PB0649 - Real world experience using rIX-FP prophylaxis in patients with haemophilia B: experience from a Spanish centre.

Background: rIX-FP, a recombinant factor IX linked with recombinant human albumin, has shown good efficacy for prophylaxis in patients with haemophilia B (PWHB)

Aims: This study reports real-world experience of managing rIX-FP prophylaxis in a Spanish reference centre

Methods: Retrospective data was collected from PWHB who switched from standard half-life (SHL) FIX products to rIX-FP. Data was also collected from one previously untreated patient (PUP) who began prophylaxis with rIX-FP
Data was collected from medical records for the 12 months prior to and 12 months after switching to rIX-FP, including age, infusion frequency and dose, and annualised bleeding rates (ABR). A pharmacokinetic analysis was conducted via the WAPPS-Hemo platform

Results: Five patients with severe haemophilia B were initiated on rIX-FP prophylaxis. The mean age was 25 years old, (range 1-60).

4 of these patients (3 adults and 1 paediatric) were previously treated with twice a week prophylaxis with SHL-FIX products (3 with recombinant and one with plasma-derived). One was a paediatric previously untreated patient.

All patients began prophylaxis with rIX-FP every 7 days. After being well-controlled on this regimen, two previously treated patients (one adult and one paediatric) switched to dosing every 14 days. Two of the adult previously treated patients further extended dosing to every 21 days.
In all previously treated patients (PTPs), annualised spontaneous bleeding rates were maintained at 0.00, when compared to their previous regimen. In PTPs across all dosing intervals with rIX-FP prophylaxis: mean FIX levels at Day 7 post-infusion were 19.2%

No adverse events were reported after switching to or initiating rIX-FP

Conclusion(s): Patients with haemophilia B who switched to rIX-FP from a SHL-FIX were able to reduce their infusion frequency and factor consumption, whilst maintaining bleed control and increasing their FIX trough level