WASHINGTON, D.C. — The U.S. Food and Drug Administration approved Hepcludex as the first authorized treatment for chronic hepatitis delta virus infection in the United States, giving patients with the rare but severe liver disease access to a federally approved therapy for the first time.
The treatment, developed by Gilead Sciences, was approved for adults with chronic hepatitis delta virus, or HDV, infection who do not have cirrhosis or who have compensated cirrhosis, according to the FDA.
The approval addresses a long-standing treatment gap for HDV, an aggressive liver disease that can accelerate fibrosis, liver failure, and liver cancer and has historically lacked FDA-approved therapies despite carrying significantly higher mortality risks than hepatitis B infection alone.
HDV occurs only in patients already infected with hepatitis B virus because the virus depends on HBV to replicate. Federal health officials said risk factors include injection drug use, unprotected sex, and occupational blood exposure.
The FDA granted the drug Breakthrough Therapy and Orphan Drug designations and reviewed the application under its accelerated approval pathway, which allows earlier authorization for therapies targeting serious diseases with limited treatment options.
Approval was supported by data from the Phase 3 MYR301 trial, which evaluated patients receiving daily Hepcludex injections against a delayed-treatment group.
At 48 weeks, 48% of treated patients achieved the trial’s combined primary endpoint — defined as either undetectable HDV RNA or a substantial viral decline alongside normalized liver enzyme levels — compared with 2% in the delayed-treatment group.
The percentage of patients reaching undetectable HDV RNA levels increased over time, reaching 36% at week 96 and 50% at week 144, according to the FDA.
The drug carries a boxed warning stating that discontinuation may trigger severe acute exacerbations of both hepatitis delta and hepatitis B infections.
Reported adverse effects included injection-site reactions, abdominal pain, fatigue, itching, headaches, and hypersensitivity reactions, including anaphylaxis.
“Today’s approval fills a critical gap in care for patients with chronic HDV infection, who until now have had no FDA-approved therapies available,” said Wendy Carter.
The approval expands Gilead’s position in antiviral and liver-disease therapeutics as regulators continue accelerating reviews for treatments targeting rare infectious diseases with limited commercial competition.
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