Daclatasvir: a review of its use in adult patients with chronic hepatitis C virus infection

The ameliorating role of sofosbuvir and daclatasvir on thioacetamide-induced kidney injury in adult albino rats

Thioacetamide (TAA) exposure and hepatitis C virus infection are usually associated with renal dysfunction. Sofosbuvir (SFV) and daclatasvir (DAC) drugs combination has great value in the treatment of hepatitis C. The study aimed to identify the nephrotoxic effects of TAA and to evaluate the ameliorative role of SFV and DAC in this condition. Forty-eight adult male albino rats were divided into eight groups and received saline (control), SFV, DAC, SFV+DAC, TAA, TAA+SFV, TAA+DAC and TAA+SFV+DAC for eight weeks. Kidney and blood samples were retrieved and processed for histological (Hematoxylin and Eosin and Masson's trichrome), immunohistochemical (α-smooth muscle actin), and biochemical analysis (urea, creatinine, total protein, albumin, malondialdehyde, reduced glutathione, superoxide dismutase, and tumor necrosis factor-α). Examination revealed marked destruction of renal tubules on exposure to TAA with either hypertrophy or atrophy of glomeruli, increase in collagen deposition, and wide expression of α-smooth muscle actin. Also, significant disturbance in kidney functions, oxidative stress markers, and tumor necrosis factor-α. Supplementation with either SFV or DAC produced mild improvement in the tissue and laboratory markers. Moreover, the combination of both drugs greatly refined the pathology induced by TAA at the cellular and laboratory levels. However, there are still significant differences when compared to the control. In conclusion, SFV and DAC combination partially but greatly ameliorated the renal damage induced by TAA which might be enhanced with further supplementations to give new hope for those with nephropathy associated with hepatitis.

Comparative study of four innovative earth-friendly platforms for rapid analysis of daclatasvir dihydrochloride: Application on different matrices

BACKGROUND

Daclatasvir dihydrochloride has important roles not only in the management of COVID-19 pandemic symptoms but also in the treatment of chronic hepatitis C infection.

OBJECTIVE

The current research presents four novel and simple platforms including silver-nanoparticles spectrophotometric technique and three electrochemical conductometric ones for daclatasvir analysis in its tablet, biological fluids, and dissolution media.

METHODS

The spectrophotometric platform involved the synthesis of silvernanoparticles through a redox reaction between the reducing agent (daclatasvir) and the oxidizing agent (silver nitrate) in presence of polyvinylpyrrolidone as a stabilizing agent. The produced silver-nanoparticles have an intense surface plasmon resonance peak at 421 nm where the measured absorbance values were utilized for quantitative spectrophotometric determination of daclatasvir. While the electrochemical conductometric platforms involved the reaction of daclatasvir with three different precipitating reagents (silver nitrate, phosphomolybdic acid, and ammonium reineckate) to form ion associates between these reagents and daclatasvir in the aqueous system.

RESULTS

All proposed platforms were validated in line with recommendations of the international conference on harmonization producing satisfactory outcomes within the agreed boundaries.

CONCLUSION

The proposed platforms are green alternatives for routine rapid assay of daclatasvir at the cheapest cost because their results were observed to be nearly similar to those of the reported platform. Moreover, the suggested spectrophotometric platform's sensitivity can be employed for investigating daclatasvir bioequivalence.

Sofosbuvir with daclatasvir and the outcomes of patients with COVID-19: a systematic review and meta-analysis with GRADE assessment

PURPOSE

This systematic review and meta-analysis aimed to evaluate the effect of sofosbuvir/daclatasvir (SOF/DCV) on mortality, the need for intensive care unit (ICU) admission or invasive mechanical ventilation (IMV) and clinical recovery in patients with COVID-19.

METHODS

We performed a systematic literature search through the PubMed, Scopus and Embase from the inception of databases until 6 April 2021. The intervention group was SOF/DCV, and the control group was standard of care. The primary outcome was mortality, defined as clinically validated death. The secondary outcomes were (1) the need for ICU admission or IMV and (2) clinical recovery. The pooled effect estimates were reported as risk ratios (RRs).

