Experimental gene-silencing therapy offers hope for hepatitis B cure

by Paul Arnold, Medical Xpress

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Chronic hepatitis B is a long-lasting condition caused by the hepatitis B virus (HBV) that affects about 240 million people worldwide. Most people infected show no symptoms for years, but when symptoms do appear, they can include fatigue, jaundice and abdominal pain. Current antiviral treatments are designed to keep the virus under control, but they are not a cure, and medications are usually taken indefinitely.

That has prompted scientists to search for a way to stop the infection without lifelong medication. One approach showing early promise is an experimental therapy that has switched off hepatitis B genes in human liver cells and mouse models.

Researchers led by John Marlowe at genetic medicines company nChroma Bio treated cultures of human liver cells infected with hepatitis B with a genetic package they designed called CRMA-1001. This microscopic delivery vehicle includes a targeting guide RNA to find the viral DNA and instructions for making a gene-silencing protein, all wrapped in protective lipid bubbles.

It is designed to travel directly to the viral DNA and attach chemical tags called methyl groups. These tags act like a mute button, keeping the virus switched off without cutting or altering any underlying DNA.

Testing the treatment

CRMA-1001 reduced levels of two viral proteins by 98% in human liver cells. Encouraged by these results, the research team moved on to testing the therapy in mice carrying HBV DNA.

In one mouse model, a single dose lowered one viral marker in the blood by more than 1,000-fold. This suppression lasted for six months. Giving three monthly doses worked even better. Six months after this treatment, up to 90% of the mice had undetectable levels of hepatitis B surface antigen in their blood. Their viral DNA levels also fell so low they could no longer be measured.

"Three doses resulted in up to 90% of animals with undetectable hepatitis B surface antigen and HBV DNA by six months post-treatment," wrote the team in their paper published in Nature Biomedical Engineering.

A step closer to testing in humans

To see if the therapy could reach the liver in a body similar to a human's, the scientists tested it in healthy monkeys. It went mainly to the liver as intended and caused only a temporary rise in liver enzymes at the highest repeated dose.

Later tests in uninfected human liver cells from healthy donors found no detectable unintended changes in gene expression or DNA methylation elsewhere in the human genome.

While these results are promising, the researchers caution that animal models cannot fully mirror how hepatitis B behaves in people.

"Notably, none of the available HBV in vivo models fully recapitulate human infection and pathobiology; however, these models remain valuable preclinical tools."

Nonetheless, the study authors believe their findings support the start of clinical development of CRMA-1001 in humans.

Written for you by our author Paul Arnold, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you.

Publication details

Yesseinia Anglero-Rodriguez et al, Development of an investigational epigenetic silencer therapy to transcriptionally inactivate viral DNA in chronic hepatitis B, Nature Biomedical Engineering (2026). DOI: 10.1038/s41551-026-01802-8

Journal information: Nature Biomedical Engineering

Key medical concepts

Hepatitis B, ChronicHepatitis B Surface AntigensDNA Methylation

Clinical categories

Infectious diseasesCommon illnesses & PreventionClinical pharmacologyGastroenterology Who's behind this story?

Paul Arnold

BSc Biology from University of London. BBC documentary producer with world travel experience. Freelances from southern Spain. Full profile →

Gaby Clark

MA in English, copy editor since 2021 with experience in higher education and health content. Dedicated to trustworthy science news. Full profile →

Robert Egan

Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →

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Citation: Experimental gene-silencing therapy offers hope for hepatitis B cure (2026, September 25) retrieved 25 September 2026 from https://medicalxpress.com/news/2026-09-experimental-gene-silencing-therapy-hepatitis.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.