Adaptive multi-epitope targeting and avidity-enhanced nanobody platform for ultrapotent, durable antiviral therapy.

Pathogens constantly evolve and can develop mutations that evade host immunity and treatment. Addressing these escape mechanisms requires targeting evolutionarily conserved vulnerabilities, as mutations in these regions often impose fitness costs. We introduce adaptive multi-epitope targeting with enhanced avidity (AMETA), a modular and multivalent nanobody platform that conjugates potent bispecific nanobodies to a human immunoglobulin M (IgM) scaffold. AMETA can display 20+ nanobodies, enabling superior avidity binding to multiple conserved and neutralizing epitopes. By leveraging multi-epitope SARS-CoV-2 nanobodies and structure-guided design, AMETA constructs exponentially enhance antiviral potency, surpassing monomeric nanobodies by over a million-fold. These constructs demonstrate ultrapotent, broad, and durable efficacy against pathogenic sarbecoviruses, including Omicron sublineages, with robust preclinical results. Structural analysis through cryoelectron microscopy and modeling has uncovered multiple antiviral mechanisms within a single construct. At picomolar to nanomolar concentrations, AMETA efficiently induces inter-spike and inter-virus cross-linking, promoting spike post-fusion and striking viral disarmament. AMETA's modularity enables rapid, cost-effective production and adaptation to evolving pathogens.

Single-cell analysis of memory B cells from top neutralizers reveals multiple sites of vulnerability within HCMV Trimer and Pentamer.

Human cytomegalovirus (HCMV) can cause severe diseases in fetuses, newborns, and immunocompromised individuals. Currently, no vaccines are approved, and treatment options are limited. Here, we analyzed the human B cell response of four HCMV top neutralizers from a cohort of 9,000 individuals. By single-cell analyses of memory B cells targeting the pentameric and trimeric HCMV surface complexes, we identified vulnerable sites on the shared gH/gL subunits as well as complex-specific subunits UL128/130/131A and gO. Using high-resolution cryogenic electron microscopy, we revealed the structural basis of the neutralization mechanisms of antibodies targeting various binding sites. Moreover, we identified highly potent antibodies that neutralized a broad spectrum of HCMV strains, including primary clinical isolates, that outperform known antibodies used in clinical trials. Our study provides a deep understanding of the mechanisms of HCMV neutralization and identifies promising antibody candidates to prevent and treat HCMV infection.

Cytomegalovirus Therapy: Role of Letermovir in Prophylaxis and Treatment in Transplant Recipients.

Cytomegalovirus (CMV) is a common viral pathogen in the transplant population and is associated with significant morbidity and mortality. CMV prevention is paramount; however, selecting the best preventive strategy depends on many factors including donor-recipient CMV serostatus, transplant-specific risks, antiviral toxicities and cost. Novel CMV therapeutics such as letermovir (LTV) are desperately needed to optimize CMV management. Uniquely among CMV antiviral therapies, LTV inhibits the viral terminase complex in the CMV DNA synthesis pathway and disrupts viral genome packaging. Further, it lacks side effects frequently associated with other CMV antiviral therapies and evades common mechanisms of resistance. LTV is approved by the US Food and Drug Administration for CMV prevention in adult CMV-seropositive hematopoietic cell transplant recipients but is increasingly applied off-label for prophylaxis and treatment. This review summarizes important concepts of CMV management in transplantation, with a specific focus on LTV pharmacology and clinical experience to date alongside future prospects for its application.

The ZCCHC14/TENT4 complex is required for hepatitis A virus RNA synthesis.

