FAQs about gene therapy for hemophilia B

Last updated June 3, 2024, by Lindsey Shapiro, PhD
Fact-checked by Patrícia Silva, PhD

Here are answers to some of the most common questions about the use of gene therapy for treating hemophilia B.

What is gene therapy for hemophilia B?

Gene therapy for hemophilia B is an approved treatment with potential to be given as a one-time infusion. It addresses the underlying cause of hemophilia B by providing the body with a healthy version of the F9 gene. The F9 gene is needed to produce factor IX (FIX), which is the blood clotting factor lacking in people with the disease. Gene therapy is expected to control bleeding with little or no other routine preventive therapies needed.

Is gene therapy a cure for hemophilia B?

In theory, gene therapy could offer a potential cure for hemophilia B by increasing FIX to near normal levels to prevent bleeding episodes throughout a person’s life. However, everyone responds differently to treatments. It is not guaranteed bleeds will be completely controlled without the need for other hemophilia treatments.

How long do the effects of gene therapy last?

Since gene therapy for hemophilia B is a relatively new treatment option, it is not yet known how long it will effectively control bleeds. The hope is that after a single infusion a person will stop having uncontrolled bleeding throughout their life. But it is too early to know this for sure as those who have received the treatment need to be followed for a longer period of time.

Who is eligible for gene therapy for hemophilia B?

In general, adult men with hemophilia B are eligible for treatment with the currently available gene therapies. To be considered eligible, you would undergo tests prior to receiving gene therapy. The tests will check your general health and ensure you don’t have antibodies against the FIX protein. You also may be tested for antibodies against the virus that is being used as a carrier for the gene therapy under consideration.

How is gene therapy administered?

Gene therapy for hemophilia B is given as a single intravenous (into-the-vein) infusion by a trained medical professional in a hospital setting or treatment center. You will then be monitored for a few hours to make sure you don’t have any reaction to the treatment before being cleared to go home.

What are the potential risks of gene therapy?

Risks associated with gene therapy for hemophilia B may include infusion-related reactions, liver toxicity, and a theoretical risk of liver cancer. As scientists learn more about gene therapies in the long term, what is known about the risks may change. The risks also may vary based on the specific therapy.

What is the recovery time for gene therapy?

Hemophilia gene therapy is given in an outpatient setting. Typically, it does not require an overnight stay at a hospital or treatment center. In most cases, if you haven’t had any reaction to treatment after a few hours, you’ll be able to go home. It’s important to speak to your doctor about how long to wait before you can resume daily activities, such as exercise.

Do people continue other hemophilia B treatments after gene therapy?

After receiving gene therapy, you will, at first, continue on routine preventive therapies while your doctor monitors the effects. If FIX levels become high enough and bleeds are under control, the therapies may be reduced or stopped. Some patients in clinical trials were able to stop FIX replacement therapy altogether, but long-term follow-up is still needed to know for sure whether the effects of gene therapy will lessen over time, and if other hemophilia B treatments would eventually need to be resumed, restarted, or increased.

Is gene therapy for hemophilia B covered by insurance?

Whether or not gene therapy for hemophilia B is covered by insurance may depend on the specific insurer and the exact therapy. In general, insurance companies may cover treatment provided you meet certain eligibility requirements and the treatment is considered medically necessary. You should talk with your insurance company and healthcare providers to better understand your coverage.

Can children be treated with gene therapy?

At this time, available hemophilia B gene therapies are not approved for children; they are only approved for adults ages 18 and older. Before gene therapy for children with hemophilia B can be approved, clinical studies would have to show that they are safe and effective in pediatric populations, similar to how they are for adults.

Do the benefits of gene therapy pass onto a person’s children?

In short, no, the benefits of a hemophilia B gene therapy are not passed on to a child. Hemophilia B gene therapies work specifically in the liver. They do not correct the faulty F9 gene in the reproductive cells (i.e., sperm or egg cells), which is how genetic material is passed on to a child.

Is gene therapy the same as gene editing?

Gene editing is considered a type of gene therapy. It involves correcting a person’s DNA as a way to remove or bypass the genetic defect that is causing problems. While currently there aren’t any gene editing therapies approved for hemophilia B, scientists are investigating it.

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