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Bypass Agent — Haemophilia with Inhibitors Pregnancy: Use only if clearly indicated — limited data; consult haemophilia centre and obstetric team for delivery planning

Recombinant Factor VIIa

Brand names: NovoSeven

Adult dose

Dose: 90 mcg/kg IV bolus every 2–3 hours until haemostasis
Route: IV bolus injection over 2–5 minutes
Frequency: Every 2–3 hours until haemostasis, then every 4–6 hours
Max: No established maximum; high doses (270 mcg/kg single dose — CONTROL trial) under evaluation
Indicated for: haemophilia A or B with inhibitors, congenital Factor VII deficiency, Glanzmann thrombasthenia (platelet function disorder with inhibitors or refractoriness). Also used off-label in intractable surgical bleeding and ICH (limited evidence — FAST trial did not improve outcome).

Paediatric dose

Dose: 90 mcg/kg mcg/kg
Route: IV bolus
Frequency: Every 2–3 hours until haemostasis
Max: Per haematology guidance
BNFc: children with haemophilia and inhibitors — same weight-based dosing as adults. Higher clearance in children may require more frequent dosing.

Dose adjustments

Renal

No dose adjustment required

Hepatic

Use with caution in severe hepatic impairment

Paediatric weight-based calculator

BNFc: children with haemophilia and inhibitors — same weight-based dosing as adults. Higher clearance in children may require more frequent dosing.

Clinical pearls

  • Mechanism: supraphysiological doses activate Factor X on platelet surface independently of FVIII/FIX — bypasses the intrinsic pathway; produces a thrombin burst at site of injury
  • Haemophilia with inhibitors: rFVIIa and aPCC (FEIBA) are the two bypass agents — choice based on inhibitor titre, availability, and patient history
  • FAST trial (ICH): rFVIIa did not improve functional outcome in spontaneous ICH vs placebo despite reducing haematoma expansion
  • Thrombotic risk: arterial thrombosis most concerning — avoid in patients with high cardiovascular risk or recent thrombotic event
  • Short half-life (~2–3 hours) — frequent dosing essential; continuous infusion used in some centres
  • Emicizumab (Hemlibra) — bispecific antibody bridging FIXa and FX — has largely replaced rFVIIa for prophylaxis in haemophilia A with inhibitors (HAVEN trials); rFVIIa retained for breakthrough bleeds

Contraindications

  • Hypersensitivity to Factor VIIa or mouse/hamster/bovine proteins
  • Disseminated intravascular coagulation (relative — thrombotic risk)

Side effects

  • Arterial thromboembolism (stroke, MI — most serious)
  • Venous thromboembolism
  • Fever
  • Coagulopathy changes (monitor)

Interactions

  • Activated prothrombin complex concentrates (aPCC — FEIBA) — avoid concurrent use; increased thrombosis risk

Monitoring

  • Clinical haemostasis (primary endpoint)
  • Coagulation tests (PT/aPTT) — limited utility at supraphysiological doses
  • Signs of thromboembolism
  • Factor VII activity (if monitoring dose)

Reference: BNFc; BNF 90; BNFc; FAST Trial (Mayer et al. NEJM 2008); BSH Haemophilia with Inhibitors Guidelines; UKHCDO. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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