Despite excellent vaccines, resurgent outbreaks of hepatitis A have caused thousands of hospitalizations and hundreds of deaths within the United States in recent years. There is no effective antiviral therapy for hepatitis A, and many aspects of the hepatitis A virus (HAV) replication cycle remain to be elucidated. Replication requires the zinc finger protein ZCCHC14 and noncanonical TENT4 poly(A) polymerases with which it associates, but the underlying mechanism is unknown. Here, we show that ZCCHC14 and TENT4A/B are required for viral RNA synthesis following translation of the viral genome in infected cells. Cross-linking immunoprecipitation sequencing (CLIP-seq) experiments revealed that ZCCHC14 binds a small stem-loop in the HAV 5' untranslated RNA possessing a Smaug recognition-like pentaloop to which it recruits TENT4. TENT4 polymerases lengthen and stabilize the 3' poly(A) tails of some cellular and viral mRNAs, but the chemical inhibition of TENT4A/B with the dihydroquinolizinone RG7834 had no impact on the length of the HAV 3' poly(A) tail, stability of HAV RNA, or cap-independent translation of the viral genome. By contrast, RG7834 inhibited the incorporation of 5-ethynyl uridine into nascent HAV RNA, indicating that TENT4A/B function in viral RNA synthesis. Consistent with potent in vitro antiviral activity against HAV (IC50 6.11 nM), orally administered RG7834 completely blocked HAV infection in Ifnar1-/- mice, and sharply reduced serum alanine aminotransferase activities, hepatocyte apoptosis, and intrahepatic inflammatory cell infiltrates in mice with acute hepatitis A. These results reveal requirements for ZCCHC14-TENT4A/B in hepatovirus RNA synthesis, and suggest that TENT4A/B inhibitors may be useful for preventing or treating hepatitis A in humans.

Insight into Preventing Global Dengue Spread: Nanoengineered Niclosamide for Viral Infections.

Millions of cases of dengue virus (DENV) infection yearly from Aedes mosquitoes stress the need for effective antivirals. No current drug effectively combats dengue efficiently. Transient immunity and severe risks highlight the need for broad-spectrum antivirals targeting all serotypes of DENV. Niclosamide, an antiparasitic, shows promising antiviral activity against the dengue virus, but enhancing its bioavailability is challenging. To overcome this issue and enable niclosamide to address the global dengue problem, nanoengineered niclosamides can be the solution. Not only does it address cost issues but also with its broad-spectrum antiviral effects nanoengineered niclosamide offers hope in addressing the current health crisis associated with DENV and will play a crucial role in combating other arboviruses as well.

Drug Resistance Assessed in a Phase 3 Clinical Trial of Maribavir Therapy for Refractory or Resistant Cytomegalovirus Infection in Transplant Recipients.

BACKGROUND: This drug resistance analysis of a randomized trial includes 234 patients receiving maribavir and 116 receiving investigator-assigned standard therapy (IAT), where 56% and 24%, respectively, cleared cytomegalovirus DNA at week 8 (treatment responders). METHODS: Baseline and posttreatment plasma samples were tested for mutations conferring drug resistance in viral genes UL97, UL54, and UL27. RESULTS: At baseline, genotypic testing revealed resistance to ganciclovir, foscarnet, or cidofovir in 56% of patients receiving maribavir and 68% receiving IAT, including 9 newly phenotyped mutations. Among them, 63% (maribavir) and 21% (IAT) were treatment responders. Detected baseline maribavir resistance mutations were UL27 L193F (n = 1) and UL97 F342Y (n = 3). Posttreatment, emergent maribavir resistance mutations were detected in 60 (26%) of those randomized to maribavir, including 49 (48%) of 103 nonresponders and 25 (86%) of the 29 nonresponders where viral DNA initially cleared then rebounded while on maribavir. The most common maribavir resistance mutations were UL97 T409M (n = 34), H411Y (n = 26), and C480F (n = 21), first detected 26 to 130 (median 56) days after starting maribavir. CONCLUSIONS: Baseline maribavir resistance was rare. Drug resistance to standard cytomegalovirus antivirals did not preclude treatment response to maribavir. Rebound in plasma cytomegalovirus DNA while on maribavir strongly suggests emerging drug resistance. CLINICAL TRIALS REGISTRATION: NCT02931539.

