Components of the phosphatidylserine endoplasmic reticulum to plasma membrane transport mechanism as targets for KRAS inhibition in pancreatic cancer.

KRAS is mutated in 90% of human pancreatic ductal adenocarcinomas (PDACs). To function, KRAS must localize to the plasma membrane (PM) via a C-terminal membrane anchor that specifically engages phosphatidylserine (PtdSer). This anchor-binding specificity renders KRAS-PM localization and signaling capacity critically dependent on PM PtdSer content. We now show that the PtdSer lipid transport proteins, ORP5 and ORP8, which are essential for maintaining PM PtdSer levels and hence KRAS PM localization, are required for KRAS oncogenesis. Knockdown of either protein, separately or simultaneously, abrogated growth of KRAS-mutant but not KRAS-wild-type pancreatic cancer cell xenografts. ORP5 or ORP8 knockout also abrogated tumor growth in an immune-competent orthotopic pancreatic cancer mouse model. Analysis of human datasets revealed that all components of this PtdSer transport mechanism, including the PM-localized EFR3A-PI4KIIIα complex that generates phosphatidylinositol-4-phosphate (PI4P), and endoplasmic reticulum (ER)-localized SAC1 phosphatase that hydrolyzes counter transported PI4P, are significantly up-regulated in pancreatic tumors compared to normal tissue. Taken together, these results support targeting PI4KIIIα in KRAS-mutant cancers to deplete the PM-to-ER PI4P gradient, reducing PM PtdSer content. We therefore repurposed the US Food and Drug Administration-approved hepatitis C antiviral agent, simeprevir, as a PI4KIIIα inhibitor In a PDAC setting. Simeprevir potently mislocalized KRAS from the PM, reduced the clonogenic potential of pancreatic cancer cell lines in vitro, and abrogated the growth of KRAS-dependent tumors in vivo with enhanced efficacy when combined with MAPK and PI3K inhibitors. We conclude that the cellular ER-to-PM PtdSer transport mechanism is essential for KRAS PM localization and oncogenesis and is accessible to therapeutic intervention.

Inhibitory effects of simeprevir on Staphylococcusepidermidis and itsbiofilm in vitro. / è¥¿å’ªåŒ¹éŸ¦å¯¹è¡¨çš®è‘¡è„çƒèŒåŠå ¶ç”Ÿç‰©è†œçš„ä½“å¤–æŠ‘åˆ¶ä½œç”¨.

OBJECTIVES: Staphylococcus epidermidis (S. epidermidis) is a Gram-positive opportunistic pathogen that often causes hospital infections. With the abuse of antibiotics, the resistance of S. epidermidis gradually increases, and drug repurposing has become a research hotspot in the treating of refractory drug-resistant bacterial infections. This study aims to study the antimicrobial and antibiofilm effects of simeprevir, an antiviral hepatitis drug, on S. epidermidis in vitro. METHODS: The micro-dilution assay was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of simeprevir against S. epidermidis. Crystal violet staining assay was used to detect the biofilm inhibitory effect of simeprevir. The antimicrobial activity of simeprevir against S. epidermidis and its biofilm were explored by SYTO9/PI fluorescent staining. The combined effect between simeprevir and gentamycin was assessed by checkerboard assay and was confirmed by time-inhibition assay. RESULTS: Simeprevir showed significant antimicrobial effects against S. epidermidis type strains and clinical isolates with the MIC and MBC at 2-16 µg/mL and 4-32 µg/mL, respectively. The antimicrobial effects of simeprevir were confirmed by SYTO9/PI staining. Simeprevir at MIC could significantly inhibit and break the biofilm on cover slides. Similarly, simeprevir also significantly inhibit the biofilm formation on the surface of urine catheters either in TSB [from (0.700±0.020) to (0.050±0.004)] (t=54.03, P<0.001), or horse serum [from (1.00±0.02) to (0.13±0.01)] (t=82.78, P<0.001). Synergistic antimicrobial effect was found between simeprevir and gentamycin against S. epidermidis with the fractional inhibitory concentration index of 0.5. CONCLUSIONS: Simeprevir shows antimicrobial effect and anti-biofilm activities against S. epidermidis.

