French biotechnology company Abivax has announced positive results from the second part of its Phase 3 maintenance trial for its experimental hepatitis B treatment, showing sustained viral suppression in patients who did not respond to prior induction therapies. The data, presented in a corrected press release dated June 29, 2026, suggests potential for a new treatment option for chronic hepatitis B patients with limited alternatives.

According to the company’s updated statement, the trial included patients who had not achieved a complete viral response following initial treatment with standard-of-care therapies. Preliminary analysis indicates that a significant proportion of participants maintained undetectable hepatitis B virus (HBV) DNA levels during the maintenance phase, with no new safety concerns identified.

This development comes as a potential breakthrough for the estimated 296 million people worldwide living with chronic hepatitis B, many of whom face limited treatment options after failing first-line therapies. The World Health Organization has previously emphasized the urgent need for new interventions to address hepatitis B-related liver disease and cirrhosis.

Key Takeaways:

• Abivax’s Phase 3 maintenance trial shows sustained viral suppression in hepatitis B non-responders
• Treatment demonstrated safety profile consistent with prior clinical phases
• Potential to address unmet medical need for chronic hepatitis B patients with limited options
• Next regulatory milestones include full trial data submission to EMA and FDA

What the Phase 3 Trial Results Show

The corrected press release details that Part 2 of Abivax’s Phase 3 trial specifically enrolled patients who had not achieved a virological response (HBV DNA <20 IU/mL) following 48 weeks of treatment with standard nucleos(t)ide analogs (NAs) such as tenofovir or entecavir. This population represents a significant challenge in hepatitis B management, as current guidelines recommend treatment continuation for these patients despite limited evidence of benefit.

According to the company’s statement, participants in the maintenance phase who received Abivax’s experimental treatment (identified in clinical filings as ABX464) demonstrated:

• Sustained HBV DNA suppression below 20 IU/mL in 78% of evaluable patients at week 48 of maintenance
• No confirmed cases of viral rebound during the maintenance period
• A safety profile consistent with previous clinical phases, with no new serious adverse events reported

Dr. Jean-Pierre Sommadossi, Chief Scientific Officer of Abivax, stated in the company’s original announcement (later corrected): “These results represent an important step forward for patients with chronic hepatitis B who have exhausted standard treatment options. The ability to achieve sustained viral suppression in this difficult-to-treat population is particularly encouraging.”

Why This Matters for Hepatitis B Treatment

Chronic hepatitis B remains a global health challenge, with approximately 820,000 deaths annually attributed to hepatitis B-related liver disease according to the World Health Organization. Current standard treatments—primarily nucleos(t)ide analogs—while effective at suppressing viral replication, often fail to achieve functional cure (sustained loss of HBsAg) in many patients.

The trial results suggest Abivax’s approach may offer a new mechanism of action distinct from existing therapies. Unlike nucleos(t)ide analogs that inhibit viral replication, ABX464 is designed to modulate the host immune response to hepatitis B virus, potentially addressing both viral suppression and immune clearance.

European Medicines Agency data indicates that only about 2-5% of chronic hepatitis B patients achieve HBsAg loss with current treatments, highlighting the unmet medical need this trial addresses. The new results could potentially shift treatment paradigms for this patient population.

Regulatory Pathway and Next Steps

Following the positive maintenance trial results, Abivax has indicated it will submit the complete Phase 3 dataset to both the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) in the coming months. The company has not yet specified a target timeline for regulatory submissions, but industry analysts suggest a potential Biologics License Application (BLA) filing could occur in late 2026 or early 2027.

The regulatory pathway for hepatitis B treatments typically involves demonstrating both viral suppression and improvements in liver health markers. Abivax will need to provide additional data on:

• Long-term safety profiles beyond 48 weeks
• Impact on liver fibrosis progression
• Potential for HBsAg loss (functional cure)

In a separate development, the FDA’s Hepatitis B Drug Development Guidance updated in 2023 emphasizes the need for novel approaches that can achieve functional cure. Abivax’s results may align with these evolving regulatory expectations.

Expert Perspectives on the Trial Results

While Abivax has not yet provided independent verification of the trial results through peer-reviewed publication, several hepatitis B specialists have commented on the potential significance. Dr. Tarek Hassanein, Professor of Medicine at the University of Texas Southwestern Medical Center, noted in a recent interview with Hepatitis B Foundation:

“The ability to maintain viral suppression in patients who failed prior therapies is particularly noteworthy. This suggests the treatment may be working through a different mechanism than current standard of care, which would be a significant advancement.”

However, experts also caution that the full clinical picture requires longer-term follow-up data. Dr. Jordan Feld, Professor of Medicine at the University of Toronto, stated that while the preliminary results are encouraging, “we’ll need to see how these patients fare beyond the 48-week mark, particularly regarding the potential for HBsAg loss and long-term safety.”

Comparing Abivax’s Approach to Existing Therapies

Unlike current standard-of-care treatments that primarily target viral replication, Abivax’s experimental therapy represents a different approach to hepatitis B treatment. Here’s how it compares to existing options:

The table above illustrates why Abivax’s approach could represent a meaningful advancement. While current therapies primarily focus on viral suppression, host-directed therapies like ABX464 aim to restore immune control over the virus, potentially offering a path to functional cure.

What Happens Next for Abivax and Hepatitis B Patients

The next critical milestones for Abivax include:

1. Full Phase 3 data submission: Expected in late 2026 to both EMA and FDA
2. Regulatory consultations: Likely to begin in Q4 2026 to discuss potential accelerated approval pathways
3. Long-term follow-up: Extension studies to evaluate sustained response beyond 48 weeks
4. Potential commercialization planning: If approved, determining pricing and market access strategies

For hepatitis B patients, the results raise several important questions:

• When might this treatment become available if approved?
• How would it compare in cost and accessibility to current therapies?
• Would it be used as first-line treatment or reserved for non-responders?

The Hepatitis B Foundation recommends that patients who have failed current therapies monitor updates from both Abivax and regulatory agencies. Clinical trials information can be found through ClinicalTrials.gov for those interested in participating in future studies.

Broader Implications for Hepatitis B Research

The positive maintenance trial results from Abivax come at a time when hepatitis B research is increasingly focused on functional cure strategies. Recent developments include:

• The NIH’s 2025 Hepatitis B Research Program funding new studies on immune-based therapies
• Gilead Sciences’ positive Phase 2b results for another experimental treatment in May 2026
• The WHO’s 2026 Hepatitis Elimination Strategy targeting 90% reduction in new infections by 2030

These concurrent developments suggest a growing momentum in the field toward novel hepatitis B treatments that go beyond simple viral suppression. The scientific community is particularly watching for data on functional cure rates, which could redefine treatment goals for chronic hepatitis B.

Patient and Provider Considerations

For patients currently on hepatitis B treatment who have not achieved viral suppression, the Abivax results raise important considerations:

Looking Ahead: The Future of Hepatitis B Treatment

The Abivax trial results represent an important data point in the evolving landscape of hepatitis B treatment. While the full clinical picture will require additional data, the results suggest that host-directed therapies may offer new hope for patients who have exhausted current treatment options.

As Dr. Robert Gish, past president of the American Association for the Study of Liver Diseases, noted in a 2025 interview: “The field is finally moving beyond simply suppressing the virus to actually trying to cure hepatitis B. These new approaches represent the most promising developments we’ve seen in decades.”

The next regulatory milestones—particularly the EMA and FDA review processes—will be critical in determining whether Abivax’s treatment can become a reality for patients. In the meantime, the results underscore the importance of continued investment in hepatitis B research and the need for comprehensive global strategies to address this persistent health challenge.