Sofosbuvir treatment and hepatitis C virus infection

Sofosbuvir Polymorphs Distinguished by Linearly and Circularly Polarized Raman Microscopy

Most currently marketed pharmaceuticals are manufactured in the solid state, where the bioavailability of the active pharmaceutical ingredient (API) can be optimized through different polymorphs, cocrystals, solvates, or salts. Efficient techniques are needed to monitor the structure of pharmaceuticals during production. Here, we explore the potential of linearly and circularly polarized Raman microscopy for distinguishing three polymorphs of sofosbuvir, an antiviral drug used to treat hepatitis C. Raman spectra were recorded on a Raman microscope for a polycrystalline API diluted in a KBr matrix. To understand spectral features including the low-frequency region, we simulated band frequencies and intensities using quantum-chemical computational strategies based on cluster and transfer approaches. Very good agreement was achieved between simulated and experimental intensities. The 20 to 200 cm-1 wavenumber region appeared particularly useful for polymorph discrimination already based on unpolarized measurements. The depolarization ratios obtained from linearly polarized Raman spectra made the distinction even more reliable. Moreover, circularly polarized Raman spectra and normalized degrees of circularity provided useful additional information and revealed several tentative markers of the different polymorphs of sofosbuvir. Although in some spectral regions the differences were less obvious, the results indicate that polarized Raman microscopy is a handy tool for discriminating between polymorphs of APIs and other compounds.

Alpha-mangostin, piperine and beta-sitosterol as hepatitis C antivirus (HCV): In silico and in vitro studies

Hepatitis C is still a serious liver case of health. Up to now the development of anti-Hepatitis C Virus (HCV) drugs is challenging, especially the development of natural material compounds as anti-HCV. In the present study, we evaluated the probability of α-mangostin, piperine, and β-sitosterol as anti-HCV with the in silico and in vitro approaches. Molecular docking was performed between nonstructural protein 5B (NS5B, PDB ID 3FQL) with α-mangostin, piperine, and β-sitosterol by Autodock Tools® and BIOVIA Discovery Studio®. Subsequently, molecular dynamics simulations were conducted for 200 ns, evaluating the dynamic interaction between the ligands and the viral protein NS5B. Furthermore, compound characterization at the hepatocarcinoma cell line was employed. α-Mangostin with NS5B complex demonstrated the most negative binding free energy value based on MM-PBSA calculation with a value of -9.13 kcal/mol. In vitro test showed that IC50 of α -mangostin was 2.70 ± 0.92 μM, IC50 of piperine was 52.18 ± 3.21 μM, IC50 of β-sitosterol was >100 μM. α-Mangostin can serve as a valuable lead compound for further development of the anti-HCV.

Sofosbuvir in the Treatment of Hepatitis E virus Infection: A Review of in vitro and in vivo Evidence

Chronic hepatitis E virus (HEV) infection, which occurs almost exclusively in immunocompromised patients, if untreated may progress to cirrhosis and possibly hepatocellular carcinoma. The reduction of immunosuppression and/or administration of ribavirin is frequently curative but there remain many immunocompromised individuals whose HEV infection is refractory to these therapeutic strategies. Moreover, the haematological toxicity of ribavirin limits its use. Pegylated interferon has demonstrated success in a small number of patients with chronic HEV infection; however, the potentially increased risk of graft rejection associated with its use renders it unsuitable for many transplant recipients. Alternative therapeutic strategies are therefore required. This article reviews the in vitro and in vivo literature to date of the antiviral agent sofosbuvir (well established in the treatment of hepatitis C) in the treatment of HEV infection.

Sofosbuvir plus ribavirin combination regimen boost liver functions and antioxidant profile in hepatitis C virus patients

Hepatitis C virus is an infectious pathogen affecting thousands of people causing great damage to the liver and consider an important cause of morbidity and mortality in developing countries. This research was conducted on 30 patients infected with hepatitis C virus and 10 control normal volunteers after taking consent of them in order to evaluate the liver function and antioxidants profile after treatment with combination of Sofosbuvir and Ribaverin in hepatitis C virus patients. The results showed significant reduction of elevated levels of L-Malondialdhyde, Alanine Aminotrasferase, Aspartate Aminotrasferase, Alkaline Phosphatase, Albumin, Total protein, Total bilirubin and α-fetoprotein mean while significant increase in glutathione peroxidase, catalase, superoxide dismutase activity upon treatment with combination of sofosbuvir plus ribavirin. In conclusion, the present finding suggest that, treatment of hepatitis C virus patient with combination of Sofosbuvir and Ribavirin significantly improve liver function parameters and antioxidant profile.

Expedient synthesis and biological evaluation of alkenyl acyclic nucleoside phosphonate prodrugs

The importance of phosphonoamidate prodrugs (ProTides) of acyclic nucleoside phosphonate (ANPs) is highlighted by the approval of Tenofovir Alafenamide Fumarate for the treatment of HIV and HBV infections. In the present paper we are reporting an expedient, one-pot, two-steps synthesis of allyl phosphonoamidates and diamidates that offers a time saving strategy when compared to literature methods. The use of these substrates in the cross metathesis reactions with alkenyl functionalised thymine and uracil nucleobases is reported. ANPs prodrugs synthesized via this methodology were evaluated for their antiviral activities against DNA and RNA viruses. It is anticipated that the use of 5,6,7,8-tetrahydro-1-napthyl as aryloxy moiety is capable to confer antiviral activity among a series of otherwise inactive uracil ProTides.

Biophysical Mode-of-Action and Selectivity Analysis of Allosteric Inhibitors of Hepatitis C Virus (HCV) Polymerase

Allosteric inhibitors of hepatitis C virus (HCV) non-structural protein 5B (NS5B) polymerase are effective for treatment of genotype 1, although their mode of action and potential to inhibit other isolates and genotypes are not well established. We have used biophysical techniques and a novel biosensor-based real-time polymerase assay to investigate the mode-of-action and selectivity of four inhibitors against enzyme from genotypes 1b (BK and Con1) and 3a. Two thumb inhibitors (lomibuvir and filibuvir) interacted with all three NS5B variants, although the affinities for the 3a enzyme were low. Of the two tested palm inhibitors (dasabuvir and nesbuvir), only dasabuvir interacted with the 1b variant, and nesbuvir interacted with NS5B 3a. Lomibuvir, filibuvir and dasabuvir stabilized the structure of the two 1b variants, but not the 3a enzyme. The thumb compounds interfered with the interaction between the enzyme and RNA and blocked the transition from initiation to elongation. The two allosteric inhibitor types have different inhibition mechanisms. Sequence and structure analysis revealed differences in the binding sites for 1b and 3a variants, explaining the poor effect against genotype 3a NS5B. The indirect mode-of-action needs to be considered when designing allosteric compounds. The current approach provides an efficient strategy for identifying and optimizing allosteric inhibitors targeting HCV genotype 3a.

Assessment of new triplet forming artificial nucleobases as RNA ligands directed towards HCV IRES IIId loop

We report the synthesis of two new artificial nucleobase scaffolds, 1 and 2, featuring adequate hydrogen bonding donors and acceptors for the molecular recognition of U:A and C:G base pairs, respectively. The tethering of these structures to various amino acids and the assessment of these artificial nucleobase-amino acid conjugates as RNA ligands against a model of HCV IRES IIId domain are also reported. Compound 1e displayed the highest affinity (K_d twice lower than neomycin - control). Moreover, it appears that this interaction is enthalpically and entropically favored.

Nidovirus RNA polymerases: Complex enzymes handling exceptional RNA genomes

Coronaviruses and arteriviruses are distantly related human and animal pathogens that belong to the order Nidovirales. Nidoviruses are characterized by their polycistronic plus-stranded RNA genome, the production of subgenomic mRNAs and the conservation of a specific array of replicase domains, including key RNA-synthesizing enzymes. Coronaviruses (26-34 kilobases) have the largest known RNA genomes and their replication presumably requires a processive RNA-dependent RNA polymerase (RdRp) and enzymatic functions that suppress the consequences of the typically high error rate of viral RdRps. The arteriviruses have significantly smaller genomes and form an intriguing package with the coronaviruses to analyse viral RdRp evolution and function. The RdRp domain of nidoviruses resides in a cleavage product of the replicase polyprotein named non-structural protein (nsp) 12 in coronaviruses and nsp9 in arteriviruses. In all nidoviruses, the C-terminal RdRp domain is linked to a conserved N-terminal domain, which has been coined NiRAN (nidovirus RdRp-associated nucleotidyl transferase). Although no structural information is available, the functional characterization of the nidovirus RdRp and the larger enzyme complex of which it is part, has progressed significantly over the past decade. In coronaviruses several smaller, non-enzymatic nsps were characterized that direct RdRp function, while a 3'-to-5' exoribonuclease activity in nsp14 was implicated in fidelity. In arteriviruses, the nsp1 subunit was found to maintain the balance between genome replication and subgenomic mRNA production. Understanding RdRp behaviour and interactions during RNA synthesis and subsequent processing will be key to rationalising the evolutionary success of nidoviruses and the development of antiviral strategies.

