Ixinity (Recombinant Factor IX): Uses, Dosage, Side Effects, and How It Works for Hemophilia B

Ixinity is a prescription medication that is given as an intravenous (IV) infusion to hemophilia B patients. Ixinity helps to manage and prevent prolonged bleeding caused by injuries, surgery, or even spontaneous internal bleeding in people with hemophilia B. 

It is also known by its generic name, coagulation factor IX (recombinant), and received its first approval from the U.S. Food and Drug Administration (FDA) in April 2015 as an on-demand treatment for managing bleeds in hemophilia B patients (ages 12 years and older). Later, in March 2024, the FDA expanded Ixinity approval to include children younger than 12 years old with hemophilia B. 

If a healthcare provider has prescribed Ixinity to you or your child, then it is important to understand key information about this medication, including what it is, how it works, how it is used, and what to expect during treatment. 

Ixinity: Usage or Indication

Ixinity (coagulation factor IX) is commonly used to treat and prevent certain types of bleeding episodes in people with hemophilia B. These bleeding episodes can occur due to an injury or surgery, or without any clear cause. 

Ixinity is prescribed to both adults and children with hemophilia B under the following conditions:

• To treat bleeding episodes when they occur
• To manage excessive bleeding before, during, or after a surgical procedure
• For routine prophylaxis to prevent or reduce the frequency of bleeding episodes 

You should NOT take Ixinity if you have hemophilia A with factor VIII deficiency. 

Working Mechanism 

To understand how Ixinity works, let’s first briefly review what hemophilia B is.

Hemophilia B is an inherited bleeding disorder caused by a deficiency in coagulation factor IX (a protein that causes blood clotting). This results in more frequent bleeding into joints, muscles, or internal organs, either spontaneously or as a result of accidental or surgical trauma. 

Ixinity is a lab-produced version of human coagulation factor IX that closely mimics the natural protein (factor IX) found in the body. When a person with Hemophilia B receives Ixinity, the infused recombinant factor IX enters the bloodstream and temporarily replaces the missing or low levels of natural factor IX.

Once in circulation, Ixinity helps the blood to clot more efficiently and prevents excessive blood loss in hemophilia B patients.  

Ixinity: Dosage Forms and Strengths

Ixinity comes as a lyophilized powder in single-use, color-coded glass vials that contain six different dosage strengths: 

• Yellow vial: 250 international units (IU)
• Blue vial: 500 IU
• Green vial: 1,000 IU
• Orange vial: 1,500 IU
• Red vial: 2,000 IU
• Brown vial: 3,000 IU

Ixinity lyophilized powder is mixed in the provided diluent (sterile water) before infusion. 

Note: IU (International Unit) tells how much clotting power a dose of factor IX provides.

Dosage and Administration

The dose and frequency depend on the patient’s body weight (kg), severity of factor IX deficiency, extent of bleeding, and whether it is used for treatment or for surgery.

The recommended dose is first mixed with a diluent and administered through intravenous (IV) infusion (injected directly into a vein). 

1. Ixinity Dosage for Routine Prophylaxis

For routine prophylaxis, Ixinity is typically administered twice a week at 40-70 international units per kilogram of body weight (IU/kg), in people aged 12 years and older, and at 35-75 IU/kg for children younger than 12. 

Children often clear clotting factors more quickly, so their doses may be adjusted within this range to maintain good protection against bleeding. 

2. Dosage for On-Demand Treatment 

When Ixinity is used to treat active bleeding rather than for routine prevention, doses are calculated to raise the person’s factor IX level to a desired target based on the severity of the bleed. Treatment is given until healing is achieved. For:

• Minor bleeds: Factor IX levels are raised to 30–60 IU/dl, with Ixinity given once every 24 hours for 1–3 days. 
• Moderate bleeds: Factor IX levels are increased to 40–60 IU/dl, with dosing every 24 hours for 2–7 days.
• Major or life-threatening bleeds: Higher factor IX levels of 60–100 IU/dl are needed, with Ixinity given every 12–24 hours for 2–14 days or longer under medical supervision.

3. Dosage To Control Bleeding Surrounding Surgery

Ixinity is also used to control bleeding before or after surgery in hemophilia B patients. For a minor surgical procedure, Ixinity is given every 24 hours after surgery to maintain factor IX activity levels at 30–80 IU/dl. 

For major surgical procedures, higher and more carefully controlled factor IX levels are required. Before surgery, levels are raised to 60–80 IU/dl. After surgery, factor IX levels are maintained at 40–60 IU/dl during the early recovery period, gradually reduced to 30–50 IU/dl, and then to 20–40 IU/dl as healing continues. 

Possible Side Effects

The most common side effect observed in >2% of patients in clinical trials was headache. Though it’s rare, Ixinity may also cause serious side effects, which include:

• Allergic reactions: 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.
• Kidney problems (nephrotic syndrome)
• Blood clots (thromboembolism)

Warnings

Patients who have had a history of anaphylactic or severe hypersensitivity (allergic) reactions to hamster (CHO) protein, which is present in trace amounts in the Ixinity, should not take this drug. 

Some patients may develop neutralizing antibodies (inhibitors) to Ixinity that can reduce the effectiveness of factor IX treatments. If there is a chance of this happening, your healthcare provider may perform an assay to measure factor IX inhibitor concentration. 

Precautionary Measures 

Always consult your healthcare provider before taking Ixinity if you:

• Are pregnant or plan to become pregnant (because Ixinity may harm your unborn baby)
• Are breastfeeding or plan to breastfeed
• Have any allergies, including allergies to hamster (CHO) protein
• Are taking any over-the-counter or prescription medications, especially  other coagulation factors like carfilzomib, efgartigimod alfa, or rozanolixizumab, supplements, or herbal products
• Have or have had any medical problems
• Have been told that you have inhibitors to factor IX (because Ixinity may not work for you)

Ixinity: Estimated Cost

Ixinity is generally expensive because it is a specialized biologic medication. However, some insurance plans and manufacturer programs may help reduce out-of-pocket costs for patients. For instance, Ixinity’s savings programs can provide up to $12,000 per year in support for people with commercial insurance, and there may be trial offers or assistance options available. Contact us if you are interested in exploring financial assistance opportunities for Ixinity.