Novo Nordisk developed the treatment. The U.S. Food and Drug Administration (FDA) approved it for both adults and children with the disease. The European Medicines Agency (EMA) approved the treatment to treat hemophilia B patients ages 12 and older.
Rebinyn/Refixia is an injection. Dosing depends on the patient’s weight (above or below 40 kg, or 88 lbs).
How does Rebinyn/Refixia work?
Mutations in the gene carrying instructions for cells to make clotting factor IX cause hemophilia B. Factor IX is one of the proteins that help in normal blood clotting. The mutations result in a deficiency of factor IX protein, which results in bleeding problems.
Rebinyn/Refixia is a modified form of factor IX. Patients can use it as replacement therapy to replenish the deficient protein in their body. It contains a polyethylene glycol (PEG) molecule attached to the portion of factor IX protein that breaks off when the clotting factor becomes active. The addition of PEG helps extend the half-life of factor IX. This process is called PEGylation. It prevents the premature breakdown of factor IX by naturally occurring antibodies. (This is the normal process the body uses to remove excess factor IX.)
The factor IX protein in Rebinyn/Refixia is produced in a Chinese hamster ovary cell line before the PEGylation process.
During a bleeding episode, Rebinyn/Refixia is capable of acting like factor IX and successfully contributing to the formation of a blood clot to stop the bleeding.
People with hemophilia B may use Rebinyn/Refixia as a form of prevention against bleeding. They also can use it as an “on-demand” treatment to stop bleeding after an accident or injury.
Rebinyn/Refixia in clinical trials
A Phase 1 clinical trial (NCT00956345) evaluated the safety and pharmacokinetics (movement in the body) of Rebinyn/Refixia in non-bleeding hemophilia B male patients, ages 18 to 65. Participants received increasing single doses of the treatment (25U per kg, 50U per kg, and 100U per kg) through a vein. The results showed that Rebinyn/Refixia was successful in treating bleeds in a dose-dependent manner.
A multi-national Phase 3 study (NCT01333111) assessed the safety and effectiveness of Rebinyn/Refixia in 74 male patients with hemophilia B, ages 13 to 70. Participants randomly received either a low (10U per kg) or high dose (40U per kg) of Rebinyn/Refixia once weekly for 52 weeks. The results showed that patients treated with 40U per kg of Rebinyn/Refixia were less likely to have a bleed than those treated with a 10U per kg.
Researchers evaluated the long-term safety and efficiency of Rebinyn/Refixia treatment in a Phase 3 extension study (NCT01395810). The results showed that the treatment’s effectiveness was maintained for at least two years.
A Phase 3 study (NCT01467427) tested the safety, effectiveness, and pharmacokinetics of Rebinyn/Refixia in male children up to age 12 with hemophilia B who had received some treatment in the past. Participants received a single weekly dose of 40U per kg of Rebinyn/Refixia for 52 weeks. This was successful in treating a significant number of bleeds resolving 99% of bleeds. Moreover, bleeds into the joint were resolved in patients on the higher dose of Rebinyn/Refixia (80U per kg) within 12 months. The treatment also had a positive impact on patients’ health-related quality of life.
Another Phase 3 clinical trial (NCT01386528) tested the ability of Rebinyn/Refixia to prevent and treat bleeding in hemophilia B patients before and after major surgery. Thirteen male patients, ages 13 to 70, enrolled in the study. They received a single dose of Rebinyn/Refixia (80U per kg) four hours before surgery. After surgery, they received another 40U per kg of treatment at the doctor’s discretion. Researchers confirmed the hemostatic effect (ability to stop bleeding) of the treatment during surgery with a 100% success rate in 13 major procedures, including nine major orthopedic surgeries in patients ages 15 to 56.
A Phase 3 study (NCT03075670) evaluated the safety and effectiveness of Rebinyn/Refixia in adults with hemophilia B. Results demonstrated that treatment significantly improved levels of factor IX protein.
A Phase 1 study (NCT03075670) compared the pharmacokinetics of Rebinyn/Refixia to that of Alprolix, another factor IX replacement therapy in patients with hemophilia B. Results of the study demonstrated that Rebinyn/Refixia has favorable pharmacokinetics — meaning that the treatment lasts significantly longer in patients’ bodies than Alprolix.
Ongoing clinical trials
Another global Phase 3 study (NCT02141074) is enrolling participants worldwide to assess the safety and effectiveness of Rebinyn/Refixia in preventing and treating bleeding in previously untreated boys, ages 6 and younger, with hemophilia B, presenting a factor IX activity below 2%. The study aims to enroll 60 children.
Interim data from 37 participants in the study indicates the treatment is safe and effective; patients reported only mild side effects. However, two boys out of 37 had to withdraw from the study due to an allergic reaction. Among boys treated with weekly preventive treatment, about 67% had no reported bleeds and 85% had no spontaneous bleeds. Researchers expect to conclude the study in October 2022.
Last updated: Aug. 25, 2020
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