Real-world experience with interferon-free, direct acting antiviral therapies in Asian Americans with chronic hepatitis C and advanced liver disease

Real-life data on interferon (IFN)-free direct acting antiviral (DAA) therapies for chronic hepatitis C (CHC) is limited for Asian Americans.To evaluate sustained virologic response (SVR) and adverse events (AE) in Asian Americans treated with sofosbuvir (SOF)-based, IFN-free DAA therapies.This is a retrospective study of 110 consecutive Asian Americans with HCV genotypes 1 to 3 or 6 treated with IFN-free SOF-based regimens for 8 to 24 weeks between February 2014 and March 2016 at a university center in Northern California.Mean age was 63 ± 12 years, mean BMI was 25 ± 6 (kg/m), and about half (52%) were male. Most patients were infected with HCV genotype 1 (HCV-1, 64%), followed by HCV-2 (14%), HCV-6 (13%), and HCV-3 (8%). Half had cirrhosis, and the majority of these (67%) had decompensation. Overall SVR12 was 93% (102/110), and highest among patients without cirrhosis, liver transplant, or HCC (100%, 37/37). SVR12 was lower among patients with HCC (82%, 14/17), decompensated cirrhosis (84%, 31/37), or liver transplant (89%, 17/19), regardless of treatment and genotype. Most common AEs were anemia (25%), fatigue (20%), and headache (12%). Anemia was highest in patients receiving SOF/RBV (67%). There was 1 treatment-unrelated serious adverse effect (SAE). There were 7 dose reductions due to anemia or fatigue from RBV and 2 treatment discontinuations due to fatigue or loss of insurance authorization.This real-life cohort of Asian American CHC patients treated with IFN-free SOF-based therapies showed high overall treatment response and good tolerability, despite very high rates of advanced disease and prior treatment failure.

Interferon-free treatment for HCV-infected patients with decompensated cirrhosis

Progress in interferon-free treatment against hepatitis C virus (HCV) has remained a challenge in patients with decompensated cirrhosis due to a paucity of information on efficacy and safety profiles. This review illustrates that interferon-free treatment could result in greater than 85 % sustained virological response (SVR) rates in patients with HCV genotype 1 and decompensated cirrhosis. The combination of pangenotypic HCV NS5A inhibitor velpatasvir and HCV NS5B inhibitor sofosbuvir has demonstrated high SVR rates in patients with HCV genotypes 1, 2, 3, 4 or 6 and decompensated cirrhosis. Certain patients discontinued treatment due to adverse events, death or having liver transplantation. Taken together, interferon-free treatment could produce higher SVR rates in decompensated hepatic cirrhosis. However, as adverse events were occasionally observed, liver transplantation should always be considered as well. Further improvements in treatment are called for in patients with decompensated cirrhosis.

Accelerating Drug Development: Antiviral Therapies for Emerging Viruses as a Model

Drug discovery and development is a lengthy and expensive process. Although no one, simple, single solution can significantly accelerate this process, steps can be taken to avoid unnecessary delays. Using the development of antiviral therapies as a model, we describe options for acceleration that cover target selection, assay development and high-throughput screening, hit confirmation, lead identification and development, animal model evaluations, toxicity studies, regulatory issues, and the general drug discovery and development infrastructure. Together, these steps could result in accelerated timelines for bringing antiviral therapies to market so they can treat emerging infections and reduce human suffering.

How hepatitis C patients manage the treatment process of pegylated interferon and ribavirin therapy: a qualitative study

BACKGROUND

Hepatitis C virus (HCV) infection is a global public health issue. Adequate treatment for hepatitis C patients is important, but anticipated side effects make patients fearful of receiving treatment. Little is known about the experiences of hepatitis C patients who have completed treatment with pegylated interferon and ribavirin. The purpose of this study was to explore the experiences of hepatitis C patients who had undergone therapy with pegylated interferon and ribavirin and gain an understanding of what factors contributed to completion of treatment.

METHOD

This was a qualitative study with 21 adult hepatitis C patients purposively sampled from outpatient liver clinics of a medical university hospital in Taichung City, Taiwan. Participants had completed 6-12 months of therapy with pegylated interferon and ribavirin. Data were collected through individual, face-to-face, in-depth interviews conducted in the participants' homes from June-October 2013. Data were analysed using conventional content analysis.

RESULTS

Data analysis revealed three themes that described the strategies employed to alleviate and ease symptoms and manage the processes involved: restructuring their lifestyle, adopting a positive attitude, and seeking support.

CONCLUSION

Hepatitis C patients face many challenges during treatment with pegylated interferon and ribavirin. These findings provide knowledge that can be used in designing effective programs to help other Hepatitis C patients manage the side effects of pegylated interferon and ribavirin therapy, complete treatment and improve quality of life.