A simeprevir-inducible molecular switch for the control of cell and gene therapies.

Chemical inducer of dimerization (CID) modules can be used effectively as molecular switches to control biological processes, and thus there is significant interest within the synthetic biology community in identifying novel CID systems. To date, CID modules have been used primarily in engineering cells for in vitro applications. To broaden their utility to the clinical setting, including the potential to control cell and gene therapies, the identification of novel CID modules should consider factors such as the safety and pharmacokinetic profile of the small molecule inducer, and the orthogonality and immunogenicity of the protein components. Here we describe a CID module based on the orally available, approved, small molecule simeprevir and its target, the NS3/4A protease from hepatitis C virus. We demonstrate the utility of this CID module as a molecular switch to control biological processes such as gene expression and apoptosis in vitro, and show that the CID system can be used to rapidly induce apoptosis in tumor cells in a xenograft mouse model, leading to complete tumor regression.

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.

Effects of simeprevir on the replication of SARS-CoV-2 in vitro and in transgenic hACE2 mice.

In a bid to contain the current COVID-19 (coronavirus disease 2019) pandemic, various countermeasures have been applied. To date, however, there is a lack of an effective drug for the treatment of COVID-19. Through molecular modelling studies, simeprevir, a protease inhibitor approved for the management of hepatitis C virus infection, has been predicted as a potential antiviral against SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the causative agent of COVID-19. Here we assessed the efficacy of simeprevir against SARS-CoV-2 both in vitro in Vero E6 cells and in vivo in a human angiotensin-converting enzyme 2 (hACE2) transgenic mouse model. The results showed that simeprevir could inhibit SARS-CoV-2 replication in Vero E6 cells with a half-maximal effective concentration (EC50) of 1.41 ± 0.12 µM. In a transgenic hACE2 mouse model of SARS-CoV-2 infection, intraperitoneal administration of simeprevir at 10 mg/kg/day for 3 consecutive days failed to suppress viral replication. These findings collectively imply that simeprevir does not inhibit SARS-CoV-2 in vivo and therefore do not support its application as a treatment against COVID-19 at a dosage of 10 mg/kg/day.

Repurposing simeprevir, calpain inhibitor IV and a cathepsin F inhibitor against SARS-CoV-2 and insights into their interactions with Mpro.

The world has come to a sudden halt due to the incessant spread of a viral pneumonia dubbed COVID-19 caused by the beta-coronavirus, SARS-CoV-2. The main protease of SARS-CoV-2 plays a key role in the replication and propagation of the virus in the host cells. Inhibiting the protease blocks the replication of the virus; therefore it is considered as an attractive therapeutic target. Here we describe the screening of the DrugBank database, a public repository for small molecule therapeutics, to identify approved or experimental phase drugs that can be repurposed against the main protease of SARS-CoV-2. The initial screening was performed on more than 13,000 drug entries in the target database using an energy optimised pharmacophore hypothesis AARRR. A sub-set of the molecules selected based on the fitness score was further screened using molecular docking by sequentially filtering the molecules through the high throughput virtual screening, extra precision and standard precision docking modalities. The best hits were subjected to binding free energy estimation using the MM-GBSA method. Approved drugs viz, Cobicistat, Larotrectinib and Simeprevir were identified as potential candidates for repurposing. Drugs in the discovery phase identified as inhibitors include the known cysteine protease inhibitors, Calpain inhibitor IV and an experimental cathepsin F inhibitor. In order to analyse the stability of the binding interactions, the known cysteine protease inhibitors viz, Simeprevir, calpain inhibitor IV and the cathepsin F inhibitor in complex Mpro were subjected to molecular dynamics simulations at 100 ns. Based on the results Simeprevir was found to be a strong inhibitor of SARS-CoV-2 Mpro.Communicated by Ramaswamy H. Sarma.

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.

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.

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.

An integrated drug repurposing strategy for the rapid identification of potential SARS-CoV-2 viral inhibitors.

The Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). The virus has rapidly spread in humans, causing the ongoing Coronavirus pandemic. Recent studies have shown that, similarly to SARS-CoV, SARS-CoV-2 utilises the Spike glycoprotein on the envelope to recognise and bind the human receptor ACE2. This event initiates the fusion of viral and host cell membranes and then the viral entry into the host cell. Despite several ongoing clinical studies, there are currently no approved vaccines or drugs that specifically target SARS-CoV-2. Until an effective vaccine is available, repurposing FDA approved drugs could significantly shorten the time and reduce the cost compared to de novo drug discovery. In this study we attempted to overcome the limitation of in silico virtual screening by applying a robust in silico drug repurposing strategy. We combined and integrated docking simulations, with molecular dynamics (MD), Supervised MD (SuMD) and Steered MD (SMD) simulations to identify a Spike protein - ACE2 interaction inhibitor. Our data showed that Simeprevir and Lumacaftor bind the receptor-binding domain of the Spike protein with high affinity and prevent ACE2 interaction.

Anti-HCV and anti-malaria agent, potential candidates to repurpose for coronavirus infection: Virtual screening, molecular docking, and molecular dynamics simulation study.

AIMS: Coronavirus disease 2019 (COVID-19) has appeared in Wuhan, China but the fast transmission has led to its widespread prevalence in various countries, which has made it a global concern. Another concern is the lack of definitive treatment for this disease. The researchers tried different treatment options which are not specific. The current study aims to identify potential small molecule inhibitors against the main protease protein of SARS-CoV-2 by the computational approach. MAIN METHODS: In this study, a virtual screening procedure employing docking of the two different datasets from the ZINC database, including 1615 FDA approved drugs and 4266 world approved drugs were used to identify new potential small molecule inhibitors for the newly released crystal structure of main protease protein of SARS-CoV-2. In the following to validate the docking result, molecular dynamics simulations were applied on selected ligands to identify the behavior and stability of them in the binding pocket of the main protease in 150 nanoseconds (ns). Furthermore, binding energy using the MMPBSA approach was also calculated. KEY FINDINGS: The result indicates that simeprevir (Hepatitis C virus NS3/4A protease inhibitor) and pyronaridine (antimalarial agent) could fit well to the binding pocket of the main protease and because of some other beneficial features including broad-spectrum antiviral properties and ADME profile, they might be a promising drug candidate for repurposing to the treatment of COVID-19. SIGNIFICANCE: Simeprevir and pyronaridine were selected by the combination of virtual screening and molecular dynamics simulation approaches as a potential candidate for treatment of COVID-19.

Identification of potential inhibitors against SARS-CoV-2 by targeting proteins responsible for envelope formation and virion assembly using docking based virtual screening, and pharmacokinetics approaches.

WHO has declared the outbreak of COVID-19 as a public health emergency of international concern. The ever-growing new cases have called for an urgent emergency for specific anti-COVID-19 drugs. Three structural proteins (Membrane, Envelope and Nucleocapsid protein) play an essential role in the assembly and formation of the infectious virion particles. Thus, the present study was designed to identify potential drug candidates from the unique collection of 548 anti-viral compounds (natural and synthetic anti-viral), which target SARS-CoV-2 structural proteins. High-end molecular docking analysis was performed to characterize the binding affinity of the selected drugs-the ligand, with the SARS-CoV-2 structural proteins, while high-level Simulation studies analyzed the stability of drug-protein interactions. The present study identified rutin, a bioflavonoid and the antibiotic, doxycycline, as the most potent inhibitor of SARS-CoV-2 envelope protein. Caffeic acid and ferulic acid were found to inhibit SARS-CoV-2 membrane protein while the anti-viral agent's simeprevir and grazoprevir showed a high binding affinity for nucleocapsid protein. All these compounds not only showed excellent pharmacokinetic properties, absorption, metabolism, minimal toxicity and bioavailability but were also remain stabilized at the active site of proteins during the MD simulation. Thus, the identified lead compounds may act as potential molecules for the development of effective drugs against SARS-CoV-2 by inhibiting the envelope formation, virion assembly and viral pathogenesis.

Synergistic anti-hepatitis C virus activity of Ruta angustifolia extract with NS3 protein inhibitor.

