The Use of Tenofovir Disoproxil Fumarate in the Management of eAg-Negative Chronic Hepatitis B Infection.

Background/Objectives: Currently, there are insufficient data to recommend the treatment of patients with hepatitis B e antigen (HBeAg)-negative chronic infection who have normal ALT and low HBV DNA, since the prognosis is generally regarded as favorable. The aim of this pilot study was to determine whether the use of tenofovir disoproxil fumarate (TDF) 300 mg/day for 3 years was able to achieve functional cure (HBsAg loss) and HBsAg seroconversion in HBeAb-positive individuals. Methods: Fifty patients not on antiviral therapy (40% men, mean age 48.9 ± 10.9 years, 84% Asians) with minimal fibrosis were enrolled. Results: TDF reduced HBV DNA significantly to undetectable levels after 6 months. Overall, 48.3% of inactive carriers (baseline HBV DNA < 2000 IU/mL) remained HBV DNA negative 6 months after treatment withdrawal, which was significantly higher than the 5.6% in those who were not inactive carriers (baseline HBV DNA ≥ 2000 IU/mL) (p = 0.003). The HBsAg levels did not drop throughout the study period with no difference between inactive carriers versus those who were not. Five inactive carriers achieved functional cure, but none of these were amongst those who were not inactive carriers. No renal dysfunction or ALT flare on treatment withdrawal was observed. Conclusions: TDF could potentially be used to induce functional cure in patients who are inactive carriers with normal ALT, low HBV DNA and without advanced fibrosis.

Long-term open-label vebicorvir for chronic HBV infection: Safety and off-treatment responses.

Background & Aims: The investigational first-generation core inhibitor vebicorvir (VBR) demonstrated safety and antiviral activity over 24 weeks in two phase IIa studies in patients with chronic HBV infection. In this long-term extension study, patients received open-label VBR with nucleos(t)ide reverse transcriptase inhibitors (NrtIs). Methods: Patients in this study (NCT03780543) previously received VBR + NrtI or placebo + NrtI in parent studies 201 (NCT03576066) or 202 (NCT03577171). After receiving VBR + NrtI for ≥52 weeks, stopping criteria (based on the treatment history and hepatitis B e antigen status in the parent studies) were applied, and patients either discontinued both VBR + NrtI, discontinued VBR only, or continued both VBR + NrtI. The primary efficacy endpoint was the proportion of patients with HBV DNA <20 IU/ml at 24 weeks off treatment. Results: Ninety-two patients entered the extension study and received VBR + NrtI. Long-term VBR + NrtI treatment led to continued suppression of HBV nucleic acids and, to a lesser extent, HBV antigens. Forty-three patients met criteria to discontinue VBR + NrtI, with no patients achieving the primary endpoint; the majority of virologic rebound occurred ≥4 weeks off treatment. Treatment was generally well tolerated, with few discontinuations due to adverse events (AEs). There were no deaths. Most AEs and laboratory abnormalities were related to elevations in alanine aminotransferase and occurred during the off-treatment or NrtI-restart phases. No drug-drug interactions between VBR + NrtI and no cases of treatment-emergent resistance among patients who adhered to treatment were observed. Conclusions: Long-term VBR + NrtI was safe and resulted in continued reductions in HBV nucleic acids following completion of the 24-week parent studies. Following treatment discontinuation, virologic relapse was observed in all patients. This first-generation core inhibitor administered with NrtI for at least 52 weeks was not sufficient for HBV cure. Clinical trial number: NCT03780543. Impact and implications: Approved treatments for chronic hepatitis B virus infection (cHBV) suppress viral replication, but viral rebound is almost always observed after treatment discontinuation, highlighting an unmet need for improved therapies with finite treatment duration producing greater therapeutic responses that can be sustained off treatment. First-generation core inhibitors, such as vebicorvir, have mechanisms of action orthogonal to standard-of-care therapies that deeply suppress HBV viral replication during treatment; however, to date, durable virologic responses have not been observed after treatment discontinuation. The results reported here will help researchers with the design and interpretation of future studies investigating core inhibitors as possible components of finite treatment regimens for patients with cHBV. It is possible that next-generation core inhibitors with enhanced potency may produce deeper and more durable antiviral activity than first-generation agents, including vebicorvir.

Addition of PEG-interferon to long-term nucleos(t)ide analogue therapy enhances HBsAg decline and clearance in HBeAg-negative chronic hepatitis B: Multicentre Randomized Trial (PAS Study).

