Real-world data demonstrate improved bleed control and extended dosing intervals for patients with haemophilia B after switching to recombinant factor IX Fc fusion protein (rFIXFc) for up to 5 years.

INTRODUCTION

In clinical trials, recombinant factor IX fusion protein (rFIXFc) has demonstrated safety, efficacy and prolonged activity with extended dosing intervals for treatment of haemophilia B.

AIM

To assess the real-world clinical utility of rFIXFc in a variable patient population and routine clinical practice.

METHODS

A multicentre, retrospective chart review was conducted of patients with haemophilia B who had received rFIXFc prophylaxis or on-demand treatment for ≥6 months across six sites in the United States.

RESULTS

Sixty-four eligible patients were identified who had a median (range) duration on rFIXFc of 2.7 (0.5-5.0) years. Of 32 patients on rFIXFc prophylaxis who switched from prophylaxis with another factor treatment (ie pre-rFIXFc) and had a known pre-rFIXFc dosing interval, the initial dosing interval was lengthened for 26 (81%) patients and maintained for the remaining 6 (19%) patients. Most (n = 48 [91%]) patients who received rFIXFc prophylaxis from the beginning to the end of the chart review period (n = 53) maintained or lengthened the dosing interval from first through last dose of rFIXFc. For patients receiving rFIXFc prophylaxis, there was an approximate 50% reduction in weekly factor consumption compared with pre-rFIXFc prophylaxis. Overall annualized bleed rates, annualized spontaneous bleed rates and annualized joint bleed rates decreased after switching to rFIXFc prophylaxis (n = 24 with bleed data). Compliance to recommended treatment improved or remained stable in most patients with available data (30/31).

CONCLUSION

Recombinant factor IX fusion protein prophylaxis improved bleed control, reduced overall consumption, reduced frequency of infusion and improved compliance for patients with haemophilia B in a real-world setting.