Etranacogene dezaparvovec for hemophilia B gene therapy.

The treatment landscape for hemophilia has been rapidly changing with introduction of novel therapies. Gene therapy for hemophilia is a promising therapeutic option for sustained endogenous factor production to mitigate the need for prophylactic treatment to prevent spontaneous and traumatic bleeding. Etranacogene dezaparvovec is an investigational factor IX (FIX) gene transfer product that utilizes the adeno-associated virus (AAV) 5 vector with a liver-specific promoter and a hyperactive FIX transgene. Here, the development of etranacogene dezaparvovec and available efficacy and safety data from clinical trials are reviewed. Overall, etranacogene dezaparvovec provides sustained FIX expression for more than 2 years and allows for a bleed and infusion-free life in the majority of patients. Safety, efficacy, and quality-of-life data will inform shared decision-making for patients who are considering gene therapy. Long-term follow-up regarding duration of expression and safety are crucial.