We studied whether 48 weeks of PEG-IFN alfa-2a add-on increases HBsAg-decline and clearance in HBeAg-negative patients on long-term nucleo(s)tide analogue (NA) therapy. In this investigator-initiated, randomized, controlled trial conducted in Europe and Canada, HBeAg-negative patients treated with NA > 12 months, with HBVDNA < 200 IU/mL, were enrolled. Patients were randomized 2:1 to 48 weeks of PEG-IFN alfa-2a add-on (180 µg per week) or continued NA-monotherapy with subsequent follow-up to Week 72. Endpoints were HBsAg decline (≥1 log10 IU/mL) and HBsAg clearance at Week 48. Of the 86 patients in the modified-intention-to-treat analysis, 58 patients received PEG-IFN add-on, and 28 continued NA monotherapy. At Week 48, 16(28%) patients achieved HBsAg decline ≥1 log10 in the add-on arm versus none on NA-monotherapy (p < .001), and HBsAg clearance was observed in 6 (10%) PEG-IFN add-on patients versus 0% NA-monotherapy (p = .01). HBVRNA was only detected in 2% after PEG-IFN treatment versus 19% in NA-monotherapy (p = .002) at Week 48. PEG-IFN add-on therapy was well tolerated in majority of patients. Low baseline HBsAg levels (<10 IU/mL) identified patients most likely to achieve HBsAg loss with PEG-IFN add-on, whereas an HBsAg level > 200 IU/mL at on-treatment Week 12 was highly predictive of non-response (NPV = 100%). Addition of PEG-IFN to long-term NA enhanced HBsAg decline and increased the chance of HBsAg clearance in HBeAg-negative patients on long-term NA. On-treatment HBsAg levels >200 IU/mL identify patients unlikely to benefit from PEG-IFN add-on and could be used as a potential stopping-rule for PEG-IFN therapy. Our findings support further exploration of immune modulation add-on to antiviral therapy, preferably using response-guided strategies, to increase functional cure rates in patients with CHB.

Safety, pharmacodynamics, and antiviral activity of selgantolimod in viremic patients with chronic hepatitis B virus infection.

Background & Aims: Novel finite therapies for chronic hepatitis B (CHB) are needed, since lifelong treatment is usually required with current available oral antivirals. This phase II study (NCT03615066) evaluated the safety, pharmacodynamics, and antiviral activity of selgantolimod (a Toll-like receptor 8 agonist [TLR8]) with tenofovir alafenamide (TAF). Methods: Viremic patients with CHB not receiving treatment were stratified by HBeAg status and randomized 2:2:1 to TAF 25 mg/day with selgantolimod 3 mg orally once weekly (QW), selgantolimod 1.5 mg QW, or placebo. Combination therapy continued until week (W)24, followed by TAF monotherapy until W48; patients then discontinued TAF and were followed until W96 (treatment-free follow-up [TFFU] period). The primary efficacy endpoint was the proportion with ≥1 log10 IU/ml HBsAg decline at W24. Results: Sixty-seven patients received study drug; 27 were followed during TFFU. Nausea, headache, vomiting, fatigue, and dizziness were the most common adverse events. Most adverse events were grade 1. Alanine aminotransferase flares were not observed up to W48. Four patients experienced alanine aminotransferase and hepatitis flares during TFFU; all had HBV DNA increases. Selgantolimod increased serum cytokines and chemokines and redistributed several circulating immune cell subsets. No patients achieved the primary efficacy endpoint. Mean HBsAg changes were -0.12, -0.16, and -0.12 log10 IU/ml in the selgantolimod 3 mg, selgantolimod 1.5 mg, and placebo groups, respectively, at W48; HBV DNA declined in all groups by ≥2 log10 IU/ml as early as W2, with all groups rebounding to baseline during TFFU. No HBsAg or HBeAg loss or seroconversion was observed throughout TFFU. Conclusions: Selgantolimod up to 3 mg was safe and well tolerated. Pharmacodynamics and antiviral activity in viremic patients support continued study of selgantolimod in combination CHB therapies. Impact and implications: Novel therapeutics for chronic HBV infection are needed to achieve a functional cure. In this study, we confirmed the safety and tolerability of selgantolimod (formerly GS-9688, a TLR8) when administered with tenofovir alafenamide over 24 weeks in viremic patients with chronic HBV infection. Overall, declines in HBsAg levels with selgantolimod treatment were modest; subgroup analysis indicated that patients with alanine aminotransferase levels greater than the upper limit of normal had significantly greater declines compared to those with normal alanine aminotransferase levels (-0.20 vs. -0.03 log10 IU/ml; p <0.001). These findings suggest a potential differential response to selgantolimod based on patients' baseline HBV-specific immune response, which should be considered in future investigations characterizing the underlying mechanisms of selgantolimod treatment and in HBV cure studies using similar immunomodulatory pathways. Clinical trial number: NCT03615066 be found at https://www.gileadclinicaltrials.com/transparency-policy/.

Alveolar Echinococcus in a 70-year-old man in Ontario.

Background: Alveolar echinococcus, caused by the tapeworm Echinococcus multilocularis, mimics hepatic malignancy, and carries a mortality rate exceeding 90% in untreated patients. Methods: Diagnosis of E. multilocularis infection is established through clinical, radiographic, and microbiological assessments. Currently available laboratory diagnostics in Ontario are fresh tissue microscopy and histopathology. However, genus-specific Echinococcus enzyme-linked immunosorbent assay (ELISA) serology as well as confirmatory testing with species-specific serology and E. multilocularis polymerase chain reaction (PCR) can be obtained from external reference laboratories. Results: The article presents the first case report of human alveolar echinococcus in Ontario. We outline the multidisciplinary approach of diagnosis as well as surgical and medical management of E. multilocularis infection in a 70-year-old man in Ontario. We describe prior literature of alveolar echinococcus in Canadian settings and highlight its emerging nature with recent human case clusters in the Prairies and reports of E. multilocularis in recent veterinary literature in Ontario. Conclusion: E. multilocularis is an emerging parasitic infection in Canadian settings including Ontario. Clinicians should be aware of the emergence of this invasive infection, especially in those with close contact to canids.

