Gene-Editing Therapy Achieves First Direct Elimination of Hepatitis B's Hidden Viral Reservoir

A First in the Fight Against Hepatitis B

For the first time, a gene-editing therapy has been shown to directly eliminate cccDNA, the hidden viral reservoir that has long made chronic hepatitis B effectively impossible to cure. The data, presented as a late-breaking poster at the European Association for the Study of the Liver Congress 2026 in Barcelona, come from liver biopsies taken from patients in the Phase 1 ELIMINATE-B trial.

Why cccDNA Has Been the Central Obstacle

cccDNA is a stable ring of viral genetic material that lodges inside the nucleus of infected liver cells. It serves as the sole template for viral replication, which is why current nucleoside analogue therapies can suppress circulating virus but never remove the source. That limitation forces an estimated 296 million people worldwide to remain on lifelong treatment, with the virus rebounding whenever therapy stops.

What the Trial Showed

The therapy uses a proprietary gene-editing platform delivered through lipid nanoparticles, which the liver naturally absorbs from the bloodstream. Biopsy findings revealed a 1-log, or 10-fold, reduction in cccDNA-derived transcripts following treatment. In the small fraction of cccDNA that survived, additional edits inactivated viral polymerase, permanently disabling its ability to replicate. After three doses, roughly 80% of remaining cccDNA had been edited, indicating cumulative antiviral activity with repeat dosing.

The effect was also visible in blood biomarkers. All six patients with detectable pregenomic RNA at baseline achieved complete loss of that marker, and all 15 evaluated patients showed substantial declines in hepatitis B surface antigen across every dose level.

Safety and Next Steps

Across 38 doses administered to 16 patients in five cohorts, no dose-limiting toxicities were observed. The most common adverse events were transient infusion-related reactions and reversible liver enzyme elevations. One patient at the highest dose level of 0.8 mg/kg experienced serious hypotension-related events, prompting a mitigation protocol that has since prevented any recurrence.

The company held an investor webcast on 27 May to discuss the findings with hepatitis B experts. It plans to enrol additional patients, gather further biopsy data, and advance towards Part 2 of the ELIMINATE-B trial, with the next update expected by the end of 2026. Regulators have granted the programme Fast Track designation and signalled that sustained loss of viral DNA could serve as an approvable endpoint, a marker of just how significant a functional cure would be.