Factor Ix

Patients with hemophilia B are deficient in coagulation Factor IX, which is required for effective hemostasis. Treatment with REBINYN temporarily replaces the missing coagulation Factor IX.

• REBINYN, Coagulation Factor IX (Recombinant), GlycoPEGylated, is a recombinant DNA-derived coagulation Factor IX concentrate indicated for use in adults and children with hemophilia B (congenital Factor IX deficiency) for: • On-demand treatment and control of bleeding episodes • Perioperative management of bleeding • Routine prophylaxis to reduce the frequency of bleeding episodes Limitations of Use : REBINYN is not indicated for immune tolerance induction in patients with hemophilia B. REBINYN, Coagulation Factor IX (Recombinant), GlycoPEGylated, is a recombinant DNA-derived coagulation Factor IX concentrate indicated for use in adults and children with hemophilia B (congenital Factor IX deficiency) for: • On-demand treatment and control of bleeding episodes • Perioperative management of bleeding • Routine prophylaxis to reduce the frequency of bleeding episodes Limitations of Use : REBINYN is not indicated for immune tolerance induction in patients with hemophilia B ( 1 ).

• REBINYN is contraindicated in patients who have known hypersensitivity to REBINYN or its components (including hamster proteins) [ see Warnings and Precautions ( 5.1 ) and Description ( 11 ) ] Do not use in patients who have known hypersensitivity to REBINYN or its components, including hamster proteins ( 4 ).contraindicated

For intravenous infusion after reconstitution only. For intravenous infusion after reconstitution only ( 2 ). • Each carton and vial label for REBINYN states the actual Factor IX potency in international units (IU) ( 2.1 ). On-demand treatment and control of bleeding episodes: • 40 IU/kg body weight for minor and moderate bleeds, and 80 IU/kg body weight for major bleeds. Additional doses of 40 IU/kg can be given ( 2.1 ). Perioperative management: • Pre-operative dose of 40 IU/kg body weight for minor surgery, and 80 IU/kg body weight for major surgery. As clinically needed for the perioperative management of bleeding, repeated doses of 40 IU/kg (in 1-3 day intervals) within the first week after major surgery may be administered. • Frequency may be extended to once weekly after the first week until bleeding stops and healing is achieved ( 2.1 ). Routine prophylaxis : • 40 IU/kg body weight once weekly ( 2.1 ). 2.1 Dosing Guidelines • Dose and duration of treatment depend on the location and extent of bleeding, and the patient’s clinical condition. • If monitoring of Factor IX activity is performed, use a chromogenic assay or selected one-stage clotting assay validated for use with REBINYN [ see Warnings and Precautions ( 5.5 ) ]. • Each carton and vial label for REBINYN states the actual Factor IX potency in IU. On-demand Treatment and Control of Bleeding Episodes REBINYN dosing for on-demand treatment and control of bleeding episodes is provided in Table 1.

• Hypersensitivity reactions, including anaphylaxis, have occurred. Should hypersensitivity reactions occur, discontinue REBINYN and administer appropriate treatment ( 5.1 ). • Neutralizing antibodies (inhibitors) to Factor IX have occurred following administration of REBINYN. Perform an assay that measures Factor IX inhibitor concentration if bleeding is not controlled with the recommended dose of REBINYN or if plasma Factor IX activity level fails to increase as expected (5.2 , 5.5 ). • The use of Factor IX- products has been associated with the development of thromboembolic complications ( 5.3 ). • Nephrotic syndrome has been reported following immune tolerance induction with Factor IX-containing products in hemophilia B patients with Factor IX inhibitors and a history of allergic reactions to Factor IX. ( 5.4 ) • Factor IX activity assay results may vary with the type of activated partial thromboplastin time reagent used ( 5.5 ). 5.1 Hypersensitivity Reactions Allergic-type hypersensitivity reactions, including anaphylaxis, have occurred with REBINYN. The product may contain traces of hamster proteins which in some patients may cause allergic reactions. Signs of allergic reactions, which can progress to anaphylaxis, may include angioedema, chest tightness, difficulty breathing, wheezing, urticaria, and itching. Observe patients for signs and symptoms of acute hypersensitivity reactions, particularly during the early phases of exposure to the product. Discontinue use of REBINYN if allergic- or anaphylactic - type reactions occur, and initiate appropriate treatment.

Common adverse reactions (incidence ≥ 1%) in PTPs reported in clinical trials for REBINYN were itching and injection site reactions. Common adverse reactions (incidence ≥ 1%) in PUPs reported in clinical trials for REBINYN were rash, FIX inhibitors, hypersensitivity, itching, injection site reaction, and anaphylactic reaction. The most frequently reported adverse reactions (≥ 1%) in previously treated patients (PTPs) and previously untreated patients (PUPs) were itching and injection site reactions ( 6 ). Additional frequently reported adverse reactions (≥ 1%) in PUPs included rash, Factor IX inhibition, hypersensitivity, and anaphylactic reaction ( 6 ). In animals administered repeat doses of REBINYN, accumulation of polyethylene-glycol (PEG) was observed in the choroid plexus, pituitary, circumventricular organs, and cranial motor neurons ( 8.4 and 13.2 ). The potential clinical implications of these animal findings are unknown ( 6.3 ). To report SUSPECTED ADVERSE REACTIONS, contact Novo Nordisk Inc. at 1-877-668-6777 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in clinical trials of another drug and may not reflect the rates observed in clinical practice.

