Related Experiment Video
Updated: Jun 18, 2025
Tail Vein Transection Bleeding Model in Fully Anesthetized Hemophilia A Mice
Published on: September 30, 2021
Real-world usage and effectiveness of recombinant factor VIII/factor IX Fc in hemophilia A/B: final data from the
Christoph Bidlingmaier1, Christine Heller2, Florian Langer3
1Department of Pediatrics, Dr. von Hauner Children's Hospital, Pediatric Hemophilia Center, LMU Munich, Munich, Germany.
Background:
Real-world experience with efmoroctocog alfa (a recombinant factor [F]VIII Fc fusion protein [rFVIIIFc]) and eftrenonacog alfa (a recombinant factor IX Fc fusion protein [rFIXFc]) is needed to bridge evidence gaps.
Objectives:
To describe rFVIIIFc/rFIXFc usage and effectiveness over a 24-month prospective period.
Methods:
PREVENT (NCT03055611), a noninterventional study across 25 German hemophilia treatment centers, enrolled previously treated persons with hemophilia A and B (all ages/severities) on individualized rFVIIIFc/rFIXFc prophylaxis before/at enrollment. Primary endpoints included annualized bleeding rate (ABR), injection frequency (IF), and factor consumption (FC). Additionally, up to 12 months of retrospective FVIII/FIX data were collected. Physician and patient satisfaction, and safety outcomes were also assessed.
Results:
Overall, 150 patients received ≥1 rFVIIIFc dose and 47 patients received ≥1 rFIXFc dose, with median prospective follow-up of 20.6 and 21.0 months, respectively. rFVIIIFc/rFIXFc demonstrated low median ABR (0.5/1.7), annualized IF (121.8/52.2 injections/y), and FC (4611.7/2423.9 IU/kg) in line with product labels. Compared with previous FVIII/FIX, there was a 56.0% reduction in ABR for rFVIIIFc (rate ratio, 0.44; 95% CI, 0.31-0.64), with no change for rFIXFc (rate ratio, 0.93; 95% CI, 0.66-1.31); rFVIIIFc/rFIXFc reduced annualized IF (rFVIIIFc, mean difference, -31.7; 95% CI, -40.3 to -23.1; rFIXFc, mean difference, -37.3; 95% CI, -46.9 to -27.8), while FC remained stable (rFVIIIFc, +374.1; 95% CI, +46.8 to +701.3; rFIXFc, +503.9; 95% CI, +95.4 to +912.4). Most physicians and patients were satisfied or highly satisfied with rFVIIIFc/rFIXFc. rFVIIIFc/rFIXFc were well tolerated, with no inhibitor development or treatment-related serious adverse events.
Conclusion:
Real-world PREVENT data complement phase 3 trials and show that individualized rFVIIIFc/rFIXFc prophylaxis provided stable bleed protection with low IF and maintained FC. Compared with previous FVIII, ABR was considerably reduced with rFVIIIFc, with stable annualized FC. For rFIXFc, bleed protection was maintained vs previous FIX while reducing annualized IF.
