RIXUBIS (Nonacog Gamma): Uses, Dosage & Side Effects
Recombinant human coagulation factor IX for hemophilia B
Quick Facts About RIXUBIS
Key Takeaways About RIXUBIS
- RIXUBIS treats hemophilia B: A recombinant factor IX that replaces the missing clotting factor in patients with Christmas disease, enabling normal blood coagulation
- Suitable for all ages: Approved for both children and adults for on-demand treatment and long-term prophylaxis of bleeding episodes
- Home treatment possible: Patients or caregivers can learn to prepare and administer the injection at home after receiving proper training from healthcare professionals
- Monitor for inhibitors: Some patients may develop antibodies (inhibitors) that reduce the effectiveness of RIXUBIS, particularly those who are new to factor IX treatment
- Do not use if allergic to hamster proteins: RIXUBIS is produced using hamster cell lines, and patients with known hypersensitivity to hamster proteins must not use this product
What Is RIXUBIS and What Is It Used For?
RIXUBIS contains nonacog gamma, a recombinant human coagulation factor IX used to treat and prevent bleeding in patients with hemophilia B (Christmas disease). It works by replacing the deficient factor IX protein, restoring the body's ability to form blood clots effectively.
Hemophilia B, also known as Christmas disease, is an inherited bleeding disorder caused by a deficiency or absence of coagulation factor IX in the blood. Factor IX is a critical component of the intrinsic coagulation pathway — a cascade of reactions that ultimately leads to the formation of a stable blood clot. Without sufficient factor IX, patients experience prolonged bleeding after injuries, surgeries, or sometimes spontaneously into joints and muscles.
RIXUBIS is a third-generation recombinant factor IX product manufactured using Chinese hamster ovary (CHO) cell technology. Unlike plasma-derived factor IX concentrates, recombinant products like RIXUBIS carry no risk of transmitting blood-borne infections such as hepatitis B, hepatitis C, or HIV, as no human blood or plasma is used in the manufacturing process. This represents a significant safety advantage, particularly for patients who require lifelong replacement therapy.
RIXUBIS is indicated for use in patients with hemophilia B across all age groups. It can be used both for on-demand treatment of acute bleeding episodes and for routine prophylaxis to reduce the frequency and severity of bleeding events. Clinical studies have demonstrated that regular prophylactic use of factor IX concentrates significantly reduces the incidence of spontaneous joint bleeds (hemarthroses), which are a major cause of long-term joint damage and disability in hemophilia patients.
Hemophilia B affects approximately 1 in 25,000 to 30,000 male births worldwide, according to the World Federation of Hemophilia (WFH). It is an X-linked recessive disorder, meaning it primarily affects males while females are typically carriers. The severity of the condition depends on the residual factor IX activity: severe (<1%), moderate (1-5%), or mild (5-40%).
The active substance nonacog gamma has been specifically engineered to have the same structure and function as naturally occurring human factor IX. When administered intravenously, it integrates into the patient's coagulation cascade and participates in the series of enzymatic reactions needed to generate thrombin and ultimately form a fibrin clot. The pharmacological effect is immediate, making RIXUBIS suitable for both the treatment of acute bleeds and the prevention of bleeding during surgical procedures.
What Should You Know Before Taking RIXUBIS?
Do not use RIXUBIS if you are allergic to nonacog gamma or hamster proteins. Stop the infusion immediately and seek medical help if you experience signs of allergic reaction. Tell your doctor about liver or heart disease, recent surgery, or if you are pregnant or breastfeeding.
Contraindications
RIXUBIS must not be used in patients who have a known allergy (hypersensitivity) to nonacog gamma or to any of the other ingredients in the formulation. Importantly, because RIXUBIS is produced using Chinese hamster ovary (CHO) cell lines, patients with a known allergy to hamster proteins must not receive this product. Allergic reactions to hamster-derived proteins can be severe and potentially life-threatening.
Warnings and Precautions
Hypersensitivity reactions of the allergic type are possible with RIXUBIS. Early signs of allergic reactions include hives, skin rash, chest tightness, wheezing, low blood pressure, and anaphylaxis — a severe allergic reaction that can make it difficult to swallow or breathe and may cause facial or hand swelling. If any of these signs occur during infusion, stop the administration immediately and contact a doctor or seek emergency medical care.