Comparative Emergence of Maribavir and Ganciclovir Resistance in a Randomized Phase 3 Clinical Trial for Treatment of Cytomegalovirus Infection.

BACKGROUND: Among 547 patients receiving maribavir or valganciclovir for first-episode cytomegalovirus infection after hematopoietic cell transplant, the treatment response rate was 69.6% and 77.4% respectively. Development of maribavir and ganciclovir resistance was compared after receiving either drug. METHODS: Viral mutations conferring drug resistance were analyzed in plasma DNA extracts at baseline and post-treatment. RESULTS: Prior antiviral drug exposure was limited, with only 2 instances of baseline drug resistance detected. An equal number (n=241) received valganciclovir or maribavir for at least 21 days (median 55-56 days). Among them, drug resistance mutations were detected in 24 (10%) maribavir recipients at 35-125 days (median 56) after starting therapy, including in 12 of 14 who experienced a viral load rebound while on therapy. Ganciclovir resistance mutations developed in 6 (2.5%) valganciclovir recipients at 66-110 days (median 90). One maribavir recipient developed a novel UL97 gene mutation (P-loop substitution G343A) that conferred strong maribavir and ganciclovir resistance in vitro. Viral clearance was confirmed in 17 (74%) of 23 patients with emergent maribavir resistance after re-treatment with an alternative CMV antiviral drug. CONCLUSION: After 3-8 weeks of therapy, maribavir resistance emerged earlier and more frequently than ganciclovir resistance but was usually treatable using alternative therapy. CLINICAL TRIALS REGISTRATION: NCT02927067 (AURORA).

Fibrotic Burden in Patients With Hepatitis B Virus-Related Cirrhosis Is Independently Associated With Poorer Kidney Outcomes.

BACKGROUND: We investigated whether higher fibrotic burden was independently associated with poorer kidney outcomes in patients with hepatitis B virus (HBV)-related cirrhosis. METHODS: A total of 1691 patients with radiologically diagnosed HBV-related cirrhosis but without baseline chronic kidney disease (CKD) who underwent transient elastography (TE) between March 2012 and August 2018 were selected. The study outcome was the composite of development of incident CKD, defined as the occurrence of estimated glomerular filtration rate (eGFR) <60 mL/minute/1.73 m2 or proteinuria (≥1+ on dipstick test) on 2 consecutive measurements during follow-up, 50% decline in eGFR or onset of end-stage kidney disease (initiation of chronic dialysis), or all-cause mortality. RESULTS: The mean age was 53.4 years and 1030 (60.9%) patients were male. During 8379 person-years of follow-up (median 5.2 years), 60 (3.5%) patients experienced study outcomes. When stratified according to TE-defined fibrotic burden, multivariable Cox models revealed that risk of poorer kidney outcomes was 2.77-fold (95% confidence interval, 1.16-6.63; P < .001) higher in patients with liver stiffness range indicating cirrhosis (≥11.7 kPa), compared to those without significant liver fibrosis (<7.9 kPa). These associations remained significant even after adjusting for vigorous confounders. CONCLUSIONS: Higher fibrotic burden assessed using TE was independently associated with poorer kidney outcomes in patients with HBV-related cirrhosis.

Effects of tenofovir disoproxil fumarate on intrahepatic viral burden and liver immune microenvironment in patients with chronic hepatitis B.

