infection: Design, Development, and Place in Therapy

On June 8, 2018, an NS3/4A protease inhibitor called danoprevir was approved in China to treat the infections of HCV genotype (GT) 1b – the most common HCV genotype worldwide. Based on phase 2 and 3 clinical trials, the 12-week regimen of ritonavir-boosted danoprevir (danoprevir/r) plus peginterferon alpha-2a and ribavirin offered 97.1% (200/206) of sustained virologic response at post-treatment week 12 (SVR12) in treatment-naïve non-cirrhotic patients infected with HCV genotype 1b. Adverse events such as anemia, fatigue, fever, and headache were associated with the inclusion of peginterferon alpha-2a and ribavirin in the danoprevir-based regimen. Moreover, drug resistance to danoprevir could be traced to amino acid substitutions (Q80K/R, R155K, D168A/E/H/N/T/V) near the drug-binding pocket of HCV NS3 protease. Despite its approval, the clinical use of danoprevir is currently limited to its combination with peginterferon alpha-2a and ribavirin, thereby driving its development towards interferon-free, ribavirin-free regimens with improved tolerability and adherence. In the foreseeable future, pan-genotypic direct-acting antivirals with better clinical efficacy and less adverse events will be available to treat HCV infections worldwide.

Glecaprevir and Maraviroc are high-affinity inhibitors of SARS-CoV-2 main protease: possible implication in COVID-19 therapy

Due to the lack of efficient therapeutic options and clinical trial limitations, the FDA-approved drugs can be a good choice to handle Coronavirus disease (COVID-19). Many reports have enough evidence for the use of FDA-approved drugs which have inhibitory potential against target proteins of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Here, we utilized a structure-based drug design approach to find possible drug candidates from the existing pool of FDA-approved drugs and checked their effectiveness against the SARS-CoV-2. We performed virtual screening of the FDA-approved drugs against the main protease (M^pro) of SARS-CoV-2, an essential enzyme, and a potential drug target. Using well-defined computational methods, we identified Glecaprevir and Maraviroc (MVC) as the best inhibitors of SARS-CoV-2 M^pro. Both drugs bind to the substrate-binding pocket of SARS-CoV-2 M^pro and form a significant number of non-covalent interactions. Glecaprevir and MVC bind to the conserved residues of substrate-binding pocket of SARS-CoV-2 M^pro. This work provides sufficient evidence for the use of Glecaprevir and MVC for the therapeutic management of COVID-19 after experimental validation and clinical manifestations.