Historique: Causée par le ténia Echinococcus multilocularis, l'échinococcose alvéolaire, qui imite le cancer du foie, est associée à un taux de décès de plus de 90 % chez les patients non traités. Méthodologie: Le diagnostic d'infection par l'E multilocularis est posé par une évaluation clinique, radiographique et microbiologique. La microscopie sur tissus frais et l'histopathologie sont les diagnostics microbiologiques actuellement offerts en Ontario. Cependant, il est possible d'obtenir une analyse sérologique par la méthode d'immunoabsorption enzymatique (ELISA) spécifique du genre Echinococcus ainsi que des tests de confirmation par analyse sérologique spécifique à l'espèce et par amplification en chaîne par polymérase (PCR) de l'E multilocularis auprès de laboratoires de référence externes. Résultats: L'article présente le premier rapport de cas d'échinococcose alvéolaire humaine en Ontario. Les chercheurs soulignent l'approche multidisciplinaire du diagnostic, de même que la prise en charge chirurgicale et médicale de l'infection à E multilocularis chez un homme de 70 ans de l'Ontario. Ils décrivent les publications scientifiques antérieures sur l'échinococcose alvéolaire au Canada et soulignent l'émergence de cette maladie parasitaire dans une récente grappe de cas humains des Prairies, de même que les comptes rendus de cas d'E multilocularis dans les récentes publications vétérinaires de l'Ontario. Conclusion: L'E multilocularis est une infection parasitaire en émergence au Canada, y compris en Ontario. Les cliniciens devraient être informés de l'émergence de cette infection invasive, notamment chez les personnes en contact étroit avec des canidés.

Atherosclerotic cardiovascular disease risk profile of patients with chronic hepatitis B treated with tenofovir alafenamide or tenofovir disoproxil fumarate for 96 weeks.

BACKGROUND: Patients with chronic hepatitis B (CHB) who switch from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF) show changes in lipid profiles. AIM: To evaluate how these changes affect cardiovascular risk. METHODS: This pooled analysis, based on two large prospective studies, evaluated fasting lipid profiles of patients with CHB who were treated with TAF 25 mg/day or TDF 300 mg/day for 96 weeks. Patients who fulfilled the American College of Cardiology criteria (age 40-79 years, high-density lipoprotein [HDL] 20-100 mg/dL, total cholesterol [TC] 130-320 mg/dL and systolic blood pressure 90-200 mmHg) required to assess 10-year atherosclerotic cardiovascular disease (ASCVD) risk with baseline lipid data and at least one post-baseline measurement were included in the ASCVD-risk population. The 10-year ASCVD risk was calculated for patients in this population, and changes from baseline to Week 96 were assessed using intermediate- (≥7.5%) and high-risk (≥20%) cut-offs. RESULTS: Among 1632 patients, 620 (38%) met the criteria for the ASCVD-risk population. At Week 96, fasting levels of all lipids, except TC:HDL ratio, were lower with TDF than TAF. No significant increase was observed in overall ASCVD risk or in any ASCVD-risk categories during the 96-week treatment period compared with baseline. A similar proportion of patients in the TAF and TDF treatment groups (1.3% and 2.3%, respectively; p = 0.34) reported cardiovascular events. CONCLUSION: Despite on-treatment differences in lipid profiles with TAF and TDF, predicted cardiovascular risk and clinical events were similar for both groups after 96 weeks.

Tenofovir alafenamide and tenofovir disoproxil fumarate reduce incidence of hepatocellular carcinoma in patients with chronic hepatitis B.

Background & Aims: Antiviral therapy may attenuate the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B (CHB). We aimed to explore how tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) affect HCC risk in patients with CHB. Methods: The REACH-B, aMAP, and mPAGE-B models were utilized to assess HCC risk in patients with CHB from two global randomized-controlled trials evaluating the impact of TAF vs. TDF treatment. Standard incidence ratios (SIRs) were calculated using data from the REACH-B model as a ratio of observed HCC cases in the TAF- or TDF-treated patients vs. predicted HCC cases for untreated historical controls. Proportions of treated patients shifting aMAP and mPAGE-B risk categories between baseline and Week 240 were calculated. Results: Of the 1,632 patients (TAF, n = 1,093; TDF, n = 539) followed for up to 300 weeks, 22 HCC cases developed. Those receiving TAF had an SIR that was lower compared to the SIR of individuals receiving TDF: 0.32 (p <0.001) vs. 0.56 (p = 0.06). In the general study population, individuals without cirrhosis at baseline had an SIR that was lower compared to the SIR of individuals with cirrhosis at baseline: 0.37 (p <0.001) vs. 0.58 (p = 0.15). Of the patients at low risk of HCC at baseline, the majority (97%) remained low risk by mPAGE-B and aMAP scoring at Week 240. Among those at medium or high risk at baseline, substantial portions shifted to a lower risk category by Week 240 (mPAGE-B: 22% and 42%; aMAP: 39% and 63%, respectively). Conclusions: This evaluation provides evidence that treatment with TAF or TDF can reduce HCC risk in patients with CHB, particularly in patients without cirrhosis. Impact and implications: Despite the substantial impact of HCC on long-term outcomes of patients with CHB, the differential risk of HCC development among those receiving treatment with TAF vs. TDF has not been well elucidated. Using three validated risk prediction models, we found that TAF is at least as effective as TDF in reducing HCC risk in patients with CHB. While TDF is well-studied in the context of HCC risk reduction, our novel findings underscore the effectiveness of TAF as a treatment option for patients with CHB. Clinical trial numbers: NCT01940341; NCT02836249; NCT01940471; NCT02836236.

