Hemophilia B, also called factor IX (FIX) deficiency, is an inherited condition that prevents blood from clotting normally. This means that if you experience a cut, scrape, or injury, the bleeding lasts longer than it would for someone without a bleeding disorder. Bleeding in hemophilia B can be internal or external, and the severity depends on the level of factor IX in the blood.
- Mild hemophilia B (6%-49% FIX in the blood) causes bleeding mostly after major injuries or surgery.
- Moderate hemophilia B (1%-5% FIX) leads to bleeding after injuries and sometimes may even cause spontaneous bleeds.
- Severe hemophilia B (less than 1% FIX) causes frequent spontaneous bleeding, especially in joints and muscles.
Rebinyn (coagulation factor IX recombinant, glycopegylated) is a medicine used to treat adults and children with hemophilia B. It is approved for three main purposes: treating and managing active bleeding episodes, controlling bleeding during or after surgery, and providing routine preventive therapy to lower the number of bleeding events.
How Does Rebinyn Work?
People with hemophilia B do not have enough factor IX, a protein that the body needs to help stop bleeding. Rebinyn provides a temporary supply of this missing factor IX, allowing blood to clot the way it should. The factor IX protein in Rebinyn is attached to a small molecule called polyethylene glycol (PEG). This helps the medicine stay in the bloodstream longer, so it does not leave the body as quickly.
How Is Rebinyn Used?
Rebinyn is a powder that must be mixed with the liquid (diluent) that comes in the package. After mixing, it is given as an infusion into a vein (an IV). Your hemophilia treatment center or health care provider will train you on each step. Do not try to infuse Rebinyn on your own until you have been trained.
Your health care provider will also review important safety steps with you, including:
- Allergies: Tell your health care provider if you have ever had an allergic reaction to factor IX products or hamster proteins. Rebinyn should not be used if you are allergic to these.
- Laboratory tests: Sometimes the body can develop “inhibitors,” which are antibodies that block factor IX from working properly. This can happen in people using Rebinyn. If yourfactor IX levels do not rise as expected or if your bleeding does not improve after treatment, your health care provider will need to run a blood test to check for these inhibitors.
Your health care provider will determine the correct dose of Rebinyn for you by considering factors such as your weight and whether you are treating a bleed, preparing for surgery, or using the medicine for regular preventive (prophylaxis) therapy. Your dose is measured in international units (IU), and it is important not to change the amount you take without your provider’s guidance.
If you miss a dose, use Rebinyn as soon as you remember, but do not take two doses at once; simply return to your usual schedule and contact your provider if you are unsure what to do. You should call your health care provider right away if your bleeding does not stop after treatment with Rebinyn because this may signal the development of inhibitors.
How Can I Manage the Side Effects of Rebinyn?
In studies, the most common side effects of Rebinyn were infusion site reactions, itching, and rash. Infusion site reactions may include bruising, bleeding, pain, swelling, and redness/discoloration. These side effects are usually temporary.
Some people may choose to use a cool compress to soothe discomfort or swelling. Let your health care provider know if Rebinyn side effects bother you. They may recommend an over-the-counter (OTC) pain reliever for pain or an OTC antihistamine for itchiness.
Get medical help right away if you:
- Notice symptoms of an allergic reaction, such as hives, trouble breathing, wheezing, chest tightness, or swelling of the face
- Develop signs of a possible blood clot, including chest pain, difficulty breathing, or swelling and pain in your leg
How Was Rebinyn Studied for the Management of Hemophilia B?
To assess the safety and effectiveness of Rebinyn, several clinical trials were done to see how well it works and how safe it is for people with hemophilia B. These studies looked at how Rebinyn treats bleeding episodes, helps control bleeding during surgeries, and works when used regularly to prevent bleeds. In total, 105 people took part, including adults, teenagers, and children. Everyone in the studies had already received factor IX (FIX) replacement therapy in the past.
One study followed 74 teens and adults (aged 13-65) from 13 different countries. Everyone in the study had very low levels of factor IX (≤ 0.02 IU/mL). The goal was to learn how safe and effective Rebinyn would be for preventing and treating bleeds. Participants chose either prophylaxis (regular preventive treatment) or on‑demand treatment. Those on prophylaxis were randomly assigned to one of two weekly doses: 10 IU/kg or 40 IU/kg. People in the on‑demand group only received treatment when they had a bleed. The prophylaxis groups were followed for 52 weeks, and the on‑demand group was followed for 28 weeks. A total of 345 bleeds were treated during the study.
Results: About 92% were successfully controlled, and most bleeds (87%) stopped with just one infusion of Rebinyn. People on the higher‑dose prophylaxis (40 IU/kg) had the best results: 99% of their bleeds stopped with a single dose, compared to 84% in both the 10 IU/kg and on-demand groups.
Another study included 13 teens and adults (aged 15-56 years) from eight different countries who were preparing for major surgeries such as knee or hip replacements, foot surgery, or complicated dental procedures. All participants had very low factor IX levels (≤ 0.02 IU/mL). Before surgery, everyone received a single 80 IU/kg dose of Rebinyn, and after surgery, they were given 40 IU/kg doses only as needed.
Results: During surgery, bleeding control was rated as excellent or good in 100% of cases, and none of the people required extra doses on the day of surgery beyond the initial dose. Across all procedures, bleeding was well controlled with very low factor consumption: Most people only needed two doses after surgery in the first week, and a total of about three doses within the two weeks after surgery. Nobody developed inhibitors, and there were no treatment‑related allergic reactions, blood clots, or deaths.
A third study followed 25 children (aged 1-12 years) from eight different countries who had very low levels of factor IX (≤ 0.02 IU/mL). Every child received once‑weekly prophylaxis with a 40 IU/kg dose of Rebinyn, and most stayed in the trial long enough to reach at least 50 exposure days.
Results: A total of 42 bleeds were treated during the study, and about 93% were successfully controlled, with most bleeds (86%) stopping after just one infusion. Children on treatment had very low bleeding rates overall: Younger children (aged 0-6 years) had a median of zero bleeds per year, and older children (7-12 years) had a median of two bleeds per year. The treatment kept estimated average factor IX levels around 15%-19%, which is within the range of mild hemophilia. No child developed inhibitors, and there were no allergic reactions, blood clots, or treatment‑related serious side effects.
Your results may vary from what was seen in studies.
Are There Any Special Steps Required to Get Rebinyn?
Rebinyn is a “specialty” medicine. This means that you can only get it from a specialty pharmacy, and that it may require prior authorization from your insurance company.
Is There Any Cost Assistance Available?
You can find a savings card from the maker of Rebinyn. Your eligibility depends on whether you have prescription insurance and what type of insurance you have. You can find out more about Rebinyn cost support and financial assistance options by calling 844-668-6732 or visiting the NovoCare website.