Chronic hepatitis B: a scoping review on the guidelines for stopping nucleos(t)ide analogue therapy

Expanding treatment indications in chronic hepatitis B: Should we treat all patients?

Nucleos(t)ide analogues (NUCs) are first-line agents for chronic hepatitis B (CHB). Current guidelines provide recommendations for NUC initiation, yet the guidelines are complex and restrictive. Accumulating data on hepatitis B virus (HBV) replication and HBV integration suggests that there are no real quiescent disease phases in CHB, and treatment-ineligible patients in current guidelines still have substantial risks of cirrhosis and hepatocellular carcinoma. Expanding CHB treatment indications can effectively reduce the risks of liver-related complications. Furthermore, treatment indication expansion can be cost-effective, and can simplify care pathways to remove treatment barriers. Potential caveats for treatment expansion include risks of non-compliance, long-term side effects from NUCs, and poor patient acceptability. Nonetheless, these caveats are not insurmountable, and the benefits of treatment expansion outweigh the disadvantages. There is consensus among hepatologists in supporting treatment indication expansion, although expert panels have varying recommendations on treatment strategies. A treat-all approach, which involves treating all CHB patients, has also been proposed. A treat-all strategy is straightforward, and should yield the greatest benefits from a population health perspective. However, the feasibility of new treatment strategies, especially the treat-all approach, is influenced by multiple factors including local epidemiology, healthcare resource availability, and socioeconomic factors. A one-size-fits-all approach is not optimal, and treatment expansion strategies that are tailored based on local data should yield the greatest impact toward hepatitis elimination.

Prospect of emerging treatments for hepatitis B virus functional cure

Functional cure, defined as sustained hepatitis B surface antigen (HBsAg) seroclearance with unquantifiable hepatitis B virus (HBV) DNA at 24 weeks off treatment, is a favorable treatment endpoint in chronic hepatitis B (CHB). Nonetheless, functional cure is rarely attained with the current treatment modalities of nucleos(t)ide analogues (NUCs) and pegylated interferon alpha. Multiple novel virus-targeting agents and immunomodulators are under development for HBV with functional cure as the treatment goal. Among virus-targeting agents, antisense oligonucleotides and small-interfering RNAs are the most advanced in the developmental pipeline, and can induce potent and sustainable HBsAg suppression. The other virus-targeting agents have varying effects on HBsAg and HBV DNA, depending on the drug mechanism. In contrast, immunomodulators have modest effects on HBsAg and have limited roles in monotherapy. Multiple combination regimens incorporating RNA interference agents with immunomodulators have been studied through many ongoing clinical trials. These combination strategies demonstrate synergistic effects in inducing functional cure, and will likely be the future direction of development. Despite the promising results, research is warranted to optimize treatment protocols and to establish criteria for NUC withdrawal after novel therapies. Functional cure is now an attainable target in CHB, and the emerging novel therapeutics will revolutionize CHB management.

Investigational RNA Interference Agents for Hepatitis B

Functional cure of chronic hepatitis B (CHB)-defined as sustained seroclearance of hepatitis B surface antigen (HBsAg) with unquantifiable hepatitis B virus (HBV) DNA at 24 weeks off treatment, is an optimal treatment endpoint. Nonetheless, it cannot be consistently attained by current treatment modalities. RNA interference (RNAi) is a novel treatment strategy using small-interfering RNA (siRNA) or antisense oligonucleotide (ASO) to target HBV post-transcriptional RNA, in turn suppressing viral protein production and replication. Hence, RNAi has indirect effects in promoting host immune reconstitution against HBV. Multiple RNAi therapeutics have entered phase II/III clinical trials, demonstrating potent, dose-dependent, and sustainable effects in suppressing HBsAg. Incidences of HBsAg seroclearance, particularly with the use of ASO, have also been documented. The combination of RNAi with other antivirals/immunomodulators (e.g. pegylated interferon), have shown promising results in potentiating RNAi effects and enhancing treatment durability. Further research will be required to establish predictors of response, optimal treatment protocols, and long-term outcomes in patients on RNAi. RNAi therapeutics have shown promising results and will likely be the keystone of future HBV treatment.