Efficacy of antiviral therapy and host-virus interactions visualised using serial liver sampling with fine-needle aspirates.

Background & Aims: Novel therapies for chronic hepatitis B (CHB), such as RNA interference, target all viral RNAs for degradation, whereas nucleoside analogues are thought to block reverse transcription with minimal impact on viral transcripts. However, limitations in technology and sampling frequency have been obstacles to measuring actual changes in HBV transcription in the liver of patients starting therapy. Methods: We used elective liver sampling with fine-needle aspirates (FNAs) to investigate the impact of treatment on viral replication in patients with CHB. Liver FNAs were collected from patients with CHB at baseline and 12 and 24 weeks after starting tenofovir alafenamide treatment. Liver FNAs were subjected to single-cell RNA sequencing and analysed using the Viral-Track method. Results: HBV was the only viral genome detected and was enriched within hepatocytes. The 5' sequencing technology identified protein-specific HBV transcripts and showed that tenofovir alafenamide therapy specifically reduced pre-genomic RNA transcripts with little impact on HBsAg or HBx transcripts. Infected hepatocytes displayed unique gene signatures associated with an immunological response to viral infection. Conclusions: Longitudinal liver sampling, combined with single-cell RNA sequencing, captured the dynamic impact of antiviral therapy on the replication status of HBV and revealed host-pathogen interactions at the transcriptional level in infected hepatocytes. This sequencing-based approach is applicable to early-stage clinical studies, enabling mechanistic studies of immunopathology and the effect of novel therapeutic interventions. Impact and Implications: Infection-dependent transcriptional changes and the impact of antiviral therapy on viral replication can be measured in longitudinal human liver biopsies using single-cell RNA sequencing data.

Long-term Treatment With Tenofovir Alafenamide for Chronic Hepatitis B Results in High Rates of Viral Suppression and Favorable Renal and Bone Safety.

OBJECTIVES: Results from two Phase 3 studies, through 2 years, in chronic hepatitis B infection (CHB) showed tenofovir alafenamide (TAF) had similar efficacy to tenofovir disoproxil fumarate (TDF) with superior renal and bone safety. Here, we report updated results through 5 years. METHODS: Patients with HBeAg-negative or -positive CHB with or without compensated cirrhosis were randomized (2:1) to TAF 25 mg or TDF 300 mg once daily in double-blind (DB) fashion for up to 3 years, followed by open-label (OL) TAF up to 8 years. Efficacy (antiviral, biochemical, serologic), resistance (deep sequencing of polymerase/reverse transcriptase and phenotyping), and safety, including renal and bone parameters, were evaluated by pooled analyses. RESULTS: Of 1298 randomized and treated patients, 866 receiving TAF (DB and OL) and 432 receiving TDF with rollover to OL TAF at year 2 (n = 180; TDF→TAF3y) or year 3 (n = 202; TDF→TAF2y) were included. Fifty (4%) TDF patients who discontinued during DB were excluded. At year 5, 85%, 83%, and 90% achieved HBV DNA < 29 IU/mL (missing = failure) in the TAF, TDF→TAF3y, and TDF→TAF2y groups, respectively; no patient developed TAF or TDF resistance. Median eGFR (by Cockcroft-Gault) declined < 2.5 mL/min, and mean declines of < 1% in hip and spine bone mineral density were seen at year 5 in the TAF group; patients in the TDF→TAF groups had improvements in these parameters at year 5 after switching to OL TAF. CONCLUSIONS: Long-term TAF treatment resulted in high rates of viral suppression, no resistance, and favorable renal and bone safety.

Longitudinal liver sampling in patients with chronic hepatitis B starting antiviral therapy reveals hepatotoxic CD8+ T cells.

Accumulation of activated immune cells results in nonspecific hepatocyte killing in chronic hepatitis B (CHB), leading to fibrosis and cirrhosis. This study aims to understand the underlying mechanisms in humans and to define whether these are driven by widespread activation or a subpopulation of immune cells. We enrolled CHB patients with active liver damage to receive antiviral therapy and performed longitudinal liver sampling using fine-needle aspiration to investigate mechanisms of CHB pathogenesis in the human liver. Single-cell sequencing of total liver cells revealed a distinct liver-resident, polyclonal CD8+ T cell population that was enriched at baseline and displayed a highly activated immune signature during liver damage. Cytokine combinations, identified by in silico prediction of ligand-receptor interaction, induced the activated phenotype in healthy liver CD8+ T cells, resulting in nonspecific Fas ligand-mediated killing of target cells. These results define a CD8+ T cell population in the human liver that can drive pathogenesis and a key pathway involved in their function in CHB patients.

