Tune Therapeutics Presents Positive Phase 1b/2a Proof of Concept Data on TUNE-401: A First-in-Class Epigenetic Silencer for Patients with Hepatitis B at EASL 2026

Key Takeaways

• TUNE-401 achieved dose‑dependent suppression of all HBV biomarkers
• 100% biomarker repression observed at doses 2‑4
• cccDNA pgRNA loss in 4 of 7 HBeAg‑negative patients
• Single dose effects lasted up to 17 months
• Safety profile remained mild with no cumulative toxicity

Pulse Analysis

Chronic hepatitis B remains a global health challenge, affecting over 240 million people and generating roughly $3 billion in annual US healthcare costs. Existing nucleos(t)ide analogues suppress viral replication but rarely eradicate the covalently closed circular DNA (cccDNA) reservoir, meaning most patients require lifelong therapy. The inability to directly target cccDNA has stalled progress toward a finite cure, prompting intense research into gene‑editing and epigenetic approaches that could permanently silence the virus.

Tune Therapeutics' Phase 1b/2a data provide the first clinical proof that epigenetic silencing can inactivate cccDNA in humans. Participants receiving TUNE‑401 showed dose‑dependent reductions across HBsAg, pgRNA, HBeAg, HBcrAg and P‑HBcAg, with 100% biomarker repression at mid‑to‑high doses and durable effects persisting for up to 17 months after a single infusion. Importantly, the therapy demonstrated a clean safety profile, limited to mild infusion reactions and transient transaminase elevations, and no added toxicity with multiple doses. These results suggest a viable pathway to a finite, potentially curative regimen that could dramatically reduce treatment duration and long‑term drug costs.

Looking ahead, Tune plans a larger Phase 2 trial in late 2026 to refine dosing and expand multi‑dose cohorts. If efficacy and safety are confirmed, TUNE‑401 could become the first epigenetic backbone therapy for HBV, challenging incumbents like Gilead and Bristol‑Myers Squibb and attracting significant investor interest. The market opportunity is sizable, given the chronic nature of HBV and the unmet need for a cure, positioning Tune Therapeutics as a potential game‑changer in liver disease therapeutics.