The US Food and Drug Administration (FDA) has approved CSL Behring’s (CSL) Hemgenix (etranacogene dezaparvovec) as the first gene therapy for adult patients with haemophilia B.
Specifically, Hemgenix is indicated for the treatment of adults with haemophilia B who currently use factor IX prophylaxis therapy, have current or historical life-threatening haemorrhage, or have repeated, serious spontaneous bleeding episodes.
Haemophilia B is a genetic bleeding disorder resulting from missing or insufficient levels of blood clotting factor IX, a protein needed to produce blood clots to stop bleeding.
Patients with moderate-to-severe haemophilia B typically require a routine treatment regimen of intravenous (IV) infusions of factor IX replacement products to maintain sufficient levels of clotting factor to prevent bleeding episodes.
While these therapies are effective, patients must adhere to strict, lifelong infusion schedules. They may also continue to experience spontaneous bleeding episodes as well as limited mobility, joint damage or severe pain as a result of the disease.
For appropriate patients, Hemgenix allows people living with haemophilia B to produce their own factor IX, after a one-time single dose by IV infusion.
The company’s application was supported by results from the pivotal HOPE-B trial, which demonstrated that Hemgenix allowed patients to produce mean factor IX activity of 39% at six months and 36.7% at 24 months post infusion.
The mean adjusted annualised bleeding rate for all bleeds was reduced by 54% at seven to 18 months post-infusion, compared to the six-month lead-in period on factor IX prophylactic replacement therapy.
Additionally, 94% of Hemgenix-treated patients discontinued use of prophylaxis and remained free of previous continuous routine prophylaxis therapy, the company reported.
“Today’s approval provides a new treatment option for patients with haemophilia B and represents important progress in the development of innovative therapies for those experiencing a high burden of disease associated with this form of haemophilia,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research.
Matt Kapusta, chief executive officer of uniQure, also said the approval represented a “major milestone in the field of genomic medicine and ushers in a new treatment paradigm for patients living with haemophilia B”.
CSL licensed the exclusive global rights to Hemgenix from gene therapy company uniQure in May 2021 and is now solely responsible for the further development, registration and commercialisation of the therapy.