Your doctor may perform blood tests to check whether you have developed neutralizing antibodies (inhibitors) against factor IX. Inhibitors reduce or completely block the effectiveness of replacement therapy, meaning that higher doses or alternative treatments may be needed. The risk of developing inhibitors is highest in patients who have never previously received factor IX replacement therapy or who are in the early stages of treatment, particularly young children. Patients with certain genetic mutations of the factor IX gene — especially large deletions — may have a higher likelihood of developing inhibitors and experiencing allergic reactions during the initial treatment period.
Patients with factor IX inhibitors may be at increased risk of anaphylaxis during subsequent treatment with any factor IX product. If you have been told that you have inhibitors, your doctor will monitor you more closely. Speak to your doctor immediately if your bleeding does not stop as expected or if you notice a significant increase in the amount of RIXUBIS needed to control bleeding.
Patients with liver disease, heart disease, or those who have recently undergone major surgery should inform their doctor before using RIXUBIS, as there is an increased risk of thromboembolic complications (blood clots) in these situations. Although thromboembolic events have not been specifically observed with RIXUBIS, they can occur with any factor IX product and may include heart attack, deep vein thrombosis, or pulmonary embolism.
Kidney disease (nephrotic syndrome) has been reported following high doses of factor IX in hemophilia B patients who have factor IX inhibitors and a history of allergic reactions. This is a rare but serious complication that requires medical supervision.
It is recommended to record the product name and batch number each time RIXUBIS is used (for example, in a treatment diary). This documentation helps track which specific product batches have been administered and is important for safety monitoring.
Drug Interactions
No interactions between RIXUBIS and other medications have been identified in clinical studies. However, you should always inform your healthcare provider about all medications you are currently taking, have recently taken, or plan to take, including prescription medications, over-the-counter drugs, and herbal supplements. This is standard practice to ensure comprehensive medical oversight and to detect any potential interactions that may not have been previously documented.
Pregnancy and Breastfeeding
If you are pregnant or breastfeeding, think you may be pregnant, or are planning to have a baby, consult your doctor before using RIXUBIS. Hemophilia B is an X-linked genetic condition that occurs almost exclusively in males. However, female carriers may occasionally have reduced factor IX levels and may require treatment in certain clinical situations, particularly during surgery or childbirth. The decision to use RIXUBIS during pregnancy or breastfeeding should be made on a case-by-case basis by a specialist in hemophilia management, weighing the potential benefits against any theoretical risks.
Driving and Using Machines
RIXUBIS has no known effect on the ability to drive or operate machinery. Patients can continue their normal daily activities after administration, although they should be mindful of any bleeding episodes that may impair their ability to perform tasks safely.
Sodium Content
RIXUBIS contains less than 1 mmol (23 mg) of sodium per vial and is therefore essentially sodium-free. However, depending on body weight and the required dose, multiple vials may be needed for a single treatment. This should be taken into consideration by patients on a controlled sodium diet.
How Does RIXUBIS Interact with Other Drugs?
No direct drug interactions with RIXUBIS have been identified. However, certain medications and clinical conditions may affect coagulation and should be discussed with your healthcare provider. The table below outlines potential considerations.
While no formal drug-drug interaction studies have revealed specific interactions with RIXUBIS, healthcare providers should be aware of medications and conditions that affect the coagulation system. Concomitant use of anticoagulants, antiplatelet agents, or thrombolytic drugs may alter the hemostatic balance and complicate the management of hemophilia B patients.
| Drug Category | Examples | Potential Effect | Clinical Action |
|---|---|---|---|
| Anticoagulants | Warfarin, heparin, DOACs | May counteract the clotting effect of RIXUBIS | Close monitoring of coagulation parameters |
| Antiplatelet Agents | Aspirin, clopidogrel | Increased bleeding risk due to platelet inhibition | Use with caution; monitor for bleeding |
| Thrombolytic Agents | Alteplase, tenecteplase | Dissolution of clots formed with factor IX | Avoid concomitant use if possible |
| Antifibrinolytics | Tranexamic acid, aminocaproic acid | May enhance clot stability; potentially synergistic | Often used adjunctively; monitor for thrombosis |
| Emicizumab | Hemlibra | Designed for hemophilia A, not B; no direct interaction | Not applicable for hemophilia B patients |
It is important to note that the table above lists theoretical considerations rather than confirmed interactions. The product information for RIXUBIS states that no drug interactions are known. Nevertheless, comprehensive disclosure of all concurrent medications to your hemophilia treatment center is essential for safe and effective management.
What Is the Correct Dosage of RIXUBIS?
