The US Food and Drug Administration (FDA) has approved the first gene therapy for for hemophilia B, etranacogene dezaparvovec-drlb (Hemgenix®).

“This is uniQure’s second internally-developed gene therapy to achieve approval and the world’s first gene therapy for hemophilia B, an historic achievement based on more than a decade of research and clinical development, as well as the tireless dedication of our employees, clinicians, patients and their families,” said Matt Kapusta, chief executive officer of uniQure.

“This groundbreaking approval delivers on this promise by providing people with hemophilia B the possibility of being liberated from burdensome infusions and an ability to unlock the potential in their daily lives,” he added. “We offer our sincere gratitude to the hemophilia community, without whose years of dedication and invaluable support this medical breakthrough could not have been achieved.”

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Results from the ongoing clinical trial showed that patients treated with etranacogene dezaparvovec-drlb had a lower rate of annual bleeds, with most (94%) being able to discontinue factor IX prophylaxis and remain prophylaxis free. In a clinical trial, a one-time infusion with etranacogene dezaparvovec-drlb allowed patients to produce mean factor IX activity of 39% and 36.7% at 6 and 24 months, respectively.

“Hemgenix is unique in its approach to increase mean factor IX activity and hemostatic protection in those with hemophilia B, and today’s approval could fundamentally transform the treatment paradigm for this life-long condition,” said Steven Pipe, MD, lead investigator in the HOPE-B trial.

“As a clinician, I look forward to being able to provide a new treatment option that may help patients treated with Hemgenix become free from the regular infusion schedule that many people living with hemophilia B rely on to protect them from the debilitating effects of the condition.”

The most common side effects of etranacogene dezaparvovec-drlb treatment, with an incidence of 5% or less, included elevated liver enzymes and a certain blood enzyme, headache, flu-like symptoms, infusion-related reactions, fatigue, nausea, and feeling unwell.

Kim Phelan, chief operating officer of the Coalition for Hemophilia B, confessed to being thrilled to witness such approval. “Over the years we have seen a variety of advancements for the hemophilia community, but gene therapy is the first treatment option to offer those living with hemophilia B and caregivers the possibility of freedom from the need for regular, ongoing infusions.”

Etranacogene dezaparvovec-drlb will be available to adults 18 years of age and older diagnosed with hemophilia B.

CSL Behring is now solely responsible for further developing, registering, and commercializing etranacogene dezaparvovec-drlb globally (the licensing transition was completed in May 2021).

“Today’s historic approval builds on CSL’s promise to put patients first in all that we do to discover, develop and deliver biotherapeutics and vaccines that meet their needs,” said Bill Mezzanotte, MD, head of research and development and chief medical officer of CSL. “With Hemgenix, CSL now offers people living with hemophilia B another remarkable option for better and more durable control over their disease.”


uniQure announces FDA approval of first gene therapy for adults with hemophilia B. News release. uniQure Inc.; November 23, 2022.