BACKGROUND: The impact of nucleos(t)ide analogues on intrahepatic viral burden and immune microenvironment in patients with chronic hepatitis B (CHB) is not clear. OBJECTIVE: We aimed to characterise the effects of tenofovir disoproxil fumarate (TDF) on intrahepatic viral burden and the liver immune microenvironment in patients with CHB. DESIGN: Core liver biopsies were collected at baseline and year 3 from patients with CHB with minimally raised serum alanine aminotransferase in a double-blind placebo-controlled trial (NCT01522625). Paired biopsies were analysed by RNA-sequencing (n=119 pairs), a custom multiplex immunofluorescence assay (n=30 pairs), and HBV-targeted long-read DNA sequencing (n=49 pairs). RESULTS: Both non-integrated and integrated HBV DNA were present in all patients at baseline, with >65% having interchromosomal translocations. Treatment significantly reduced the frequency of HBV core+ hepatocytes and intrahepatic (integrated and non-integrated) HBV DNA, but had no effect on HBsAg+ hepatocytes. Clonally expanded integrations were enriched for HBsAg coding regions and showed dysregulation of nearby genes. At baseline, there was significant enrichment of intrahepatic CD8+ T cell proximity to HBV core+ hepatocytes, but not to HBsAg+ cells. The densities of T cells and B cells were significantly reduced by TDF. Transcriptomic analyses found TDF induced widespread downregulation of immune-related genes including inhibitory and regulatory genes. CONCLUSION: TDF significantly reduced intrahepatic integrated and non-integrated HBV DNA, exerting disparate effects on HBV core+ and HBsAg+ cells and on different immune cell subsets. Our data suggest there may be differential cytotoxic T cell-mediated killing of HBV core+ versus HBsAg+ hepatocytes, providing insights for HBV cure strategies.

'Unusual' HCV genotype subtypes: origin, distribution, sensitivity to direct-acting antiviral drugs and behaviour on antiviral treatment and retreatment.

The high genetic diversity of hepatitis C virus (HCV) has led to the emergence of eight genotypes and a large number of subtypes in limited geographical areas. Currently approved pangenotypic DAA regimens have been designed and developed to be effective against the most common subtypes (1a, 1b, 2a, 2b, 2c, 3a, 4a, 5a and 6a). However, large populations living in Africa and Asia, or who have migrated from these regions to industrialised countries, are infected with 'unusual', non-epidemic HCV subtypes, including some that are inherently resistant to currently available direct-acting antiviral (DAA) drugs due to the presence of natural polymorphisms at resistance-associated substitution positions. In this review article, we describe the origin and subsequent global spread of HCV genotypes and subtypes, the current global distribution of common and unusual HCV subtypes, the polymorphisms naturally present in the genome sequences of unusual HCV subtypes that may confer inherently reduced susceptibility to DAA drugs and the available data on the response of unusual HCV subtypes to first-line HCV therapy and retreatment. We conclude that the problem of unusual HCV subtypes that are inherently resistant to DAAs and its threat to the global efforts to eliminate viral hepatitis are largely underestimated and warrant vigorous action.

Novel function of MOTS-c in mitochondrial remodelling contributes to its antiviral role during HBV infection.

OBJECTIVE: Hepatitis B virus (HBV) infection causes substantial harm to mitochondrial activity, which hinders the development of effective treatments for chronic hepatitis B (CHB). The discovery of the mitochondrial-derived short peptide MOTS-c, which possesses multiple bioactivities, offers a promising new approach in treating HBV infection. This study aims to explore the diagnostic and therapeutic potential of MOTS-c in HBV-related diseases and its molecular mechanism. DESIGN: In total, 85 healthy subjects and 404 patients with HBV infection, including 20 clinical treatment cohorts, were recruited for this study. MOTS-c levels were measured by ELISA and its diagnostic value was evaluated by receiving operating characteristic curve analysis. The therapeutic effect of MOTS-c was observed in multiple HBV-infected mice and cells through various techniques, including transcriptomic sequencing, flow cytometry, immunofluorescence and electron microscopy. Additionally, MOTS-c's potential interaction with myosin-9 (MYH9) and actin was predicted using immunoprecipitation, proteomics and target prediction software. RESULTS: MOTS-c negatively correlates with HBV DNA expression (R=-0.71), and its AUC (the area under the curve) for distinguishing CHB from healthy controls is 0.9530, and IA (immune reactive) from IC (inactive HBV carrier) is 0.8689. Inhibition of HBV replication (with a 50-70% inhibition rate) was observed alongside improved liver function without notable toxicity in vitro or in vivo. MOTS-c was found to promote mitochondrial biogenesis and enhance the MAVS (mitochondrial antiviral signalling protein) signalling pathway. The impact is dependent on MOTS-c's ability to regulate MYH9-actin-mediated mitochondrial homeostasis. CONCLUSION: MOTS-c has the potential to serve as a biomarker for the progression of HBV infection while also enhancing antiviral efficacy. These findings present a promising innovative approach for effectively treating patients with CHB. Furthermore, our research uncovers a novel role for MOTS-c in regulating MYH9-actin-mediated mitochondrial dynamics and contributing to mitochondrial biogenesis.