RESULTS

There were four studies with a total of 231 patients in this meta-analysis. Three studies were randomised controlled trial, and one study was non-randomised. SOF/DCV was associated with lower mortality (RR: 0.31 (0.12, 0.78); p=0.013; I2: 0%) and reduced need for ICU admission or IMV (RR: 0.35 (0.18, 0.69); p=0.002; I2: 0%). Clinical recovery was achieved more frequently in the SOF/DCV (RR: 1.20 (1.04, 1.37); p=0.011; I2: 21.1%). There was a moderate certainty of evidence for mortality and need for ICU/IMV outcome, and a low certainty of evidence for clinical recovery. The absolute risk reductions were 140 fewer per 1000 for mortality and 186 fewer per 1000 for the need for ICU/IMV. The increase in clinical recovery was 146 more per 1000.

CONCLUSION

SOF/DCV may reduce mortality rate and need for ICU/IMV in patients with COVID-19 while increasing the chance for clinical recovery.

PROTOCOL REGISTRATION

PROSPERO: CRD42021247510.

Influence of Piperine and Omeprazole on The Regional Absorption of Daclatasvir from Rabbit Intestine

The study assessed the site dependent intestinal absorption of daclatasvir and investigated the effects of piperine and omeprazole on such absorption utilizing in situ rabbit intestinal perfusion technique. The intestinal absorption of daclatasvir was assessed in four segments: duodenum, jejunum, ileum, and colon. The effect of co-perfusion with omeprazole was monitored through the tested anatomical sites. The effect of piperine, a P-glycoprotein (P-gp) inhibitor on daclatasvir absorption from jejunum and ileum was tested. The results showed that daclatasvir was incompletely absorbed from the rabbit small and large intestine. The absorptive clearance per unit length (PeA/L) was site dependent and was ranked as colon > duodenum > jejunum > ileum. This rank is the opposite of the rank of P-gp intestinal content suggesting possible influence for P-gp. Co-perfusion with omeprazole increased PeA/L and this was evidenced also with reduced the L95% of daclatasvir from both small and large intestinal segments. Significant enhancement in daclatasvir absorption through jejunum and ileum was shown in presence of piperine. Daclatasvir showed site dependent intestinal absorption in a manner suggesting its affection by P-gp efflux. This effect was inhibited by piperine. Co-administration of daclatasvir with omeprazole can enhance intestinal absorption a phenomenon which requires extension to human pharmacokinetic investigation. This article is protected by copyright. All rights reserved.

Applying different spectroscopic techniques for the selective determination of daclatasvir using merbromin as a probe: Applications on pharmaceutical analysis

In this study, rapid resonance Rayleigh scattering (RRS), spectrophotometric, and spectrofluorimetric methods were performed for facile quantitation of daclatasvir dihydrochloride without interference from sofosbuvir (a co-formulated anti-hepatitis C virus drug). The proposed approaches were based on forming a binary complex between daclatasvir dihydrochloride and merbromin reagent at pH 4.1. The binary complex was measured spectrophotometrically at λ_max = 544 nm. The spectrofluorimetric approach relied on the quenching effect of daclatasvir dihydrochloride on the fluorescence strength of merbromin at λ_Emission = 545 nm. The RRS approach depended on augmentation in the merbromin RRS spectrum at 363 nm upon addition of daclatasvir dihydrochloride. The presented methodologies were linear over the concentration ranges 2.5-15.0, 0.2-1.6 and 0.15-3.0 μg ml^-1 with detection limits of 0.45, 0.046, and 0.036 μg ml^-1 for the spectrophotometric approach, the spectrofluorometric approach, and RRS approach, respectively. Current approaches were validated in compliance with International Council for Harmonisation guidelines and utilized practically to estimate daclatasvir dihydrochloride either in binary mixtures with sofosbuvir or in its commercial tablet dosage form with good results. Moreover, the test for content uniformity was applied successfully on commercial tablets using the current spectroscopic approaches.