RIXUBIS dosing is individualized based on body weight, severity of factor IX deficiency, location and extent of bleeding, and clinical condition. The dose is calculated using the formula: Required IU = body weight (kg) x desired factor IX increase (%) x reciprocal of observed recovery. Treatment should always be initiated by a physician experienced in hemophilia care.
RIXUBIS treatment should be started and supervised by a physician experienced in the management of hemophilia B. The dose and duration of replacement therapy depend on the severity of the factor IX deficiency, the location and extent of bleeding, and the patient's clinical condition, age, and pharmacokinetic parameters. Factor IX activity levels must be monitored regularly through appropriate coagulation assays to guide dosing decisions.
One international unit (IU) of factor IX activity corresponds to the amount of factor IX present in one milliliter of normal human plasma. Factor IX activity in plasma is expressed either as a percentage (relative to normal human plasma) or in international units.
Adults and Adolescents (12 Years and Older)
In patients aged 12 years and older, one IU of factor IX per kilogram of body weight increases plasma factor IX activity by approximately 0.9 IU/dL (range: 0.5 to 1.4 IU/dL). The dose is calculated using the following formula:
Dose Calculation Formula (Adults ≥ 12 years)
Required IU = Body weight (kg) × Desired factor IX increase (%) × 1.1 dL/kg
Based on an incremental recovery of 0.9 IU/dL per IU/kg
Children (Under 12 Years)
In children under 12 years of age, the incremental recovery is lower at approximately 0.7 IU/dL per IU/kg (range: 0.31 to 1.0 IU/dL). This means that children typically require higher doses per kilogram of body weight to achieve the same plasma factor IX levels as adults.
Dose Calculation Formula (Children < 12 years)
Required IU = Body weight (kg) × Desired factor IX increase (%) × 1.4 dL/kg
Based on an incremental recovery of 0.7 IU/dL per IU/kg
| Bleeding Type / Surgery | Required Factor IX Level (%) | Dosing Frequency |
|---|---|---|
| Early hemarthrosis, muscle bleeding, oral bleeding | 20 – 40% | Every 24 hours. At least 1 day until pain resolves or healing occurs |
| Extensive hemarthrosis, muscle bleeding, or hematoma | 30 – 60% | Every 24 hours for 3–4 days until pain and acute disability resolve |
| Life-threatening hemorrhages | 60 – 100% | Every 8–24 hours until the threat is resolved |
| Minor surgery (including dental extraction) | 30 – 60% | Every 24 hours, at least 1 day until healing occurs |
| Major surgery | 80 – 100% | Every 8–24 hours until adequate wound healing, then maintain 30–60% for at least 7 more days |
Prophylaxis
For long-term prophylaxis against bleeding in patients with severe hemophilia B, the recommended dose regimens are:
- Adults and adolescents (≥12 years): 40 to 60 IU per kg body weight every 3 to 4 days
- Children (<12 years): 40 to 80 IU per kg body weight every 3 to 4 days
In some cases, depending on the individual patient's pharmacokinetics, age, bleeding pattern (phenotype), and physical activity level, shorter dosing intervals or higher doses may be required to achieve optimal protection. Your doctor will adjust the prophylactic regimen based on regular monitoring of your factor IX levels and bleeding frequency.
RIXUBIS is designed for intermittent intravenous bolus injection only. It should not be administered as a continuous infusion. The maximum infusion rate should not exceed 10 mL per minute, adjusted to the patient's comfort level.
Missed Dose
If you miss a scheduled prophylactic dose of RIXUBIS, do not take a double dose to compensate. Instead, continue with the next scheduled injection and follow your doctor's instructions for resuming your regular dosing schedule. If you are unsure about what to do, contact your hemophilia treatment center for guidance.
Overdose
Always use RIXUBIS exactly as your doctor has prescribed. If you have injected more RIXUBIS than recommended, contact your doctor as soon as possible. Although no specific overdose symptoms have been described, excessive doses of any factor IX product could theoretically increase the risk of thromboembolic events, particularly in patients with pre-existing risk factors such as liver disease, cardiovascular disease, or post-operative status.
Stopping Treatment
Do not stop using RIXUBIS without consulting your doctor. Sudden discontinuation of prophylactic treatment can lead to unprotected periods during which spontaneous bleeding episodes may occur, potentially causing joint damage and other complications.
How Is RIXUBIS Prepared and Administered?
RIXUBIS is reconstituted by mixing the powder with the provided sterile water using the BAXJECT II needle-free device. After reconstitution, the clear solution is drawn into a syringe and injected intravenously through a butterfly needle at a rate not exceeding 10 mL per minute. Use immediately after preparation.
