A recent study published in the New England Journal of Medicine reveals that HEMGENIX (etranacogene dezaparvovec-drlb) demonstrates long-term durability and safety over a five-year period in adults with hemophilia B. The findings, reported by CSL (ASX:CSL; USOTC:CSLLY) on December 7, 2025, underscore the potential of this gene therapy to transform the management of hemophilia B.
The pivotal Phase 3 HOPE-B study showed that 94% of patients (51 of 54) remained free from the burden of continuous prophylactic treatment five years after a single infusion of HEMGENIX. The therapy not only maintained a mean factor IX activity level of 36.1% but also exhibited a favorable safety profile throughout the study.
Significant Long-Term Benefits
The data highlighted the sustained therapeutic benefits of HEMGENIX, with participants experiencing a remarkable reduction in bleeding episodes. The adjusted annualized bleeding rate (ABR) for all types of bleeds dropped by approximately 90% from the lead-in period (4.16, n=54) to year five (0.40, n=51). Joint bleeds were reduced by 93% and spontaneous bleeds by 94%, showcasing the therapy’s effectiveness in preventing bleeding complications.
Dr. Steven Pipe, a leading expert in the field and a Professor at the University of Michigan, commented on the study’s implications, stating, “The five-year HOPE-B results mark a pivotal milestone for gene therapy, providing clear, long-term data of the ability of HEMGENIX to potentially transform care for adults with hemophilia B.” He emphasized the significance of achieving lasting bleed control from a single treatment, allowing patients greater freedom from ongoing therapy.
Safety Profile and Future Monitoring
The study affirmed that HEMGENIX maintains a favorable safety profile, with no serious adverse events directly linked to the treatment. A total of 100 treatment-related adverse events were documented, most occurring within the first four months after infusion. Notably, only five adverse events were reported between years four and five, indicating a stable safety record.
Following the completion of the HOPE-B study, participants who consented will continue to be monitored in the extended follow-up study, IX-TEND 222-3003, which will track their health outcomes for up to 15 years post-treatment. This initiative aims to gather more comprehensive long-term data regarding HEMGENIX.
HEMGENIX is currently the only commercially available gene therapy for adults with hemophilia B, approved in multiple countries including the United States, Canada, the United Kingdom, and various nations in Europe and Asia. More than 75 individuals across eight countries have received HEMGENIX in real-world settings, reflecting an increasing global adoption of this innovative treatment.
In conclusion, the five-year results from the HOPE-B study reinforce HEMGENIX’s role as a viable treatment option for adults living with hemophilia B. As the medical community continues to explore the long-term effects and benefits of gene therapy, HEMGENIX stands as a promising advancement in hemophilia care, potentially alleviating the physical and emotional burdens faced by those affected by this condition. For further details on HEMGENIX, visit www.Hemgenix.com.