Hamostaseologie 2025; 45(S 01): S40-S41
DOI: 10.1055/s-0044-1801605
Abstracts
Topics
T-07 Hereditary bleeding disorders

Long-term Outcomes With Efanesoctocog Alfa Prophylaxis for Previously Treated Children With Severe Hemophilia A, an Interim Analysis of the Phase 3 XTEND-ed Study

Authors

  • L Malec

    1   Versiti Blood Research Institute, Milwaukee, USA
    2   Medical College of Wisconsin, Division of Hematology & Oncology, Departments of Medicine and Pediatrics, Milwaukee, USA

  • C Königs

    3   Goethe University Frankfurt, University Hospital, Department of Pediatrics and Adolescent Medicine, Frankfurt am Main, Germany

  • B Nolan

    4   Children's Health Ireland at Crumlin, Dublin, Ireland

  • A K Chan

    5   McMaster Children’s Hospital, McMaster University, Hamilton, Canada

  • M Albisetti

    6   University Children’s Hospital Zurich, Zurich, Switzerland

  • S-C Chou

    7   National Taiwan University Hospital, College of Medicine, Department of Internal Medicine, Division of Hematology, Taipei, Taiwan

  • B Zulfikar

    8   Istanbul University Oncology Institute, Inherited Bleeding Disorders Center, Department of Pediatric Hematology, Istanbul, Turkey

  • M Simpson

    9   Rush University Medical Center, Rush Hemophilia and Thrombophilia Center, Chicago, USA

  • L Feng

    10   Sanofi, Shanghai, China

  • H Palmborg

    11   Sobi, Stockholm, Sweden

  • G Neill

    12   Sanofi, Reading, UK

  • L Abad-Franch

    13   Sobi, Basel, Switzerland

  • S Gunawardena

    14   Sanofi, Bridgewatererdam, USA

  • K Fijnvandraat

    15   Emma Kinderziekenhuis/AMC, University of Amsterdam, Amsterdam, Netherlands
Weitere Informationen
Auch verfügbar auf
 

Introduction: Efanesoctocog alfa (formerly BIVV001) is a first-in-class high-sustained factor VIII (FVIII) replacement therapy designed to overcome the von Willebrand factor–imposed half-life ceiling. Once-weekly efanesoctocog alfa 50 IU/kg was well tolerated and provided highly effective bleed protection and factor activity within normal to near-normal levels (>40%) for 3 days, and of ~10% at Day 7, in children with severe hemophilia A in the XTEND-Kids study (NCT04759131). The aim is to evaluate long-term data on safety and efficacy of efanesoctocog alfa in previously treated children with severe hemophilia A in the XTEND-ed study (NCT04644575).

Method: XTEND-ed is a multicenter, open-label study that enrolled participants from previous Phase 3 studies, including children<12 years of age who received weekly efanesoctocog alfa prophylaxis for≤52 weeks in XTEND-Kids, and continue weekly 50 IU/kg prophylaxis in XTEND-ed. The primary endpoint is the occurrence of FVIII inhibitors. Secondary endpoints include annualized bleed rates (ABRs), efficacy for bleed treatment, and safety. Participants provided informed consent and XTEND-ed was approved by applicable ethics committees. First Interim Analysis Data cut: June 8, 2023.

Results: Seventy-one of 74 males (96%) rolled over from XTEND-Kids to XTEND-ed. The mean (standard deviation [SD]) efficacy period was 35.8 (14.1) weeks. No FVIII inhibitors were detected. The mean (SD) ABR was 0.70 (1.27; 6-monthly data: [Fig. 1]), thus maintaining the low mean ABR observed in the parent study (0.88). Most bleeds (86%; 30/35) resolved with a single dose of efanesoctocog alfa 50 IU/kg, with 96% (23/24) of hemostatic responses rated as excellent or good. Overall, 43 (61%) participants experienced≥1 treatment-emergent adverse event (TEAE) and 2 (3%) experienced≥1 serious TEAE ([Fig. 2]).

Zoom
Fig. 1  Summary of annualized bleed rates by 6-month interval for treated bleeding episodes among children (<12 years old) receiving once-weekly prophylaxis with efanesoctocog alfa (50 IU/kg) in XTEND-ed
Zoom
Fig. 2  Summary of adverse eventsfor children (<12 years old) receiving once-weekly prophylaxis with efanesoctocog alfa (50 IU/kg) in XTEND-ed

Conclusion: Long-term results in children with severe hemophilia A in XTEND-ed show that once-weekly efanesoctocog alfa continues to be well tolerated, with no FVIII inhibitors reported, and provides highly effective bleed protection.

Funded by Sanofi and Sobi.



Publikationsverlauf

Artikel online veröffentlicht:
13. Februar 2025

© 2025. Thieme. All rights reserved.

Georg Thieme Verlag KG
Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany