A first-of-its-kind drug for hepatitis B is allowing some patients to stop treatment without showing signs of the dangerous liver virus, researchers reported Thursday. In two international studies published in the New England Journal of Medicine, about 1 in 5 patients given the experimental drug saw their virus reduced to levels low enough for the immune system to keep in check — what's called a "functional cure."

The drug is bepirovirsen, nicknamed "bepi" and developed by GSK and Ionis Pharmaceuticals. It 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.

Chronic hepatitis B can cause liver cancer or liver failure and kills approximately 1.1 million people around the world each year. The condition affects more than 250 million people globally and about 1.7 million people in the United States who have the chronic form that gradually damages the liver over time.

What the Left Is Saying

Progressive health advocates and Democratic lawmakers focused on global health equity welcomed the findings as a potential breakthrough for underserved populations. Dr. Seng Gee Lim of the National University Health System of Singapore, who helped lead the GSK-funded studies, said the research represents significant progress toward addressing a long-standing gap in hepatitis treatment options.

"We have not had a treatment which has come to this level of cure," Lim told reporters before presenting the findings at a scientific meeting in Barcelona, Spain. He noted that current lifelong therapies can be difficult for patients to maintain and are often inaccessible in lower-income countries where hepatitis B is most prevalent.

Public health advocates argue that a functional cure could reduce the burden on healthcare systems by decreasing cases of liver cancer and liver failure requiring expensive treatments. They also point to the potential for expanded access in developing nations if the drug receives approval from international regulatory bodies.

What the Right Is Saying

Conservative critics raised concerns about the cost of new specialty drugs and questioned whether insurance coverage would be adequate for patients who need it. Some Republican health policy experts called for transparency around pricing once the FDA makes its decision, noting that similar innovative treatments have drawn criticism for high list prices.

Dr. Anna Lok, a hepatitis expert at the University of Michigan who wasn't involved in the research but wrote an accompanying editorial in NEJM, cautioned that more study is needed to determine how long the remission-like state lasts beyond three years of follow-up data from earlier-stage studies.

Lok noted that the trials did not include patients with cirrhosis, high S protein levels, or other complicating factors, meaning the findings may not apply to all chronic hepatitis B patients. "We need longer-term data and studies in broader patient populations," she wrote.

What the Numbers Show

The Phase 2b trials included 1,838 patients assigned to receive either a bepirovirsen shot or a placebo weekly for six months, in addition to their regular oral medications. If the virus was undetectable for six months after stopping the shots, participants could also discontinue their standard pills.

In approximately 20% of bepirovirsen recipients, the virus remained undetectable for six additional months after they stopped all treatment — achieving that functional cure status. No patients given placebo injections achieved this outcome.

The annual global death toll from chronic hepatitis B stands at about 1.1 million people per year. More than 250 million people worldwide have the chronic form of the infection, with roughly 1.7 million cases in the United States.

The Bottom Line

The FDA is expected to rule on bepirovirsen by October, which would mark the first treatment capable of producing functional cures in a subset of patients with chronic hepatitis B. Researchers are conducting additional studies to understand why only about one in five patients responded to the therapy and what factors predict successful outcomes.

Patients currently managing chronic hepatitis B should consult their healthcare providers before considering any changes to their treatment regimen, as the drug has not yet received regulatory approval.