Pediatric Use: No dose adjustment is needed ( 8.4 ). 8.1 Pregnancy Risk Summary There are no data with REBINYN use in pregnant women to determine whether there is a drug-associated risk. Animal reproduction studies have not been conducted with REBINYN. It is unknown whether REBINYN can cause fetal harm when administered to a pregnant woman or can affect fertility. In the U.S. general population, the estimated background risk of major birth defect and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. 8.2 Lactation Risk Summary There is no information regarding the presence of REBINYN in human milk, the effect on the breastfed infant, and the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for REBINYN and any potential adverse effects on the breastfed infant from REBINYN or from the underlying maternal condition. 8.4 Pediatric Use Safety and efficacy of REBINYN were evaluated in four clinical trials that included 43 PTPs and in one clinical trial that included 50 pediatric PUPs [ see Adverse Reactions ( 6 ) and Clinical Studies ( 14 ) ]. Twelve of these subjects were ≤ 6 years of age; 13 subjects were 7 to 12 years of age; and 18 subjects were 13 to 17 years of age.

Metabolism

Pharmacokinetic (PK) parameters of REBINYN were evaluated in previously treated subjects, including a subset of subjects in the adult/adolescent trial and all subjects in the main phase of the pediatric trial [ see Clinical Studies (14) ]. PK samples were collected prior to dosing and at multiple time points up to 168 hours after dosing.

1. 1Haemorrhage1012%
2. 2Haemarthrosis910%
3. 3Headache67.0%
4. 4Arthralgia55.8%
5. 5Drug Ineffective55.8%
6. 6Nausea55.8%
7. 7Dizziness44.7%
8. 8Epistaxis44.7%
9. 9Upper Limb Fracture44.7%
10. 10Anaphylactic Reaction33.5%
11. 11Dyspnoea33.5%
12. 12Erythema33.5%
13. 13Mouth Haemorrhage33.5%
14. 14Pregnancy33.5%
15. 15Therapeutic Response Decreased33.5%

Recent PubMed references pinned to Factor Ix as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Pseudoexon inclusion induced by three deep intronic variants in hemophilia B and correction achieved through an antisense oligonucleotide-based strategy.
  Thrombosis research · 2026 · Chen G, Zhang J, Lin L, et al.
  PMID 41996774DOI 10.1016/j.thromres.2026.109682
• FIXa-triggered thrombin generation correlates with FVIII levels less than 1% in reconstituted plasma mimicking samples obtained from patients with severe hemophilia A.
  Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis · 2026 · Huang M, Gantioqui J, Chan AKC, et al.
  PMID 41846404DOI 10.1097/MBC.0000000000001422
• Optimized AAVrh10 and Factor 9 vectors demonstrate improved phenotypic rescue in hemophilia B mice.
  Thrombosis research · 2026 · Huda S, Senthilkumar MB, Bihani D, et al.
  PMID 41844492DOI 10.1016/j.thromres.2026.109655
• Enhanced peripartum hemostatic management does not decrease postpartum hemorrhage incidence in hemophilia carriers: the Pregnancy and Inherited Bleeding Disorders study.
  Journal of thrombosis and haemostasis : JTH · 2026 · de Vaan A, Kruip MJHA, Eikenboom J, et al.
  PMID 41796747DOI 10.1016/j.jtha.2026.02.031
• Contrary to current guidance, antenatal factor IX levels increase in female carriers of hemophilia B.
  Journal of thrombosis and haemostasis : JTH · 2026 · Kelly C, Cleary J, Keenan C, et al.
  PMID 41786034DOI 10.1016/j.jtha.2026.01.029
• Safety, efficacy, and patient-reported outcomes 6 years after fidanacogene elaparvovec in adults with hemophilia B.
  Blood advances · 2026 · Samelson-Jones BJ, Rasko JEJ, Ducore JM, et al.
  PMID 41734390DOI 10.1182/bloodadvances.2025019174
• The MAPTO survey: worldwide approaches on unmasking factor VIII inhibitors in children with emicizumab treatment: communication from the ISTH SSC Subcommittee on Factor VIII, Factor IX and Rare Coagulation Disorders.
  Journal of thrombosis and haemostasis : JTH · 2026 · van Stam LE, Daisy Horstman BJ, Angchaisuksiri P, et al.
  PMID 41643940DOI 10.1016/j.jtha.2026.01.006
• Balancing Promise and Peril: Hemophilia Gene Therapy Insights.
  IUBMB life · 2026 · Akula S, Borroni E, Cottonaro A, et al.
  PMID 41549917DOI 10.1002/iub.70087