A phase 2, open-label, randomized, multiple-dose study evaluating Inarigivir in treatment-naïve patients with chronic hepatitis B.

BACKGROUND/AIMS: Novel agents acting against hepatitis B virus (HBV) are needed to improve HBsAg seroclearance or termed as 'functional cure'. Inarigivir (retinoic acid-inducible gene I agonist) has immunomodulatory and direct antiviral actions against HBV. We aimed to determine the safety and efficacy of Inarigivir for the treatment of HBV infection. PATIENTS/METHODS: 80 treatment-naïve patients were randomized in 4 ascending dose cohorts to receive 12 weeks of Inarigivir 25, 50, 100, 200 mg or placebo in a ratio of 4:1. All patients were then given tenofovir for another 12 weeks. RESULTS: Least squares (LS) mean reductions in HBV DNA from baseline increased with higher doses of Inarigivir (0.6116 in 25 mg and 1.5774 in 200 mg groups vs. 0.0352 in placebo group) (95% CI 0.9518-0.2011 and 1.921-1.1634 respectively). LS mean changes in HBV RNA and HBsAg from baseline ranged from -0.3856 to -0.5794 versus -0.1474 and -0.0956 to -0.1818 versus +0.0026 in Inarigivir-treated versus placebo groups respectively. During the tenofovir-treated period, LS mean reductions in HBsAg in the Inarigivir-treated groups ranged from 0.1709 to 0.3529 versus 0.1984 in the placebo group. Inarigivir-treated groups showed mean reductions in ALT from baseline between 23.3 and 33.8 versus 0.7 U/L in the placebo group. Treatment-emergent adverse events related to Inarigivir and placebo occurred in 4.7% and 6.3% patients respectively. CONCLUSIONS: Twelve-week Inarigivir up to 200 mg dose was associated with a reduction of HBV DNA, HBV RNA and antigen levels. A trend for greater HBsAg reduction was observed in Inarigivir pre-treated patients after switching to tenofovir.

Clinical Outcomes and Quantitative HBV Surface Antigen Levels in Diverse Chronic Hepatitis B Patients in Canada: A Retrospective Real-World Study of CHB in Canada (REVEAL-CANADA).

BACKGROUND: Hepatitis B surface antigen (HBsAg) loss is associated with improved clinical outcomes for individuals with chronic hepatitis B (CHB); however, the effects of varying HBsAg levels on clinical outcomes in diverse cohorts are understudied. METHODS: In this cross-sectional, multicentre, retrospective study, the data on adult subjects enrolled in the Canadian HBV Network with CHB seen from 1 January 2012 to 30 January 2021 with the treatment and virologic data within 1 year of HBsAg testing were analyzed. Patients were tested for HBsAg using qualitative (for HBsAg-negative samples) and/or commercial quantitative assays. Fibrosis or hepatic necroinflammation was determined by the liver stiffness measurement (LSM). The baseline data were summarized using descriptive statistics and compared by using univariable/multivariable analyses. RESULTS: This study included 844 CHB patients, with a median age of 49.6 years (IQR 40.1-60.5), and 37% were female. In total, 751 patients (78.6%) had known ethnicity data, and 76.7% self-reported as Asian, 11.4% as Black, 6.8% as White, and 4.8% as other. Among the 844 patients, 237 (28.0%) were HBsAg (-) (1000 IU/mL. Overall, 80% (682) had known HBeAg status at the last follow-up, and the majority (87.0%) were HBeAg-negative. In addition, 54% (461/844) had prior antiviral therapy, 19.7% of which (16.3, 23.7, n = 91) were HBsAg (-). The treated patients had a lower risk of cirrhosis (16.46, 95% CI 1.89-143.39, p = 0.01) or HCC (8.23, 95% CI 1.01-67.39, p = 0.05) than the untreated patients. A lower proportion of the HBsAg-loss group had cirrhosis (5.7% vs. 10.9%, p = 0.021) and HCC (0.9% vs. 6.2%, p = 0.001). CONCLUSION: In this retrospective, ethnically diverse cohort study, CHB patients who received antiviral therapy and/or had HBsAg loss were less likely to develop cirrhosis and HCC, confirming the results of the studies in less diverse cohorts. No association was found between the qHBsAg level and fibrosis determined with LSM. Individuals who achieved HBsAg loss had low-level qHBsAg within 1 year of seroclearance.

Ribavirin Does Not Enhance Hepatitis B Virus Nucleotide Antiviral Activity: A Pilot Study.

