A new paper published in The Lancet Haematology journal includes data from the HOPE-B clinical trial program that is investigating the hemophilia B gene therapy etranacogene dezaparvovec – the product’s commercial name is Hemgenix® (CSL Behring).


Hemgenix is an adeno-associated virus (AAV) vector-based hemophilia gene therapy product that was approved by the U.S. Food and Drug Administration in November 2022. It is indicated for the treatment of adults with hemophilia B who currently use factor IX (FIX) prophylaxis therapy, or have current or historical life-threatening hemorrhage, or have repeated, serious spontaneous bleeding episodes.


The report includes results from a “post-hoc” analysis of safety and efficacy data. Post-hoc study refers to a subsequent analysis of data from an earlier study. In this case, investigators analyzed data from a single arm of phase 3 HOPE-B, which included 54 participants with severe or moderately severe hemophilia B with or without pre-existing AAV5 neutralizing antibodies. These hemophilia patients were enrolled between 2018 and 2022 and each received a single infusion of etranacogene dezaparvovec, with median follow-up was 26.5 months.


The analysis showed a significant reduction in mean adjusted annualized bleeding rates to 1.51, compared to 4.18 during the pre-gene therapy lead in period. The mean stable and sustained factor IX activity level was 36.7%. Further, 96% of patients were able to forgo continuous prophylactic replacement therapy. Investigators reported no new safety concerns, treatment-related serious adverse events, or treatment-related deaths. The most common treatment-related adverse events were increases in liver enzymes, headaches, and flu-like symptoms.


“Ongoing follow-up of participants in this trial and others might provide further insights regarding the effects of etranacogene dezaparvovec up to 15 years after infusion,” reported the authors.


The full paper was published online March 1, 2024, in The Lancet Haematology. It also appears in the April edition of the journal, in volume 11, Issue 4.


Funding for this report was provided by uniQure and CSL Behring.


Source: Hematology Advisor, April 1, 2024