Key Clinical Breakthroughs for Hepatitis B Treatment
Recent data from a late-breaker presentation highlights Imdusiran's potential to achieve a functional cure in chronic hepatitis B (cHBV) patients when paired with VTP-300 and low-dose nivolumab.
In the Phase 1a/1b clinical trial, the oral PD-L1 inhibitor AB-101 demonstrated safety and tolerance, showcasing high receptor occupancy without causing liver dysfunction in cHBV patients.
Arbutus Biopharma Corporation (Nasdaq: ABUS), a pioneering clinical-stage biopharmaceutical company dedicated to advancing treatments for infectious diseases, has presented compelling evidence at the European Association for the Study of the Liver (EASL) Congress 2025. Their focus has been on two promising assets: Imdusiran, an RNAi therapeutic, and AB-101, an oral PD-L1 inhibitor.
During a late-breaker poster presentation, significant findings were revealed from the Phase 2a clinical trial (IM-PROVE II, AB-729-202). This trial evaluated the efficacy of Imdusiran (60mg every 8 weeks) alongside a stable nucleos(t)ide analogue (NA) therapy for 24 weeks. The exciting data emerges from various groups of cHBV patients, including those treated with Barinthus Biotherapeutic's VTP-300 supplemented with low-dose nivolumab.
Key Findings from Clinical Trials
Noteworthy highlights from the data include:
- In Group C, three patients who received nivolumab showed HBsAg loss (HBsAg < LLOQ) by the end of the treatment period (week 48) and subsequently seroconverted. All three had baseline HBsAg levels below 1000 IU/mL.
- Of those in Group C with baseline HBsAg <1000 IU/mL, 25% (2 out of 8) achieved functional cure, contributing to an overall functional cure rate of 15.3% in this group.
- Most participants treated with Imdusiran managed to maintain HBsAg levels consistently lower than their pre-treatment values during the follow-up period.
- Compared to the placebo Group B, a greater number of patients treated with Imdusiran and VTP-300 (Group A) successfully remained off NA therapy, even without achieving a functional cure.
- The combination treatment was well tolerated, with no serious adverse events or early discontinuations reported, and a lack of immune-related adverse effects, such as thyroid abnormalities.
Dr. Grace Lai-Hung Wong, a prominent professor at The Chinese University of Hong Kong, remarked on the trial's success: “The clinical trial demonstrated a clear benefit in lowering HBsAg with Imdusiran before introducing additional therapies aimed at stimulating HBV-specific immune responses. The findings indicate that adding low-dose nivolumab enhances HBsAg loss and functional cure rates in CHB patients.”
Across all Phase 2a studies to date for Imdusiran, Arbutus has reported a total of eight patients achieving functional cure, with seven of those having baseline HBsAg levels below 1000 IU/mL.
Insights on AB-101 and Its Role
At EASL, Arbutus also presented compelling pre-clinical and clinical findings regarding AB-101. This compound, currently in its Phase 1a/1b clinical trial (AB-101-001), focuses on therapeutics for cHBV. Data from the first cohort receiving 10mg of AB-101 once daily for 28 days showed it was well tolerated. Notably, PD-L1 receptor occupancy in these patients was on par with healthy volunteers taking repeated doses of AB-101, and crucially, no immune-related adverse events were reported.
In understanding the significance of these findings, it’s important to note that hepatitis B is a serious liver infection caused by the hepatitis B virus (HBV). The effects of chronic HBV infection can be devastating, resulting in complications like cirrhosis and liver cancer. Unfortunately, millions are affected globally, underlining the urgency of effective treatment options.
About Arbutus Biopharma
Arbutus Biopharma Corporation (Nasdaq: ABUS) stands at the forefront of innovative approaches to combat infectious diseases. The company is committed to developing Imdusiran (AB-729) and the oral PD-L1 inhibitor AB-101 as therapeutic strategies for chronic HBV infection. In a complementary effort, Arbutus is working closely with its licensee, Genevant Sciences, to protect its intellectual property, which is at the center of ongoing legal actions against major pharmaceutical companies involving COVID-19 vaccines.
Patients and stakeholders interested in the latest updates from Arbutus can explore the implications of these breakthroughs by visiting the official Arbutus website.
Frequently Asked Questions
What is the significance of the Phase 2a clinical trial for Imdusiran?
The Phase 2a clinical trial for Imdusiran highlights its potential to achieve functional cure in chronic hepatitis B patients, showcasing effective combination therapy with VTP-300 and nivolumab.
How safe is AB-101 based on recent trial data?
AB-101 has shown to be generally safe and well-tolerated in patients, with high receptor occupancy and no liver dysfunction observed during trials.
What does the term 'functional cure' mean in the context of HBV?
A functional cure refers to the eradication of detectable hepatitis B surface antigen (HBsAg) levels, allowing the immune system to control the virus without ongoing antiviral therapy.
What are the potential impacts of these treatments on chronic HBV infection?
These innovative treatments could significantly reduce the global burden of chronic HBV, improving patient outcomes and potentially decreasing liver cancer and cirrhosis-related deaths.
How can patients stay informed about Arbutus Biopharma's research?
Patients can follow Arbutus Biopharma's developments through their official website and press releases detailing ongoing clinical trials and treatment advancements.