Non-linear association of baseline viral load with on-treatment hepatocellular carcinoma risk in chronic hepatitis B.

OBJECTIVE: The association between baseline pretreatment serum HBV DNA levels and on-treatment hepatocellular carcinoma (HCC) risk remains controversial in patients with chronic hepatitis B (CHB). We aimed to investigate the association between baseline HBV viral load and on-treatment HCC risk in CHB patients without cirrhosis. DESIGN: Using a multicentre historical cohort study including 4693 hepatitis B e antigen (HBeAg)-negative and HBeAg-positive, adult CHB patients without cirrhosis who initiated antiviral treatment, HCC risk was estimated by baseline HBV viral load as a categorical variable. RESULTS: During a median of 7.6 years of antiviral treatment, 193 patients developed HCC (0.53 per 100 person- years). Baseline HBV DNA level was independently associated with on-treatment HCC risk in a non-linear, parabolic pattern. Patients with moderate baseline viral loads (5.00-7.99 log10 IU/mL) exhibited the highest HCC risk (HR, 2.60; p<0.001), followed by those with low viral loads (3.30-4.99 log10 IU/mL; HR, 1.66; p=0.11). Patients with high viral loads (≥8.00 log10 IU/mL) presented the lowest HCC risk. Particularly, patients with baseline HBV DNA levels 6.00-6.99 log10 IU/mL had the highest on-treatment HCC risk (HR, 3.36; p<0.001) compared with those with baseline HBV DNA levels≥8.00 log10 IU/mL. These findings were more prominent among HBeAg-positive patients, younger patients, or those with less advanced hepatic fibrosis. CONCLUSION: Patients with moderate baseline viral load, particularly around 6 log10 IU/mL, demonstrated the highest on-treatment HCC risk, despite long-term antiviral treatment. Early initiation of antiviral treatment, tailored to viral load, should be considered to minimise HCC risk in adult CHB patients without cirrhosis.

Chimeric antigen receptors of HBV envelope proteins inhibit hepatitis B surface antigen secretion.

OBJECTIVES: Chronic hepatitis B (CHB) caused by HBV infection greatly increases the risk of liver cirrhosis and hepatocellular carcinoma. Hepatitis B surface antigen (HBsAg) plays critical roles in the pathogenesis of CHB. HBsAg loss is the key indicator for cure of CHB, but is rarely achieved by current approved anti-HBV drugs. Therefore, novel anti-HBV strategies are urgently needed to achieve sustained HBsAg loss. DESIGN: We developed multiple chimeric antigen receptors (CARs) based on single-chain variable fragments (scFvs, namely MA18/7-scFv and G12-scFv), respectively, targeting HBV large and small envelope proteins. Their impacts on HBsAg secretion and HBV infection, and the underlying mechanisms, were extensively investigated using various cell culture models and HBV mouse models. RESULTS: After secretory signal peptide mediated translocation into endoplasmic reticulum (ER) and secretory pathway, MA18/7-scFv and CARs blocked HBV infection and virion secretion. G12-scFv preferentially inhibited virion secretion, while both its CAR formats and crystallisable fragment (Fc)-attached versions blocked HBsAg secretion. G12-scFv and G12-CAR arrested HBV envelope proteins mainly in ER and potently inhibited HBV budding. Furthermore, G12-scFv-Fc and G12-CAR-Fc strongly suppressed serum HBsAg up to 130-fold in HBV mouse models. The inhibitory effect lasted for at least 8 weeks when delivered by an adeno-associated virus vector. CONCLUSION: CARs possess direct antiviral activity, besides the well-known application in T-cell therapy. Fc attached G12-scFv and G12-CARs could provide a novel approach for reducing circulating HBsAg.

iDVEIP: A computer-aided approach for the prediction of viral entry inhibitory peptides.