PURPOSE: There is a need for effective and affordable treatments that achieve hepatitis B virus (HBV) functional cure and prevent long-term complications. The use of immune-modulators combined with HBV antivirals is a promising therapeutic strategy to achieve these goals. Based on ribavirin (RBV) monotherapy data, we hypothesized that RBV could improve virological responses when used in combination with tenofovir.  Methods: In this randomized, open label, controlled pilot trial, we evaluated RBV (n=4) dosed for the initial 24 weeks of treatment versus no RBV (n=4) in tenofovir recipients dosed over 48 weeks.  Results: Although well tolerated and safe in combination with tenofovir, RBV demonstrated no beneficial effects on virologic, biochemical or immunological markers of chronic HBV infection over 48 weeks of serial evaluation.  Conclusions: Our data does not suggest a HBV-specific immunomodulatory effect or an impact of RBV on HBV virological and antigen suppression.

Brief Report: Effect of Antiretroviral Switch From Tenofovir Disoproxil fumarate to Tenofovir Alafenamide on Alanine Aminotransferase, Lipid Profiles, and Renal Function in HIV/HBV-Coinfected Individuals in a Nationwide Canadian Study.

OBJECTIVE: Tenofovir alafenamide (TAF) achieves increased renal safety and improved alanine aminotransferase (ALT) normalization but increased lipid profile in hepatitis B virus (HBV)-monoinfected patients switched from tenofovir disoproxil fumarate (TDF). It is unclear whether HIV coinfection perturbs these biochemical changes. To this end, we assessed these parameters in HIV/HBV-coinfected patients switched from TDF to TAF. DESIGN: Retrospective, multicenter, observational study. METHODS: HIV/HBV-coinfected patients switched from TDF to TAF-based antiretroviral therapy (ART) at 6 Canadian Hepatitis B Network (CanHepB) academic sites were included. Changes in lipid profile, estimated glomerular filtration rate (eGFR), and ALT were evaluated using linear mixed effect model regression. RESULTS: Eighty-two HIV/HBV-coinfected patients with a mean 103-week follow-up duration were identified. At time of TAF switch, 80 of 82 (98%) were HBV virally suppressed, 29 of 82 (35%) had elevated ALT levels, and 63 of 82 (77%) had eGFR of ≥60 mL/min per 1.73 m 2 . Twenty-six/Eighty-two (32%) had preexisting renal comorbidities. There were no changes in total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglyceride levels 2 years after TAF switch. Those with elevated ALT levels achieved greater ALT normalization after TAF switch (-0.004 [-0.008 to 0.0] log 10 U/L/mo, P = 0.03). eGFR decline rate while on TDF (-0.66 [-0.23 to -1.08] mL/min/month, P < 0.005) was diminished after switching to TAF (-0.02 [-0.16 to 0.11] mL/min/mo, P = 0.7) and those with eGFR of <60 mL/min experienced increase in eGFR after TAF switch (0.45 [0.03-0.87] mL/min/mo, P = 0.04). CONCLUSIONS: Our study supports switching from TDF to TAF with positive influence on overall long-term biochemical profile in HIV/HBV-coinfected individuals.

Early virologic relapse predicts alanine aminotransferase flares after nucleos(t)ide analogue withdrawal in patients with chronic hepatitis B.

When patients with chronic hepatitis B (CHB) stop nucleos(t)ide analogue (NA) therapy before achieving HBsAg loss, flares often ensue which are challenging to predict early. We determined the incidence, severity, outcome and predictors of flares after NA withdrawal. Forty-five patients enrolled in an RCT were included; 107 patients from an external, prospective cohort were used for validation. Retreatment criteria were pre-defined. Pre- and post-treatment predictors of alanine aminotransferase (ALT) flare (>5× ULN) were evaluated by Cox proportional-hazards regression. Seventy-two weeks after NA withdrawal, 23/45 (51%) patients had developed >5× ULN and 14 (31%) >20× ULN. Median time to develop ALT >5× ULN was 12 weeks after NA withdrawal. Independent predictors of ALT >5× ULN were male sex (HR [95% CI] 3.2 [1.2-8.9]; p = 0.03) and serum HBV DNA (1.2 [1.0-1.8]; p = 0.03) at Week 6 off-therapy. Specifically, week 6 HBV DNA >10,000 IU/ml predicted ALT >5× ULN (3.4 [1.4-8.4]; p = 0.01), which was externally validated. In conclusion, this study on post-treatment flares revealed a high cumulative incidence in CHB. Week 6 HBV DNA >10,000 IU/ml independently predicted flares. The proposed threshold enables prediction of imminent flares in patients who may benefit from closer monitoring and earlier retreatment.

Nationwide retrospective study of hepatitis B virological response and liver stiffness improvement in 465 patients on nucleos(t)ide analogue.

