Naturally Occurring Resistance-Associated Variants to Hepatitis C Virus Direct-Acting Antiviral Agents in Treatment-Naive HCV Genotype 6a-Infected Patients

Comparative efficacy and safety of Sofosbuvir/Velpatasvir and Danoprevir for the treatment of chronic hepatitis C: the real-world data in China

BACKGROUND

Sofosbuvir/Velpatasvir (Epclusa, ECS) is the first pan-genotype direct-acting antiviral agent (DAA) for hepatitis C virus (HCV) infection, and Danoprevir (DNV) is the first DAA developed by a Chinese local enterprise, which is suitable for combined use with other drugs to treat genotype 1b chronic hepatitis C. However, previous reports have never compared the real-world data of ECS and DNV.

PATIENTS AND METHODS

178 chronic hepatitis C patients were retrospectively recruited, and 94cases were accepted with Sofosbuvir/Velpatasvir ± Ribavirin (ECS group), and others (n = 84 treated with DNV combination therapy (DNV group). The HCV genotype, virological response, adverse effects and some laboratory biochemical indexes were contrasted between above two groups in the real world study.

RESULTS

DNV group had significantly lower level of alpha-fetoprotein (AFP), lower rates of decompensated cirrhosis ( P < 0.05). ECS group possessed more 6a (31.91% vs.13.10%) while DNV group was provided with more 1b (48.81% vs. 22.34%) patients. Significantly poor liver function was detected in ECS group at 4-week treatment (ALT and AST) and 12-week follow-up (AST) (all P < 0.05). The SVR12 undetectable rates of both groups were 100%, and no serious event was observed during the treatment and follow-up in both groups.

CONCLUSION

In this retrospective real-world study, the efficacy of DNV combined therapy is similar to Sofosbuvir/Velpatasvir ± Ribavirin for chronic HCV infection, and the safety is comparable. DNV based therapy is a promising regimen for chronic hepatitis C.

Efficacy decrease of antiviral agents when administered to ongoing hepatitis C virus infections in cell culture

We report a quantification of the decrease of effectiveness of antiviral agents directed to hepatitis C virus, when the agents are added during an ongoing infection in cell culture vs. when they are added at the beginning of the infection. Major determinants of the decrease of inhibitory activity are the time post-infection of inhibitor administration and viral replicative fitness. The efficacy decrease has been documented with antiviral assays involving the combination of the direct-acting antiviral agents, daclatasvir and sofosbuvir, and with the combination of the lethal mutagens, favipiravir and ribavirin. The results suggest that strict antiviral effectiveness assays in preclinical trials may involve the use of high fitness viral populations and the delayed administration of the agents, relative to infection onset.

Extracellular vesicles from the inflammatory microenvironment regulate the osteogenic and odontogenic differentiation of periodontal ligament stem cells by miR-758-5p/LMBR1/BMP2/4 axis

Background

Extracellular vesicles (EVs) play a key role in constructing a microenvironment that favors the differentiation of stem cells. The present work aimed to determine the molecular mechanisms by which EV derived from inflammatory dental pulp stem cell (iDPSC-EV) influence periodontal ligament stem cells (PDLSCs) and provide a potential strategy for bone and dental pulp regeneration.

Methods

The osteogenic and odontogenic differentiation was assessed by quantitative real-time polymerase chain reaction (qRT-PCR), western blot, alkaline phosphatase (ALP) activity assay, ALP staining, alizarin red S (ARS) staining, and immunofluorescence staining. To detect proliferation, the Cell Counting Kit-8 (CCK-8) assay, and flow cytometry analysis were used. EVs were isolated by the Exoperfect kit and ultrafiltration and characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blot. The expression profile of miRNAs in EVs was studied using miRNA sequence and bioinformatics, and one of the upregulated miRNAs was evaluated on PDLSCs.

Results

The inflammatory microenvironment stimulated osteogenic and odontogenic differentiation of DPSCs and iDPSC-EV behaved alike on PDLSCs. MiR-758-5p was upregulated in iDPSC-EV and was demonstrated to play a significant role in the osteogenic and odontogenic commitment of PDLSCs. A dual-luciferase reporter assay confirmed the binding site between miR-758-5p and limb development membrane protein 1 (LMBR1). The knockdown of LMBR1 also enhanced the above potential. Mechanically, bone morphogenetic protein (BMP) signaling was activated.

Conclusions

EVs from the inflammatory microenvironment enhanced the osteogenic and odontogenic differentiation of PDLSCs partly by shuttering LMBR1-targeting miR-758-5p via BMP signaling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03412-9.

Naturally Occurring Resistance Associated Substitutions in Non-Cirrhotic, Treatment Naive HCV-HIV Co-Infected Patients Does Not Affect the Treatment Response for Anti-HCV Antiviral Therapy

Purpose

Limited literature on the prevalence of baseline resistance associated substitutions (BL-RAS) among HCV–HIV co-infected patients and their association with treatment outcomes is available especially from India. Hence, the present study aimed to study naturally occurring RAS among non-cirrhotic HCV–HIV co-infected patients and their impact on the response to anti-HCV therapy.

