Final Analysis of Pivotal HOPE-B Study Demonstrates Durable and Sustained Therapeutic Effect of Etranacogene Dezaparvovec Gene Therapy in Hemophilia B - Data Presented at EAHAD 2022

- Data from the largest gene therapy study in Hemophilia B to date shows that etranacogene dezaparvovec is statistically superior in reducing annualized bleeding rate compared to baseline FIX prophylactic therapy

- Following a single administration of etranacogene dezaparvovec, participants maintained stable Factor IX (FIX) activity through 18 months

- Therapeutic benefit observed in patients with pre-existing anti-capsid neutralizing antibody levels up to a titer of 1:678

KING OF PRUSSIA, Pa., Feb. 4, 2022 /PRNewswire/ -- Global biotherapeutics leader CSL Behring today announced positive long-term results from the Phase 3 HOPE-B clinical trial evaluating etranacogene dezaparvovec (EtranaDez), an investigational adeno-associated virus five (AAV5)-based gene therapy for people living with hemophilia B, a life-threatening bleeding disorder. Following a single infusion of etranacogene dezaparvovec, participants experienced a stable and durable increase in mean Factor IX (FIX) activity and hemostatic protection at 18 months. The final data, from the largest gene therapy study in hemophilia B, were presented as part of the latest clinical trial results session at the European Association of Haemophilia and Allied Disorders (EAHAD) 2022 Annual Meeting.

"The final 18-month results from the pivotal HOPE-B study continue to establish the durability of etranacogene dezaparvovec gene therapy, which produced Factor IX levels that remained stable and consistent over the course of the study, while also significantly reducing the rate of annual bleeds after a single infusion," said Professor Wolfgang Miesbach, Head of the Department of Coagulation Disorders and the Comprehensive Care Centre from the University Hospital of Frankfurt, Germany, and an investigator for the HOPE-B trial. "Hemophilia B, like many other genetic diseases, is an ideal target for gene therapy because the disease stems from a single faulty gene, making its replacement with a fully functional F9 gene a robust therapeutic intervention."

Key Data from the Phase 3 HOPE-B Study

The Phase 3, open label, single-dose, single arm HOPE-B trial, which included 54 male participants with severe or moderately severe hemophilia B, demonstrated that etranacogene dezaparvovec produced mean FIX activity of 39.0 IU/dL at six months and 36.9 IU/dL at 18 months post infusion. After the six-month lead-in period post-infusion, the adjusted annualized bleeding rate (ABR) (1.51) for all bleeds was reduced by 64 percent (p=0.0002) and all FIX-treated bleeds was reduced by 77 percent (3.65 to 0.83; p