BACKGROUND: Hepatitis B virus (HBV) nucleos(t)ide analog (NA) therapy reduces liver disease but requires prolonged therapy to achieve hepatitis B surface antigen (HBsAg) loss. There is limited North American real-world data using non-invasive tools for fibrosis assessment and few have compared 1st generation NA or lamivudine (LAM) to tenofovir disoproxil fumarate (TDF). AIM: To assess impact of NA on virological response and fibrosis regression using liver stiffness measurement (LSM) (i.e., FibroScan®). METHODS: Retrospective, observational cohort study from the Canadian HBV Network. Data collected included demographics, NA, HBV DNA, alanine aminotransferase (ALT), and LSM. Patients were HBV monoinfected patients, treatment naïve, and received 1 NA with minimum 1 year follow-up. RESULTS: In 465 (median 49 years, 37% female, 35% hepatitis B e antigen+ at baseline, 84% Asian, 6% White, and 9% Black). Percentage of 64 (n = 299) received TDF and 166 were LAM-treated with similar median duration of 3.9 and 3.7 years, respectively. The mean baseline LSM was 11.2 kPa (TDF) vs 8.3 kPa (LAM) (P = 0.003). At 5-year follow-up, the mean LSM was 7.0 kPa in TDF vs 6.7 kPa in LAM (P = 0.83). There was a significant difference in fibrosis regression between groups (i.e., mean -4.2 kPa change in TDF and -1.6 kPa in LAM, P < 0.05). The last available data on treatment showed that all had normal ALT, but more TDF patients were virologically suppressed (< 10 IU/mL) (n = 170/190, 89%) vs LAM-treated (n = 35/58, 60%) (P < 0.05). None cleared HBsAg. CONCLUSION: In this real-world North American study, approximately 5 years of NA achieves liver fibrosis regression rarely leads to HBsAg loss.

Safety and efficacy of vebicorvir administered with entecavir in treatment-naïve patients with chronic hepatitis B virus infection.

BACKGROUND & AIMS: Nucleos(t)ide reverse transcriptase inhibitors do not completely suppress HBV DNA in chronic HBV infection (cHBV). Vebicorvir (VBR) is an investigational core inhibitor that interferes with multiple aspects of HBV replication. This phase II trial evaluated the safety and efficacy of VBR in combination with entecavir (ETV) in treatment-naïve patients with cHBV. METHODS: HBeAg-positive, treatment-naïve patients without cirrhosis were randomised 1:1 in a double-blind manner to once-daily VBR 300 mg+ETV 0.5 mg or placebo (PBO)+ETV 0.5 mg for 24 weeks. The primary endpoint was change in mean log10 HBV DNA from Baseline to Week 12 and 24. RESULTS: All patients in both treatment groups (PBO+ETV: 12/12; VBR+ETV: 13/13) completed the study. At Week 12, VBR+ETV led to a greater mean (SD) reduction from Baseline in log10 IU/ml HBV DNA (-4.45 [1.03]) vs. PBO+ETV (-3.30 [1.18]; p = 0.0077). At Week 24, VBR+ETV led to a greater reduction from Baseline in log10 IU/ml HBV DNA (-5.33 [1.59]) vs. PBO+ETV (-4.20 [0.98]; p = 0.0084). Greater mean reductions in pregenomic RNA were observed at Week 12 and 24 in patients receiving VBR+ETV vs. PBO+ETV (p <0.0001 and p <0.0001). Changes in viral antigens were similar in both groups. No drug interaction between VBR and ETV was observed. Two patients experienced HBV DNA rebound during treatment, with no resistance breakthrough detected. The safety of VBR+ETV was similar to PBO+ETV. All treatment-emergent adverse events and laboratory abnormalities were Grade 1/2. There were no deaths, serious adverse events, or evidence of drug-induced liver injury. CONCLUSIONS: In this 24-week study, VBR+ETV provided additive antiviral activity over PBO+ETV in treatment-naïve patients with cHBV, with a favourable safety and tolerability profile. CLINICAL TRIAL NUMBER: NCT03577171 LAY SUMMARY: Hepatitis B is a long-lasting viral infection of the liver. Current treatments can suppress hepatitis B virus but do not offer the opportunity of cure, hence, new treatment approaches are required. Herein, we show that the combination of the novel core inhibitor vebicorvir with an existing antiviral (entecavir) in treatment-naïve patients chronically infected with hepatitis B virus demonstrated greater antiviral activity than entecavir alone. Additionally, vebicorvir was safe and well tolerated. Thus, further studies evaluating its potential role in the treatment of chronic hepatitis B are warranted.

Safety and efficacy of vebicorvir in virologically suppressed patients with chronic hepatitis B virus infection.

