Real-World Effectiveness of rFIXFc Prophylaxis in Patients with Haemophilia B Switched from Standard Half-Life Therapy in Three European Countries

Abstract

Introduction The current study describes real-world clinical outcomes and factor usage among patients with haemophilia B switching from standard half-life factor IX (SHL FIX) treatment to recombinant factor IX Fc fusion protein (rFIXFc) prophylaxis in European treatment centres. Methods This non-interventional, retrospective, multicentre chart review evaluated medical records from adult and paediatric patients with haemophilia B in Denmark, Germany and the UK. Patients had documented SHL FIX treatment, on-demand or prophylaxis, for ≥ 6 months before starting rFIXFc prophylaxis, and subsequent data for ≥ 6 months afterwards (up to 24 months). Primary endpoints included annualised bleeding rates (ABRs), prophylactic factor consumption and injection frequency. Results Data from 30 patients (24/30 [80.0%] with severe disease) showed overall mean (standard deviation, SD) ABRs of 4.7 (6.3) on SHL FIX treatment and 1.7 (2.3) after switching to rFIXFc prophylaxis. The reduction in mean (SD) ABRs was greater when switching from SHL FIX on-demand treatment ( n = 6), with a decrease from 10.5 (9.9) to 2.6 (4.5), than when switching from SHL FIX prophylaxis ( n = 24), with a decrease from 3.3 (4.3) to 1.5 (1.4). Among prior SHL FIX prophylaxis patients, switching to rFIXFc prophylaxis increased the proportion of those with zero bleeds from 21.7% to 45.8% during the 6 months before and after switching, respectively. In the total population, five of six target joints (83.3%) present when patients started rFIXFc prophylaxis subsequently resolved. In patients switching from SHL FIX prophylaxis to rFIXFc prophylaxis, mean (SD) weekly injection frequency was reduced by 1.0 (0.7) and mean (SD) factor consumption was reduced by 27.7 (49.6) IU/kg/week. Conclusion This study demonstrates the effectiveness of rFIXFc prophylaxis in real-world clinical practice. Improvements in both clinical effectiveness and factor usage associated with rFIXFc prophylaxis may potentially reduce patient burden and improve quality of life. Supplementary Information The online version contains supplementary material available at 10.1007/s12325-023-02559-1.

Pattern of use and clinical outcomes with rIX‐FP in pediatric/adolescent patients with haemophilia B in Italy: Results from IDEAL real‐world study

“…Though infusion interval was increased, prophylaxis with rIX‐FP was highly effective in bleeding prevention, as demonstrated by a low mean ABR and a 0.0 median ABR maintained across all the prophylaxis regimens. ABR reported in our study encompass also traumatic events (at least 42% of all events) and are aligned with phase III trials and real‐world evidence published involving other FIX 21–26 …”

Recombinant factor IX Fc for the treatment of hemophilia B

“…F I G U R E 1 Overview of key interventional clinical trials and prospective, non-interventional, real-world studies for rFIXFc. 11,[14][15][16]33,34,[37][38][39][40]80 ABR, annualized bleed rate; AE, adverse event; FIX, factor IX; OD, on demand; PK, pharmacokinetic; PPX, primary prophylaxis; PTPs, previously treated patients; PUPs, previously untreated patients.…”

“…A European retrospective study 37 included 30 patients with hemophilia B (mild, moderate, or severe) from Denmark, Germany, and the UK. All patients had switched from SHL FIX treatment (on demand [ n = 6] or prophylaxis [ n = 24]) to rFIXFc prophylaxis.…”