ISTH: Sanofi Strengthens Hemophilia Leadership with New Data on ALTUVIIIO and Fitusiran

Sanofi is set to present new data from its hemophilia portfolio at the 32nd Congress of the International Society on Thrombosis and Haemostasis (ISTH), occurring from June 22-26, 2024, in Bangkok, Thailand. Key presentations on ALTUVIIIO [Antihemophilic Factor (Recombinant), Fc-VWF-XTEN Fusion Protein] will highlight long-term interim phase 3 data on its efficacy and safety in adults and children with severe hemophilia A. Abstracts on fitusiran will cover surgical experiences and long-term safety data from the ATLAS phase 3 clinical development program in adults and adolescents with hemophilia A or B, irrespective of inhibitor status.

Dietmar Berger Chief Medical Officer, Global Head of Development “Our participation in this year’s congress underscores our ongoing commitment to providing innovative, first- and best-in-class solutions for the hemophilia community. Hemophilia is a lifelong condition that significantly impacts individuals, from the risk of bleeds and poor joint health to increased surgical risks. These data emphasize the importance of treatment options like ALTUVIIIO and fitusiran that deliver effective outcomes across various scenarios and throughout a person’s life. We are eager to collaborate with regulatory agencies to continue introducing novel treatments for those living with hemophilia.”


Interim analyses of the XTEND-ed phase 3 long-term extension study indicate that ALTUVIIIO provides highly effective bleed prevention and maintains or improves joint health over two years in both adult and pediatric populations, with a consistent safety profile. The following abstracts will be presented:

  • First Interim Analysis of Clinical Outcomes in Adults and Adolescents With Severe Hemophilia A Receiving Efanesoctocog Alfa Prophylaxis in XTEND-ed: Previously treated patients (≥12 years old) from XTEND-1 (Arm A/B) had a mean annualized bleed rate (ABR) of 0.72 (SD=1.26) for arm A and 0.42 (SD=0.89) for arm B. No factor VIII inhibitors were detected (abstract OC50.1).
  • Interim Analysis of Joint Outcomes in Adult and Adolescent Patients with Severe Hemophilia A Receiving Efanesoctocog Alfa During the Phase 3 XTEND-ed Long-Term Extension Study: Patients receiving weekly ALTUVIIIO (50 IU/kg) showed improved or maintained joint health over two years, as measured by various joint health scores (abstract OC01.4).
  • 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: No factor VIII inhibitors were detected, with a mean ABR of 0.70 (SD=1.27), similar to XTEND-Kids (abstract OC50.2).

Further data demonstrate ALTUVIIIO’s effective bleed protection in perioperative management for severe hemophilia A:

  • Perioperative Management with Efanesoctocog Alfa in Adults, Adolescents, and Children with Severe Hemophilia A in the Phase 3 XTEND Clinical Program: Among 41 patients who underwent 49 major surgeries, hemostasis was maintained in all surgeries, and the hemostatic response was rated as excellent in 43 of 49 surgeries (abstract OC14.1).


Additional analyses at ISTH will highlight fitusiran’s potential as a first-in-class treatment offering consistent bleed protection for hemophilia A or B patients, regardless of inhibitor status. Key findings include:

  • Surgical Experience in People with Hemophilia A or B with and without Inhibitors Receiving Fitusiran: Out of 60 major surgeries, including 24 in patients with inhibitors, major surgeries were safely and effectively conducted with fitusiran prophylaxis following bleed management guidelines (abstract OC14.2).

Additional data demonstrate fitusiran’s favorable safety profile and its efficacy in mitigating thrombotic events (TEs) and reducing liver enzyme elevations and gallbladder issues:

  • Incidence of Thrombotic Events in the Fitusiran Clinical Development Program: Under an antithrombin-based dosing regimen (AT-DR), fitusiran led to a significant reduction in TEs (abstract OC40.2).
  • Hepatobiliary Events in the Fitusiran Clinical Development Program with the Revised AT-based Dose Regimen: The AT-DR regimen reduced liver transaminase elevations and cholecystitis/cholelithiasis events, with these issues resolving without clinical complications and no dose interruptions or discontinuations (abstract OC40.3).

These presentations reinforce data from the ATLAS-OLE study, showing that maintaining antithrombin activity levels between 15-35% results in meaningful bleed control and an improved benefit-risk profile for hemophilia A or B patients.

Regulatory submissions for fitusiran for treating hemophilia A or B in adults and adolescents with or without inhibitors have been completed in China, Brazil, and the US, with a US FDA target action date of March 28, 2025. The FDA granted fitusiran Breakthrough Therapy Designation for hemophilia B with inhibitors in December 2023.

Source Link

Newsletter Updates

Enter your email address below and subscribe to our newsletter