Background Medicinal plants are known to perform many pharmacological actions due to their chemical metabolites, which include antiviral effects. Previously, the extract of Ruta angustifolia was shown to have potential anti-hepatitis C virus (HCV) activity without any cytotoxicity, with a 50% inhibitory concentration of 3.0 µg/mL and a 50% cytotoxicity concentration of >100 µg/mL. Furthermore, the combination of medicinal plants and current anti-HCV agents, such as a direct-acting antiviral agent, was shown to potentiate their overall effectiveness. In the course of this study, the ethanolic extract of R. angustifolia was evaluated for its anti-HCV effects; specifically, the mechanism of action on HCV NS3 and NS5A protease was investigated. Methods Analysis of the use of this extract in conjunction with current NS3 inhibitor drugs, simeprevir (SMV) and telaprevir (TVR), was performed. Anti-HCV activity was performed by in vitro culture of hepatocyte cells. The cells were infected and treated with various concentrations of the sample. HCV inhibition was calculated and CompuSyn software analysis was used to determine the synergistic effect of the combination. Results Results demonstrated that R. angustifolia extract inhibited the post-entry step and decreased the protein levels of HCV NS3 and NS5A. The combination of extract and SMV and TVR mediated a synergistic effect. Conclusions These findings suggest that combining R. angustifolia extract with current anti-HCV drugs should be considered when developing alternative and complementary anti-HCV medicines.

Antiviral effects of simeprevir on multiple viruses.

Simeprevir was developed as a small molecular drug targeting the NS3/4A protease of hepatitis C virus (HCV). Unexpectedly, our current work discovered that Simeprevir effectively promoted the transcription of IFN-ß and ISG15, inhibited the infection of host cells by multiple viruses including Zika virus (ZIKV), Enterovirus A71 (EV-A71), as well as herpes simplex virus type 1 (HSV-1). However, the inhibitory effects of Simeprevir on ZIKV, EV-A71 and HSV-1 were independent from IFN-ß and ISG15. This study thus demonstrates that the application of Simeprevir can be extended to other viruses besides HCV.

A proof-of-concept study in HCV-infected Huh7.5 cells for shortening the duration of DAA-based triple treatment regimens.

With the development of more effective direct-acting antivirals (DAAs), dual- or triple-therapy regimens represent the major strategy used to cure chronic hepatitis C virus (HCV) infection. Thus, shorter treatment duration regimens with low burden, few adverse effects and good patient adherence are urgently needed. This study theoretically demonstrates a proof-of-concept approach for shortening therapy duration by examining HCV-infected Huh7.5 cells after treatment with a high or low fixed dose of three DAAs (simeprevir + daclatasvir + sofosbuvir) for 6-15 days. The results demonstrated that HCV-infected Huh7.5 cells achieved an ultrarapid virologic response with undetectable HCV RNA and protein and were cured after treatment with the triple-therapy regimen for 15 days. When the treatment duration was shortened, virologic relapse might occur after treatment with a low fixed dose of the three DAAs for 9 days and did occur after treatment with a low fixed dose for 6 days, although HCV was below detectable levels at the end of treatment. However, virologic relapse could be avoided with treatment of a high fixed dose of the three DAAs for 9 or 6 days. Although a virologic breakthrough occurred after an intermittent treatment regimen at the low fixed dose, the high fixed dose cured HCV-positive Huh7.5 cells with intermittent treatment. In conclusion, HCV is persistently present below detectable levels in HCV-infected Huh7.5 cells for a long time after treatment, and a shortened therapy duration is associated with an increased risk of virologic relapse, but virologic relapse or breakthrough might be avoided by treatment with a combination of more highly effective DAAs.

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.

Combinations of two drugs among NS3/4A inhibitors, NS5B inhibitors and non-selective antiviral agents are effective for hepatitis C virus with NS5A-P32 deletion in humanized-liver mice.

BACKGROUND: The emergence of a deletion mutant at hepatitis C virus (HCV) NS5A-P32 (P32del) has recently been reported in a subset of chronic hepatitis C patients who experience virologic failure after direct-acting antiviral drug (DAA) treatment. This mutation confers extremely high resistance to NS5A inhibitors. No effective treatment has been established for cases with this mutation. METHODS: We used a JFH1-based recombinant virus with NS5A from a genotype 1b strain to introduce a P32del mutation. We inoculated human hepatocyte chimeric mice with sera from a patient with ledipasvir/sofosbuvir therapy failure carrying a genotype 1b HCV with NS5A L31M and P32del or from a DAA-naïve patient carrying wild-type virus. RESULTS: JFH1-based chimeric viruses with P32del showed sufficient levels of replication for in vitro assay despite the suppression of viral growth and infectious virus production. Variants with P32del exhibited severe resistance to all tested NS5A inhibitors, including daclatasvir, ledipasvir, elbasvir and velpatasvir, but were as susceptible to NS3/4A inhibitors, NS5B inhibitors, interferon alfa-2b, and ribavirin as wild-type viruses in the in vitro assay. The P32del mutant virus caused persistent infection in all inoculated chimeric mice with high viral titer and frequency. The virus was resistant to the ledipasvir/GS-558093 (a nucleotide analog inhibitor of NS5B polymerase) regimen but susceptible to either simeprevir plus GS-558093 or peg-interferon alfa-2b, compared to the wild-type virus. CONCLUSION: Therapies combining at least two drugs among NS3/4A inhibitors, NS5B inhibitors and non-selective antiviral agents may be effective for HCV-infected patients with NS5A-P32del.

