For 19% of people who received Hibsago in clinical trials, hepatitis B remained under control six months after they had stopped all treatment—and a viral protein was no longer detectable in their blood.
The U.S. Food and Drug Administration approved Hibsago, also called bepirovirsen, for certain adults with chronic hepatitis B. The long-term infection affects about 1.7 million people in the United States, according to GSK, the drug’s maker. Over time, it can scar the liver, a condition called cirrhosis, and raise the risk of liver cancer. Most current treatment relies on a daily antiviral pill, often taken for more than a year and sometimes for years to keep the virus suppressed.
Hibsago is the first hepatitis B drug of its kind. Rather than working like existing antiviral pills, it disrupts the genetic messages the virus uses to multiply. Patients receive it as an injection under the skin for up to six months, while continuing their usual medicine. After the first dose, GSK says, patients can choose to give themselves the injections.
The approval applies only to adults who meet specific conditions. They must not have cirrhosis, must have taken antiviral medicine for at least six months, and must already have a suppressed virus and low levels of a viral protein called hepatitis B surface antigen. After completing the injections, patients continue their regular medicine for a period. Those who meet health and lab requirements after six months off the shots may then be able to stop that medicine, too.
In two clinical trials, 24% of people treated with Hibsago met the requirements to stop their regular medicine; none of those given a placebo, an inactive treatment, did. Six months after stopping all hepatitis B treatment, 19% of Hibsago patients were still keeping the virus in check, and the surface antigen could not be detected in their blood. GSK calls this outcome a “functional cure”: the immune system controls the infection without medicine. It does not mean hepatitis B has been completely eliminated from the body.
Dr. Norah Terrault, chief of gastroenterology and hepatology at USC’s Keck Medical Center in Los Angeles, described the approval as “the start of a new era.” She said reaching a functional cure after a short course of treatment has long been a goal for patients and doctors. The results offer a possibility beyond ongoing daily pills, though the trial figures also show that stopping treatment is not an outcome everyone can expect.
Hibsago carries serious risks. The FDA’s strongest type of safety warning, called a boxed warning, covers severe liver reactions and low platelet levels. Platelets are blood cells that help stop bleeding, and very low levels can lead to life-threatening bleeding. Patients need frequent blood tests before and during treatment.
There is still no complete cure for hepatitis B, the Hepatitis B Foundation cautions. People with the infection should continue regular checkups with a liver specialist, usually every six months, whether or not they take medicine. For eligible patients, Hibsago adds a new option to discuss with their doctors—but careful monitoring remains part of the path forward.