Is gene therapy right for you? Eligibility requirements and other considerations

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

Gene therapy is a relatively new treatment option for hemophilia B. It can offer long-lasting bleed control with a single infusion into the bloodstream. By providing a healthy version of the F9 gene — mutations in this gene are the cause of hemophilia B — it enables the body to continuously produce the factor IX (FIX) blood clotting protein it lacks.

There are a number of factors that a person with hemophilia B and their healthcare team will want to consider when determining if gene therapy is the right choice for them, including eligibility requirements, risks and benefits, other treatment options, and costs.

Eligibility requirements

While eligibility requirements for hemophilia B gene therapies vary based on the specific treatment, there are a few general clinical criteria that a doctor will consider when deciding if someone is eligible for treatment. These include:

• age, as gene therapies for hemophilia B are currently only approved for use in adults (18 years and older)
• treatment history, gene therapies for hemophilia B are intended for people who are currently using preventive FIX replacement therapy, have a history of life-threatening bleeds, or repeated, serious, spontaneous bleeding episodes
• sex, as current hemophilia B gene therapies are not intended for women because of the chromosomal location of the F9 gene (located on the X chromosome, one of the two sex-determining chromosomes in humans)
• pretreatment testing, as people will only be eligible for gene therapy if they test negative for neutralizing antibodies (inhibitors) against FIX. Patients also may be tested for antibodies against the virus that is being used as a carrier for the gene therapy under consideration and to make sure any HIV infection is well controlled.
• liver health, as people with certain liver conditions or liver-related risk factors may not be eligible for hemophilia gene therapies given that these therapies may cause changes in liver enzymes. Tests of liver health will be performed before a person receives the treatment.

Benefits and risks

Gene therapies for hemophilia B may be a way to permanently correct the error caused by the F9 gene mutation and the resulting factor IX deficiency. With just one infusion, it  offers bleed control and allows decreasing or stopping other preventive therapies.

Like most treatments, gene therapy for hemophilia B may have some risks, including the possibility of liver toxicity, and theoretically liver cancer associated with the viral vector that helps carry the therapy into a person’s cells. It’s also possible to have an immune response during treatment, which could lead to severe reactions.

Because gene therapy is a relatively new treatment option for hemophilia B, its long-term effects are not completely known — the earliest treated patients in clinical trials have been followed for less than a decade. It is also too soon to say whether gene therapies for hemophilia B have a lasting effect, or if there are other risks or safety concerns scientists might learn more about over time.

Lastly, it is important to be aware that gene therapy is not reversible.

Costs and insurance

The cost of gene therapy for hemophilia B is around $3.5 million. Still, it is believed the cost-effectiveness of the one-time treatments may be greater than the lifetime costs of regular preventive therapies and care related to bleeding episodes.

Many health insurance providers will cover the treatment, but only if a person meets certain criteria and the treatment is deemed medically necessary for their care. It is likely that a preapproval process will be required before coverage for treatment will be guaranteed. Depending on the health insurance plan, you may be responsible for covering part of the cost. It’s important to always talk with the insurance company to better understand the specifics of coverage.

In addition to insurance, there may also be options to help with out-of-pocket costs for hemophilia B gene therapy. Some companies manufacturing gene therapies may offer assistance programs for underinsured or uninsured patients, as well as personalized support for explaining the specifics of coverage. A person’s doctor may help connect them to any available resources.

Some advocacy organizations offer financial assistance programs to help families affected by hemophilia cover medical costs, for example, the Hemophilia Federation of America’s Helping Hands Program. While such programs may not directly cover gene therapy, they could help ease the overall financial burden by helping out with things such as medical-related travel.

Gene therapy and other hemophilia B treatments

The goal of gene therapy is to offer long-term bleed control, and eliminate or significantly reduce the need for routine prophylaxis (preventive) treatments such as factor replacement therapy. Based on data from early clinical trials, it seems the therapy is working as intended, and some patients were able to stop using replacement therapy. Still, it’s too early to know whether these benefits are long lasting, and if people will be able to stay off prophylaxis for the rest of their lives.

After receiving gene therapy, a person with hemophilia B will continue using prophylactic treatments while their care team monitors FIX levels. After that, replacement therapy may be reduced or eliminated as doctors deem appropriate, but might need to be resumed if FIX levels drop or bleeds are not properly controlled.

In general, there aren’t any hemophilia B treatments that cannot be used after a person receives gene therapy, but patients should discuss all medications they are taking with a doctor, who will help them decide if and when any medication needs to be reduced or stopped.

Hemophilia News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.