Direct-acting antiviral interactions with opioids, alcohol or illicit drugs of abuse in HCV-infected patients

The hepatitis C virus (HCV) prevalence is extremely high in patients who consume and inject illicit drugs. Concerns about poor adherence and fear of interaction with drugs of abuse could constitute further disincentive for treatment initiation in these patients. We discussed the pharmacokinetics (PKs) and pharmacodynamics (PD) of currently prescribed direct antiviral agents (NSA5 inhibitors: daclatasvir, elbasvir, ledipasvir, pibrentasvir, velpatasvir; NS5B inhibitor: sofosbuvir; NS3/4A protease inhibitors: glecaprevir, grazoprevir, voxilaprevir) and most common substances of abuse (opioids: buprenorphine, fentanyl, heroin, methadone, morphine, oxycodone; stimulants: amphetamines, cathinones, cocaine; cannabinoids; ethanol). Overall, most direct-acting antivirals (DAAs) are substrates and inhibitors of the transmembrane transporter P-glycoprotein (P-gp), and several of them are metabolized by cytochrome P450 enzymes. Clinically relevant interactions are associated with P-gp and CYP3A modulators. Most substances of abuse are eliminated by Phase I and Phase II metabolizing enzymes, but none of them are either major inhibitors or inducers. PK studies did not show any relevant interactions between DAA and methadone or buprenorphine. Based on pharmacological considerations, neither efficacy loss nor adverse drug event associated with detrimental interaction are expected with opioids, stimulants, cannabinoids and ethanol. In summary, our literature review shows that the interaction potential of DAA with most opioids and illicit drugs is limited and should not be a hurdle to the initiate DAA.

Validated RP-HPLC Method for Simultaneous Determination of Ribavirin, Sofosbuvir and Daclatasvir in Human Plasma: A Treatment Protocol Administered to HCV Patients in Egypt

Egypt has the highest prevalence of hepatitis C virus (HCV) in the world thus it launched a national program for eliminating HCV aiming to treat 300,000 HCV patients per year. Three anti-HCV co-administered drugs; ribavirin (RBV), sofosbuvir (SF) daclatasvir (DAC) were simultaneously determined in human plasma by a validated, simple and sensitive RP-HPLC method using propyl paraben as an internal standard. Liquid-liquid extraction using ethyl acetate was used for samples extraction. Chromatographic separation was achieved on Scharlau® C18 column (250 × 4.6 mm2, 5 μm). Gradient elution was employed with a mobile phase mixture of water and acetonitrile at a flow rate 1 mL/min. UV detection using photodiode array detector was carried out at 207, 260 and 312 nm for RBV, SF and DAC, respectively. Method validation was performed according to the FDA guidelines for bioanalytical method validation. The calibration curves were linear over the ranges (0.5-80, 0.1-40 and 0.5-80 μg/mL) with average recoveries (100.64-108.28%, 98.48-105.91% and 97.68-101.38%) for RBV, SF and DAC, respectively. The intra-day and inter-day precision and accuracy results were within the acceptable limits. Stability assays revealed that the three studied analytes were stable during sample storage, preparation and injection. The method can be successfully applied in routine analysis of plasma of HCV patients treated with this combination therapy which aids in therapeutic drug monitoring and patients' follow-up especially in Egypt and other developing countries fighting HCV.

Micellar spectrofluorimetric protocol for the innovative determination of HCV antiviral (daclatasvir) with enhanced sensitivity: Application to human plasma and stability study

Daclatasvir dihydrochloride (DAC) is a new, direct-acting antiviral drug with powerful inhibitory effect against all hepatitis C virus (HCV) genotypes. A sensitive, simple, fast and specific fluorometric method for estimation of DAC in the presence of sofosbuvir was developed and validated. The method is based on reinforcement the fluorescence intensity of DAC by 170% of its original value in an aqueous solution of hexadecyl trimethyl ammonium bromide (pH 5.5, Teorell and Stenhagen buffer). The fluorescence intensity measurements were accomplished at 387 nm with 328 nm for excitation wavelength. A linear relationship was achieved between the DAC concentration and the fluorescence intensity in a range of 50.0-2000.0 ng ml^-1 with 0.9998 and 0.9999 for the determination and correlation coefficients, respectively. The detection and quantitation limits were 13.4, 40.8 ng ml^-1, respectively. The excellent sensitivity and specificity of the proposed method allowed the efficient estimation of DAC in real human plasma with adequate recovery (81.78 ± 1.57), and the selective determination for DAC in its commercial dosage form without interference from tablet excipient. Moreover, the proposed method was expanded to examine the stability of DAC by determination the parent drug of DAC in the presence of its oxidative, alkaline, acidic, UV, daylight and sunlight degradations products in agreement with ICH guidelines. Furthermore, the kinetic study of acidic and oxidative degradations of DAC was inspected. In addition, the half-life times of the reaction (t_1/2) and the first-order reaction rate constants were estimated. Moreover, a suggestion for the degradation pathway was supposed.

