It may help some people with chronic hepatitis B control the virus and stop taking their medication. While this is an advancement, it is not for everyone, and there are safety concerns, so patients will need close monitoring.
The U.S. Food and Drug Administration (FDA) approved Hibsago (bepirovirsen) on October 20, 2026, for some adults aged 18 years and older with chronic hepatitis B who meet certain medical criteria. In clinical trials, 19% of patients who stopped all hepatitis B treatment maintained control of the virus, with an undetectable level of hepatitis B surface antigen, 24 weeks after stopping all treatment.
That is positive, but what do these outcomes mean for patients, and is it possible that this medicine could eventually mean patients will not need to take medication for the rest of their lives to control the virus?
What Is Hibsago, and Why Is It Important?
Hibsago is a medicine that contains bepirovirsen, which is an antisense oligonucleotide. Antisense oligonucleotides are designed to bind to a specific area of genetic material to ultimately help regulate the production of a certain protein. For example, bepirovirsen helps reduce hepatitis B virus-associated RNA and proteins.
Unlike conventional antiviral medicines that suppress viral replication, bepirovirsen targets hepatitis B RNA. This may ultimately help the immune system gain control of chronic hepatitis B infection.
The FDA approved it for use in combination with existing antiviral therapy, not as a replacement for existing therapy.
There is a big difference between the two. Chronic hepatitis B can slowly and steadily damage your liver, increasing your risk of cirrhosis and liver cancer over a long period of time. There are medicines that can help suppress the virus. However, patients may need to take these medicines for years.
The new hepatitis B treatment offers another way to achieve control of the virus after treatment has stopped. Not everyone in the clinical trials achieved this outcome.
Who Can Receive Hibsago?
Not everyone with chronic hepatitis B will qualify for this treatment. The FDA states that, to qualify, you must:
- Not have cirrhosis.
- Have been on existing hepatitis B antiviral therapy for at least 6 months.
- Have suppressed hepatitis B virus levels.
- Have a hepatitis B surface antigen (HBsAg) level of 3,000 IU/mL or less, measured using an FDA-authorized test.
Doctors will also assess your platelet count, liver and kidney function, and other safety concerns before treatment.
Bepirovirsen is not for patients who have just been diagnosed with chronic hepatitis B and have not started treatment with antivirals. Bepirovirsen is intended to be used along with other medicines to control hepatitis B in patients who are already receiving treatment.
What Were the Results of Clinical Trials?
The FDA approved this treatment based on the results of Phase 3 clinical trials that compared bepirovirsen with a placebo alongside existing hepatitis B treatment.
The results give us some things to be hopeful about.
- 24% of patients receiving bepirovirsen were able to stop their current hepatitis B treatment, compared with none of the patients receiving a placebo.
- Around 19% of patients successfully maintained viral control after stopping all treatment, with undetectable HBsAg, at the 24-week mark.
- The majority of patients could not achieve this outcome during the observed follow-up period.
The number to focus on here is 19%. The 24% figure refers to the patients who qualified to stop their existing hepatitis B treatment.
A functional cure does not mean complete eradication of the virus from the body. It means the infection is controlled without ongoing treatment and meets defined clinical criteria.
These results, reported by the FDA and the drug manufacturer, show meaningful progress, but longer-term follow-up will give a clearer picture of how sustainable this outcome is.
What Side Effects Should Patients Know About?
Serious side effects are a major concern. The FDA has required the manufacturer to include a boxed warning for potentially serious liver problems and very low platelet counts.
Additional key safety information:
- Rising liver enzymes: If liver enzyme levels rise significantly, treatment may need to be temporarily stopped or discontinued.
- Low platelet counts: A severely low number of platelets in the blood can cause serious and life-threatening bleeding.
- Kidney problems: Worsening kidney function can occur.
- Inflammatory reactions: Severe immune-related reactions, including vasculitis, can occur.
- Common side effects: Injection-site reactions, fever, fatigue, and headache.
The drug label states that patients will need liver and kidney function tests before and during treatment to assess for worsening of these functions. Platelet counts will also need to be checked weekly during treatment.
Report any unusual bruising or bleeding to your doctor. Watch for yellowing of the skin or eyes, dark urine, or abdominal pain. Prompt medical evaluation may prevent potentially life-threatening complications.
For more details on safety, see GSK plc‘s proprietary information.
How Does Hibsago Differ From Other Hepatitis B Medicines?
Established medicines that help treat chronic hepatitis B, including entecavir and tenofovir, reduce the risk of worsening liver disease by lowering the viral load. They are therefore important for managing the condition. However, long-term treatment is often needed to control the viral load.
Hibsago is unique because it acts by blocking viral RNA and thus has the potential to reduce HBsAg levels and achieve remission.
Hibsago treatment does not remove the need for routine monitoring, and patients must not discontinue antiviral treatment independently. Stopping treatment can result in a flare-up of hepatitis B, and it may take months for the liver to return to baseline and for the patient’s condition to stabilize.
For patients who are eligible, treatment may lead to the possibility of eventually discontinuing all treatment. For other patients, established antiviral treatment remains very important.
Frequently Asked Questions
1. Can Hibsago Cure Hepatitis B?
While Hibsago is not a universal cure, some participants in the clinical trials achieved a functional cure, in which HBsAg was undetectable for at least 24 weeks after all treatment was discontinued. However, the virus may still be present in the body.
2. How Long Does Treatment Take?
Treatment lasts for up to 24 weeks and consists of a series of injections. After the final injection, patients must continue taking their antiviral treatment for at least an additional 24 weeks before stopping under a physician’s supervision.
3. Can People With Cirrhosis Use It?
The FDA-approved indication does not include people with cirrhosis. It is not indicated for all patients with chronic hepatitis B, and eligibility must be determined by a qualified specialist.
4. Does Hibsago Prevent Hepatitis B Transmission?
It has not been shown to prevent the transmission of hepatitis B. Patients should continue to follow recommended precautions to prevent transmission, even if their viral markers improve.
5. Can Patients Stop Tenofovir or Entecavir After Receiving It?
Not automatically. A healthcare professional must assess the patient’s viral markers and other clinical indicators before treatment can be stopped. Hepatitis B can reactivate after treatment is discontinued.
6. Is Hibsago Available in India?
FDA approval is specific to the United States. The manufacturer must apply for and receive approval from the relevant authorities to make this drug available in India. FDA approval of a drug in the US does not guarantee that it will be available in India.
