albutrepenonacog alfa
Idelvion (albutrepenonacog alfa) is a long-acting recombinant factor IX product from CSL Behring for haemophilia B. Fused to albumin, it replaces the clotting factor that patients lack, preventing and treating bleeding episodes and reducing the need for frequent infusions.
This page is based on the EMA medicine record and Health Canada product information for Idelvion; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
Haemophilia B is like a construction crew missing one essential tool, so every repair job on a wound stalls. Idelvion delivers a long-lasting replacement tool - factor IX - that stays in circulation for days, letting the clotting crew finish repairs whenever an injury occurs.
In simple terms
In haemophilia B the body cannot make enough functional factor IX, a protein needed for blood to clot, so injuries lead to prolonged or spontaneous bleeding. Idelvion supplies a laboratory-made copy of factor IX by infusion. The infused factor joins the patient's own clotting cascade, allowing normal clots to form. Because it is linked to albumin, it remains active in the blood longer than standard factor IX products.
In depth
Albutrepenonacog alfa is a recombinant human factor IX fused to recombinant albumin via a non-cleavable linker, produced in CHO cells. The albumin moiety exploits neonatal Fc receptor (FcRn)-mediated recycling, extending the half-life to roughly four to five times that of standard recombinant factor IX. Once infused, it is activated by factor XIa or the tissue factor-factor VIIa complex and supports thrombin generation on phospholipid surfaces, restoring haemostasis in factor IX-deficient patients.
Target: Coagulation factor IX
A clotting factor in the intrinsic coagulation pathway that helps generate thrombin and a stable fibrin clot; people with haemophilia B carry a defective factor IX gene and cannot form clots properly.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in European Union
EMAas of Aug 23, 2026- Treatment and prophylaxis of bleeding in patients with haemophilia B (congenital factor IX deficiency)
Official sources
The statements on this page trace back to these records.
- Health Canada: Idelvion (albutrepenonacog alfa) product information
Health Canada · Retrieved Aug 23, 2026
- EMA medicine record: Idelvion (albutrepenonacog alfa)
European Medicines Agency · Retrieved Aug 23, 2026
Editorial review
- Reviewed
- Aug 23, 2026
- Next review
- Feb 23, 2027
- Cross-checked by
- researcher-regulatory - EMA and Health Canada product information · researcher-nlm - cross-check · editor - plain-language paraphrase and cross-check
- Method
- independent multi-source collection -> cross-check for agreement -> original English paraphrase -> item-by-item verification against the evidence bundle
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.