With the notable surge in therapeutic peptide development, various peptides have emerged as potential agents against virus-induced diseases. Viral entry inhibitory peptides (VEIPs), a subset of antiviral peptides (AVPs), offer a promising avenue as entry inhibitors (EIs) with distinct advantages over chemical counterparts. Despite this, a comprehensive analytical platform for characterizing these peptides and their effectiveness in blocking viral entry remains lacking. In this study, we introduce a groundbreaking in silico approach that leverages bioinformatics analysis and machine learning to characterize and identify novel VEIPs. Cross-validation results demonstrate the efficacy of a model combining sequence-based features in predicting VEIPs with high accuracy, validated through independent testing. Additionally, an EI type model has been developed to distinguish peptides specifically acting as Eis from AVPs with alternative activities. Notably, we present iDVEIP, a web-based tool accessible at http://mer.hc.mmh.org.tw/iDVEIP/, designed for automatic analysis and prediction of VEIPs. Emphasizing its capabilities, the tool facilitates comprehensive analyses of peptide characteristics, providing detailed amino acid composition data for each prediction. Furthermore, we showcase the tool's utility in identifying EIs against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2).

Association of Cytomegalovirus (CMV) DNAemia With Long-Term Mortality in a Randomized Trial of Preemptive Therapy and Antiviral Prophylaxis for Prevention of CMV Disease in High-Risk Donor Seropositive, Recipient Seronegative Liver Transplant Recipients.

In a post-hoc analysis of the association of CMV DNAemia with long-term mortality in a randomized trial of CMV preemptive therapy vs. antiviral prophylaxis in D+R- liver transplant recipients, post-intervention CMV DNAemia was associated with increased mortality after adjusting for study arm.

Cardiac Adverse Events and Remdesivir in Hospitalized Patients With COVID-19: A Post Hoc Safety Analysis of the Randomized DisCoVeRy Trial.

BACKGROUND: We aimed to evaluate the cardiac adverse events (AEs) in hospitalized patients with coronavirus disease 2019 (COVID-19) who received remdesivir plus standard of care (SoC) compared with SoC alone (control), as an association was noted in some cohort studies and disproportionality analyses of safety databases. METHODS: This post hoc safety analysis is based on data from the multicenter, randomized, open-label, controlled DisCoVeRy trial in hospitalized patients with COVID-19. Any first AE that occurred between randomization and day 29 in the modified intention-to-treat (mITT) population randomized to either remdesivir or control group was considered. Analysis was performed using Kaplan-Meier survival curves, and Kaplan-Meier estimates were calculated for event rates. RESULTS: Cardiac AEs were reported in 46 (11.2%) of 410 and 48 (11.3%) of 423 patients in the mITT population (n = 833) enrolled in the remdesivir and control groups, respectively. The difference between both groups was not significant (hazard ratio [HR], 1.0; 95% confidence interval [CI], .7-1.5; P = .98), even when serious and nonserious cardiac AEs were evaluated separately. The majority of reports in both groups were of arrhythmic nature (remdesivir, 84.8%; control, 83.3%) and were associated with a favorable outcome. There was no significant difference between the two groups in the occurrence of cardiac AE subclasses, including arrhythmic events (HR, 1.1; 95% CI, .7-1.7; P = .68). CONCLUSIONS: Remdesivir treatment was not associated with an increased risk of cardiac AEs compared with control in patients hospitalized with moderate or severe COVID-19. These results are consistent with other randomized, controlled trials and meta-analyses. Clinical Trials Registration. NCT04315948; EudraCT 2020-000936-23.

