Characterization of Hepatitis B virus polymerase mutations A194T and CYEI and tenofovir disoproxil fumarate or tenofovir alafenamide resistance

Switching from combination therapy with entecavir hydrate plus tenofovir alafenamide fumarate to tenofovir alafenamide fumarate monotherapy in patients with chronic hepatitis B based on nucleotide sequences of hepatitis B virus pregenome RNA

AIM

Patients with chronic hepatitis B virus (HBV) infection experiencing viral breakthrough (BTH) or partial response (PR) during lamivudine (LAM) or entecavir hydrate (ETV) administration often took ETV plus tenofovir alafenamide fumarate (TAF) due to the emergence of a drug-resistance mutation. However, in patients lacking drug-resistance mutation against TAF, sufficient antiviral effects may be achievable with TAF monotherapy. We assessed the drug-resistance profile through nucleotide sequences of HBV pregenome RNA, and subsequently changed to TAF monotherapy from ETV plus TAF.

METHODS

This prospective study included 25 patients with serum HBV-DNA below 20 IU/mL under ETV plus TAF administration. Pregenome RNA nucleotide sequences of HBV in the sera were analyzed using direct sequencing and deep sequencing. ETV was discontinued in patients without rtA194T and rtS106C + rtH126Y + rtD134E + rtL269I quadruple mutations in direct sequencing.

RESULTS

LAM-PR, LAM-BTH, ETV-PR, and ETV-BTH were observed in 1, 16, 7, and 1 patient(s), respectively. Pregenome RNA nucleotide sequences were analyzable in 20 patients. Among the 12 patients classified as LAM-BTH, six patients showed rtL180M + rtM204V/I in direct sequencing, and one patient showed minor clones containing rtL180M + rtM204V + A194T in deep sequencing at a frequency of 0.3%. In the six patients classified as ETV-PR, one patient harbored rtM204I. No clones showing rtS106C + rtH126Y + rtD134E + rtL269I quadruple mutation were detected in deep sequencing. Subsequently, ETV was discontinued, and serum HBV-DNA remained undetectable up to 48 weeks in all patients.

CONCLUSION

Patients receiving ETV plus TAF due to partial response or BTH during initial LAM or ETV administration were able to safely transition to TAF monotherapy based on nucleotide sequences of HBV pregenome RNA in the sera.

Maternal A90V mutation in the PreS1 gene of sub-genotype C2 hepatitis B virus is associated with intrauterine transmission

PreS/S gene mutations could impact virus secretion, infection and immune evasion. However, the relationship between PreS/S mutations and intrauterine transmission has not yet been clarified. Thus, we aimed to explore the associations between PreS/S gene mutations of HBV isolated from mothers and intrauterine transmission. We analyzed the mutations of PreS/S regions of the HBV genome in mothers with HBV DNA levels ≥ 106 IU/mL whose neonates experienced HBV intrauterine transmission (transmission group, GT) and those whose neonates did not experience intrauterine transmission (control group, GC) analyzed using clone-based sequencing. In total, 206 sequences were successfully amplified, including 98 sequences (from 21 mothers) from GT and 108 sequences (from 20 mothers) from GC of genotype C for mutational analysis. Among the 1203 nucleotides of PreS/S regions, there were 219 (18.20%) base substitutions, of which 103 (47.03%) base mutations caused amino acid changes. F80S, A90V and I68T were mutation hotspots. Mothers in GT had a higher mutation rate of A90V in the PreS1 gene than mothers in GC. The A90V mutation increased the risk of HBV intrauterine transmission after adjusting the maternal age and the mode of delivery (OR = 6.23, 95% CI: 1.18-32.97). Moreover, the area under the ROC curve (AUC) for intrauterine transmission due to A90V and a combination of A90V with the mode of delivery were 0.723 (95% CI: 0.575 to 0.891, P = 0.011) and 0.848 (95% CI: 0.723 to 0.972, P < 0.001), respectively. Mothers with the A90V mutation in the PreS1 gene may be a potential risk factor for HBV intrauterine transmission.

Advanced Theranostic Strategies for Viral Hepatitis Using Carbon Nanostructures

There are several treatment protocols for acute viral hepatitis, and it is critical to recognize acute hepatitis in its earliest stages. Public health measures to control these infections also rely on rapid and accurate diagnosis. The diagnosis of viral hepatitis remains expensive, and there is no adequate public health infrastructure, while the virus is not well-controlled. New methods for screening and detecting viral hepatitis through nanotechnology are being developed. Nanotechnology significantly reduces the cost of screening. In this review, the potential of three-dimensional-nanostructured carbon substances as promising materials due to fewer side effects, and the contribution of these particles to effective tissue transfer in the treatment and diagnosis of hepatitis due to the importance of rapid diagnosis for successful treatment, were extensively investigated. In recent years, three-dimensional carbon nanomaterials such as graphene oxide and nanotubes with special chemical, electrical, and optical properties have been used for the diagnosis and treatment of hepatitis due to their high potential. We expect that the future position of nanoparticles in the rapid diagnosis and treatment of viral hepatitis can be better determined.

Synthesis and evaluation of N-sulfonylpiperidine-3-carboxamide derivatives as capsid assembly modulators inhibiting HBV in vitro and in HBV-transgenic mice

The hepatitis B virus (HBV) capsid assembly modulators (CAMs) have been developed as effective anti-HBV agents in the treatment of chronic HBV infection by targeting the HBV core protein and inducing the formation of aberrant or morphologically normal capsid. However, some CAMs have been observed adverse events such as ALT flares and rash. Therefore, finding new CAMs is of great importance. In this report, we synthesized N-sulfonylpiperidine-3-carboxamides (SPCs) derivatives and evaluated their anti-HBV activities. Among the SPC derivatives, compound C-49 notably suppressed HBV replication in HepAD38, HepG2-HBV1.3 and HepG2-NTCP cells. Moreover, treatment with C-49 for 12 days exhibited potent anti-HBV activity (100 mg/kg; 2.42 log reduction of serum HBV DNA) in HBV-transgenic mice without apparent hepatotoxicity. Our findings provided a new SPC derivative as HBV capsid assembly modulator for developing safe and efficient anti-HBV therapy.

Review article: switching patients with chronic hepatitis B to tenofovir alafenamide-a review of current data

BACKGROUND

The nucleos(t)ide analogues (NAs) entecavir (ETV), tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) are preferred treatment options for patients with chronic hepatitis B infection (CHB). However, resistance to ETV has been reported, especially with prior exposure to other NAs, and long-term TDF treatment has been associated with decline in renal function and loss of bone mineral density in some patients. Consequently, TAF may be preferable to ETV, TDF or other NAs in specific circumstances such as in patients with risk of bone or renal complications, elderly patients or those with previous NA experience.

AIM

To provide a summary of the available efficacy and safety data following switch to TAF from other NAs in patients with CHB in clinical studies and real-world settings.

METHODS

Literature searches were performed on PubMed and abstracts from three major international liver congresses between 2019 and 2021. Studies that included efficacy and/or safety data for patients with CHB switching from any NA to TAF were selected.

RESULTS

Thirty-six papers and abstracts were included in this narrative review. Switching from TDF to TAF maintained or improved virological and biochemical responses with improved bone and renal safety. Switching from ETV or other NAs to TAF maintained or improved virological and biochemical responses and varying results for bone and renal safety.

CONCLUSIONS

Switching to TAF appears to maintain or improve virological, biochemical and bone- and renal-related safety outcomes. These data support the concept of switching to TAF in some patients with CHB based on their individual circumstances.

Effectiveness of tenofovir alafenamide for chronic hepatitis B patients with a poor response to the previously used nucleos(t)ide analogs

BACKGROUND

Few studies have demonstrated the potency of tenofovir alafenamide (TAF) in patients with poor response to other nucleos(t)ide analogs (NAs).

METHODS

We conducted a retrospective study comprising consecutive 40 patients exhibiting a poor response to other NAs, who subsequently received TAF-containing regimens. The primary outcome was the prevalence of virological response (VR) at each time and maintained virological response (MVR) under TAF-containing regimens until week 96.

RESULTS

In the entire cohort, the prevalence of MVR was 71.1% (27/38). Further, poor tenofovir disoproxil fumarate (TDF) response was significantly associated with a lower prevalence of MVR (p = 0.014). In TDF-naïve patients, the prevalence of MVR was 92.3% (12/13) and 62.5% (5/8) in patients with lamivudine resistance (LAM-r) and entecavir resistance (ETV-r), respectively. Further, viral load and HBeAg status at baseline were associated with a lower prevalence of MVR (p = 0.013). Among the seven patients with prior TDF exposure, 2 patients achieved MVR. Among them, one patient with development of viral breakthrough during TDF/LAM achieved MVR after switching to TAF/ETV. In contrast, one of the five patients with non-MVR had three substitutions (rtS106C, rtD134N/S, and rtL269I) of quadruple mutations in addition to ETV-r. Other patients with rtA181T + rtN236T also could not achieve MVR.

CONCLUSION

TAF exhibited high antiviral potency in patients with LAM-r and ETV-r. However, TAF potency was associated with previous TDF response, viral load, and HBeAg status at baseline. Additionally, a quadruple mutation may impact tenofovir resistance; however, further studies are needed to verify this.