Bulevirtide Combined with Pegylated Interferon for Chronic Hepatitis D

Meeting Report of the 37th International Conference on Antiviral Research in Gold Coast, Australia, May 20-24, 2024, organized by the International Society for Antiviral Research

The 37th International Conference on Antiviral Research (ICAR) was held in Gold Coast, Australia, May 20-24, 2024. ICAR 2024 featured over 75 presentations along with two poster sessions and special events, including those specifically tailored for trainees and early-career scientists. The meeting served as a platform for the exchange of cutting-edge research, with presentations and discussions covering novel antiviral compounds, vaccine development, clinical trials, and therapeutic advancements. A comprehensive array of topics in antiviral science was covered, from the latest breakthroughs in antiviral drug development to innovative strategies for combating emerging viral threats. The keynote presentations provided fascinating insight into two diverse areas fundamental to medical countermeasure development and use, including virus emergence at the human-animal interface and practical considerations for bringing antivirals to the clinic. Additional sessions addressed a variety of timely post-pandemic topics, such as the hunt for broad spectrum antivirals, combination therapy, pandemic preparedness, application of in silico tools and AI in drug discovery, the virosphere, and more. Here, we summarize all the presentations and special sessions of ICAR 2024 and introduce the 38th ICAR, which will be held in Las Vegas, USA, March 17-21, 2025.

Virological markers for clinical trials in chronic viral hepatitis

Chronic hepatitis virus infections remain a major public health problem, despite significant therapeutic advances over the past two decades. Considerable progress has been made in the treatment of chronic viral hepatitis, but continued efforts are needed to develop and bring to market new drugs to fill the gaps in the current therapeutic armamentarium. Thus, clinical trials to assess the safety and efficacy of these new therapeutic approaches, including the selection of reliable and objective treatment endpoints, are still needed. Virological biomarkers play an important role in the diagnosis, monitoring, and evaluation of antiviral treatment efficacy. They are often used as primary or secondary endpoints in the evaluation of new treatments for chronic viral hepatitis. However, these markers are not all equally informative. The aim of this review article is to provide a comprehensive overview of the available virological tests for chronic viral hepatitis due to hepatitis B, D, C and E viruses, the information they provide and lack, the specific challenges associated with each, and their use in clinical trials of new treatments.

MiRNome Profiling of Circulating Extracellular Vesicles in Patients With Chronic Hepatitis D Undergoing Pegylated Interferon Alpha Treatment

Micro-RNAs (miRNAs) are involved in the modulation of viral replication and host immune antiviral response. Using next-generation sequencing, we investigated the miRNome profile of circulating extracellular vesicles in 20 patients with chronic hepatitis D virus (HDV) infection undergoing pegylated interferon alpha (Peg-IFNα) treatment. Circulating miRNAs' expression was analysed according to virologic response (i.e., HDV RNA clearance maintained at least 6 months after the end of therapy). Overall, 8 patients (40%) achieved a virologic response to Peg-IFNα treatment. At baseline, 14 miRNAs were differentially expressed between responders and non-responders; after 6 months of Peg-IFNα treatment, 7 miRNAs (miR-155-5p, miR-1246, miR-423-3p, miR-760, miR-744-5p, miR-1307-3p and miR-146a-5p) were consistently de-regulated. Among de-regulated miRNAs, miR-155-5p showed an inverse correlation with HDV RNA (at baseline: rs = -0.39, p = 0.092; at 6 months: rs = -0.53, p = 0.016) and hepatitis B surface antigen (HBsAg) (at baseline: rs = -0.49, p = 0.028; at 6 months: rs-0.71, p < 0.001). At logistic regression analysis, both miR-155-5p (at baseline: OR = 4.52, p = 0.022; at 6 months: OR = 5.30, p = 0.029) and HDV RNA (at baseline: OR = 0.19, p = 0.022; at 6 months: OR = 0.38, p = 0.018) resulted significantly associated to virologic response. Considering that Peg-IFNα still has a relevant role in the treatment of patients with chronic hepatitis D infection, the assessment of EV miR-155-5p may represent an additional valuable tool for the management of HDV patients undergoing Peg-IFNα treatment.

Hepatitis Delta Coinfection Rates and All-Cause Mortality Among Hepatitis B-Infected Veterans in the USA

Screening for hepatitis D virus (HDV) is recommended for all individuals with hepatitis B virus (HBV) infection. Coinfected individuals experience more severe liver-related outcomes. We determined the HDV testing and coinfection rates and all-cause mortality among those infected with HBV. We used the US Department of Veterans Affairs (VA) healthcare system's national databases to identify individuals with HBV infection. We determined the proportion of individuals referred to gastroenterologists/hepatologists, or infectious diseases providers, and the proportion screened and tested positive for HDV. We calculated the HBV treatment rates, defined as ≥ 3 months of continuous prescription with an approved drug. Finally, we calculated all-cause mortality stratified by HDV coinfection and HBV treatment status. Among 44,951 individuals with at least one positive HBsAg, HBeAg or HBV DNA test, 5964 (13.3%) were screened for HDV (180 [3.0%] tested positive), and 28,291 (62.9%) were referred to gastroenterology/hepatology or infectious diseases. Treatment for HBV was prescribed for 73 (40.5%) of HDV-coinfected and 2425 (41.9%) HDV-uninfected individuals. All-cause mortality rate per 100 person-years was lower among those without HDV coinfection (2.98 for untreated HBV, 2.53 for treated HBV; p < 0.001) compared with those with HDV coinfection (5.14 for untreated HBV, 3.0 for treated HBV; p = 0.02). Kaplan-Meier curves demonstrated a significantly higher mortality among HDV-coinfected individuals who were not treated for HBV (log-rank p < 0.0001). Screening rates for HDV among HBV-infected individuals are suboptimal. While HDV coinfection is associated with higher all-cause mortality, HBV treatment may confer a survival benefit.

Viral etiologies of acute liver failure

Acute liver failure (ALF) is a rare cause of liver-related mortality worldwide, with an estimated annual global incidence of more than one million cases. While drug-induced liver injury, including acetaminophen toxicity, is the leading cause of ALF in the Western world, viral infections remain a significant cause of ALF and the most common cause in many developing nations. Given the high mortality rates associated with ALF, healthcare providers should be aware of the broad range of viral infections that have been implicated to enable early diagnosis, rapid treatment initiation when possible, and optimal management, which may include liver transplantation. This review aims to provide a summary of viral causes of ALF, diagnostic approaches, treatment options, and expected outcomes.