Anti-hepatitis C virus drug simeprevir: a promising antimicrobial agent against MRSA.

Staphylococcus aureus is a major human pathogen, and the appearance of methicillin-resistant S. aureus (MRSA) renders S. aureus infections more challenging to treat. Therefore, new antimicrobial drugs are urgently needed to combat MRSA infections. Drug repurposing is an effective and feasible strategy. Here, we reported that the clinically approved anti-hepatitis C virus drug simeprevir had strong antibacterial activity against MRSA, with a minimum inhibitory concentration of 2-8 µg/mL. Simeprevir did not easily induce in vitro resistance. In addition, simeprevir significantly prevented S. aureus biofilm formation. Furthermore, simeprevir displayed limited toxicity in in vitro and in vivo assays. Moreover, simeprevir showed synergistic antimicrobial effects against both type and clinical strains of S. aureus. Simeprevir combined with gentamicin effectively reduced the bacterial burden in an MRSA-infected subcutaneous abscess mouse model. Results from a series of experiments, including membrane permeability assay, membrane potential assay, intracellular ATP level assay, and electron microscope observation, demonstrated that the action of simeprevir may be by disrupting bacterial cell membranes. Collectively, these results demonstrated the potential of simeprevir as an antimicrobial agent for the treatment of MRSA infections. KEY POINTS: • Simeprevir showed strong antibacterial activity against MRSA. • The antibacterial mechanism of simeprevir was mediated by membrane disruption and intracellular ATP depletion. • In vitro and in vivo synergistic antimicrobial efficacy between simeprevir and gentamicin was found.

Antiviral drug design based on the opening mechanism of spike glycoprotein in SARS-CoV-2.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters the host cell after the receptor binding domain (RBD) of the virus spike (S) glycoprotein binds to the human angiotensin-converting enzyme 2 (hACE2). This binding requires the RBD to undergo a conformational change from a closed to an open state. In the present study, a key pair of salt bridges formed by the side chains of K537 and E619, residues at the interfaces of SD1 and SD2, respectively, was identified to promote the opening of the RBD. Mutations of K537Q and E619D reduced their side chain lengths and eliminated this pair of salt bridges; as a result, the opening of the RBD was not observed in the MD simulations. Thus, blocking the formation of this pair of salt bridges is a promising approach for treating novel coronavirus disease 2019 (COVID-19). FDA approved drug molecules were screened by their capabilities of blocking the formation of the key pair of salt bridges, achieved by their positional stabilities in the cavity containing the side chains of K537 and E619 formed in the interface between SD1 and SD2. Simeprevir, imatinib, and naldemedine were identified to possess the desired capability with the most favorable interaction energies.

Evaluation of the genetic toxicity of sofosbuvir and simeprevir with and without ribavirin in a human-derived liver cell line.

Direct-acting antivirals have revolutionized the treatment of chronic hepatitis C. Sofosbuvir and simeprevir are prescribed worldwide. However, there is a scarcity of information regarding their genotoxicity. Therefore, the present study assessed the cytotoxic and genotoxic effects of sofosbuvir and simeprevir, alone and combined with ribavirin. HepG2 cells were analyzed using the in vitro cytokinesis-block micronucleus cytome assay. Cells were treated for 24 h with sofosbuvir (0.011-1.511 mM), simeprevir (0.156-5.0 µM), and their combinations with ribavirin (0.250-4.0 mM). No significant differences were observed in the nuclear division cytotoxicity index, reflecting the absence of cytotoxic effects associated to sofosbuvir. However, the highest concentration of simeprevir showed a significant difference for the nuclear division cytotoxicity index. Moreover, significant results were observed for nuclear division cytotoxicity index in two combinations of sofosbuvir plus ribavirin and only in the highest combination of simeprevir plus ribavirin. Additionally, our results showed that sofosbuvir did not increase the frequency of chromosomal damage, but simeprevir significantly increased the frequency of micronuclei at the highest concentrations. The combination index demonstrated that both sofosbuvir and simeprevir produced antagonism to the genotoxic effects of ribavirin. In conclusion, our results showed that simeprevir, but not sofosbuvir, has genotoxic effects in HepG2 cells.

