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    Poster Networking

    Hemophilia and Rare Bleeding Disorders

    Poster Networking Session

    PB0650 - Safety and Efficacy of Recombinant Fusion Protein Linking Coagulation Factor IX with Albumin (rIX-FP) in Pediatric Patients with Hemophilia B: A review of results from Phase 3 trial studies

    Monday, June 26, 2023
    18:30 – 19:30 ET
    Room: Exhibition

      Co-Author(s)

    • HC

      Hervé Chambost

      Professor and Head of the Comprehensive Care Centre for Congenital Bleeding Disorders
      AP-HM, Department of Pediatric Hematology Oncology, Children Hospital La Timone & Aix Marseille University, INSERM, INRA, C2VN, Marseille, France
      Marseille, Provence-Alpes-Cote d'Azur, France

      • Presenting Author(s)

    • Douglass Drelich, MD

      Associate Director, Global Medical Affairs - Hematology
      CSL Behring, King of Prussia, Pennsylvania, USA
      King of Prussia, Pennsylvania, United States

      • Co-Author(s)

    • WS

      Wilfried Seifert

      Director Clinical Development
      CSL Behring, Marburg, Germany
      Marburg, Hessen, Germany

      • Co-Author(s)

    • Giancarlo Castaman, MD

      Medical Director
      Center for Bleeding Disorders and Coagulation, Careggi University Hospital, Florence, Italy
      Florence, Toscana, Italy

    Background: Recombinant fusion protein linking coagulation factor IX (FIX) with albumin (rIX-FP) is an efficacious and well tolerated treatment in patients with hemophilia B, with potential for prolonged dosing intervals.

    Aims: To demonstrate the safety and efficacy of rIX-FP for routine clinical use in pediatric and adolescent patients, including previously untreated patients (PUPs).

    Methods: Previously treated patients (PTPs) and PUPs with severe hemophilia B (FIX ≤2%) aged ≤18 years who participated in the PROLONG-9FP clinical trial program were included. PTPs received weekly rIX-FP prophylaxis (35–50 IU/kg); well-controlled patients could extend to a 10-day then a 14-day regimen (50–75 IU/kg) at any 6-month follow-up. PUPs received weekly rIX-FP prophylaxis (25–50 IU/kg) for
    ≥ 50 exposure days. Efficacy, pharmacokinetic (PK), and safety data were collected.

    Results: The analysis included 7 adolescent (≥12–≤18 years) and 24 pediatric (0– < 12 years) PTPs, and 12 PUPs (0–11 years). Efficacy and PK data are outlined in Tables 1 and 2. Mean (SD) annual spontaneous bleeding rates (AsBR) for 7-day regimens for all patient cohorts were < 1.0; for the 10-day regimen AsBR was 0.0 for adolescents and PUPs, and 1.6 (2.5) for the pediatric cohort. Reported AsBR for the 14-day regimen was 1.7 (2.0) and 0.3 (0.6) for the pediatric and adolescent cohorts, respectively. Mean incremental recovery rates across all cohorts were >1.0, with mean steady-state trough FIX levels of >10 IU/dL. Mean (SD) terminal half-life values for the pediatric and adolescent cohorts were 91.4 (17.5) and 70.5 (23.8), respectively. Overall, 319 adverse events were reported, of which 3 were related to rIX-FP: one inhibitor development resulting in discontinuation from the study, and an injection site hematoma and mild rash, both resolved.

    Conclusion(s): rIX-FP is an effective treatment option with a favorable safety profile for patients 0– < 18 years, with hemophilia B.