Patients and Methods

In this retrospective study, archived blood samples of 80 HCV–HIV co-infected patients, before anti-HCV therapy initiation, were tested for substitutions at the drug acting sites (NS5a and NS5b) in the HCV genome by direct PCR sequencing.

Results

BL-RAS were seen in 19 (23.7%) patients. As well as BL-RAS, all patients were given sofosbuvir (SOF) 400 mg+ daclatasvir (DCV) 60 mg for 12 weeks. Overall, sustained virological response (SVR) was achieved in 63 (78.8%) patients, in 13 with BL-RAS and in 50 without BL-RAS. All the SVR failure cases (n=17) were retreated with SOF (400 mg) +DCV (60 mg)+ ribavirin (RBV) for 24 weeks. SVR was eventually attained in 14 (82.3%) patients, in 4/6 (66.6%) with BL-RAS and in 10/11 (91%) without BL-RAS. On univariate analysis, age more than 30 years (OR: 11.6; 95% CI: 3.0–45.5, p-value<0.001) and female gender (OR: 8.6; 95% CI: 1.1−69, p-value <0.009) were found to be significant factors associated with the attainment of SVR.

Conclusion

BL-RAS are common in HCV–HIV co-infected patients. The existence of BL-RAS, however, did not affect the attainment of SVR among non-cirrhotic, treatment naive HCV–HIV co-infected patients.

Amino Acid Substitutions Associated with Treatment Failure for Hepatitis C Virus Infection

Despite the high virological response rates achieved with current directly acting antiviral agents (DAAs) against hepatitis C virus (HCV), around 2% to 5% of treated patients do not achieve a sustained viral response. The identification of amino acid substitutions associated with treatment failure requires analytical designs, such as subtype-specific ultradeep sequencing (UDS) methods, for HCV characterization and patient management. Using this procedure, we have identified six highly represented amino acid substitutions (HRSs) in NS5A and NS5B of HCV, which are not bona fide resistance-associated substitutions (RAS), from 220 patients who failed therapy. They were present frequently in basal and posttreatment virus of patients who failed different DAA-based therapies. Contrary to several RAS, HRSs belong to the acceptable subset of substitutions according to the PAM250 replacement matrix. Their mutant frequency, measured by the number of deep sequencing reads within the HCV quasispecies that encode the relevant substitutions, ranged between 90% and 100% in most cases. They also have limited predicted disruptive effects on the three-dimensional structures of the proteins harboring them. Possible mechanisms of HRS origin and dominance, as well as their potential predictive value for treatment response, are discussed.

Major mutations in the NS3 gene region of hepatitis C virus related to the resistance to direct acting antiviral drugs: a systematic review

Hepatitis C virus (HCV) remains a global public health problem with high prevalence rates and chronicity of infection. Present work aimed to describe the main mutations in the NS3 region of the HCV genome related to the resistance of patients to the currently available direct-acting antivirals (DAAs). To guide the study description, the preferred items in the PRISMA protocol for systematic review were used. The data collected were HCV genotypes and subtypes and mutations in HCV NS3, general and stratified by continent. The 10 papers selected for this systematic review reported studies in seven countries, on three continents, and generated data of 2937 patients. The most frequent HCV subtype was 1a. Prevalence of genotypes suggested that there were few demographic regions reached by the studies, since there were regional variations in the type of genotypes reported in the available bibliographies. Of the total study population, 35.3% (n = 1037) had mutations in the NS3 gene region of HCV, suggesting a high rate of resistance to DAAs and a low sustained virologic response among those who used some therapeutic option. Ten major mutations were identified: Q80K, V170I, S122G, V36L, T54S, D168Q, A156S, Q80G, S122R, and V55A. The Q80K mutation was the highlight of the study, appearing not only with greater representativity (61.6%) but also as the only one described in the three continents analyzed. This systematic review reinforces the need to carry out more studies of detection of these mutations to fill in all information gaps that might help in optimization of treatment.

Resistance-associated substitutions (RASs) to HCV direct-acting antivirals (DAAs) at baseline of treatment in thalassemia patients: a referral center study