Repurposing of FDA-approved drugs as inhibitors of sterol C-24 methyltransferase of Leishmania donovani to fight against leishmaniasis.

Leishmaniasis is a vector-borne disease caused by around 20 species of Leishmania. The main clinical forms of leishmaniasis are cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL). VL is caused by Leishmania infantum in Central and South America, Mediterranean Basin, Middle East, and by L. donovani in Asia and Africa. Sterol C-24 methyltransferase (LdSMT) of L. donovani is a transferase enzyme of the sterol biosynthesis pathway. This pathway is one of the major targets for drug developments in Leishmania. Due to insufficient evidence about the exact function of SMT inside the cell and the uniqueness of the SMT enzyme in the Leishmania parasites made it a significant target for an effective drug development approach. We performed virtual screening of the Food and Drug Administration (FDA)-approved drug library against LdSMT and found simeprevir, an antiviral drug on top in the binding score. It showed a significant binding affinity with LdSMT. The binding was supported by hydrogen bonds and several other interactions. Simeprevir inhibited L. donovani growth of promastigotes with 50% inhibitory concentration (IC50 ) of 51.49 ± 5.87 µM. Further studies showed that simeprevir induced ROS generation in 44.7% of parasites at 125-µM concentration. Here, we for the first time reported simeprevir as an antileishmanial lead molecule using a drug repurposing approach.

JNJ-4178 (AL-335, Odalasvir, and Simeprevir) for 6 or 8 Weeks in Hepatitis C Virus-Infected Patients Without Cirrhosis: OMEGA-1.

The combination of three direct-acting antiviral agents (AL-335, odalasvir, and simeprevir: JNJ-4178 regimen) for 6 or 8 weeks demonstrated good efficacy and safety in a phase IIa study in chronic hepatitis C virus (HCV) genotype (GT)-1-infected patients without cirrhosis and has now been evaluated in a larger phase IIb study, OMEGA-1. This multicenter, randomized, open-label study (NCT02765490) enrolled treatment-naïve and interferon (±ribavirin) treatment-experienced patients with HCV GT1, 2, 4, 5, or 6 infection. Patients with HCV GT3 infection and/or liver cirrhosis were excluded. Patients received AL-335 800 mg, odalasvir 25 mg, and simeprevir 75 mg once daily for 6 or 8 weeks. The primary endpoint was sustained virologic response 12 weeks after the end of treatment (SVR12). In total, 365 patients (GT1a, 29.3%; GT1b, 42.5%; GT2, 12.3%; GT4, 14.2%; GT5, 1.4%; GT6, 0%) were randomized to receive 6 weeks (n = 183) or 8 weeks (n = 182) of treatment. SVR12 rates after 6 weeks (98.9%) or 8 weeks (97.8%) of treatment were noninferior to a historical control (98%). Viral relapse occurred in 5 patients (1.4%; 4 with HCV GT2c; 1 with GT1a). With the exception of 4 patients in the 8-week group, including 3 patients with missing data at the SVR24 timepoint, all patients who achieved SVR12 also achieved SVR24. One GT1a-infected patient experienced late viral relapse after achieving SVR18. Most adverse events (AEs) were mild with no treatment-related serious AEs. All randomized patients completed treatment. Conclusion: In HCV-infected patients, 6 and 8 weeks of treatment with JNJ-4178 resulted in SVR12 rates of 98.9% and 97.8%, respectively, and was well tolerated.

