8-K: Arbutus Biopharma Announces Promising Functional Cure Data for Chronic Hepatitis B

Arbutus Biopharma reports significant functional cure rates in chronic hepatitis B patients using imdusiran combined with interferon, and also shows positive results with the addition of nivolumab in a separate trial.

Summary

• Arbutus Biopharma has released new data from its IM-PROVE I Phase 2a clinical trial, showing a 50% functional cure rate in HBeAg-negative patients with baseline HBsAg levels less than 1000 IU/mL when treated with six doses of imdusiran and 24 weeks of pegylated interferon alfa-2, in addition to ongoing nucleos(t)ide analogue therapy.
• The overall functional cure rate in the IM-PROVE I trial was 25% (3 out of 12 patients).
• The company also announced preliminary data from the IM-PROVE II Phase 2a clinical trial, where the addition of low-dose nivolumab to imdusiran and VTP-300 resulted in significantly greater mean declines in HBsAg levels compared to other cohorts.
• In the IM-PROVE II trial, 23% of participants receiving imdusiran, VTP-300, and low-dose nivolumab achieved HBsAg loss by Week 48.
• Arbutus is also advancing its oral PD-L1 inhibitor, AB-101, which is currently in a Phase 1a/1b clinical trial.
• The company has a strong financial position with a cash runway into Q4 2026 and is seeking damages from patent litigation related to COVID-19 vaccine sales.

Sentiment

Score: 8

Explanation: The document presents very positive clinical trial results, particularly the 50% functional cure rate in a subset of patients, and the positive results with nivolumab. The company also has a strong cash position and is actively pursuing multiple clinical trials. However, there are still risks associated with clinical trials and litigation.

Positives

• The 50% functional cure rate in a subset of patients in the IM-PROVE I trial is a significant improvement over historical rates with interferon alone.
• The combination of imdusiran and interferon was generally safe and well-tolerated.
• The addition of nivolumab in the IM-PROVE II trial showed promising results in increasing HBsAg loss rates.
• Arbutus has a strong cash position, providing financial stability for ongoing research and development.
• The company is actively pursuing multiple clinical trials with near-term catalysts.

Negatives

• The overall functional cure rate in the IM-PROVE I trial was 25%, indicating that the treatment is not effective for all patients.
• The IM-PROVE II trial data is preliminary, and further results are needed to confirm the efficacy of the combination therapy.
• The company is involved in patent litigation, which could be a distraction and may not result in the desired financial outcome.

Risks

• Clinical trials may be more costly or take longer to complete than anticipated.
• Arbutus may not receive the necessary regulatory approvals for its products.
• Economic and market conditions may worsen, impacting the company's financial stability.
• Patent litigation may not be successful and could result in significant legal costs.
• The company may experience employee turnover as a result of organizational changes.

Future Outlook

Arbutus plans to advance imdusiran into a Phase 2b clinical trial and expects preliminary data from the AB-101 Phase 1a/1b trial in the first half of 2025. The company is also seeking damages from patent litigation related to COVID-19 vaccine sales.

Management Comments

• Professor Man-Fung Yuen stated that they are seeing a meaningful percentage of HBV patients functionally cured with an RNAi therapeutic and interferon.
• Dr. Karen Sims commented that the data supports their belief that lowering surface antigen with imdusiran and incorporating an immunomodulator provides a functional cure in some patients with cHBV.
• Dr. Leon Hooftman noted that the data demonstrated the impact of combining an immune stimulant and a low dose of the checkpoint inhibitor nivolumab in helping participants reach HBsAg loss.

Industry Context

These announcements are significant in the context of the ongoing efforts to find a functional cure for chronic hepatitis B. The combination of RNAi therapeutics, immunomodulators, and checkpoint inhibitors represents a promising approach to addressing this global health issue. The results are being presented at a major industry conference, AASLD, indicating the importance of the findings.

Comparison to Industry Standards

• Historically, less than 10% of HBV patients experience a functional cure with 48 weeks of interferon treatment alone, making the 50% functional cure rate in a subset of patients in the IM-PROVE I trial a significant improvement.
• Gilead Sciences is also developing treatments for HBV, including lenacapavir, which is being studied in combination with other agents. Arbutus' approach of combining an RNAi therapeutic with immunomodulators is similar to the strategy being pursued by other companies in the field.
• The use of checkpoint inhibitors like nivolumab is also being explored by other companies in the context of HBV treatment, with Bristol Myers Squibb's Opdivo being a notable example. Arbutus' use of low-dose nivolumab in combination with other agents is a novel approach.

Legal Proceedings

• Arbutus is involved in patent litigation against Moderna and Pfizer/BioNTech related to COVID-19 vaccine sales.

Stakeholder Impact

• Shareholders may see a positive impact on the stock price due to the promising clinical trial results.
• Patients with chronic hepatitis B may benefit from the development of more effective treatments.
• Employees may be motivated by the company's progress and potential for success.
• The medical community may be encouraged by the potential for a functional cure for HBV.

Next Steps

• Arbutus plans to advance imdusiran into a Phase 2b clinical trial.
• The company expects preliminary data from the AB-101 Phase 1a/1b trial in the first half of 2025.
• The company will continue to pursue patent litigation against Moderna and Pfizer/BioNTech.

Key Dates

Keywords

Hepatitis B, cHBV, Imdusiran, RNAi, Interferon, Nivolumab, VTP-300, Functional Cure, HBsAg, Clinical Trial, AB-101, PD-L1 Inhibitor