Hepatitis E infects millions of people worldwide and leads to about 70,000 deaths each year. Despite its impact, there is still no approved vaccine or targeted treatment. That situation may soon change with the discovery of bemnifosbuvir, a compound that shows strong activity against hepatitis E viruses (HEV).

An international team of researchers from Bochum and Heidelberg in Germany and Beijing in China identified the drug while screening a collection of antiviral compounds. Bemnifosbuvir belongs to a class of molecules known as nucleotide/nucleoside analogues. Because it is already being tested in clinical trials for hepatitis C, scientists are hopeful it could be repurposed more quickly as a treatment for hepatitis E. Their findings were published in the journal Gut on March 6, 2026.

How the Drug Blocks Viral Replication

The researchers began by analyzing a commercially available library of nucleotide/nucleoside analogues, which are designed to mimic the building blocks of genetic material. "These synthetically produced molecules are constructed similarly to the building blocks of our genetic material and likewise to that of viruses," explains Dr. Mara Klöhn from Ruhr University Bochum.

To identify promising candidates, the team tested about 500 compounds using a specially engineered hepatitis E virus that produces a fluorescent signal. They infected cell cultures with this modified virus and then treated the cells with different compounds. By tracking the fluorescence, they could quickly determine whether the virus continued to replicate.

"With bemnifosbuvir we were able to see that the virus no longer replicated, while the treated cells remained healthy," reports Jungen Hu from Heidelberg University. Follow-up studies in animals confirmed that the drug reduced both viral activity and liver inflammation.

"If the ongoing clinical trials of bemnifosbuvir against hepatitis C are successful, the drug could soon also be available for off label use against hepatitis E," say Dr. Viet Loan Dao Thi and Professor Eike Steinmann.

Hepatitis E Risks and Lack of Treatments

The hepatitis E virus (HEV) is a leading cause of acute viral hepatitis. Although many infections resolve on their own in people with healthy immune systems, the virus can become chronic in individuals with weakened immunity, including organ transplant recipients and people living with HIV. It also poses a serious risk during pregnancy.

The disease was first documented in a major outbreak between 1955 to 1956, but it took decades before it became a major focus of scientific research. Even today, there is still no vaccine or specific antiviral therapy available.

International Collaboration and Research Support

This research involved the Department of Molecular and Medical Virology at Ruhr University Bochum, the Dao Thi Lab at the Center for Integrative Infectious Disease Research (CIID) of Heidelberg University Hospital, and the Lin Wang Lab at Peking University in China.

The study received support from multiple funding sources, including the National Key Research and Development Program of China (2023YFC2306900), the research program "Antiviral Therapies" of the Baden-Württemberg Stiftung, the German Research Foundation within Collaborative Research Center 1129 (project number 240245660), the German Center for Infection Research -- TTU Hepatitis Project 05.823, the Beijing Municipal Natural Science Foundation (L244032), and the National Natural Science Foundation of China (82522053).