CSL Behring Secures Canadian Reimbursement Agreement for First Gene Therapy for Hemophilia B
Key Insights
CSL Behring signed a Letter of Intent with Canada's pan-Canadian Pharmaceutical Alliance (search) for public reimbursement of HEMGENIX, the first gene therapy authorized by Health Canada for hemophilia B (search) treatment.
The Phase 3 HOPE-B trial demonstrated that 94% of patients discontinued routine prophylaxis and remained prophylaxis-free at 4 years post-treatment with sustained Factor IX activity levels of 37.4%.
HEMGENIX uses an AAV5 (search) viral vector to deliver genetic instructions enabling continuous Factor IX production, reducing annualized bleeding rates from 4.16 to 0.40 at year four.
CSL Behring Canada announced on October 6, 2025, that it has signed a Letter of Intent with the pan-Canadian Pharmaceutical Alliance (search) (pCPA) for public reimbursement of HEMGENIX® (etranacogene dezaparvovec), marking a pivotal moment for Canadian hemophilia B (search) patients. HEMGENIX represents the first one-time gene therapy authorized by Health Canada for treating adults with hemophilia B who require routine prophylaxis to prevent or reduce bleeding episodes.
The successful completion of the LOI agreement enables provinces and territories outside of Quebec to proceed with listing HEMGENIX as part of their formularies, while CSL Behring continues discussions with Quebec to secure public reimbursement.
Transformative Clinical Outcomes
The reimbursement decision was supported by compelling results from the Phase 3 HOPE-B trial, which demonstrated remarkable long-term efficacy. In July 2024, the Canadian Drug Agency (search) recommended public drug plan reimbursement based on trial data showing that a one-time infusion produced mean factor IX activity of 36.7 percent at 24 months post-infusion in adult males with severe or moderately severe hemophilia B (search).
The trial's four-year follow-up data revealed sustained therapeutic benefits, with 94% of patients (51 out of 54) discontinuing routine Factor IX prophylaxis and remaining prophylaxis-free. Mean Factor IX activity levels reached 37.4% and were sustained at near-normal levels at four years post-treatment. The mean adjusted annualized bleeding rate for all bleeds was dramatically reduced from 4.16 during the lead-in period to 0.40 at year four.
"We sincerely appreciate the pCPA for acknowledging the transformative potential of HEMGENIX for appropriate adults with hemophilia B (search)," said Marie-Eve Jacques, General Manager, CSL Canada. "This milestone represents a significant advancement in making this revolutionary treatment accessible in Canada."
Gene Therapy Mechanism and Safety Profile
HEMGENIX operates as an in vivo gene therapy that enables the body to continuously produce Factor IX, the protein deficient in hemophilia B (search) patients. The therapy utilizes a non-infectious viral vector derived from adeno-associated virus (AAV5 (search)) that carries the Padua gene variant of Factor IX to target cells in the liver. This variant generates Factor IX proteins that are 5-8 times more active than normal.
The genetic instructions remain in target cells but generally do not integrate into the patient's DNA. Once delivered, the cellular machinery produces stable levels of Factor IX, allowing patients to reduce their risk of bleeding without continuous prophylactic infusions.
The Phase III HOPE-B trial enrolled 54 adult patients with moderately severe to severe hemophilia B (search) requiring prophylactic Factor IX replacement therapy. Patients underwent a 6-month observational period to establish baseline annual bleeding rates before receiving a single intravenous administration of etranacogene dezaparvovec at the 2x10¹³ gc/kg dose.
Safety and Tolerability
Etranacogene dezaparvovec demonstrated a favorable safety profile over four years of follow-up. The therapy was generally well-tolerated, with 96 treatment-related adverse events reported, 92 (96%) of which occurred within the first six months post-treatment. No serious treatment-related adverse reactions were reported.
The most frequently reported adverse drug reactions included ALT elevations, headache, influenza-like illness, and AST elevations, with infusion-related reactions being the most common. One death from urosepsis and cardiogenic shock in a 77-year-old patient at 65 weeks post-dosing was determined unrelated to treatment. Three serious adverse events (hepatocellular carcinoma, schwannoma, and myelodysplastic syndrome) were also confirmed unrelated to treatment through independent molecular analysis.
Clinical Impact and Patient Perspectives
"The availability of gene therapy for hemophilia B (search) represents an important achievement in treatment options for our Canadian patients, with the potential to reduce the burden of regular prophylactic intravenous factor IX infusion therapy and improve quality of life," said Dr. Natasha Pardy, President of the Association of Hemophilia Clinic Directors of Canada.
Hemophilia B (search) affects patients through vulnerability to bleeds in joints, muscles, and internal organs, leading to pain, swelling, and joint damage. The constant concern about bleeding episodes restricts daily activities, with many patients finding their lives continually impacted by managing their condition.
Emil Wijnker, President of the Canadian Hemophilia Society, emphasized the importance of treatment options that meet individual patient needs: "The Letter of Intent for reimbursement of HEMGENIX is an encouraging step forward, and we urge the provinces and territories to work together, and with CSL Behring, to make this therapy accessible as soon as possible to those who need it."
Regulatory Status and Next Steps
HEMGENIX is indicated for adults aged 18 years and older with hemophilia B (search) (congenital Factor IX deficiency) who require routine prophylaxis to prevent or reduce bleeding episode frequency. The therapy has no clinical experience in patients with mild or moderate hemophilia B (FIX activity > 2%).
The successful LOI agreement represents a critical step toward making this transformative therapy accessible to Canadian patients, potentially eliminating the need for lifelong prophylactic infusions and significantly improving quality of life for those living with hemophilia B (search).