High success rates for the use of sofosbuvir/ombitasvir/paritaprevir/ritonavir + ribavirin and sofosbuvir/simeprevir/daclatasvir + ribavirin in retreatment of chronic hepatitis C infection after unsuccessful sofosbuvir/daclatasvir therapy: a real-life experience.

The aim of this work was assessment of the efficacy and tolerability of two different regimens for retreatment of hepatitis C virus (HCV) patients who failed to respond to SOF/DCV-based therapy. This prospective study included 104 HCV patients who failed to respond to SOF/DCV-based therapy. Patients were randomly allocated to two groups. Efficacy and tolerability were assessed. The 12-week sustained virological response (SVR12) rates were 96% and 94.4% in groups B and A, respectively, with no significant difference (p = 1.000). Most adverse events reported were mild to moderate, with no deaths during the study. Multi-target direct-acting antiviral (DAA) combinations are efficient for retreatment of HCV patients after failure of SOF/DCV-based therapy in real-world management.ClinicalTrials.gov identifier: NCT02992457.

Estimating Efflux Transporter-Mediated Disposition of Molecules beyond the Rule of Five (bRo5) Using Transporter Gene Knockout Rats.

Transporter gene knockout models are a practical and widely used tool for pharmacokinetic studies in drug discovery. P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) are major efflux transporters that control absorption and bioavailability, and are important when determining oral drug disposition. To the best of our knowledge, beyond the rule of five (bRo5) molecules launched on the market to date tend to be substrates for efflux transporters. The purpose of this study is to evaluate in vivo the impact of efflux transporters on the oral absorption process and systemic clearance using rats which lack P-gp and/or Bcrp expression. We administered five bRo5 substrates (asunaprevir, cyclosporine, danoprevir, ledipasvir, and simeprevir) intravenously or orally to wild-type and Mdr1a, Bcrp, and Mdr1a/Bcrp knockout rats, calculated the clearance, oral bioavailability, and absorption rate profile of each substrate, and compared the results. Systemic clearance of the substrates in knockout rats changed within approximately ±40% compared to wild-types, suggesting the efflux transporters do not have a significant influence on clearance in rats. On the other hand, the oral absorption of substrates in the knockout rats, especially those lacking Mdr1a, increased greatly-between 2- and 5-fold more than in wild-types. This suggests that rat efflux transporters, especially P-gp, greatly reduce the oral exposure of these substrates. Moreover, results on the absorption rate-time profile suggest that efflux transporters are constantly active during the absorption period in rats. Transporter knockout rats are a useful in vivo tool for estimating the transporter-mediated disposition of bRo5 molecules in drug discovery.

Microenvironment improvement protocol for the sensitive spectrofluorimetric determination of an hepatitis C virus antiviral (Simeprevir): application to human plasma.

Simeprevir (SPV) is a powerful antihepatitis C virus agent that was newly introduced into the pharmaceutical market. We here established and validated an easy, simple, and sensitive spectrofluorimetric method for its estimation at λem 427 nm (λex 337 nm). The suggested procedure was based on two times enhancement in the original emission of SPV through modifying its microenvironment in buffered aqueous solution by adding Triton X-100. The relationship between the concentration of SPV and the observed fluorescence intensity was linear in the range 0.06-1.0 µg ml-1 with a correlation coefficient of 0.9997. The limits of detection and quantitation were 21 and 64 ng ml-1 , respectively. The present method was effectively applied to quantify SPV content in pharmaceutical tablets and human plasma spiked with the drug with no interference from tablet excipients or plasma components.

Validated Reversed-Phase Liquid Chromatographic Method with Gradient Elution for Simultaneous Determination of the Antiviral Agents: Sofosbuvir, Ledipasvir, Daclatasvir, and Simeprevir in Their Dosage Forms.

