Background: s/Aims: Plasma pregenomic hepatitis B virus RNA (pgRNA) is a novel biomarker in chronic hepatitis B infection (CHB). We aimed to describe the longitudinal profile of pgRNA and factors influencing its levels in CHB patients on nucleoside analogue (NUC). Methods: Serial plasma samples from 1,354 CHB patients started on first-line NUC were evaluated. Time of NUC initiation was taken as baseline (year 0), followed by 1-year, 3-year and 5-year of NUC therapy. pgRNA was measured by Research Use Only RealTime HBV RNA v2.0 (0.2 mL) (Abbott Diagnostics) with lower limit of detection of 0.8 log U/mL (~20 copies/mL). Results: Among 1,354 subjects (median age at baseline 49.8 [interquartile range, IQR 40.2–57.3]) years, 65.2% male, 16.1% hepatitis B e antigen (HBeAg)-positive, 28.6% cirrhotic), baseline median HBV RNA was 3.68 (IQR 2.42–5.19) log U/mL. Upon NUC therapy, median pgRNA levels were 2.45 (IQR 1.82–3.62), 2.23 (IQR 1.67–3.05) and 2.14 (IQR 1.48–2.86) log U/mL at 1, 3 and 5 years, respectively, with the corresponding log U/mL reductions of 0.82, 1.20 and 1.54. Undetectable/ unquantifiable pgRNA was achieved in 13.5%, 15.9% and 20.1% of patients at 1, 3 and 5 years, respectively. Older age, male sex, HBeAg-negativity and high PAGE-B score were associated with lower pgRNA. Conclusions Plasma pgRNA declines are modest under NUC therapy, with only 16.3% achieving RNA undetectability after 5 years of first-line NUC indicating cccDNA silencing has not been achieved in the majority of patients. Clinical characteristics should be taken into consideration when interpreting the plasma pgRNA level.

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.

Background: s/Aims: Plasma pregenomic hepatitis B virus RNA (pgRNA) is a novel biomarker in chronic hepatitis B infection (CHB). We aimed to describe the longitudinal profile of pgRNA and factors influencing its levels in CHB patients on nucleoside analogue (NUC). Methods: Serial plasma samples from 1,354 CHB patients started on first-line NUC were evaluated. Time of NUC initiation was taken as baseline (year 0), followed by 1-year, 3-year and 5-year of NUC therapy. pgRNA was measured by Research Use Only RealTime HBV RNA v2.0 (0.2 mL) (Abbott Diagnostics) with lower limit of detection of 0.8 log U/mL (~20 copies/mL). Results: Among 1,354 subjects (median age at baseline 49.8 [interquartile range, IQR 40.2–57.3]) years, 65.2% male, 16.1% hepatitis B e antigen (HBeAg)-positive, 28.6% cirrhotic), baseline median HBV RNA was 3.68 (IQR 2.42–5.19) log U/mL. Upon NUC therapy, median pgRNA levels were 2.45 (IQR 1.82–3.62), 2.23 (IQR 1.67–3.05) and 2.14 (IQR 1.48–2.86) log U/mL at 1, 3 and 5 years, respectively, with the corresponding log U/mL reductions of 0.82, 1.20 and 1.54. Undetectable/ unquantifiable pgRNA was achieved in 13.5%, 15.9% and 20.1% of patients at 1, 3 and 5 years, respectively. Older age, male sex, HBeAg-negativity and high PAGE-B score were associated with lower pgRNA. Conclusions Plasma pgRNA declines are modest under NUC therapy, with only 16.3% achieving RNA undetectability after 5 years of first-line NUC indicating cccDNA silencing has not been achieved in the majority of patients. Clinical characteristics should be taken into consideration when interpreting the plasma pgRNA level.

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.

Background: s/Aims: Plasma pregenomic hepatitis B virus RNA (pgRNA) is a novel biomarker in chronic hepatitis B infection (CHB). We aimed to describe the longitudinal profile of pgRNA and factors influencing its levels in CHB patients on nucleoside analogue (NUC). Methods: Serial plasma samples from 1,354 CHB patients started on first-line NUC were evaluated. Time of NUC initiation was taken as baseline (year 0), followed by 1-year, 3-year and 5-year of NUC therapy. pgRNA was measured by Research Use Only RealTime HBV RNA v2.0 (0.2 mL) (Abbott Diagnostics) with lower limit of detection of 0.8 log U/mL (~20 copies/mL). Results: Among 1,354 subjects (median age at baseline 49.8 [interquartile range, IQR 40.2–57.3]) years, 65.2% male, 16.1% hepatitis B e antigen (HBeAg)-positive, 28.6% cirrhotic), baseline median HBV RNA was 3.68 (IQR 2.42–5.19) log U/mL. Upon NUC therapy, median pgRNA levels were 2.45 (IQR 1.82–3.62), 2.23 (IQR 1.67–3.05) and 2.14 (IQR 1.48–2.86) log U/mL at 1, 3 and 5 years, respectively, with the corresponding log U/mL reductions of 0.82, 1.20 and 1.54. Undetectable/ unquantifiable pgRNA was achieved in 13.5%, 15.9% and 20.1% of patients at 1, 3 and 5 years, respectively. Older age, male sex, HBeAg-negativity and high PAGE-B score were associated with lower pgRNA. Conclusions Plasma pgRNA declines are modest under NUC therapy, with only 16.3% achieving RNA undetectability after 5 years of first-line NUC indicating cccDNA silencing has not been achieved in the majority of patients. Clinical characteristics should be taken into consideration when interpreting the plasma pgRNA level.

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.

Chronic hepatitis B infection is a major public health challenge. With the advancement in technology, various components of the viral cycle can now be measured in the blood to assess viral activity. In this review article, we summarize the relevant data of how antiviral therapies impact viral biomarkers, and discuss their potential implications. Viral nucleic acids including hepatitis B virus (HBV) double-stranded deoxy-ribonucleic acid (DNA) and to a lesser extent, pre-genomic RNA, are readily suppressed by nucleos(t)ide analogues (NUCs). The primary role of these markers include risk prediction for hepatocellular carcinoma (HCC) and risk stratification for partial cure, defined as off-therapy virological control, or functional cure, defined as hepatitis B surface antigen (HBsAg) seroclearance plus undetectable serum HBV DNA for ≥6 months. Viral translational products including hepatitis e antigen, quantitative HBsAg and hepatitis B core-related antigen can be reduced by NUCs and pegylated interferon a. They are important in defining disease phase, delineating treatment endpoints, and predicting clinical outcomes including HCC risk and partial/ functional cure. As the primary outcome of phase III trials in chronic hepatitis B is set as HBsAg seroclearance, appropriate viral biomarkers can potentially inform the efficacy of novel compounds. Early viral biomarker response can help with prioritization of subjects into clinical trials. However, standardization and validation studies would be crucial before viral biomarkers can be broadly implemented in clinical use.