Real-World Effectiveness and Usage of Recombinant Factor IX Fc: Final Data from the B-MORE Study

Introduction Extended half-life (EHL) recombinant factor IX Fc fusion protein (rFIXFc) has an established efficacy and safety profile in people with hemophilia B across all ages. Here, we report final data from B-MORE (NCT03901755), a real-world, 24-month prospective study evaluating rFIXFc effectiveness and usage across Europe and the Middle East. Method Eligible patients, including previously untreated patients, were prescribed rFIXFc prophylaxis (PPX) or on-demand prior to/at enrolment. Twelve-month retrospective data on previous FIX (as available), baseline characteristics, and follow-up on rFIXFc (retrospective/prospective periods) are reported. Annualized endpoints only include patients with≥6 months treatment. Results B-MORE enrolled 151 patients from 29 centers (median [range] age: 20.5 [1–81] years; three patients were female). Twelve patients were previously untreated; 119 had severe hemophilia (26 moderate, 6 mild). For the primary endpoints, 137 patients prospectively treated with rFIXFc PPX were analyzed (mean [range] treatment duration: 22.4 [7.3–30.0] months). Median (interquartile range [IQR]) annualized bleeding rate (ABR) was 0.45 (0.0–1.2), annualized injection frequency (IF) was 52.5 (52.2–52.6), and annualized factor consumption (FC) was 2,442.7 (2,021.9–2,969.7) IU/kg/year. An intrapatient comparison was conducted in 92 patients switching from prior standard half-life (SHL) FIX PPX to rFIXFc PPX (mean [range] duration: 11.5 [6.4–12.0] vs 40.6 [9.8–83.3] months, since rFIXFc PPX initiation). In these patients, median (IQR) change in ABR was 0.0 (-1.0–0.4), change in IF was -52.7 (-56.6– -38.4), and change in FC was -1,379.9 (-2,594.4– -264.3; n=91) IU/kg/year. Overall, most physicians (88.5%; 69/78) and patients (90.0%; 90/100) were satisfied/highly satisfied with rFIXFc PPX, at last assessment. No inhibitor development or serious adverse events related to rFIXFc were reported. Conclusion Real-world B-MORE data confirm the effectiveness of rFIXFc and demonstrate that rFIXFc PPX can reduce IF and FC while improving/maintaining bleed protection, compared with SHL PPX. B-MORE is sponsored by Sobi. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany