Continuing besifovir dipivoxil maleate versus switching from tenofovir disoproxil fumarate for treatment of chronic hepatitis B: Results of 192-week phase 3 trial

Prediction model of hepatitis B virus-related hepatocellular carcinoma in patients receiving antiviral therapy

Chronic hepatitis B virus (HBV) infection, which ultimately leads to liver cirrhosis, hepatic decompensation, and hepatocellular carcinoma (HCC), remains a significant disease burden worldwide. Despite the use of antiviral therapy (AVT) using oral nucleos(t)ide analogs (NUCs) with high genetic barriers, the risk of HCC development cannot be completely eliminated. Therefore, bi-annual surveillance of HCC using abdominal ultrasonography with or without tumor markers is recommended for at-risk populations. For a more precise assessment of future HCC risk at the individual level, many HCC prediction models have been proposed in the era of potent AVT with promising results. It allows prognostication according to the risk of HCC development, for example, low-vs. intermediate-vs. high-risk groups. Most of these models have the advantage of high negative predictive values for HCC development, allowing exemption from biannual HCC screening. Recently, non-invasive surrogate markers for liver fibrosis, such as vibration-controlled transient elastography, have been introduced as integral components of the equations, providing better predictive performance in general. Furthermore, beyond the conventional statistical methods that primarily depend on multi-variable Cox regression analyses based on the previous literature, newer techniques using artificial intelligence have also been applied in the design of HCC prediction models. Here, we aimed to review the HCC risk prediction models that were developed in the era of potent AVT and validated among independent cohorts to address the clinical unmet needs, as well as comment on future direction to establish the individual HCC risk more precisely.

Tenofovir versus entecavir on the prognosis of hepatitis B virus-related hepatocellular carcinoma: a systematic review and meta-analysis

BACKGROUND

Tenofovir (TDF) and entecavir (ETV) are first-line treatments for patients with chronic hepatitis B virus (HBV) infection. However, the effect of TDF versus ETV on the prognosis of HBV-related hepatocellular carcinoma (HCC) has not been fully clarified yet.

RESEARCH DESIGN AND METHODS

PubMed, Embase and Web of science were searched up to March, 2021. Meta-analyses were performed for overall survival (OS), disease-free survival (DFS) and recurrence-free survival (RFS) to assess the effect of TDF versus ETV on the prognosis of HBV-related HCC.

RESULTS

A total of 10 studies comprising 4706 Asian patients were included. The pooled results revealed that TDF was associated with better OS (adjusted HR=0.50, 95% CI: 0.40-0.62; I²=36.0%, p=0.167) and better RFS/DFS (adjusted HR=0.70, 95% CI: 0.55-0.89, I²=71.9%, p=0.002) than ETV in treatment of HBV-related HCC. Subgroup analysis revealed that OS benefit from TDF was generally consistent, except for patients who underwent non-surgical treatment for HCC. Subgroup analysis also indicated that TDF reduces the risk of late recurrence (HR=0.41, 95% CI: 0.18-0.0.93; I²=63.0%, p=0.067) rather than early recurrence (HR=0.99, 95% CI: 0.64-1.52; I²=61.3%, p=0.076).

CONCLUSIONS

Compared with ETV, TDF has the advantage of improving OS and reducing late recurrence of patients with HBV-related HCC patients who underwent resection.

Comparison of kidney function decline between chronic hepatitis B patients with or without antiviral therapy

BACKGROUND AND AIMS

Kidney function can deteriorate in patients with chronic hepatitis B (CHB). We compared the risk of kidney function decline between untreated and treated CHB patients receiving antiviral therapy.

METHODS

This retrospective study included 1061 untreated CHB patients and 366 tenofovir alafenamide (TAF), 190 besifovir dipivoxil maleate (BSV), and 2029 entecavir (ETV) users. The primary outcome was kidney function decline, a ≥ one-stage increase in chronic kidney disease for ≥3 consecutive months.

RESULTS

The incidence and risk of kidney function decline were significantly higher in the 1:1 propensity score matched treated group (588 pairs) than in the untreated (2.7 per 1000 person-years [PYs] vs. 1.3 per 1000 PYs, adjusted hazard ratio [aHR] = 2.29, all p < 0.001). The matched TAF group (222 pairs) showed a similar risk for the primary outcome (aHR = 1.89, p = 0.107) despite a significantly higher incidence thereof, compared to the untreated (3.9 vs. 1.9 per 1000 PYs, p = 0.042). The matched BSV and untreated groups (107 pairs) showed no significant differences in the incidence and risk. However, ETV users (541 pairs) carried a significantly higher outcome incidence and risk than the matched untreated (3.6 vs. 1.1 per 1000 PYs, aHR = 1.05, all p < 0.001). Compared to each matched untreated group, changes in the estimated glomerular filtration rate over time were greater in the ETV group (p = 0.010), despite being similar in the TAF (p = 0.073) and BSV groups (p = 0.926).

CONCLUSIONS

Compared with untreated patients, TAF or BSV users showed similar risk, whereas ETV users showed a higher risk of kidney function decline.

Statin use is associated with better post-operative prognosis among patients with hepatitis B virus-related hepatocellular carcinoma

BACKGROUND

The high postoperative recurrence rate of hepatocellular carcinoma (HCC) is a significant challenge. Patient metabolic factors are potential disease modifiers and should be examined as risk factors for postoperative prognosis. Here, we assessed the association between long-term statin use and HCC recurrence after surgical resection of hepatitis B virus (HBV)-related HCC.

METHODS

Patients who initially underwent curative resection for HBV-related HCC between 2005 and 2015 were recruited and followed up until December 2019. Patients were classified into statin user and non-statin user groups based on whether or not they had been prescribed statins for ≥2 years. The primary outcome was HCC recurrence, and the secondary outcome was liver-related mortality. The cumulative incidence by statin use was estimated using the Kaplan-Meier method and compared using the log-rank test. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariable Cox regression.

RESULTS

Among 5653 patients with a median 6.1 years of follow-up, HCC recurrence and liver-related mortality occurred in 1603 and 316 patients, respectively. The 5-year cumulative incidence of HCC recurrence in the statin user group (15.9%) was significantly lower than that in the non-user group (21.3%; p = .019). From multivariable Cox regression analysis, statin use was significantly associated with a reduced risk of HCC recurrence (aHR 0.77, 95% CI: 0.61-0.98; p = .035) and liver-related mortality (aHR 0.48, 95% CI: 0.25-0.90; p = .023).

CONCLUSION

Long-term statin use was significantly associated with reduced risk of HCC recurrence and liver-related mortality after curative resection of HBV-related HCC.

Susceptibility of Drug Resistant Hepatitis B Virus Mutants to Besifovir

Currently, interferon alpha and nucleos(t)ide analogues (NAs) are clinically available to treat hepatitis B virus (HBV) infection. Several NAs, including lamivudine (LMV), adefovir (ADV), entecavir (ETV) and tenofovir (TDF or TAF) have been approved and administered to chronic hepatitis B (CHB) patients. NAs inhibit HBV DNA synthesis by targeting the reverse transcriptase (RT) domain of HBV polymerase. Several mutations in the RT domain which lead to drug resistance against NAs have been reported, even for TDF and TAF which are highly potent with very low resistance rate. Besifovir (BFV) is a new antiviral dGMP analogue able to be used as a new NA drug for the control of CHB infection. Drug resistance to BFV is not well known due to its shorter duration of clinical use. Recently, we reported that rtL180M (M) and rtM204V (V) mutations, already resistant to LMV, are associated with BFV resistance. However, the susceptibility to BFV of previously known HBV mutants resistant to various drugs has not been studied. To investigate this, we performed in vitro drug susceptibility assays using natural and artificial mutants that are associated with resistance to LMV, ADV, ETV or TDF. As a result, LMV-resistant mutants were not susceptible to BFV and ETV-resistant clones showed partial resistance against BFV as well. However, ADV-resistant mutants were highly sensitive to BFV. In case of tenofovir-resistant mutations, the HBV mutants harboring primary mutations to tenofovir resistance were susceptible to BFV. Therefore, our study revealed that BSV may serve as an alternative drug for patients with ADV-, ETV-, TDF- or TAF-resistance.

