FDA approves bepirovirsen, a hepatitis B drug offering a functional cure for some
US regulators have cleared bepirovirsen, sold as Hibsago, after trials showed a six-month course could leave chronic hepatitis B undetectable in some patients, even once treatment had finished.
The US Food and Drug Administration has approved bepirovirsen, sold as Hibsago, to treat chronic hepatitis B. Its maker, GSK, calls it the first “functional cure” for the condition, because it drives the virus down to levels that cannot be detected in the blood instead of merely keeping it in check.
Chronic hepatitis B is a liver disease that can bring cancer, scarring or organ failure. It is linked to more than a million deaths around the world every year. Existing medicines manage the virus, and patients may need to take antiviral tablets for years to keep it suppressed.
The approval rests on two phase 3 trials, reported in the New England Journal of Medicine. Following a six-month course of bepirovirsen, 233 of 1,220 participants, or 19 percent, met the definition of a functional cure. Among the 614 people given a placebo, not one did.
For those who responded, the virus remained undetectable for at least 24 weeks after every part of their treatment had ended. That point came 72 weeks after the trial began. The drug is given by weekly injection alongside current tablets, and the tablets could be stopped in patients who got the all-clear. In the US, patients can choose to inject themselves after the first dose.
Norah Terrault, a gastroenterologist at the University of Southern California, said the drug opens a new chapter in care, with the prospect of a functional cure after a short course.
The picture is not entirely rosy. Some patients suffered serious side effects, including liver inflammation, and the FDA advises regular blood tests to watch for it. Traces of the virus also linger, and nobody yet knows whether the benefit lasts for years after treatment stops.
Results differed from person to person. People who began with lower levels of a key hepatitis B protein, a sign of a less active infection, were more likely to respond. A test for that could be carried out before the drug is prescribed.
Researchers now plan to explore combining bepirovirsen with other medicines to improve its success rate, and GSK hopes to make it available to more patients worldwide.
Why it matters
Hepatitis B affects millions of people, and the Hepatitis B Foundation says it accounts for about 56 percent of liver cancer cases globally. A treatment that lets some patients come off medication and still keep the virus under control is a genuine departure from years of ongoing therapy. It will not work for everyone, but it is a welcome step forward, and further work on combinations and wider access could extend the benefit to more people.