A simple, rapid, sensitive, and precise reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of four direct-acting antivirals, sofosbuvir (SF), ledipasvir (LD), declatasvir (DC), and simeprevir (SM), in their respective pharmaceutical formulations. Effective chromatographic separation was achieved on an Agilent Eclipse plus C8 column (250 mm × 4.6 mm, 5 µm) at 40 °C with gradient elution using a mobile phase composed of acetonitrile:phosphate buffer (pH 6.5). The quantification of SF and DC was based on peak area measurements at 260 nm, while the quantification of LD and SM was achieved at 330 nm. The linearity was acceptable from 1.0 to 20.0 µg/mL for the studied drugs, with correlation coefficients >0.999. The analytical performance of the newly proposed HPLC procedure was thoroughly validated according to ICH guidelines in terms of linearity, precision (RSD%, 0.39-1.57), accuracy (98.05-101.90%), specificity, limit of detection (LOD) (0.022-0.039 µg/mL), limit of quantification (LOQ) (0.067-0.118 µg/mL), and robustness. The validated HPLC method was successfully used to analyze the abovementioned drugs in their pure and dosage forms without interference from common excipients present in commercial formulations.

Sofosbuvir-Based Therapy in Hepatitis C Virus-Infected Cancer Patients: A Prospective Observational Study.

BACKGROUND: Data are sparse on treatment of chronic hepatitis C virus (HCV) in cancer patients. We evaluated the efficacy and safety of sofosbuvir-based therapy (SOFBT) in cancer patients. METHODS: Patients treated with SOFBT at our center during 2014-2017 were included in a prospective observational study. Efficacy [sustained virologic response at 12 weeks after the end of treatment (SVR12)], cancer-related outcomes and adverse events (AEs) were assessed. RESULTS: We included 153 patients. Most were men (109; 71%), white (92; 60%), non-cirrhotic (105; 69%), and with HCV genotype 1 (110; 72%). The most common cancers were hepatocellular carcinoma (HCC) (27; 18%) and multiple myeloma (14; 9%). The overall SVR12 rate was 91% (128/141). SVR12 was 100% in patients treated with ledipasvir/sofosbuvir for 8 weeks. Of the 32 patients initially excluded from cancer clinical trials because of HCV, 27 (84%) were granted cancer therapy access after starting SOFBT. Six patients with indolent non-Hodgkin's lymphoma (NHL) received SOFBT without cancer treatment. Two achieved complete remission, one had partial remission, and two had stable cancer. Within 6 months after SOFBT, 5% (6/121) of patients in remission or with stable cancer, had progression or recurrence (two with HCC and one each with esophageal cancer, cholangiocarcinoma, NHL, and tonsillar cancer). No de novo HCCs occurred. AEs were most commonly grade 1-2 (90%). CONCLUSIONS: SOFBT in HCV-infected cancer patients is effective and safe, may permit access to investigational cancer therapy expanding treatment options, may induce remission of NHL, and may be used for 8 weeks.

Short-Duration AL-335, Odalasvir, With or Without Simeprevir, in Patients With HCV GT1 or 3 Infection Without Cirrhosis.

This open-label, phase IIa study assessed the safety, pharmacokinetics, and efficacy of direct-acting antiviral agent (DAA) regimens in patients with chronic hepatitis C virus (HCV) infection. Multiple 6-12-week oral regimens of 400-800 mg once daily (QD) AL-335 + 50 mg QD/every other day odalasvir ± 75-150 mg QD simeprevir were evaluated in treatment-naïve, HCV genotype (GT)1/3-infected patients without cirrhosis. Safety/pharmacokinetic parameters, HCV-RNA, and sequencing data were assessed. Treatment regimens for later study cohorts were adjusted based on emerging data. In total, 112 patients were enrolled. Three serious treatment-emergent adverse events occurred, one of which (a Mobitz type 1 second-degree atrioventricular block [Wenckebach]) was possibly related to high odalasvir exposure and resulted in premature discontinuation of study drugs. No other clinically significant safety findings were identified. GT1-infected patients receiving 3-DAA for 6-8 weeks achieved 100% sustained virologic response 12 weeks and 24 weeks after the end of treatment (sustained virologic response [SVR12/24]). GT1-infected patients receiving 2-DAA or GT3-infected patients receiving 3-DAA had SVR12/24 less than 90%, whether treated for 8 weeks or 12 weeks. Virologic failure was associated with the emergence of generally persistent NS5A and/or transient NS5B resistance-associated substitutions in most patients. Pharmacokinetic characteristics of the three drugs were also elucidated. Conclusions: In treatment-naïve subjects without cirrhosis, AL-335 + odalasvir + simeprevir for 6-8 weeks was generally safe and highly efficacious against HCV GT1. However, inadequate efficacy was observed for the 2-DAA regimen in GT1-infected subjects and the 3-DAA regimen in GT3-infected subjects.

