One in five patients with chronic hepatitis B achieved what researchers are calling a "functional cure" after just 24 weeks of treatment with an experimental drug called bepirovirsen—a breakthrough that marks the first Phase III clinical trial success in a decade-long search for a way to actually eliminate the virus.
The achievement matters because hepatitis B affects roughly 260 million people worldwide, and current treatments, while effective at controlling the virus, rarely cure it. Standard therapy uses nucleoside or nucleotide analogs that suppress the virus and reduce the risk of cirrhosis and cancer, but patients almost always relapse if they stop taking the medication. A true functional cure—where the virus stays undetectable for at least 24 weeks after treatment ends—has remained frustratingly out of reach.
The results, published in the New England Journal of Medicine, come from two duplicate Phase III trials led by Jinlin Hou, M.D., Chairman and Professor of the Hepatology Unit and Department of Infectious Diseases at Southern Medical University in Guangzhou, China. In both trials, 20% and 19% of patients receiving bepirovirsen achieved the functional cure standard, compared to zero percent in placebo groups. Even more striking: 24% of patients taking bepirovirsen were able to stop their existing antiviral therapy altogether, and none of those who discontinued treatment experienced clinical relapse—even those who didn't achieve full functional cure.
The significance of these results extends beyond the raw numbers. In 2016, University of Michigan hepatologist Anna S. Lok, M.D., convened a landmark meeting with regulators and experts from the FDA, European Medicines Agency, and major liver disease associations to establish what a functional cure for hepatitis B should actually look like. That consensus—undetectable hepatitis B surface antigen and viral DNA for at least 24 weeks after completing treatment—seemed nearly impossible to achieve. Over the next decade, dozens of clinical trials tested different combinations of antiviral and immunomodulatory agents. Until now, none had succeeded at Phase III testing.
"This is a major step toward a functional cure for hepatitis B virus infection," Lok wrote in an accompanying editorial, acknowledging both the promise and the caution warranted by preliminary results. The trials were conducted in highly selected patient populations, meaning the results may not transfer directly to all hepatitis B patients. Side effects were also more common in the bepirovirsen group, though the source material does not detail their severity or nature.
What makes this moment hopeful is not just the numbers themselves, but what they represent: proof that a functional cure is possible. For decades, hepatitis B patients faced a stark choice—take medication indefinitely or risk serious liver disease. These results suggest a third path exists, one where finite treatment might actually end the infection for some people.
Lok has signaled what she hopes comes next: testing of other drug combinations that could be safer and deliver even higher cure rates in broader patient populations. The door, after ten years of searching, appears to be opening.