Sulfur(vi) fluoride exchange as a key reaction for synthesizing biaryl sulfate core derivatives as potent hepatitis C virus NS5A inhibitors and their structure-activity relationship studies

Extremely potent, new hepatitis C virus (HCV) nonstructural 5A (NS5A) featuring substituted biaryl sulfate core structures was designed and synthesized. Based on the previously reported novel HCV NS5A inhibitors featuring biaryl sulfate core structures which exhibit two-digit picomolar half-maximal effective concentration (EC50) values against HCV genotype 1b and 2a, the new inhibitors equipped with the sulfate core structures containing diversely substituted aryl groups were explored. In this study, highly efficient, chemoselective coupling reactions between an arylsulfonyl fluoride and an aryl silyl ether, known as the sulfur(vi) fluoride exchange (SuFEx) reaction, were utilized. Among the inhibitors prepared based on the SuFEx chemistry, compounds 14, 15 and 29 exhibited two-digit picomolar EC50 values against GT-1b and single digit or sub nanomolar activities against the HCV GT-2a strain. Nonsymmetrical inhibitors containing an imidazole and amide moieties on each side of the sulfate core structures were also synthesized. In addition, a biotinylated probe targeting NS5A protein was prepared for labeling using the same synthetic methodology.

Pharmacodynamic and pharmacokinetic evaluation of the combination of daclatasvir/sofosbuvir/ribavirin in the treatment of chronic hepatitis C

INTRODUCTION

The combination of daclatasvir (DCV), sofosbuvir (SOF), and ribavirin (RBV) is a direct-acting antiviral (DAA) regimen for the treatment of hepatitis C virus (HCV) infection. The inclusion of newer effective DAAs such as SOF and DCV with high efficacy and excellent tolerance introduced a new scenario in HCV infection therapy: high rates of sustained virological response (SVR), shorter therapies, less toxicity, and interferon-free treatments. This combination was approved for the treatment of HCV in treatment-naive or treatment-experienced patients with chronic HCV genotype 1 or 3 infection. Areas covered: This review summarizes the pharmacokinetics, pharmacodynamics, efficacy, and safety of DCV plus SOF and RBV therapy in the treatment of HCV infection. The topics include data regarding drug absorption, distribution, metabolism, excretion, and antiviral activity strategies, such as clinical dose selection and treatment duration. Expert opinion: This combination, taken orally with or without food, has an excellent pharmacokinetic and pharmacodynamic profile. DAC/SOF/RBV achieves very high rates of SVR in treatment-naive and treatment-experienced patients with chronic HCV infection, including difficult-to-treat patients such as those with compensated cirrhosis, post-transplant recurrence, or HIV-1 co-infection.

Pharmacokinetic and pharmacodynamic evaluation of daclatasvir, asunaprevir plus beclabuvir as a fixed-dose co-formulation for the treatment of hepatitis C