A comparative study of the efficiency of HCV NS3/4A protease drugs against different HCV genotypes using in silico approaches.

AIMS: To investigate the efficacy of Direct Acting Antivirals (DAAs) in the treatment of different Hepatitis C Virus (HCV) genotypes. MAIN METHODS: Homology modeling is used to predict the 3D structures of different genotypes while molecular docking is employed to predict genotype - drug interactions (Binding Mode) and binding free energy (Docking Score). KEY FINDINGS: Simeprevir (TMC435) and to a lesser degree MK6325 are the best drugs among the studied drugs. The predicted affinity of drugs against genotype 1a is always better than other genotypes. P2-P4 macrocyclic drugs show better performance against genotypes 2, 3 and 5. Macrocyclic drugs are better than linear drugs. SIGNIFICANCE: HCV is one of the major health problems worldwide. Until the discovery of DAAs, HCV treatment faced many failures. DAAs target key functional machines of the virus life cycle and shut it down. NS3/4A protease is an important target and several drugs have been designed to inhibit its functions. There are several NS3/4A protease drugs approved by Food and Drug Administration (FDA). Unfortunately, the virus exhibits resistance against these drugs. This study is significant in elucidating that no one drug is able to treat different genotypes with the same efficiency. Therefore, treatment should be prescribed based on the HCV genotype.

Sofosbuvir in combination with daclatasvir or simeprevir for 12 weeks in noncirrhotic subjects chronically infected with hepatitis C virus genotype 1: a randomized clinical trial.

OBJECTIVE: To investigate the efficacy and safety of sofosbuvir (SOF) plus daclatasvir (DCV) or simeprevir (SMV) in a randomized, open-label, noninferiority trial of patients infected with hepatitis C virus genotype 1, who were previously unresponsive to pegylated interferon and ribavirin or were treatment naive. METHODS: Patients were randomly assigned to receive SOF (400 mg once daily) plus DCV (60 mg once daily) or SMV (150 mg once daily) for 12 weeks. The analysis included all participants who received at least one dose of the study drugs. The primary endpoint was sustained virologic response 12 weeks after ending treatment (SVR12; hepatitis C virus RNA measured using COBAS TaqMan RT-PCR (lower limit of detection and quantification of 12 UI/mL)). This study was registered at ClinicalTrials.gov (NCT02624063). RESULTS: A total of 125 of 127 enrolled and randomized patients started treatment (n = 65 SOF + DCV; n = 60 SOF + SMV). SVR12 was attained in 121 patients (96.8%): 65 (100%) receiving SOF + DCV (95% confidence interval (CI), 94.5 to 100) and 56 (93.3%) receiving SOF + SMV (95% CI, 83.8 to 98.2; absolute difference, 6.6%; 95% CI, -15.0 to 0). The most common adverse events were fatigue (n = 32, 25.6%), headache (n = 27, 21.6%), and mood swings (n = 24, 19.2%). No patients discontinued therapy. CONCLUSIONS: The overall SVR rate was 96.9%; SOF + DCV (100%) was higher than that of SOF + SMV (93.3%). Despite no statistically significant intergroup difference in SVR12 rates, the noninferiority of SOF + SMV to SOF + DCV could not be established because the difference in efficacy was clinically relevant.

Safety and effectiveness of direct acting antivirals for treatment of hepatitis C virus in patients with solid organ transplantation.