The 10 most recently updated of 246 ClinicalTrials.gov registrations naming Factor Ix as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• An Open-label, Multicenter Phase I/II Clinical Trial to Evaluate the Safety, Tolerability, Efficacy, and Pharmacokinetic/Pharmacodynamic (PK/PD) Characteristics of SR604 Injection in Patients With Hemophilia A/B and Congenital Factor VII Deficiency
  Recruiting · Phase 1 · Phase 2 · Interventional · 76 enrolled · Shanghai RAAS Blood Products Co., Ltd.
  NCT07644832updated 2026-06-12
• An Observational Study of Participants With Type 3 Von Willebrand Disease on Prophylactic Standard-of-Care Treatment
  Active not recruiting · Observational · 44 enrolled · Hoffmann-La Roche
  NCT06883240updated 2026-06-12
• Liver Biopsy Following Gene Therapy For Hemophilia
  Not yet recruiting · Observational · 8 enrolled · St. Jude Children's Research Hospital
  NCT05932914updated 2026-06-08
• Phase 3, Open-label, Single-dose Study of CSL222 in Adolescent Male Subjects (≥ 12 to < 18 Years of Age) With Severe or Moderately Severe Hemophilia B
  Recruiting · Phase 3 · Interventional · 20 enrolled · CSL Behring
  NCT07080905updated 2026-06-04
• A Study to Evaluate the Efficacy and Safety of Factor IX Gene Therapy With PF-06838435 in Adult Males With Moderately Severe to Severe Hemophilia B
  Active not recruiting · Phase 3 · Interventional · 51 enrolled · Pfizer
  NCT03861273updated 2026-06-01
• Safety and Effectiveness of Giroctocogene Fitelparvovec or Fidanacogene Elaparvovec in Patients With Hemophilia A or B Respectively
  Recruiting · Phase 3 · Interventional · 173 enrolled · Pfizer
  NCT05568719updated 2026-05-27
• A Study to Investigate the Efficacy and Safety of Fitusiran Prophylaxis in Male Participants Aged 1 to Less Than 12 Years With Hemophilia A or B
  Recruiting · Phase 3 · Interventional · 85 enrolled · Sanofi
  NCT07285460updated 2026-05-26
• Study of AAV5-hFIX in Severe or Moderately Severe Haemophilia B
  Completed · Observational · 9 enrolled · CSL Behring
  NCT05360706updated 2026-05-26
• International Care Bundle Evaluation in Cerebral Hemorrhage Research
  Recruiting · Phase 4 · Interventional · 3,500 enrolled · Region Skane
  NCT06429332updated 2026-05-22
• A Study to Investigate the Safety and Effectiveness of a Coagulation Factor IX Gene Insertion Therapy (REGV131-LNP1265) in Pediatric, Adolescent and Adult Participants With Hemophilia B
  Recruiting · Phase 1 · Phase 2 · Interventional · 130 enrolled · Regeneron Pharmaceuticals
  NCT06379789updated 2026-05-19

Frequently asked questions

How does Factor Ix work?

Patients with hemophilia B are deficient in coagulation Factor IX, which is required for effective hemostasis. Treatment with REBINYN temporarily replaces the missing coagulation Factor IX.

What is Factor Ix used for?

According to FDA labeling, Factor Ix carries indications including: REBINYN, Coagulation Factor IX (Recombinant), GlycoPEGylated, is a recombinant DNA-derived coagulation Factor IX concentrate indicated for use in adults and children with hemophilia B (congenital Factor IX deficiency) for: • On-demand treatment and control of bleeding episodes • Perioperative management of bleeding • Routine prophylaxis to reduce the frequency of bleeding episodes Limitations of Use : REBINYN is not indicated for immune tolerance induction in patients with hemophilia B. REBINYN, Coagulation Factor IX (Recombinant), GlycoPEGylated, is a recombinant DNA-derived coagulation Factor IX concentrate indicated for use in adults and children with hemophilia B (congenital Factor IX deficiency) for: • On-demand treatment and control of bleeding episodes • Perioperative management of bleeding • Routine prophylaxis to reduce the frequency of bleeding episodes Limitations of Use : REBINYN is not indicated for immune tolerance induction in patients with hemophilia B ( 1 ).. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Factor Ix?

Factor Ix is classified as Blood coagulation factors, Increased Coagulation Activity.

What are the brand names for Factor Ix?

Factor Ix is marketed under brand names including Alphanine SD, Balfaxar, BeneFIX, IDELVION, Ixinity, Kcentra, Rebinyn, Rixubis.

What are the contraindications for Factor Ix?

Factor Ix labeling lists contraindications including: REBINYN is contraindicated in patients who have known hypersensitivity to REBINYN or its components (including hamster proteins) [ see Warnings and Precautions ( 5.1 ) and Description ( 11 ) ] Do not use in patients who have known hypersensitivity to REBINYN or its components, including hamster proteins ( 4 ).. Always consult the full prescribing information and a clinician.