New Hepatitis B Drug Offers Functional Cure for 20%

For the first time in medical history, patients with chronic hepatitis B are stopping treatment and staying healthy.

A new experimental drug called bepirovirsen (nicknamed "bepi") is offering hope to millions living with the deadly liver virus. In two international studies involving 1,838 patients, about 20% of those who received the drug saw their virus drop to undetectable levels and stay there even after stopping all treatment.

"We have not had a treatment which has come to this level of cure," said Dr. Seng Gee Lim of the National University Health System of Singapore, who helped lead the studies. The findings were presented at a scientific meeting in Barcelona and published in the New England Journal of Medicine.

Chronic hepatitis B affects more than 250 million people worldwide and 1.7 million in the United States. The virus spreads through blood and bodily fluids, gradually destroying the liver and often leading to liver cancer or failure.

Current treatments require patients to take daily pills for life to keep the virus under control. But stopping treatment has always been dangerous because hepatitis B has a unique ability to hide in the body and rebound quickly.

Bepi works differently than existing drugs. It attacks the virus's genetic components, blocking replication and triggering the immune system to fight back. Patients received weekly shots for six months alongside their regular pills.

The results were remarkable. After the six months of shots, patients whose virus became undetectable could stop their daily pills too. For those who responded to bepi, the virus stayed silent for at least six more months without any treatment at all.

The Ripple Effect

This breakthrough could transform lives across the globe, especially in countries where accessing daily medication is difficult or expensive. GSK has tracked some patients from earlier studies who are still doing well three years after achieving a functional cure.

Researchers discovered that patients who started with lower levels of a specific viral protein were slightly more likely to achieve the functional cure. Dr. Lim is now investigating why only some people respond, which could help doctors identify the best candidates for treatment.

The drug is currently under fast-track review by the FDA, with a decision expected in October. Regulators in Japan, China, and Europe are also evaluating bepi for approval.

Side effects were generally mild, including temporary redness at injection sites and a short-term rise in liver enzymes. Dr. Anna Lok, a hepatitis expert at the University of Michigan not involved in the research, called the findings "a major step" while noting that longer studies are needed to confirm how durable the remission remains.

For decades, scientists have searched for a way to help hepatitis B patients live free from daily medication. That dream is becoming reality for one in five patients, with researchers working to understand how to make it available to even more.