INTRODUCTION

Many reports have evaluated the clinical efficacy and safety of the fixed-dose all-oral combination of daclatasvir, asunaprevir, and beclabuvir (DCV-TRIO), which was approved in Japan in December 2016 for the treatment of hepatitis C genotype (GT)-1 infection. Areas covered: This article reviews the pharmacodynamic and pharmacokinetic properties of the DCV-TRIO combination. The topics covered include data regarding the drug's absorption, distribution, metabolism, excretion, and antiviral activity strategies. Its therapeutic efficacy and safety in GT-1 infection from phase 2/3 clinical trials are also discussed. Expert opinion: The ideal regimen for the treatment of Hepatitis C virus infection should be potent, pangenotypic, Ribavirin-free, safe, co-formulated, and affordable. Considering these characteristics, DCV-TRIO is neither pangenotypic nor potent enough against GT-1a, regardless of the presence or absence of cirrhosis. Other potential limitations of this regimen are its dosification (twice-daily), and the fact that since it includes a protease inhibitor, it is contraindicated in decompensated cirrhosis. For these reasons, it has only been approved in Japan, where more than 70% of the patients are infected with GT-1b. However, this co-formulation might still have a place in the treatment of non-cirrhotic patients infected with GT-1b provided that massive access to treatment is facilitated.

Vitamin D pathway gene polymorphisms affecting daclatasvir plasma concentration at 2 weeks and 1 month of therapy

AIM

Vitamin D (VD) influences genetic expression through its receptor (VDR). VD pathway gene polymorphisms seem to influence antiviral drug pharmacokinetics and therapeutic outcome/toxicity. We investigated the association between daclatasvir (DCV) plasma concentrations and genetic variants (SNPs) associated with the VD pathway.

PATIENTS & METHODS

Chronic hepatitis C patients treated with DCV from 2014 to 2016 were included. Genotypes were assessed through real-time PCR and plasma concentrations through liquid chromatography.

RESULTS

A total of 52 patients were analyzed. DCV levels were influenced by CYP24A1 rs2248359T>C polymorphism at 2 weeks and VDR Cdx2 A>G at 1 month of treatment. Linear regression analysis showed baseline BMI, alanine aminotransferase and hematocrit as significant predictors of DCV concentrations at 2 weeks, BMI and hematocrit at baseline, VDR Cdx2 AG/GG and FokI TC/CC at 1 month.

CONCLUSION

These results showed a possible role of VD pathway gene polymorphisms in influencing DCV plasma concentrations, but further studies are required.

Fibrosing Cholestatic Hepatitis C After Liver Transplantation: Therapeutic Options Before and After Introduction of Direct-Acting Antivirals: Our Experience and Literature Review

BACKGROUND

Cirrhosis caused by hepatitis C is the most common indication for liver transplantation. The most aggressive form of hepatitis C virus (HCV) relapse after liver transplantation is fibrosing cholestatic hepatitis C, which can be observed in 2% to 15% of recipients.

METHODS

Double therapy with peg-interferon and ribavirin was characterized by low antiviral response, rapid fibrosis, and frequent graft failure within 1 year after surgery.

RESULTS

Introduction of direct-acting antivirals for HCV treatment allows for more efficient therapy with less adverse reactions, including patients with fibrosing cholestatic hepatitis C.

CONCLUSIONS

We present 4 (2.5%) cases of cholestatic viral hepatitis C recurrence in patients undergoing transplantation between 2006 and 2015 at the Transplantation Institute of Warsaw; during this period, 158 liver transplants were performed in patients with cirrhosis caused by HCV infection.

Efficacy and safety of daclatasvir-based antiviral therapy in hepatitis C virus recurrence after liver transplantation. Role of cirrhosis and genotype 3. A multicenter cohort study

Direct-acting antiviral agents (DAA) combining daclatasvir (DCV) have reported good outcomes in the recurrence of hepatitis C virus (HCV) infection after liver transplant (LT). However, its effect on the severe recurrence and the risk of death remains controversial. We evaluated the efficacy, predictors of survival, and safety of DAC-based regimens in a large real-world cohort. A total of 331 patients received DCV-based therapy. Duration of therapy and ribavirin use were at the investigator's discretion. The primary end point was sustained virological response (SVR) at week 12. A multivariate analysis of predictive factors of mortality was performed. Intention-to-treat (ITT) and per-protocol SVR were 93.05% and 96.9%. ITT-SVR was lower in cirrhosis (n = 163) (96.4% vs. 89.6% P = 0.017); the SVR in genotype 3 (n = 91) was similar, even in advanced fibrosis (96.7% vs. 88%, P = 0.2). Ten patients (3%) experienced virological failure. Therapy was stopped in 18 patients (5.44%), and ten died during treatment. A total of 22 patients (6.6%) died. Albumin (HR = 0.376; 95% CI 0.155-0.910) and baseline MELD (HR = 1.137; 95% CI: 1.061-1.218) were predictors of death. DCV-based DAA treatment is efficacious and safe in patients with HCV infection after LT. Baseline MELD score and serum albumin are predictors of survival irrespective of viral response.