ALT to qHBsAg ratio predicts long-term HBsAg seroclearance after entecavir cessation in Chinese patients with chronic hepatitis B

BACKGROUND & AIMS

Factors predicting HBsAg seroclearance after treatment cessation, irrespective of nucleos(t)ide analogue (NA) resumption, have important clinical implications. We evaluated predictors of long-term HBsAg seroclearance after entecavir cessation.

METHODS

This study followed-up Chinese patients with chronic hepatitis B from two previous studies of entecavir cessation. All patients were non-cirrhotic, HBeAg-negative, with undetectable HBV DNA (<20 IU/ml) at end-of-treatment (EOT). They were monitored closely for 48 weeks with regular HBV DNA, quantitative HBsAg (qHBsAg) and alanine aminotransferase (ALT) measurements. Entecavir was resumed at HBV DNA >2,000 IU/ml, irrespective of ALT levels. After the initial 48 weeks, patients were assessed every 6 months, regardless of entecavir resumption, to monitor for HBsAg seroclearance.

RESULTS

A total of 194 patients (63.4% male, mean age 49.9 years, on entecavir for a median of 47.2 months) were recruited; 94 (48.5%) and 158 (81.4%) patients had EOT qHBsAg <100 IU/ml and <1,000 IU/ml, respectively; 151 (77.8%) patients were eventually resumed on entecavir. After follow-up for a median of 70.7 (51.0-118.2) months, 28 (14.4%) patients had HBsAg seroclearance. qHBsAg levels at weeks 36 and 48 after EOT independently predicted HBsAg seroclearance (both p <0.01), whereas qHBsAg from EOT to week 24 only trended towards statistical significance. The ratio of ALT/qHBsAg at all time points from EOT to week 48 independently predicted HBsAg seroclearance (hazard ratios ranging from 1.003-1.028, all p <0.01) with excellent diagnostic performance (area under the receiver-operating characteristic curve 0.799-0.933, negative predictive value >90% at different time points), regardless of whether entecavir was resumed.

CONCLUSIONS

The ALT/qHBsAg ratio after entecavir cessation predicts HBsAg seroclearance, even in patients who were resumed on treatment. Its use may mitigate the risk of severe hepatitis flares in patients managed by observation without treatment resumption.

IMPACT AND IMPLICATIONS

Current predictors of HBsAg seroclearance after finite nucleos(t)ide analogue (NA) therapy have suboptimal predictive value. We demonstrated that the ALT/qHBsAg ratio may be able to reflect the balance between host control and virological activity. The ALT/qHBsAg ratio at different time points from end-of-treatment till week 48 independently and accurately predicted HBsAg seroclearance in patients who have stopped entecavir. The ALT/qHBsAg ratio may be utilized by clinicians for patient selection and retreatment decisions in finite NA therapy.

Design, Synthesis, and Biological Evaluation of Novel 2-Heteroaryl-oxazolidine-4-one Derivatives as Novel HBV Capsid Assembly Modulators

Using 2-pyrazole oxazolidine-4-one derivative 1 as the lead compound, a series of novel 2-heteroaryl-oxazolidine-4-one derivatives were designed and synthesized by replacing pyrazole moiety with other heterocycles, including methyl pyrazole, oxazole, thiazole, triazole, and reverse pyrazoles, based on the principle of bioisosterism. The structures of target compounds were established by 1H-NMR, 13C-NMR, and electrospray ionization (ESI)-MS. Majority of these compounds showed moderate to good inhibitory activities against hepatitis B virus (HBV) DNA proliferation with low cytotoxicities. Especially, compound 7g showed the most potent anti-HBV activity with EC50 value of 0.059 µM, accompanied with better selectivity index (SI) value than that of lead compound. Our research revealed the structure-activity relationship (SAR) of these newly designed compounds and compound 7g was identified as the potential HBV capsid assembly modulator.