Rebinyn (nonacog beta pegol) for hemophilia

Written by Lila Levinson, PhD | Last updated Aug. 21, 2026
Fact-checked by Lindsey Shapiro, PhD

What is Rebinyn for hemophilia?

Rebinyn (nonacog beta pegol) is an extended half-life factor IX product approved to prevent and control bleeding in people with hemophilia B, including bleeding during surgery.

In hemophilia B, a genetic mutation prevents the body from making enough working factor IX, or FIX, a protein important for blood clotting. This can lead to symptoms of easy and uncontrollable bleeding.

Replacement therapy is a common treatment approach that provides the body with a working version of FIX to improve blood clotting and control bleeds. Rebinyn, formerly known as N9-GP, is one such therapy. It contains a lab-made, or recombinant, version of FIX.

Rebinyn is an extended half-life product, meaning it is designed to last longer in the bloodstream than standard replacement therapies. It uses a technology called PEGylation that helps the protein remain in the bloodstream longer.

The therapy, given by infusion into a vein (intravenously), is sold by Novo Nordisk. In Europe, the same medication is sold under the name Refixia.

Therapy snapshot

Who can take Rebinyn?

In the U.S., Rebinyn is approved for adults and children with hemophilia B. It can be used in three ways:

• on-demand: used as needed to control bleeding episodes
• perioperative: to manage bleeding around the time of surgery
• prophylaxis: routine use to reduce the frequency of bleeding episodes

The medication is similarly approved in Canada. In the European Union, where the medication is sold as Refixia for hemophilia B, it has similar uses and can be used in people of all ages.

Rebinyn is contraindicated for people with known allergies to the drug or its components. This includes allergies to hamster proteins, because the medication is manufactured using laboratory-grown hamster cells.

Some people who use replacement products develop inhibitors, which are antibodies that target FIX and can make the medication less effective. Inhibitors can sometimes be eliminated through repeated exposure to the replacement product in a process called immune tolerance induction, but the safety and efficacy of using Rebinyn for this purpose have not been established. 

How is Rebinyn administered?

Rebinyn is given as an intravenous infusion over one to four minutes. After appropriate training from a healthcare provider, patients and caregivers may administer the therapy at home. Rebinyn comes as a dry powder that must be completely dissolved in the provided sterile liquid before use.

The exact dose and how often Rebinyn is given depend on the clinical situation, but standard dosing involves:

• prophylaxis: 40 international units (IU) per kg of body weight, given once a week
• on-demand: 40 IU/kg or 80 IU/kg, depending on the severity of the bleed, with extra doses as needed
• perioperative:  40 IU/kg or 80 IU/kg given before surgery, with additional doses as needed to control bleeding

A healthcare provider will tell patients what dose to use at home for prophylactic and on-demand treatment.

Rebinyn in clinical trials

The approval of Rebinyn for hemophilia B was supported by the Phase 3 PARADIGM clinical trial program. Key Rebinyn clinical trials include:

• PARADIGM 2 (NCT01333111) involved 74 adolescents and adults with previous exposure to FIX replacement therapy. Those who received weekly prophylactic Rebinyn at 10 or 40 IU/kg for one year had lower bleeding rates than those who used the medication only on demand. Across all groups, the medication successfully treated 92.2% of bleeds.
• PARADIGM 3 (NCT01386528) included 13 adolescents and adults with prior FIX therapy exposure who were undergoing major surgery. Treatment in the perioperative setting resulted in excellent or good control of bleeding in all 13 surgeries.
• PARADIGM 4 (NCT01395810) was a long-term extension study for PARADIGM 2 and 3, with continued prophylaxis and/or on-demand treatment. Long-term results supported the efficacy and safety of Rebinyn.
• PARADIGM 5 (NCT01467427) tested Rebinyn in 25 children, 12 and younger, with previous FIX replacement experience. Weekly preventive doses of 40 IU/kg reduced bleeding rates compared to a period before the trial, and the medication successfully treated 92.9% of bleeds over a one-year period. Bleed control was sustained for at least five years.
• PARADIGM 6 (NCT02141074) included previously untreated or minimally treated boys younger than 6. Preliminary results from 37 dosed participants showed that over two-thirds of those receiving prophylaxis were bleed-free. All 15 bleeds in the prophylaxis group were treated with a single Rebinyn injection. Overall, the study concluded that Rebinyn provided effective hemostatic coverage.

Rebinyn side effects

The most common side effects of Rebinyn in people who have previously received replacement products include:

• itching
• injection site reactions, including swelling, pain, rash, or redness.

In people who hadn’t previously been treated for hemophilia B, additional side effects included:

• rash
• development of FIX inhibitors
• allergic reactions, including severe systemic reactions called anaphylaxis

Signs of an allergic reaction may include chest tightness, wheezing, difficulty breathing, hives, itching, and/or swelling in the deeper layers of the skin or mucous membranes. Rebinyn should be discontinued if these symptoms emerge, and patients should seek immediate medical care.

If Rebinyn isn’t working as well as expected to increase FIX activity and/or control bleeds, a healthcare provider may recommend testing for inhibitors. The use of Rebinyn to induce immune tolerance in such patients is not established, and nephrotic syndrome has been reported after immune tolerance induction with FIX-containing products.

FIX-containing products have been associated with dangerous blood-clotting events called thromboembolic complications. This may still be a risk with Rebinyn.

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.