RIXUBIS comes as a powder in a glass vial together with a separate vial of sterile water for injection (diluent) and a BAXJECT II needle-free reconstitution device. Proper preparation technique is essential to ensure the product is safe and effective. Always use aseptic technique throughout the entire process.
Preparation Steps
- Temperature equilibration: If stored in the refrigerator, remove both the RIXUBIS powder vial and the diluent vial and allow them to reach room temperature (15°C to 30°C)
- Hand hygiene: Wash your hands thoroughly with soap and warm water
- Clean the stoppers: Remove the caps from both vials and clean the rubber stoppers with alcohol swabs
- Attach BAXJECT II to diluent: Open the BAXJECT II package by peeling the paper lid without touching the inside. Insert the clear plastic spike through the diluent vial stopper
- Transfer diluent: Invert the system and insert the white plastic spike through the RIXUBIS powder vial stopper. The vacuum will draw the diluent into the powder vial
- Mix gently: Swirl the vial gently until all powder is dissolved (typically within 2 minutes). The solution should be clear or slightly opalescent. Do not use if cloudy or contains particles
Administration Steps
- Remove the blue cap from the BAXJECT II device
- Connect a luer-lock syringe to the BAXJECT II (do not draw air into the syringe)
- Invert the system so the reconstituted solution vial is on top
- Draw the solution into the syringe by slowly pulling back the plunger
- Disconnect the syringe and attach a butterfly (winged infusion) needle
- Inject intravenously at a rate that is comfortable but does not exceed 10 mL per minute
Document the product name, batch number, date, and dose each time you use RIXUBIS. This information is important for safety monitoring and should be shared with your healthcare team at each visit.
What Are the Side Effects of RIXUBIS?
Common side effects of RIXUBIS include altered taste (dysgeusia) and pain in the extremities. Allergic reactions, including potentially life-threatening anaphylaxis, can occur. Stop the infusion immediately and seek emergency care if you experience hives, breathing difficulties, chest tightness, or facial swelling.
Like all medicines, RIXUBIS can cause side effects, although not everyone experiences them. Hypersensitivity reactions of the allergic type are possible and may include burning and stinging at the infusion site, chills, flushing, lethargy, restlessness, tingling, hives, itching, rash, low blood pressure, rapid heartbeat, chest tightness, wheezing, throat swelling, anaphylaxis, headache, nausea, and vomiting. If you experience any of these symptoms, stop the infusion immediately and seek medical attention.
Common Side Effects
- Altered taste (dysgeusia)
- Pain in the extremities (arms or legs)
Frequency Not Known
- Allergic reactions (hypersensitivity)
- Anaphylaxis (severe allergic reaction)
- Development of inhibitors (neutralizing antibodies)
Thromboembolic events (problems with excessive blood clotting) have not been specifically observed with RIXUBIS in clinical trials, but they are a known class effect of all factor IX products. These may include myocardial infarction (heart attack), deep vein thrombosis (blood clots in veins), and pulmonary embolism (blood clots in the lungs). The risk is higher in patients receiving high doses, those with liver disease, post-operative patients, and those with pre-existing cardiovascular risk factors.
The development of factor IX inhibitors is a particularly important adverse effect to be aware of. Inhibitors are antibodies produced by the immune system that neutralize the activity of the administered factor IX, rendering treatment less effective or ineffective. The risk is greatest in previously untreated patients and during the early phases of therapy. If you notice that your bleeding episodes are not responding to treatment as expected, or that you require increasing doses to achieve the same effect, this may indicate inhibitor development and you should contact your doctor promptly.
- Signs of allergic reaction: hives, rash, difficulty breathing, facial swelling
- Signs of anaphylaxis: rapid drop in blood pressure, loss of consciousness
- Bleeding that does not stop as expected despite treatment
- Signs of blood clots: chest pain, leg swelling, sudden shortness of breath
Reporting Side Effects
Reporting suspected side effects after a medicine has been authorized is important for ongoing safety monitoring. It allows the benefit-risk balance of the medicine to be continuously assessed. Healthcare professionals and patients are encouraged to report any suspected adverse reactions to their national pharmacovigilance authority (e.g., the FDA MedWatch program in the United States, the Yellow Card scheme in the United Kingdom, or the corresponding authority in your country).
How Should You Store RIXUBIS?
Store RIXUBIS below 30°C. Do not freeze. The reconstituted solution must be used immediately. Do not use if the solution is cloudy or contains particles. Keep out of the sight and reach of children. Check the expiration date before each use.