BACKGROUND: The direct acting antivirals (DAAs) for treatment of hepatitis C virus (HCV) infection have sustained virologic response (SVR) rates of greater than 90% in most patients. However, data evaluating DAA use in transplant patients are limited. The goal of this study was to evaluate the effectiveness and safety of HCV treatment in this high-risk population. METHODOLOGY: This single-center retrospective study included liver, kidney, lung, and/or heart transplant patients who were treated for HCV infection with DAAs. The primary objective was to identify drug-drug interactions between DAAs and immunosuppressants by comparing immunosuppression dosages and levels at baseline and week 4 of HCV treatment. As secondary objectives, we described the percentage of patients with new or worsening rejection and/or graft dysfunction during HCV treatment, and the percentage of study patients who achieved SVR. RESULTS: Of the 108 patients included, the majority had liver (76%) or kidney (13%) transplants. Simeprevir plus sofosbuvir was the most commonly prescribed HCV treatment (33.9%) and tacrolimus was the most common immunosuppressant (91%). We did not detect a statistically significant difference in immunosuppression dosages or levels during HCV treatment. Furthermore, only one patient (<1%) experienced rejection and five patients (4.6%) had six episodes of graft dysfunction while on DAAs. Efficacy was high with 98% of patients achieving SVR. CONCLUSION: DAAs appear to be safe and effective for HCV treatment in patients with a history of liver and/or kidney transplantation. More data are needed to evaluate DAAs in lung and/or heart transplant patients.

Effectiveness and tolerability of direct-acting antivirals for chronic hepatitis C patients in a Southern state of Brazil

ABSTRACT Background This study aimed to evaluate the clinical effectiveness in terms of sustained virological response and tolerability of available second generation direct-acting antivirals in Brazilian patients. Methods This was a retrospective observational study conducted in six centers in Southern Brazil. The sample comprised adult patients who were chronically infected with hepatitis C virus, regardless of virus genotype, fibrosis stage, or prior treatment. Statistical analysis was performed to compare the effectiveness among the treatments, and also to uncover the factors influencing the achievement of sustained virological response. Results A total of 296 patients were included in the study, with the majority receiving sofosbuvir with daclatasvir (59%) or sofosbuvir with simeprevir (26%). Overall sustained virological response rates were approximately 91.6%. For genotype 1, sofosbuvir with daclatasvir had an sustained virological response rate of approximately 95%, while the sustained virological response rate of sofosbuvir with simeprevir was 92%; this difference was statistically significant only for subtype 1b. The only treatment used for genotype 3 patients was sofosbuvir with daclatasvir, and lower rates of sustained virological response were observed for this group, compared to genotype 1 (84% versus 95%, p < 0.05). Apart from this difference between genotypes, and a difference between patients who achieved rapid virologic response compared with those who did not, there were no other statistically significant factors associated with sustained virological response. Conclusions The results point to the effectiveness of second-generation direct-acting antivirals in hepatitis C virus Brazilian patients, especially those with genotype 1. Furthermore, that patients with genotype 3 need more attention and adjustments in available treatment options.

Effectiveness and tolerability of direct-acting antivirals for chronic hepatitis C patients in a Southern state of Brazil.

BACKGROUND: This study aimed to evaluate the clinical effectiveness in terms of sustained virological response and tolerability of available second generation direct-acting antivirals in Brazilian patients. METHODS: This was a retrospective observational study conducted in six centers in Southern Brazil. The sample comprised adult patients who were chronically infected with hepatitis C virus, regardless of virus genotype, fibrosis stage, or prior treatment. Statistical analysis was performed to compare the effectiveness among the treatments, and also to uncover the factors influencing the achievement of sustained virological response. RESULTS: A total of 296 patients were included in the study, with the majority receiving sofosbuvir with daclatasvir (59%) or sofosbuvir with simeprevir (26%). Overall sustained virological response rates were approximately 91.6%. For genotype 1, sofosbuvir with daclatasvir had an sustained virological response rate of approximately 95%, while the sustained virological response rate of sofosbuvir with simeprevir was 92%; this difference was statistically significant only for subtype 1b. The only treatment used for genotype 3 patients was sofosbuvir with daclatasvir, and lower rates of sustained virological response were observed for this group, compared to genotype 1 (84% versus 95%, p<0.05). Apart from this difference between genotypes, and a difference between patients who achieved rapid virologic response compared with those who did not, there were no other statistically significant factors associated with sustained virological response. CONCLUSIONS: The results point to the effectiveness of second-generation direct-acting antivirals in hepatitis C virus Brazilian patients, especially those with genotype 1. Furthermore, that patients with genotype 3 need more attention and adjustments in available treatment options.