Ring-Closing Metathesis on Commercial Scale: Synthesis of HCV Protease Inhibitor Simeprevir.

The key macrocyclization step in the synthesis of simeprevir, a hepatitis C virus (HCV) antiviral drug, was studied. N-Boc substitution on the diene precursor changes the site of insertion of the metathesis catalyst and, consequently, the kinetic model of the ring closing metathesis (RCM), enabling a further increase in the macrocyclization efficiency under simulated high dilution (SHD) conditions. NMR of the inserted species of both first and second generation RCM catalysts are reported and discussed.

Safety and efficacy of the combination simeprevir-sofosbuvir in HCV genotype 1- and 4-mono-infected patients from the French ANRS CO22 hepather cohort.

BACKGROUND: Although real-life results of sofosbuvir/simeprevir have been extensively reported from the United States, data from other geographical areas are limited. In the French observational cohort, ANRS CO22 HEPATHER, 9432 patients were given the new oral antivirals from December 2013 to June 30, 2018. We report the results of sofosbuvir/simeprevir in genotypes 1- and 4-infected patients. METHODS: Demographics and history of liver disease were collected at entry in the cohort. Clinical, adverse events, and virological data were collected throughout treatment and post-treatment follow-up. The choice of treatment duration or addition of ribavirin was left up to the physician. RESULTS: Five hundred ninety-nine HCV (467 genotype 1 and 132 genotype 4) mono-infected, naïve for all oral-DAAs regimen patients were given sofosbuvir/simeprevir with (n = 63) or without ribavirin (n = 536) for 12 or 24 weeks; 56% had cirrhosis (4% decompensated) and 71% had prior treatment failure to interferon-based regimen. 7 patients (1.16%) were lost to follow-up. The overall SVR12 rate was 92.6%. The SVR12 was 90% in GT1a, 94.2% in GT1b and 91.6% in GT4 with no significant difference for genotype, treatment duration or ribavirin addition. Severity of liver disease was not associated with a lower SVR12 rate on multivariate analysis but was associated with a higher rate of severe side effects. Early treatment discontinuations were rare; no new safety signals were reported. CONCLUSION: In this real life, observational, prospective cohort study, the 12-week sofosbuvir/simeprevir+/-ribavirin combination appears to be efficient and safe. TRIAL REGISTRATION: Trial registration with ClinicalTrials.gov NCT01953458 .

Impact of hepatitis C virus and direct acting antivirals on kidney recipients: a retrospective study.

Hepatitis C virus (HCV) in kidney transplanted patients (KTx-p) carries a high risk for a worse outcome. This retrospective study evaluates the impact of HCV and of the new direct acting antivirals (DAAs) on patient and graft outcomes in KTx patients. Forty (6.5%) of the 616 KTx-p, who received a kidney transplantation (KTx) in our Centre had antibodies against HCV: 13 were positive for HCV RNA and received DAAs (Group A); 11 were HCV RNA positive and did not receive any treatment (Group B; n = 11); 16 were negative for HCV RNA (Group C). All Group A patients had HCV RNA negativity after 12 weeks of treatment, and 12 (92.30%) achieved a sustained virological response (SVR). Only two patients, who had proteinuria greater than 500 mg/day showed a worsening of proteinuria after antiviral therapy in Group A. Liver enzyme elevation and death were significantly more frequent in Group B than other groups. Our results support the notion that active HCV infection negatively affects kidney recipients and that DAA have a high safety and efficacy profile after KTx with no significant negative effect on allograft function, particularly in well-functioning renal grafts.

