Steven Pipe, MD, Professor of Pediatrics and Pathology, and Pediatric Medical Director of the Hemophilia and Coagulation Disorders Program at the University of Michigan, discusses the results of the phase III HOPE-B clinical trial that led to the recent FDA approval of etranacogene dezaparvovec (Hemgenix), a gene therapy for hemophilia B.
Hemophilia B is a congenital bleeding disorder due to dysfunction or deficiency of coagulation Factor IX (FIX). People with this condition may bleed for longer periods of time after injury or surgery. They are also susceptible to spontaneous bleeding in muscles, joints and organs, which can be extremely painful and, in some cases, life-threatening.
Etranacogene dezaparvovec is an adeno-associated virus five (AAV5)-based gene therapy for people living with hemophilia B.
In the phase 3 HOPE-B trial, 54 adult hemophilia B patients were classified as severe or moderately severe and requiring prophylactic FIX replacement therapy were enrolled. After the six-month lead-in period in which patients continued their current standard of care therapy to establish baseline mean adjusted annualized bleeding rate (ABR), patients received a single intravenous administration of etranacogene dezaparvovec. The primary endpoint was 52-week ABR after achievement of stable FIX expression compared with the six-month lead-in period, considering all bleeds regardless of investigator adjudication as true bleeds. For this endpoint, ABR was measured from month seven to month 18 after infusion, ensuring the observation period represented likely steady-state FIX transgene expression.
As Dr. Pipe explains, at the completion of the study, the mean adjusted ABR was reduced by 54% compared to the six-month lead-in period on factor IX prophylactic replacement therapy. Further, 94% of patients treated with the gene therapy discontinued use of prophylaxis and remained free of previous continuous routine prophylaxis therapy. The most common adverse events were liver enzyme elevations, headache, elevated levels of a certain blood enzyme, flu-like symptoms, infusion-related reactions, fatigue, nausea and feeling unwell.
To learn more about hemophilia B and other rare hematological disorders, visit checkrare.com/diseases/hematologic-disorders/