eftrenonacog alfa: clinical use

Prescribing considerations

• Initiate and supervise through an experienced haemophilia service.
• Assess clinical haemostasis alongside laboratory results because response, recovery and factor IX activity vary.
• Record the product name and batch number for every administration.
• Initial administrations may require medical observation because factor IX products can cause severe hypersensitivity.
• Assess thrombotic risk, particularly with liver disease, surgery, newborn infants, cardiovascular risk or risk of disseminated intravascular coagulation.
• Consider infection, bacteraemia and thrombosis if central venous access is used.

Contraindications and cautions

• Hypersensitivity to eftrenonacog alfa or any excipient.

Monitoring

• Clinical control of bleeding and plasma factor IX activity, particularly around major surgery.
• Neutralising factor IX inhibitors using an appropriate Bethesda assay when response is inadequate or after repeated exposure as clinically indicated.
• Evaluate allergic reactions for an associated factor IX inhibitor.
• Account for assay-dependent variation: kaolin-based one-stage aPTT assays may underestimate activity.
• Clinical and laboratory evidence of thrombosis or consumptive coagulopathy in higher-risk patients.

Clinical pharmacology

Eftrenonacog alfa is a fully recombinant human factor IX–IgG1 Fc fusion protein. It restores factor IX activity, while FcRn-mediated recycling prolongs its persistence in plasma.

Formulation and product differences

• Single-use powder vial supplied with sodium chloride solvent in a pre-filled syringe, vial adapter and infusion set.
• After reconstitution, the solution should be clear to slightly opalescent and colourless.
• It must not be mixed with other medicinal products. Use the supplied infusion set because adsorption to some equipment may reduce delivered factor IX.

Injection

Route: Parenteral

Strengths: 250 units, 500 units, 1000 units, 2000 units, 3000 units