Direct antiviral therapy for treatment of hepatitis C: A real-world study from Brazil.

INTRODUCTION AND OBJECTIVES: Direct antiviral agents (DAAs) including sofosbuvir (SOF), daclatasvir (DCV), simeprevir (SIM) and ombitasvir, paritaprevir and dasabuvir were introduced 2015 in Brazil for treatment of hepatitis C virus (HCV) infection. The aims of this study were to assess effectiveness and safety of HCV treatment with DAA in real-life world in a highly admixed population from Brazil. MATERIALS AND METHODS: All Brazilian reference centers for HCV treatment were invited to take part in a web-based registry, prospectively conducted by the Brazilian Society of Hepatology, to assess outcomes of HCV treatment in Brazil with DAAs. Data to be collected included demographics, disease severity and comorbidities, genotype (GT), viral load, DAA regimens, treatment side effects and sustained virological response (SVR). RESULTS: 3939 patients (60% males, mean age 58±10 years) throughout the country were evaluated. Most had advanced fibrosis or cirrhosis, GT1 and were treated with SOF/DCV or SOF/SIM. Overall SVR rates were higher than 95%. Subjects with decompensated cirrhosis, GT2 and GT3 have lower SVR rates of 85%, 90% and 91%, respectively. Cirrhosis and decompensated cirrhosis in GT1 and male sex and decompensated cirrhosis in GT3 were significantly associated with no SVR. Adverse events (AD) and serious AD occurred in 18% and 5% of those subjects, respectively, but less than 1% of patients required treatment discontinuation. CONCLUSION: SOF-based DAA regimens are effective and safe in the heterogeneous highly admixed Brazilian population and could remain an option for HCV treatment at least in low-income countries.

Effects of Age on Treatment of Chronic Hepatitis C with Direct Acting Antivirals.

INTRODUCTION AND AIM: Data on the efficacy and tolerance of interferon-free treatment in chronic hepatitis C (CHC) in elderly patients are limited in phase II-III trials. MATERIAL AND METHODS: A prospective cohort of adult patients with CHC treated in French general hospitals. RESULTS: Data from 1,123 patients, distributed into four age groups, were analyzed. Of these, 278 were > 64 years old (fourth quartile) and 133 were > 73 years old (tenth decile). Elderly patients weighed less, were more frequently treatment-experienced women infected with genotype 1b or 2, while they less frequently had genotype 3 or HIV coinfection, but had more frequent comorbidities and drug consumption. Half of the patients had cirrhosis, whatever their ages. The main treatment regimens were sofosbuvir/ledipasvir (37.8%), sofosbuvir/daclatasvir (31.8%), sofosbuvir/simeprevir (16.9%), sofosbuvir/ribavirin (7.8%); ribavirin was given to 24% of patients. The overall sustained virological response (SVR) rate was 91.0 % (95% CI: 89.292.5%) with no difference according to age. Logistic regression of the independent predictors of SVR were albumin, hepatocellular carcinoma and treatment regimen, but not age. The rate of severe adverse events (66 in 59/1062 [5.6%] patients) tended to be greater in patients older than 64 years of age (21/261,8.1%), but the only independent predictors of SAE by logistic regression were cirrhosis and baseline hemoglobin. Patient-reported overall tolerance was excellent in all age groups, and patient-reported fatigue decreased during and after treatment, independent of age. CONCLUSIONS: The high efficacy and tolerance of interferon-free regimens is confirmed in elderly patients in real-life conditions.

Efficacy, Safety, and Predictors of Direct-acting antivirals in Hepatitis C Virus Patients with Heterogeneous Liver Diseases.