Management of vulnerable patients hospitalized for COVID-19 with remdesivir: a retrospective comparative effectiveness study of mortality in US hospitals.

BACKGROUND: COVID-19 remains a major public health concern, with continued resurgences of cases and substantial risk of mortality for hospitalized patients. Remdesivir has become standard-of-care for hospitalized COVID-19 patients. Given the continued evolution of the disease, clinical management relies on evidence from the current endemic period. METHODS: Using the PINC AI Healthcare database, effectiveness of remdesivir was evaluated among adults hospitalized with a primary diagnosis of COVID-19 between December 2021 and February 2024. Three cohorts were analysed: adults, elderly (≥65 years), and those with documented COVID-19 pneumonia. Analyses were stratified by oxygen requirements. Patients receiving remdesivir were matched to those not receiving remdesivir using propensity score matching. Cox proportional hazards models were used to examine in-hospital mortality. RESULTS: 169,965 adults hospitalized for COVID-19 were included, of which 94,129 (55.4%) initiated remdesivir in the first two days of hospitalization. Remdesivir was associated with a significantly lower mortality rate as compared to no remdesivir among patients with no supplemental oxygen charges (NSOc) (aHR [95% CI]: 14-day, 0.75 [0.69-0.82]; 28-day, 0.77 [0.72-0.83]) and among those with supplemental oxygen charges (SOc): 14-day, 0.76 [0.72-0.81]; 28-day, 0.79 [0.74-0.83]) (p<0.0001, for all). Similar findings were observed for elderly patients and those hospitalized with COVID-19 pneumonia. CONCLUSIONS: This evidence builds on learnings from randomized controlled trials from the pandemic era to inform clinical practices. Remdesivir was associated with significant reduction in mortality for hospitalized patients including the elderly and those with COVID-19 pneumonia.

HBcrAg is associated with prognosis of hepatitis B virus-related hepatocellular carcinoma in patients after hepatectomy undergoing antiviral therapy.

Serum hepatitis B core-related antigen (HBcrAg) is considered a surrogate marker of the amount and activity of intrahepatic covalently closed circular DNA. This study aimed to explore the prognostic value of HBcrAg on patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) after curative hepatectomy undergoing antiviral therapy (AVT). Data of 949 consecutive patients with HBV-related HCC undergoing curative resection between 2010 and 2013 were reviewed. Serum HBcrAg levels were measured at surgery (baseline) for all patients and at the time of 2 years postoperatively (on-treatment) for those without recurrence. Primary endpoint was tumor recurrence. High HBcrAg levels are associated with malignant phenotypes. HBcrAg independently affected both recurrence and overall survival (OS) in patients with negative hepatitis B e antigen (HBeAg-, p = .007 and p = .042, respectively) but not in their positive HBeAg (HBeAg+) counterparts (p = .100 and p = .075, respectively). Patients with high baseline HBcrAg had higher late, but not early recurrence rates than those with low baseline HBcrAg levels, regardless of HBeAg status (HBeAg+: p = .307 for early, p = .001 for late; HBeAg-: p = .937 for early, p < .001 for late). On-treatment HBcrAg independently affected late recurrence in patients stratified by both cirrhosis and HBeAg (p < .001 for all). The predictive power of HBcrAg kinetics for late recurrence was better than that of the baseline and on-treatment HBcrAg. High HBcrAg levels during long-term AVT are associated with late recurrence of HCC after hepatectomy. Combining baseline and on-treatment HBcrAg might be valuable in identifying patients at a high risk of relapse and stratifying surveillance strategies postoperatively.

Long-term use of tenofovir disoproxil fumarate increases fracture risk in elderly patients with chronic hepatitis B.