Proper storage of RIXUBIS is essential to maintain the product's potency and safety. The unreconstituted powder should be stored at a temperature below 30°C (86°F). The product must not be frozen at any time, as freezing can damage the protein structure and render the medication ineffective.
Once reconstituted with the supplied sterile water for injection, the RIXUBIS solution should be used immediately. Unlike some other factor concentrates, RIXUBIS does not have an extended stability period after reconstitution. Inspect the reconstituted solution visually before administration — it should be clear or slightly opalescent and colorless. Do not use the solution if it appears cloudy, contains visible particles, or shows any discoloration.
Always check the expiration date printed on the outer carton and the vial label before use. The expiration date refers to the last day of the stated month. Do not use RIXUBIS after this date.
Unused product and waste materials should be disposed of in accordance with local regulations for pharmaceutical waste. Do not dispose of medicines in wastewater or household waste. Ask your pharmacist about proper disposal methods to protect the environment.
What Does RIXUBIS Contain?
Each vial of RIXUBIS contains nonacog gamma (recombinant human coagulation factor IX) as the active substance, available in 250, 500, 1000, 2000, or 3000 IU strengths. Inactive ingredients include sucrose, mannitol, sodium chloride, calcium chloride, L-histidine, and polysorbate 80.
RIXUBIS is supplied as a powder and solvent for solution for injection. Each package contains:
- One vial of RIXUBIS powder containing nominally 250, 500, 1000, 2000, or 3000 IU of nonacog gamma in a glass vial with a rubber stopper
- One vial of 5 mL sterile water for injection in a glass vial with a rubber stopper
- One BAXJECT II needle-free reconstitution device
After reconstitution with 5 mL of diluent, the resulting concentrations are approximately 50, 100, 200, 400, or 600 IU/mL, respectively.
Active Ingredient
The active substance is nonacog gamma, a recombinant human coagulation factor IX produced by DNA technology in Chinese hamster ovary (CHO) cells. It is purified through a series of chromatographic steps and undergoes nanofiltration for additional viral safety.
Inactive Ingredients (Excipients)
| Excipient | Function |
|---|---|
| Sucrose | Stabilizer / lyoprotectant |
| Mannitol | Bulking agent / tonicity modifier |
| Sodium chloride | Tonicity modifier |
| Calcium chloride | Stabilizer (calcium-dependent protein stability) |
| L-histidine | Buffer (pH stabilizer) |
| Polysorbate 80 | Surfactant (prevents protein aggregation) |
The diluent (solvent) is 5 mL of sterile water for injection. No preservatives or human- or animal-derived materials (other than the CHO cell-derived protein) are present in the formulation.
Frequently Asked Questions About RIXUBIS
Medical References and Sources
This article is based on current medical research, regulatory documents, and international guidelines. All claims are supported by evidence from authoritative sources.
- European Medicines Agency (EMA). "RIXUBIS – Summary of Product Characteristics (SmPC)." Official European regulatory documentation for RIXUBIS prescribing information.
- U.S. Food and Drug Administration (FDA). "RIXUBIS Prescribing Information." FDA-approved prescribing information including pharmacokinetics, clinical trial data, and safety information.
- World Federation of Hemophilia (WFH) (2024). "Guidelines for the Management of Hemophilia, 3rd Edition." Comprehensive international guidelines for hemophilia management including factor replacement therapy.
- Windyga J, et al. (2014). "Pharmacokinetics, efficacy and safety of BAX326, a novel recombinant factor IX: a prospective, controlled, multicentre phase I/III study in previously treated patients with severe or moderately severe haemophilia B." Haemophilia. 20(1):15-24. Pivotal clinical trial supporting RIXUBIS efficacy and safety.
- Blanchette VS, et al. (2016). "Recombinant factor IX (BAX326) in previously treated and untreated patients with hemophilia B: results of a prospective clinical study." Journal of Thrombosis and Haemostasis. 14(8):1539-1550. Clinical study on RIXUBIS in pediatric hemophilia B patients.
- Srivastava A, et al. (2020). "WFH Guidelines for the Management of Hemophilia, 3rd edition." Haemophilia. 26 Suppl 6:1-158. World Federation of Hemophilia consensus guidelines for hemophilia treatment.
Evidence grading: This article uses the GRADE framework (Grading of Recommendations Assessment, Development and Evaluation) for evidence-based medicine. Information is derived from EMA and FDA regulatory documents, peer-reviewed clinical trials, and international consensus guidelines.
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