bepirovirsen functional – In two international studies, the experimental hepatitis B drug bepirovirsen helped about 1 in 5 patients reach a “functional cure,” letting them stop treatment without the virus rebounding—an advance researchers say is closer than anything before, even as exp
For years, hepatitis B treatment has asked patients to commit to lifelong therapy—daily pills, constant monitoring, and the worry that the virus can quietly hide and return the moment treatment stops.
In two international studies presented Thursday in Barcelona, Spain, researchers reported results that look different. Some patients given the experimental drug bepirovirsen were able to stop their regular pills without showing signs of the dangerous virus. a state researchers describe as a “functional cure.”.
“We have not had a treatment which has come to this level of cure,” Dr. Seng Gee Lim of the National University Health System of Singapore said before presenting the findings at a scientific meeting.
The data were published Thursday in the New England Journal of Medicine.
Chronic hepatitis B can lead to liver cancer or liver failure. and it kills about 1.1 million people around the world each year. Even so, progress has been slow. Today’s standard therapy can reduce viral levels and prevent liver damage. but a true cure has remained elusive in part because hepatitis B has an unusual ability to hide in the body and rebound if treatment stops.
This drug is designed to do more than suppress the virus temporarily. Bepi. short for bepirovirsen and developed by GSK and Ionis Pharmaceuticals. is given by injection and attacks hepatitis B by binding to its genetic components. Researchers say it suppresses viral replication. targets a key viral protein known as the “S” or surface protein. and also stimulates the immune system.
GSK vice president Melanie Paff said the approach is aimed at disrupting the virus’s ability to stay hidden and keeping the immune system in control once treatment is halted.
The studies tested whether that immune control could persist after patients stopped the investigational shots—and in about 1 in 5 cases, it did.
In the trials, 1,838 patients were assigned to receive either a bepi shot or a dummy shot weekly for six months, alongside their regular pills. If the virus was undetectable for six months after stopping the shots, patients could stop their regular pills as well.
Researchers reported that in about 20% of the bepi recipients, the virus remained undetectable for six more months after stopping all treatment. That outcome—the “functional cure”—did not occur in patients given the dummy shots.
Lim said patients who started the study with lower levels of the S protein were slightly more likely to achieve a functional cure. He is conducting additional research to determine why only some people respond.
Questions about what happens next are already sitting in the background. Dr. Anna Lok. a hepatitis expert at the University of Michigan who was not involved in the research. wrote in the journal that the findings “represent a major step. ” but she cautioned that more study is needed to see how long that remission-like state lasts.
Paff offered some early reassurance. She said GSK has tracked a small number of patients from earlier-stage studies and found most still faring well up to three years later.
Safety is also part of the story. Lim said side effects included mild injection-site redness or pain and a temporary rise in enzymes that can indicate liver stress.
Not everyone, however, was represented in the trials. Lok noted that the studies did not include patients with cirrhosis, high S protein levels, or other complicating factors—details that matter because those are precisely the patients for whom treatment decisions can be the hardest.
Beyond the clinical results, the drug is now moving through the regulatory pipeline. Bepi is under fast-track review by the U.S. Food and Drug Administration, with a decision expected in October. Regulators in Japan, China and Europe also are considering the drug.
The sequence of facts is striking: the trial design allowed some patients to stop pills after an additional six-month course of injections. and in roughly one-fifth of those who received bepi. the virus stayed undetectable long enough for researchers to call it a “functional cure.” At the same time. experts are urging caution—because the trials excluded key patient groups and because durability beyond the follow-up reported remains a live question.
If bepirovirsen clears regulatory review. it could change how doctors talk about hepatitis B—not as a diagnosis that usually means staying on treatment indefinitely. but as a condition where. for some patients. stopping therapy may no longer immediately trigger a return of the virus. For now, the promise is real, but the certainty is still being tested.
hepatitis B bepirovirsen bepi functional cure GSK Ionis Pharmaceuticals FDA fast-track New England Journal of Medicine liver cancer liver failure