Ixinity for hemophilia B

Last updated Jan. 4, 2023, by Lindsey Shapiro, PhD

Fact-checked by Joana Carvalho, PhD

What is Ixinity for hemophilia B?

Ixinity (trenonacog alfa; IB1001) is a replacement therapy designed to prevent or treat bleeding episodes in people with hemophilia B.

While it was originally developed by Aptevo Therapeutics, the global rights to the therapy were acquired by Medexus Pharmaceuticals in 2o2o.

How does Ixinity work?

Hemophilia B is a bleeding disorder caused by a deficiency of one of the factors required for blood clotting — factor IX, known as FIX. As a result, blood clotting is delayed and patients may experience excessive and prolonged bleeding.

Ixinity is a lab-made version of human FIX designed to restore factor IX levels and allow normal blood clotting in hemophilia B patients.

The treatment is used on demand to control active bleeds, but also be taken as a preventive (prophylactic) treatment to reduce the frequency of bleeding episodes. Ixinity also may be used to manage blood loss during surgery.

Who can take Ixinity?

The U.S. Food and Drug Administration approved Ixinity in 2015 to treat on-demand bleeds and for surgery management in adults and children with hemophilia B, ages 12 and older. Later, the therapy was approved as a prophylactic treatment for adults and children with hemophilia B.

Who should not take Ixinity?

Patients with a known sensitivity to Ixinity or any of its ingredients, including hamster proteins, should not use the medication.

How is Ixinity administered?

Ixinity is available as a white powder in single-use glass vials containing 250, 500, 1,000, 1,500, 2,000, or 3,000 international units (IU) of FIX. The medication should be reconstituted, or diluted, in sterile water and administered as an into-the-vein (intravenous) infusion.

The appropriate dose and frequency of Ixinity treatment will be determined by a healthcare professional based on the patient’s age, body weight, and clinical condition, as well as the type of bleed, bleeding severity, and degree of FIX deficiency.

As a prophylactic therapy, Ixinity is typically administered at a dose of 40–70 IU per kilogram of body weight twice weekly, but may also be adjusted based on the factors described above.

For on-demand treatment, Ixinity is recommended to be given to maintain FIX activity levels at:

  • 30 to 60 IU/dL, with dosing every 24 hours for 1–3 days until healing is achieved, in the case of minor bleeds.
  • 40 to 60 IU/dL, with dosing every 24 hours for 2–7 days until healing is achieved, in the case of moderate bleeds.
  • 60 to 100 IU/dL, with dosing every 12–24 hours for 2–14 days until healing is achieved, in the case of major or life-threatening bleeds.

For minor surgical procedures, Ixinity should be given every 24 hours for 1–5 days after surgery to maintain FIX activity levels at 30 to 80 IU/dL. Before surgery, the medication should be given to ensure FIX activity levels are at 50 to 80 IU/dL.

For major surgical procedures, Ixinity should be given every 8–24 hours after surgery to maintain FIX activity levels at 40 to 60 IU/dL in the first three days. From days 4–6,  it should be given at 30 to 50 IU/dL, and then administered at 20 to 40 IU/dL from day seven to day 14. Before surgery, the medication should be given to ensure FIX activity levels are at 60 to 80 IU/dL.

Ixinity in clinical trials

For adults and children ages 12 and older

A multicenter Phase 2/3 trial (NCT00768287) assessed Ixinity’s safety, efficacy and pharmacokinetics — its movement into, through and out of the body — in 77 hemophilia B patients with severe or moderately severe disease. All had previously been treated with FIX replacement therapy.

The study’s first randomized, controlled part compared the pharmacokinetics of Ixinity against BeneFix (nonacog alfa), another FIX replacement therapy, finding that the pharmacokinetics were comparable between the two treatments.

In a second, open-label part, Ixinity’s safety and effectiveness at controlling or preventing bleeds was evaluated. Results showed that Ixinity was well tolerated. The most common side effect was headache, occurring five times in two people. There were no reports of FIX inhibitors during treatment.

Ixinity was effective at preventing and controlling bleeds, with one or two infusions able to resolve 84% of bleeds. Participants usually rated the treatment’s ability to control bleeds as excellent or good, and trial investigators deemed the treatment effective in more than 90% of cases.

Findings from a trial substudy demonstrated that the treatment also was beneficial for surgical management. Surgeons rated Ixinity as adequate or better than adequate at controlling bleeds during 19 major surgeries.

For children younger than 12

An analysis of pooled data from two studies showed that Ixinity also was safe and well-tolerated in 12 children younger than age 12. The treatment also showed comparable efficacy to that shown in the earlier trial involving older patients.

Of 61 total bleeding episodes, six (10%) resolved with no infusions of Ixinity, and 44 (72%) resolved after one infusion. Five bleeding episodes (8%) required two infusions, and six (10%) required 3–5 infusions.

Participants rated bleed control as excellent in 65% of the bleeds, good in 32%, and fair in 3%. The most common side effect was excessive sweating, reported in two patients.

Common side effects of Ixinity

The most common side effect of Ixinity reported in clinical trials was headache.

Allergic reactions

Allergic reactions, including anaphylaxis — a severe and life-threatening allergic reaction — have been reported in patients using Ixinity. Signs of an allergic reaction may include swelling, hives, chest or throat tightness, low blood pressure, lethargy, nausea, vomiting, difficulty swallowing, abnormal sensations, wheezing, or difficulty breathing.

Patients experiencing signs of an allergic reaction should seek medical care immediately.


Some patients also may develop neutralizing antibodies, or inhibitors, against the treatment. This can reduce the medication’s effectiveness and make allergic reactions more likely. If expected FIX levels are not attained or bleeding is not controlled with Ixinity, it is recommended that a blood test for inhibitors should be performed.

Kidney problems

Ixinity may cause nephrotic syndrome, a condition in which the body passes too much protein in the urine, usually as a result of kidney damage. Nephrotic syndrome is more likely in patients with a history of allergic reactions or inhibitor development.

Blood clots

Blood clots (thromboembolism) may occur when using Ixinity. Patients should be monitored for blood clots during treatment, with close observation given those with liver disease, individuals who have undergone surgery, and those at an increased risk of clotting events.

Pregnancy and breastfeeding

No clinical or preclinical data exist regarding the use of Ixinity in pregnant women or while breastfeeding. Patients who are pregnant or wish to become pregnant when using Ixinity should discuss this with their healthcare team.


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