BACKGROUND & AIMS: The use of tenofovir disoproxil fumarate (TDF) is associated with a reduction in bone mineral density and an increase in bone metabolism biomarkers. However, data on clinical bone fractures remain limited. We evaluated the impact of TDF compared to entecavir on the risk of fracture in elderly patients with chronic hepatitis B (CHB). METHODS: Patients with CHB aged ≥60 years receiving entecavir or TDF between January 2008 and December 2022 were identified using a territory-wide database in Hong Kong. The risk of incident fracture in entecavir- and TDF-treated patients before and after month 24 were compared after propensity score matching. RESULTS: A total of 41,531 patients with CHB (mean age 69.8±7.8 years, 61.6% male) receiving entecavir (n = 39,897 [96.1%]) and TDF (n = 1,634 [3.9%]) were analysed. At a median follow-up of 25.3 (9.1-58.5) months, 1,733 (4.2%) patients developed incident fracture. Patients with incident fracture were more likely to have diabetes, hypertension, congestive heart failure, rheumatoid arthritis, osteoporosis, and a history of fracture. Compared with propensity score-matched entecavir-treated patients, the risk of incident fracture in TDF-treated patients was comparable in the first 24 months (weighted subdistribution hazard ratio [sHR] 0.99, 95% CI 0.56-1.73, p = 0.960) but increased after month 24 (weighted sHR 1.80, 95% CI 1.11-2.93, p = 0.019). The 24-, 60-, and 96-month cumulative incidences (95% CI) of fracture in TDF-treated and entecavir-treated patients were 2.3% (1.6%-3.4%) vs. 2.6% (1.9%-3.5%), 6.4% (5.0%-8.2%) vs. 4.7% (3.8%-6.0%), and 10.2% (8.3%-12.6%) vs. 6.8% (5.4%-8.5%), respectively. CONCLUSIONS: The risk of fracture increased with TDF treatment for ≥24 months in elderly patients with CHB. Selection of nucleos(t)ide analogues should be individualised based on age and comorbidities. IMPACT AND IMPLICATIONS: Previous literature suggested that the use of tenofovir disoproxil fumarate (TDF) is associated with a decrease in bone mineral density. However, data on the impact of TDF on long-term incident clinical fracture remains scarce. In this real-world territory-wide study of 41,531 treated patients with chronic hepatitis B in Hong Kong, patients who received TDF were at a higher risk of fracture after 2 years of treatment than those who received entecavir. Given the ageing population of patients with chronic hepatitis B and the rising prevalence of comorbidities, our findings support the current treatment guidelines that recommend selecting antiviral treatment based on age and comorbidities.

Hepatitis B virus DNA integration: Implications for diagnostics, therapy, and outcome.

Hepatitis B virus (HBV) DNA integration - originally recognised as a non-functional byproduct of the HBV life cycle - has now been accepted as a significant contributor to HBV pathogenesis and hepatitis D virus (HDV) persistence. Integrated HBV DNA is derived from linear genomic DNA present in viral particles or produced from aberrantly processed relaxed circular genomic DNA following an infection, and can drive expression of hepatitis B surface antigen (HBsAg) and HBx. DNA integration events accumulate over the course of viral infection, ranging from a few percent during early phases to nearly 100 percent of infected cells after prolonged chronic infections. HBV DNA integration events have primarily been investigated in the context of hepatocellular carcinoma development as they can activate known oncogenes and other growth promoting genes, cause chromosomal instability and, presumably, induce epigenetic alterations, promoting tumour growth. More recent evidence suggests that HBsAg expression from integrated DNA might contribute to HBV pathogenesis by attenuating the immune response. Integrated DNA provides a source for envelope proteins required for HDV replication and hence represents a means for HDV persistence. Because integrated DNA is responsible for persistence of HBsAg in the absence of viral replication it impacts established criteria for the resolution of HBV infection, which rely on HBsAg as a diagnostic marker. Integrated HBV DNA has been useful in assessing the turnover of infected hepatocytes which occurs during all phases of chronic hepatitis B including the initial phase of infection historically termed immune tolerant. HBV DNA integration has also been shown to impact the development of novel therapies targeting viral RNAs.