New Epigenetic Therapy Could Permanently Switch Off Chronic Hepatitis B

Scientists are exploring a promising new strategy to address chronic hepatitis B (HBV) by targeting the virus’s ability to remain dormant within human cells. Unlike traditional antivirals that require daily administration to suppress viral replication, a novel approach known as epigenetic silencing aims to effectively turn off the virus at its source without damaging the host’s genetic blueprint.

The research, conducted by a team at the Boston-based biotechnology firm nChroma Bio, focuses on neutralizing the two ways HBV persists in the body: as stable, chromosome-like structures known as cccDNA and as fragments of viral genetic material integrated into the patient’s own genome. These hidden reservoirs allow the virus to remain undetected by the immune system and cause long-term liver damage, even when a patient appears healthy.

Silencing, Not Shredding

Previous efforts to clear persistent viral DNA often relied on gene-editing tools like CRISPR-Cas9 to physically cut or destroy the viral code. While effective, these methods carry the risk of accidental mutations or damage to the host’s DNA. The new method, detailed in Nature Biomedical Engineering, utilizes a modified, non-cutting version of Cas9 as a molecular guide. This protein is paired with enzymes that attach chemical tags to the viral DNA, a process called methylation, which effectively locks the genes in an “off” position.

In preclinical trials involving mice, this treatment demonstrated significant potential. A three-dose regimen resulted in approximately 90 percent of the subjects maintaining undetectable viral loads for at least six months after the final injection. Safety assessments conducted in cynomolgus monkeys showed that while high doses triggered temporary markers of liver stress, the subjects recovered quickly without lasting clinical damage.

Moving to Clinical Trials

The technology, designated as CRMA-1001, has officially entered Phase 1/2 clinical testing to evaluate its safety and efficacy in human patients, with trial sites currently established in the United Kingdom, New Zealand, and Hong Kong. If successful, this approach could offer a durable, long-term solution for the millions of people living with chronic HBV, potentially replacing the need for lifelong antiviral therapy.

The field is seeing rapid innovation, with other companies also advancing similar epigenetic therapies. Tune Therapeutics recently reported positive early data from a Phase 1b/2a trial for its own candidate, TUNE-401, which showed a significant reduction in viral biomarkers for over 17 months following a single dose. Meanwhile, researchers in Shanghai under the banner of Epigenic Therapeutics are also progressing toward clinical human trials.

Future Hurdles

Despite the optimism, experts caution that several challenges remain. It is currently unclear whether these therapies can effectively silence the broad variety of HBV genetic strains found globally. There is also the critical question of long-term stability and the potential for the therapy to inadvertently affect non-viral genes within the host. Furthermore, the global health community must address the logistical and economic barriers to delivering such specialized treatments to the regions most heavily burdened by the virus, particularly in sub-Saharan Africa and Southeast Asia.

Reflecting on the broader implications of this research, Dr. Marleen van der Laan and her colleagues at the University of Groningen noted in an independent review that while the transition from gene editing to epigenetic regulation represents a major step forward, further investigation is essential to confirm the safety and long-term viability of these treatments in a real-world clinical setting.