FDA Approves First-Ever Treatment for Deadly Hepatitis D Virus Infection
Bulevirtide (Hepcludex) wins FDA accelerated approval for chronic HDV, with 50% of patients achieving undetectable viral levels by 144 weeks.
Summary
The FDA has approved bulevirtide (Hepcludex), the first-ever treatment for chronic hepatitis D virus (HDV) infection — the most severe form of viral hepatitis. HDV only affects people already infected with hepatitis B and significantly raises the risk of liver failure and death. In a phase III trial, nearly half of patients on bulevirtide achieved undetectable or sharply reduced viral levels plus liver enzyme normalization at 48 weeks, compared to just 2% in the delayed-treatment group. By 144 weeks, 50% had undetectable HDV RNA. An estimated 40,000 Americans live with chronic HDV. This approval fills a long-standing treatment gap for a disease that has had no approved options in the U.S. until now.
Detailed Summary
Chronic hepatitis D virus (HDV) infection is the most aggressive form of viral hepatitis, dramatically accelerating liver disease progression, cirrhosis, and liver failure compared to hepatitis B alone. For decades, patients in the U.S. had no FDA-approved treatment. That changed when the FDA granted accelerated approval to bulevirtide (Hepcludex), a first-in-class antiviral injection developed by Gilead Sciences.
Butevirtide works by blocking the entry of both HBV and HDV into liver cells, targeting the co-infection at its root mechanism. The approval was based on results from the MYR301 phase III trial, a multicenter, randomized, open-label study. At 48 weeks, 48% of patients receiving immediate bulevirtide achieved the combined endpoint of undetectable HDV RNA or a significant viral load reduction plus normalization of ALT — a key liver enzyme — compared to only 2% in the delayed-treatment arm.
Longer-term data showed continued improvement: 36% had undetectable HDV RNA at 96 weeks, rising to 50% by 144 weeks. These are meaningful milestones for a disease known for rapid progression to serious liver complications. Common side effects included injection site reactions, headache, abdominal pain, fatigue, and itching — a manageable safety profile relative to the disease severity.
For the estimated 40,000 Americans living with chronic HDV, this approval represents a critical shift. Previously, off-label use of pegylated interferon was the only option, with limited efficacy and poor tolerability. Bulevirtide offers a targeted, better-tolerated alternative addressing a genuine unmet need.
Important caveats apply: the drug carries a boxed warning about severe viral rebound if discontinued, requiring at least six months of liver monitoring post-cessation. The approval is accelerated, meaning continued approval depends on confirmatory trial outcomes. Patients with decompensated cirrhosis are currently excluded from the indication.
Key Findings
- 48% of bulevirtide patients achieved combined viral suppression and ALT normalization at 48 weeks vs. 2% in controls.
- 50% of treated patients had undetectable HDV RNA by 144 weeks of treatment.
- Bulevirtide is the first FDA-approved therapy specifically targeting chronic HDV infection in the U.S.
- Boxed warning: stopping bulevirtide may trigger severe viral rebound; liver monitoring required for 6 months post-stop.
- Drug works by blocking both HBV and HDV cell entry, addressing the co-infection mechanism directly.
Methodology
This is a news report from MedPage Today summarizing an FDA approval and its supporting evidence. The approval is based on the phase III MYR301 randomized controlled trial, a credible evidence source. The article cites specific clinical endpoints and quotes from investigators and regulators, lending it reasonable scientific grounding.
Study Limitations
Accelerated approval means long-term confirmatory data are still pending and the approval could be revised. The trial was open-label, which may introduce bias in subjective endpoints. Details on cost, access, and real-world effectiveness are not addressed in this news report.
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