BACKGROUND & AIMS: HBV nucleos(t)ide reverse transcriptase inhibitors (NrtIs) do not completely suppress HBV replication. Previous reports indicate persistent viremia during NrtI treatment despite HBV DNA being undetectable. HBV core inhibitors may enhance viral suppression when combined with NrtIs. This phase II trial (NCT03576066) evaluated the efficacy and safety of the investigational core inhibitor, vebicorvir (VBR), in virologically- suppressed patients on NrtIs. METHODS: Non-cirrhotic, NrtI-suppressed patients with chronic HBV were randomised to VBR 300 mg once daily or matching placebo (PBO) for 24 weeks. Treatment was stratified by hepatitis B e antigen (HBeAg) status. The primary endpoint was change from Baseline in serum HBeAg or hepatitis B surface antigen (HBsAg) after 24 weeks. RESULTS: Of 73 patients enrolled, 47 were HBeAg positive and 26 were HBeAg negative. In HBeAg-positive and -negative patients, there were no differences in the change from Baseline at Week 24 for HBsAg or HBeAg. Using a novel, high-sensitivity assay to detect HBV DNA, a greater proportion of patients with detectable HBV DNA at Baseline achieved undetectable HBV DNA at Week 24 in the VBR+NrtI vs. PBO+NrtI group. In HBeAg-positive patients, a greater change from Baseline in HBV pregenomic (pg)RNA was observed at Week 24 with VBR+NrtI vs. PBO+NrtI. Treatment-emergent adverse events (TEAEs) in VBR+NrtI patients included upper respiratory tract infection, nausea, and pruritus. No serious adverse events, Grade 4 TEAEs, or deaths were reported. CONCLUSIONS: In this 24-week study, VBR+NrtI demonstrated a favourable safety and tolerability profile. While there were no significant changes in viral antigen levels, enhanced viral suppression was demonstrated by greater changes in DNA and pgRNA with the addition of VBR compared to NrtI alone. CLINICAL TRIALS NUMBER: NCT03576066. LAY SUMMARY: Core inhibitors represent a novel approach for the treatment of chronic hepatitis B virus (HBV) infection, with mechanisms of action distinct from existing treatments. In this study, vebicorvir added to existing therapy reduced HBV replication to a greater extent than existing treatment and was generally safe and well tolerated.

HBsAg Loss as a Treatment Endpoint for Chronic HBV Infection: HBV Cure.

Despite the availability of effective vaccines and antiviral therapy over the past two to three decades, chronic hepatitis B virus (HBV) infection remains a major global health threat as a leading cause of cirrhosis and liver cancer. Functional HBV cure defined as hepatitis B surface antigen (HBsAg) loss and undetectable serum HBV DNA is associated with improved clinical outcomes in patients with chronic HBV infection. However, spontaneous loss of HBsAg is rare and occurs in only 1% of all HBsAg-positive individuals annually. Furthermore, the rate of functional cure with currently available antiviral therapy is even lower, <1% patients on treatment per year. Nonetheless, HBsAg loss has become the new target or therapeutic endpoint for antiviral treatment. Recently, there has been much excitement surrounding the development of novel antiviral agents such as small interfering RNA (siRNA), core assembly modulators (CAMs), nucleic acid polymers (NAPs) among others, which may be used in combination with nucleos(t)ide analogs and possibly immunomodulatory therapies to achieve functional cure in a significant proportion of patients with chronic hepatitis B. Novel assays with improved sensitivity for detection of very low levels of HBsAg and to determine the source of HBsAg production will also be required to measure efficacy of newer antiviral treatments for HBV cure. In this narrative review, we will define HBV cure, discuss various sources of HBsAg production, evaluate rates of HBsAg loss with current and future antiviral agents, review clinical factors associated with spontaneous HBsAg loss, and explore clinical implications of functional cure.

Molecular epidemiology and clinical characteristics of hepatitis D virus infection in Canada.

Background & Aims: HDV affects 4.5-13% of chronic hepatitis B (CHB) patients globally, yet the prevalence of HDV infection in Canada is unknown. To investigate the prevalence, genotype, demographics, and clinical characteristics of HDV in Canada, we conducted a retrospective analysis of (1) HDV antibody and RNA positivity among referred specimens, and (2) a cross-sectional subset study of 135 HDV seropositive +/-RNA (HDV+) patients compared with 5,132 HBV mono-infected patients in the Canadian HBV Network. Methods: Anti-HDV IgG-positive specimens collected between 2012 and 2019 were RNA tested and the genotype determined. Patients enrolled in the Canadian HBV Network were >18 years of age and HBsAg-positive. Clinical data collected included risk factors, demographics, comorbidities, treatment, fibrosis assessment, and hepatic complications. Results: Of the referred patients, 338/7,080 (4.8%, 95% CI 4.3-5.3) were HDV seropositive, with 219/338 RNA-positive (64.8%, 95% CI 59.6-69.7). The HDV+ cohort were more likely to be born in Canada, to be White or Black/African/Caribbean than Asian, and reporting high-risk behaviours, compared with HBV mono-infected patients. Cirrhosis, complications of end-stage liver disease, and liver transplantation were significantly more frequent in the HDV+ cohort. HDV viraemia was significantly associated with elevated liver transaminases and cirrhosis. Five HDV genotypes were observed among referred patients but no association between genotype and clinical outcome was detected within the HDV+ cohort. Conclusions: Nearly 5% of the Canadian HBV referral population is HDV seropositive. HDV infection is highly associated with risk behaviours and both domestic and foreign-born patients with CHB. HDV was significantly associated with progressive liver disease highlighting the need for increased screening and surveillance of HDV in Canada. Lay summary: Evidence of HDV infection was observed in approximately 5% of Canadians who were infected with HBV referred to medical specialists. HDV-positive patients were more likely to be male, born in Canada, or White or Black/African/Caribbean compared to Asian, and to have reported high-risk activities such as injection or intranasal drug use or high-risk sexual contact compared with patients infected with only HBV. Patients infected with HDV were also more likely to suffer severe liver disease, including liver cancer, compared with HBV mono-infected patients.