NS3 protease inhibitors for treatment of chronic hepatitis C: Efficacy and safety

Finding Lead Compounds for Dengue Antivirals from a Collection of Old Drugs through In Silico Target Prediction and Subsequent In Vitro Validation

Dengue virus (DENV) infection is one of the most widely spread flavivirus infections. Despite the fatality it could cause, no antiviral treatment is currently available to treat the disease. Hence, this study aimed to repurpose old drugs as novel DENV NS3 inhibitors. Ligand-based (L-B) and proteochemometric (PCM) prediction models were built using 62,354 bioactivity data to screen for potential NS3 inhibitors. Selected drugs were then subjected to the foci forming unit reduction assay (FFURA) and protease inhibition assay. Finally, molecular docking was performed to validate these results. The in silico studies revealed that both models performed well in the internal and external validations. However, the L-B model showed better accuracy in the external validation in terms of its sensitivity (0.671). In the in vitro validation, all drugs (zileuton, trimethadione, and linalool) were able to moderately inhibit the viral activities at the highest concentration tested. Zileuton showed comparable results with linalool when tested at 2 mM against the DENV NS3 protease, with a reduction of protease activity at 17.89 and 18.42%, respectively. Two new compounds were also proposed through the combination of the selected drugs, which are ziltri (zilueton + trimethadione) and zilool (zileuton + linalool). The molecular docking study confirms the in vitro observations where all drugs and proposed compounds were able to achieve binding affinity ≥ -4.1 kcal/mol, with ziltri showing the highest affinity at -7.7 kcal/mol, surpassing the control, panduratin A. The occupation of both S1 and S2 subpockets of NS2B-NS3 may be essential and a reason for the lower binding energy shown by the proposed compounds compared to the screened drugs. Based on the results, this study provided five potential new lead compounds (ziltri, zilool, zileuton, linalool, and trimethadione) for DENV that could be modified further.

Safety of direct antiviral agents for treatment of hepatitis C virus infection

Antiviral drugs for treatment of hepatitis C have grown dramatically in recent years. The emergence of direct antiviral agents (DAAs) is a major advance in hepatitis C treatment. Since the first generation DAAs appeared in 2011, two more generations of DAAs have been approved by the Food and Drug Administration in only five years. With the advantages of coverage of all genotypes, high availability and easy administration, DAAs have been widely used worldwide in recent years. DAAs have nearly solved the main problems encountered in hepatitis C antiviral therapy. However, adverse events associated with DAAs use have been reported constantly, and the safety of DAAs has attracted more and more attention. According to recent reports, the adverse reactions of DAAs have been gradually reduced from the first generation to the third generation. When combined with other drugs, the drug-drug interactions (DDIs) need special attention. In addition, the usage of DAAs in special patient groups should be cautious. In this paper, we will summarize the adverse effects and DDIs of DAAs as well as their usage in the general population and special patient groups.

[Topical problems of antiviral therapy for chronic hepatitis C]

Antiviral therapy using interferon-free regimens for chronic hepatitis C (CHC) is being more frequently practiced by hepatologists due to the high efficiency of a short treatment cycle and the lowest rate of adverse events. The review discusses the most topical problems that will present themselves in practicing hematologists when treating patients with CHC under the present-day conditions. The use of direct-acting antiviral drugs requires knowledge and skills for physicians to orient themselves in the list of these drugs to create their based regimens, the efficiency and safety of which are proven in the context of evidence-based medicine. The review gives data on the efficiency and safety of 3D therapy for CHC according to the baseline characteristics of patients.

Hepatitis C virus: Virology, diagnosis and treatment

More than twenty years of study has provided a better understanding of hepatitis C virus (HCV) life cycle, including the general properties of viral RNA and proteins. This effort facilitates the development of sensitive diagnostic tools and effective antiviral treatments. At present, serologic screening test is recommended to perform on individuals in the high risk groups and nucleic acid tests are recommended to confirm the active HCV infections. Quantization and genotyping of HCV RNAs are important to determine the optimal duration of anti-viral therapy and predict the likelihood of response. In the early 2000s, pegylated interferon plus ribavirin became the standard anti-HCV treatment. However, this therapy is not ideal. To 2014, boceprevir, telaprevir, simeprevir, sofosbuvir and Harvoni are approved by Food and Drug Administration for the treat of HCV infections. It is likely that the new all-oral, interferon-free, pan-genotyping anti-HCV therapy will be available within the next few years. Majority of HCV infections will be cured by these anti-viral treatments. However, not all patients are expected to be cured due to viral resistance and the high cost of antiviral treatments. Thus, an efficient prophylactic vaccine will be the next challenge in the fight against HCV infection.

HIV and HCV Medications in End-Stage Renal Disease

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