Identification and Characterization of Besifovir-Resistant Hepatitis B Virus Isolated from a Chronic Hepatitis B Patient

Hepatitis B virus (HBV) is known to cause severe liver diseases such as acute or chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Chronic hepatitis B (CHB) infection is a major health problem with nearly 300 million individuals infected worldwide. Currently, nucleos(t)ide analogs (NAs) and interferon alpha are clinically approved treatments for HBV infection. NAs are potent antiviral agents that bind to HBV polymerase and block viral reverse transcription and replication. Besifovir dipivoxil maleate (BSV) is a newly developed NA against HBV in the form of acyclic nucleotide phosphonate that is available for oral administration similar to adefovir and tenofovir. Until now, resistance to BSV treatment has not been reported. In this study, we found a CHB patient who showed viral breakthrough after long-term treatment with BSV. The isolated HBV DNA from patient’s serum were cloned into the replication-competent HBV 1.2 mer and the sequence of reverse transcriptase (RT) domain of HBV polymerase were analyzed. We also examined the drug susceptibility of generated clones in vitro. Several mutations were identified in HBV RT domain. A particular mutant harboring ten RT mutations showed resistance to BSV treatment in vitro. The ten mutations include rtV23I (I), rtH55R (R), rtY124H (H), rtD134E (E), rtN139K (K), rtL180M (M), rtM204V (V), rtQ267L (L), rtL269I (I) and rtL336M (M). To further identify the responsible mutations for BSV resistance, we performed in vitro drug susceptibility assay on several artificial clones. As a result, our study revealed that rtL180M (M) and rtM204V (V) mutations, already known as lamivudine-resistant mutations, confer resistance to BSV in the CHB patient.

Besifovir dipivoxil maleate: a novel antiviral agent with low toxicity and high genetic barriers for chronic hepatitis B

INTRODUCTION

Chronic hepatitis B is an important public health concern. Introduction of oral nucleos(t)ide analogs (NAs), inhibitors of hepatitis B virus (HBV) polymerase, was a milestone that lowered the high viral loads associated with an increased risk of liver-related complications.

AREAS COVERED

Although the currently available NAs are effective in suppressing viral replication, anti-HBV treatment in principle requires lifelong drug administration, and some patients have limitations such as the incidence of liver cancer and the likelihood of toxicities following long-term treatment despite viral suppression. Besifovir dipivoxil maleate (BSV), an oral nucleotide analog, is a prodrug that is metabolized to its active form. It has consistent and well-characterized pharmacokinetics in animals and human. In clinical studies, BSV exhibits significant and potent viral suppression of HBV replication with maintenance of antiviral efficacy for over 192 weeks without resistance, or renal and bone toxicities. Herein, the authors discuss the data of BSV and provide the reader with their expert opinion.

EXPERT OPINION

BSV is a newly developed antiviral agent against HBV. This new agent has strong antiviral activity with low toxicity and a high barrier to resistance. Because there is concern that patients treated with a high dose of BSV require carnitine supplementation, BSV with carnitine supplementation is recommended during antiviral therapy.

Entecavir versus tenofovir in patients with chronic hepatitis B: Enemies or partners in the prevention of hepatocellular carcinoma

Over the past several decades, entecavir (ETV) and tenofovir disoproxil fumarate (TDF) have remained the first-line antiviral agents in several international guidelines. These two antiviral agents have shown similar short to intermediateterm efficacy, including virologic, biochemical, serologic, and histologic responses. However, huge controversies regarding the antiviral efficacy of ETV and TDF in preventing the development of hepatocellular carcinoma (HCC) still exist. In this review, we summarized recent studies that compared the treatment efficacy of ETV and TDF in terms of HCC development.