Safety, efficacy, and predictor factors of sustained-virological-response after 24 weeks of new direct-acting antivirals were evaluated in hepatitis C virus patients with different stages of hepatic disease. 260 patients, median age 60 years, of whom 48.1% cirrhotics, 17.7% liver transplant recipients, and 45.7% naïve were treated with Sofosbuvir+Ribavirine, Sofosbuvir+Simeprevir±Ribavirine, Sofosbuvir+Daclatasvir± Ribavirine, Sofosbuvir+Ledispavir±Ribavirine, Ombitasvir/Paritaprevir/Ritonavir+Ribavirine and Ombitasvir/Paritaprevir/Ritonavir+Dasabuvir±Ribavirine. Therapy outcomes, hematochemical parameters, viral replication, genotype, and resistance-associated-mutations were analyzed retrospectively. Sustained virological response was 90.4% in the whole population, 83.2% in cirrhotics, 85% in patients with previous virological failure, 93.6% in patients >60 years, and 95.6% in liver transplant recipients. SVR24 for each drug regimen was 75% Sofosbuvir+Ribavirine, 80.4% Sofosbuvir+Simeprevir±Ribavirine, 94.3% Sofosbuvir+Daclatasvir±Ribavirine, 98.7% Sofosbuvir+Ledispavir±Ribavirine, 100% Ombitasvir/ Paritaprevir/Ritonavir+Ribavirine and Ombitasvir/Paritaprevir/Ritonavir+Dasabuvir±Ribavirine. The highest sustained virological response rates were obtained with genotype-1b (95.9%). Twenty-five patients, mostly cirrhotics or suffering from severe liver complications, manifested relapse (84%), breakthrough (12%), or non-response (4%). Mild side effects were observed in 41.1% of patients. Model-for-End-Liver- Disease score <10 and alanine aminotransferase ≤20 U/L at week 8 of therapy proved positive predictors of sustained virological response. Direct-acting antiviral therapy is efficacious and safe even in patients with advanced liver disease and/ or previous virological failure; Model-for-End-Liver-Disease <10 and alanine aminotransferase reduction during therapy were found to be reliable predicting markers of sustained-virological-response.

Unraveling the structural basis of grazoprevir potency against clinically relevant substitutions in hepatitis C virus NS3/4A protease from genotype 1a.

Grazoprevir is a potent pan-genotype and macrocyclic inhibitor of hepatitis C virus (HCV) NS3/4A protease and was developed for treating chronic HCV infection. In HCV genotype (GT) 1a, grazoprevir maintains potent activity against a majority of NS3 resistance-associated amino acid substitutions, including the highly prevalent and naturally occurring Q80K polymorphism that impacts simeprevir, another NS3/4A protease inhibitor. The basis for an unexpected difference in the clinical impact of some NS3 substitutions was investigated. Phenotypic analysis of resistance-associated substitutions identified in NS3 from GT1a-infected patients who failed therapy with grazoprevir (in combination with elbasvir, an inhibitor of HCV NS5A protein) showed that positions 56, 156, and 168 in NS3 were most impactful because they diminished protein-inhibitor interactions. Although an amino acid substitution from aspartic acid to alanine at position 168 (D168A) reduced the potency of grazoprevir, its combination with R155K unexpectedly nullified this effect. Molecular dynamics and free-energy surface studies indicated that Asp-168 is important in anchoring Arg-155 for ligand binding but is not critical for Lys-155 because of the inherent flexibility of its side chain. Moreover, modeling studies supported a strong direct cation-heterocycle interaction between the Lys-155 side chain of the double substitution, R155K/D168A, and the lone pair on the quinoxaline in grazoprevir. This unique interaction provides a structural basis for grazoprevir's higher potency than simeprevir, an inhibitor to which the double substitution confers a significant reduction in potency. Our findings are consistent with the detection of R155K/D168A in NS3 from virologic failures treated with simeprevir but not grazoprevir.