Patients with thalassemia major are at high risk of hepatitis C through blood transfusion from donors infected by hepatitis C virus (HCV). The use of direct-acting antiviral (DAA) therapy against such HCV infections has increased in different populations. However, resistant viral variants can affect treatment outcomes, and therefore improved surveillance strategies are needed. Accordingly, we aimed to evaluate resistance-associated substitutions (RASs) to HCV DAAs at the baseline of treatment in thalassemia patients in a referral center. Out of 89 thalassemia patients who suffered from HCV infection and were referred to our center between 2016 and 2017, 43 underwent further analysis of the HCV nonstructural proteins NS5A and NS5B using polymerase chain reaction (PCR) sequencing methods. Unique primers were designed using bioinformatics software for separate detection of HCV subtypes 1a, 3a, and 1b. Detection of RASs was performed based on previously published literature. Statistical analysis was carried out using SPSS version 19. The participants, 60.4% (26/43) of whom were male, had a mean age ± standard deviation (SD) of 33.0 ± 5.0 years. HCV subtype 1a was found in 27 cases, 3a in 13, and 1b in three. In HCV subtype 1a there were 163 mutations in NS5A and 212 mutations in NS5B. The frequency of RASs was 20.9% (8 RASs in 9 patients), including M28V and H58P in subtype 1a, L28M, R30Q, C316N, and C316S in subtype 1b, and S24F in subtype 3a. Statistically, the subtype 1b and a higher mutation rate in NS5A were associated with RASs (p-value < 0.05). The emergence of natural RASs to HCV DAAs serves as a warning of the risk of drug resistance in response to the broad usage of antivirals. However, relapses in these DAA-treated HCV-infected thalassemia patients are rarely reported. Our findings indicate that the prevalence of RASs prevalence at baseline was 20.9% in these patients, and this calls for extrapolation to a larger population study, as highlighted in other studies, with larger sample sizes, high-throughput methods, and follow-up in order to fully evaluate treatment outcomes in RASs-detected individuals. Optimized therapeutic strategies, particularly in complex, difficult-to-cure patients, can effectively prevent DAA treatment failure as a result of selection for RASs.

Dissection of two drug-targeted regions of Hepatitis C virus subtype 4a infecting Egyptian patients

Recently, treatment of HCV infection has been improved after the development of direct acting antivirals (DAAs) which target different viral proteins (NS3-4A, NS5A and NS5B). The activity and effectiveness of these DAAs are affected by the presence of resistance associated substitutions (RASs). This study aimed to characterize HCV genotypes circulating among Egyptian HCV patients, to dissect the full sequences of HCV NS3-4A and NS5B regions, and to characterize RASs associated with NS3-4A and NS5B inhibitors in HCV treatment-naïve patients. Genotyping of 80 HCV samples from treatment-naïve patients was done using restriction fragment length polymorphism and phylogenetic analysis based on some full NS5B sequences. Results showed the prevalence of HCV subtype 4a. Twenty four new full sequences of NS3-4A and NS5B regions of subtype 4a were deposited in the GenBank database. In general, the substitutions associated with NS3-4A-targeting drugs were absent predicting possible responsiveness of Egyptian HCV patients to these drugs. In addition, the absence of amino acid substitutions associated with resistance to Sofosbuvir may predict good response to treatment with Sofosbuvir. Some amino acid substitutions associated with resistance to different classes of non-nucleoside inhibitors were detected. Further investigations on treated Egyptian HCV patients may evaluate the effectiveness of the massively used drugs. Many predicted T-cell-binding epitopes in NS3-4A and NS5B regions were found to be highly conserved in the currently studied isolates; a finding that might be important for HCV vaccine development. We demonstrated potential NS3 epitopes that could be used in engineering T cells against HCV epitopes.

Pre-existing resistance associated polymorphisms to NS3 protease inhibitors in treatment naïve HCV positive Pakistani patients

Chronic Hepatitis C Virus (HCV) infection is still a major health issue especially in endemic areas where fewer direct-acting virals (DAAs) are treatment options. Some HCV variants are associated with resistance and it reduces DAAs success where pre-existing variants prevail. In this study, we investigated resistance-associated polymorphisms (RAPs) in the HCV NS3 region from DAAs naïve Pakistani patients. 277 chronic HCV treatment naïve patients infected with genotype 1a, 3a and 3b were selected from various clinical centers in the capital city of Khyber Pakhtunkhwa province Pakistan. All the patients were included in this study after taking informed consent. HCV NS3 region was amplified and Sanger sequencing was performed to analyze RAPs to NS3 protease inhibitors. Of the total 29.24% (81/277) patients had detected with known RAPs viz V36A/G/L, T54S, V55A/D/I, Q80K/R, S122G/T/R, R155K/T/I, V158I, D168T/Q, and I170V. Among HCV-1a subjects overall RAPs found were 26.09% (12/46) and most prevalent substitutions were V36A/G (10.87%, 5/46) and R155K/T/I (8.70%, 4/46). Of the total HCV-3a infected patients, 30.95% were observed with RAPS. Ammon these, the most frequent substitutions were Q80R (13.69%, 23/168) followed by V36L (18.33%, 14/168) and V55I (5.95%, 10/168). Among HCV-3b patients, 26.98% were found with RAPs and S122R and Q80R were the dominant variants detected in 17.46 (11/63) and 12.70% (8/63) patients respectively. All these substitutions were associated with Boceprevir, Simeprevir, Telaprevir, and Paritaprevir. Single substitution in one sequence was found in 18.77% (52/277) and multiple in 10.46% (29/277). More than one RAP was frequent in HCV-3a sequences. Natural RAPs are common in chronic HCV patients infected with genotype 1a, 3a and 3b, the most prevalent subtypes in Pakistan. High prevalence of HCV NS3 RAPs suggested a large scale study of the NS3 gene before the introduction of NS3 protease inhibitors in Pakistan.