Interferon-free regimens in patients with hepatitis C infection and renal dysfunction or kidney transplantation

Treatment of patients with chronic kidney disease (CKD) and chronic hepatitis C (CHC) differs from that used in the general CHC population mostly when glomerular filtration rate (GFR) is below 30 mL/min, as sofosbuvir, the backbone of several current regimens, is officially contraindicated. Given that ribavirin free regimens are preferable in CKD, elbasvir/grazoprevir is offered in CHC patients with genotype 1 or 4 and ombitasvir/paritaprevir and dasabuvir in genotype 1b for 12 wk. Although regimens containing peginterferon with or without ribavirin are officially recommended for patients with CKD and genotype 2, 3, 5, 6, such regimens are rarely used because of their low efficacy and the poor safety and tolerance profile. In this setting, especially in the presence of advanced liver disease, sofosbuvir-based regimens are often used, despite sofosbuvir contraindication. It seems to have good overall safety with only 6% or 3.4% of CKD patients to discontinue therapy or develop serious adverse events without drug discontinuation. In addition, sustained virological response (SVR) rates with sofosbuvir based regimens in CKD patients appear to be comparable with SVR rates in patients with normal renal function. Treatment recommendations for kidney transplant recipients are the same with those for patients with CHC, taking into consideration potential drug-drug interactions and baseline GFR before treatment initiation. This review summarizes recent data on the current management of CHC in CKD patients highlighting their strengths and weaknesses and determining their usefulness in clinical practice.

Molecular simulations to delineate functional conformational transitions in the HCV polymerase

Hepatitis C virus (HCV) is a global health concern for which there is no vaccine available. The HCV polymerase is responsible for the critical function of replicating the RNA genome of the virus. Transitions between at least two conformations (open and closed) are necessary to allow the enzyme to replicate RNA. In this study, molecular dynamic simulations were initiated from multiple crystal structures to understand the free energy landscape (FEL) explored by the enzyme as it interconverts between these conformations. Our studies reveal the location of distinct states within the FEL as well as the molecular interactions associated with these states. Specific hydrogen bonds appear to play a key role in modulating conformational transitions. This knowledge is essential to elucidate the role of these conformations in replication and may also be valuable in understanding the basis by which this enzyme is inhibited by small molecules. © 2016 Wiley Periodicals, Inc.

Limiting the access to direct-acting antivirals against HCV: an ethical dilemma

Hepatitis C virus (HCV) infection affects about 200 million people worldwide and represents a leading cause of liver-related mortality. Eradication of HCV infection, achieved mainly through direct-acting antivirals (DAA), results in a decrease of mortality and an improvement of quality of life. These drugs have a maximal efficacy and an optimal tolerability. However, their high cost precludes a universal access even in wealthy countries. Areas covered: This article deals with the policies adopted for the use of the new anti-HCV drugs, especially in Europe and most of all in Italy, supposedly the developed country with the highest HCV prevalence. The literature search was performed using Pubmed and Web of Science. Moreover, national regulatory institutional websites were consulted. Expert commentary: The current policy of limitation to the access of the DAA presents a series of ethical issues that makes it non-applicable. A 'treat-all' strategy should resolve all ethical dilemmas, by virtue of the wide benefits of anti-HCV treatment not only for the advanced stage of infection, but also for the initial stages. A reduction in price of the drugs is the actual condition to achieve such a change.

Optimum combination therapy regimens for HIV/HCV infection

HIV-HCV co-infection mostly affects intravenous drug users, in whom prevalence has tended to decrease in recent years, while it has increased in men who have sex with men, with occurrence of acute hepatitis C. Hepatitis C has a poorer prognosis in patients co-infected with HIV, as clinical progression is faster and degree of hepatic fibrosis is greater. However, optimized ARV treatment is clearly associated with slower progression to hepatic complications. Interactions between HCV and HIV drugs are numerous, which underlines the importance of pharmacological advice for HIV-treated patients before they start HCV treatment. In HIV-HCV co-infection, treatment of hepatitis C has to be offered as in mono-infected patients (US and European countries) or to all patients (French guidelines). In most patients, HCV eradication is achieved with different DAA associations, the choice and duration being driven by HCV genotype, hepatic fibrosis stage, and whether patients have been previously treated or not.

