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hemgenix-logo-bg mobile-menu-bg HEMGENIX® (etranacogene dezaparvovec-drlb)


DNA Spiral with people sitting

Patient portrayal; HEMGENIX not intended for women


What is gene therapy?

Gene therapy uses advanced science to address the gene causing a condition. It either provides a working copy of the existing gene or turns off or changes the existing gene.

Gene therapies are of particular interest for the treatment of both hemophilia A and hemophilia B because each is caused by a single gene mutation in either the F8 or F9 gene, respectively. However, because the mutations are in different genes, hemophilia B cannot be treated with the same gene therapy used to treat hemophilia A.

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Hemophilia B is an appropriate target for treatment with gene therapy because:

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It is caused by a mutation of a single gene (the F9 gene)

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The F9 gene is small and can be packaged into an adeno-associated viral (AAV) vector

Here’s how gene transfer therapy works
for hemophilia B

Working gene

The working gene

It starts by developing a package of genetic instructions—the functional, or working, gene

Delivery truck

The delivery vehicle

Then AAV vectors are created, which will eventually enter targeted liver cells

Bringing the working gene to the delivery truck

Bringing the two together

The package of genetic instructions is loaded into an AAV vector, acting as a delivery truck

Delivery of working gene

Special delivery

Through a single IV infusion, the delivery truck heads toward the liver with its package

Liver generating FIX

Generating their own factor IX

Once delivered into the liver cells, the package of instructions enables the liver to start generating factor IX, with the goal of allowing a person to produce their own elevated and protective levels of factor IX

Regenerating FIX in liver

Keep the factor IX going

After delivering its package, the AAV vector shell is broken down and eliminated. However, the genetic instructions remain to continue producing factor IX

Current unmet needs in hemophilia B

While there have been advances in hemophilia B treatment, the current standard of care for hemophilia B is lifelong infusions of factor IX replacement therapy. People who regularly infuse factor IX replacement products can still experience breakthrough bleeds, leading to joint damage, pain, and reduced quality of life.

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Joint damage

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Reduced quality of life

People living with hemophilia B may benefit from a one-time infusion that offers consistent bleed protection lasting years instead of weeks

A recent CSL Behring–sponsored survey assessed the burdens of living with hemophilia B in 110 people who were receiving short-term prophylaxis or long-term prophylaxis.* It showed that:

Despite being on prophylaxis, those surveyed still experienced

an average of


spontaneous bleeds

over the past 6 months

The majority of people in the survey experienced joint damage and pain:

The majority of people in the survey frequently experienced joint damage and pain:



had joint damage

The majority of people in the survey frequently experienced joint damage and pain:



experienced joint pain at least a few times per month

*Short-term prophylaxis is prolonged treatment following a bleed until full recovery and prophylaxis prior to physical activity. Long-term prophylaxis is regular preventative injections. Of the 110 people surveyed, 29 were being treated with short-term prophylaxis only, 74 were being treated with long-term prophylaxis only, and 7 were being treated with both short-term and long-term prophylaxis.

Discover the possibilities of a one-time infusion

Elevated factor IX levels from gene therapy can offer:

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Ongoing prevention

Reduce risk of bleeding, including the risk of joint bleeds

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Reduce or even eliminate the burdens of regular, long-term prophy

Redefine how you live with hemophilia B

See how HEMGENIX works

HEMGENIX is the first ever gene therapy for hemophilia B

See study results
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HEMGENIX®, etranacogene dezaparvovec-drlb, is a one-time gene therapy for the treatment of adults with hemophilia B who:

  • Currently use Factor IX prophylaxis therapy, or
  • Have current or historical life-threatening bleeding, or
  • Have repeated, serious spontaneous bleeding episodes.

HEMGENIX is administered as a single intravenous infusion and can be administered only once.

What medical testing can I expect to be given before and after administration of HEMGENIX?

To determine your eligibility to receive HEMGENIX, you will be tested for Factor IX inhibitors. If this test result is positive, a retest will be performed 2 weeks later. If both tests are positive for Factor IX inhibitors, your doctor will not administer HEMGENIX to you. If, after administration of HEMGENIX, increased Factor IX activity is not achieved, or bleeding is not controlled, a post-dose test for Factor IX inhibitors will be performed.

HEMGENIX may lead to elevations of liver enzymes in the blood; therefore, ultrasound and other testing will be performed to check on liver health before HEMGENIX can be administered. Following administration of HEMGENIX, your doctor will monitor your liver enzyme levels weekly for at least 3 months. If you have preexisting risk factors for liver cancer, regular liver health testing will continue for 5 years post-administration. Treatment for elevated liver enzymes could include corticosteroids.

What were the most common side effects of HEMGENIX in clinical trials?

In clinical trials for HEMGENIX, the most common side effects reported in more than 5% of patients were liver enzyme elevations, headache, elevated levels of a certain blood enzyme, flu-like symptoms, infusion-related reactions, fatigue, nausea, and feeling unwell. These are not the only side effects possible. Tell your healthcare provider about any side effect you may experience.

What should I watch for during infusion with HEMGENIX?

Your doctor will monitor you for infusion-related reactions during administration of HEMGENIX, as well as for at least 3 hours after the infusion is complete. Symptoms may include chest tightness, headaches, abdominal pain, lightheadedness, flu-like symptoms, shivering, flushing, rash, and elevated blood pressure. If an infusion-related reaction occurs, the doctor may slow or stop the HEMGENIX infusion, resuming at a lower infusion rate once symptoms resolve.

What should I avoid after receiving HEMGENIX?

Small amounts of HEMGENIX may be present in your blood, semen, and other excreted/secreted materials, and it is not known how long this continues. You should not donate blood, organs, tissues, or cells for transplantation after receiving HEMGENIX.

Please see full prescribing information for HEMGENIX.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit, or call 1-800-FDA-1088.

You can also report side effects to CSL Behring’s Pharmacovigilance Department at 1-866-915-6958.