Dual daclatasvir and sofosbuvir for treatment of genotype 3 chronic hepatitis C virus infection

Chronic hepatitis C virus (HCV) infection is one of the most common etiologies of liver-related mortality throughout the world. Traditionally, therapy has been focused on pegylated interferon in combination with ribavirin, with clinical trials demonstrating that HCV genotype 1 had the lowest response rate (40-50%), while genotype 3 had an intermediate response rate (60-70%). Recently, significant advances have been made with all-oral direct-acting antiviral (DAA) therapy, which have significantly improved cure rates for HCV genotype 1. Accordingly, HCV genotype 3 is now potentially the most difficult to treat. One of the most potent DAA medications is sofosbuvir, a pan-genotypic nucleotide analogue that inhibits the NS5B polymerase of HCV. Daclatasvir, a pan-genotypic inhibitor of the HCV NS5A replication complex, was recently approved in the United States for treatment of HCV genotype 3 in conjunction with sofosbuvir. This combination may provide a powerful tool in the treatment of HCV genotype 3.

New potent biaryl sulfate-based hepatitis C virus inhibitors

The discovery of a new series of potent hepatitis C virus (HCV) NS5A inhibitors containing biaryl sulfone or sulfate cores is reported. Structure-activity relationship (SAR) studies on inhibitors containing various substitution patterns of the sulfate or sulfone core structure established that m-,m'- substituted biaryl sulfate core-based inhibitors containing an amide moiety (compound 20) or an imidazole moiety (compound 24) showed extremely high potency. Compound 20 demonstrated double-digit pM potencies against both genotype 1b (GT-1b) and 2a (GT-2a). Compound 24 also exhibited double-digit pM potencies against GT-1b and sub nM potencies against GT-2a. Furthermore, compounds 20 and 24 exhibited no cardiotoxicity in an hERG ligand binding assay and showed acceptable plasma stability and no mutagenic potential in the Ames test. In addition, these compounds showed distinctive additive effects in combination treatment with the NS5B targeting drug sofosbuvir (Sovaldi^®). The results of this study showed that the compounds 20 and 24 could be effective HCV inhibitors.

Discovery of 1-((2R,4aR,6R,7R,7aR)-2-Isopropoxy-2-oxidodihydro-4H,6H-spiro[furo[3,2-d][1,3,2]dioxaphosphinine-7,2'-oxetan]-6-yl)pyrimidine-2,4(1H,3H)-dione (JNJ-54257099), a 3'-5'-Cyclic Phosphate Ester Prodrug of 2'-Deoxy-2'-Spirooxetane Uridine Triphosphate Useful for HCV Inhibition

JNJ-54257099 (9) is a novel cyclic phosphate ester derivative that belongs to the class of 2'-deoxy-2'-spirooxetane uridine nucleotide prodrugs which are known as inhibitors of the HCV NS5B RNA-dependent RNA polymerase (RdRp). In the Huh-7 HCV genotype (GT) 1b replicon-containing cell line 9 is devoid of any anti-HCV activity, an observation attributable to inefficient prodrug metabolism which was found to be CYP3A4-dependent. In contrast, in vitro incubation of 9 in primary human hepatocytes as well as pharmacokinetic evaluation thereof in different preclinical species reveals the formation of substantial levels of 2'-deoxy-2'-spirooxetane uridine triphosphate (8), a potent inhibitor of the HCV NS5B polymerase. Overall, it was found that 9 displays a superior profile compared to its phosphoramidate prodrug analogues (e.g., 4) described previously. Of particular interest is the in vivo dose dependent reduction of HCV RNA observed in HCV infected (GT1a and GT3a) human hepatocyte chimeric mice after 7 days of oral administration of 9.