EU approves Hemgenix, one-time gene therapy for hemophilia B

Long-term efficacy seen in adults with moderate to severe disease, no inhibitors

Steve Bryson, PhD avatar

by Steve Bryson, PhD |

Share this article:

Share article via email
A woman making a public announcement using a megaphone.

The European Commission has conditionally approved Hemgenix (etranacogene dezaparvovec), a one-time gene therapy to treat adults with hemophilia B.

Hemgenix, originally developed by uniQure, is approved for adults with severe and moderately severe hemophilia B without a history of inhibitors. It’s the first gene therapy for hemophilia B available to patients across all European Union member states, plus Iceland, Liechtenstein, and Norway.

“The European approval of Hemgenix represents another major milestone in the field of genomic medicine and innovation in the treatment of people living with hemophilia B,” Matt Kapusta, uniQure’s CEO, said in a press release.

“This achievement is based on more than a decade of research and clinical development led by uniQure, and we are grateful for the tireless dedication of our employees, clinicians, patients and their families who made this possible,” Kapusta said.

Recommended Reading
An illustration of different types of pills.

Hemophilia linked to greater use of medications for pain, mental health

Most patients stopped using replacement therapies across Phase 3 trial

The approval decision came on the heels of a favorable recommendation for the therapy from the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP). Hemgenix will marketed by CSL Behring, which acquired worldwide commercialization and licensing rights under a May 2021 agreement.

The F9 gene provides instructions to make clotting factor IX (FIX), a protein that promotes the formation of blood clots to stop bleeding. People with hemophilia B carry mutations in the F9 gene, leading to either low levels of FIX or the production of a faulty protein, both of which impair the blood clotting process.

Current treatments for moderate to severe hemophilia B include prophylactic (preventative) injections of FIX replacement therapy to temporarily supplement blood-clotting factor levels. Although these therapies are effective, patients must follow a strict, lifelong regimen and may still experience spontaneous bleeds, limited mobility, pain, and joint damage.

Hemgenix, formerly known as EtranaDez or AMT-061, uses a modified and harmless virus to deliver FIX-Padua, a highly functional version of the F9 gene, to liver cells, which are the main producers of clotting factors in the body. Given by intravenous (into-the-vein) infusion, the therapy aims to restore the production of a functional FIX, helping to prevent and control bleeds in the long term.

Data from the ongoing and open-label Phase 3 HOPE-B (NCT03569891) trial mainly supported the gene therapy’s approval. Patients with inhibitors, or neutralizing antibodies against FIX, were excluded from the study.

Trial findings at two years post-treatment showed Hemgenix led to stable and sustained increases in FIX levels among 54 men, ages 18 and older, with moderate to severe hemophilia B.

The annualized bleeding rate dropped by 64% seven to 24 months after treatment, and almost all patients (94%) stopped taking their routine replacement therapies altogether for up to two years. The therapy also was found to be generally well tolerated, with no serious treatment-related side effects reported.

“This approval marks an important step forward in the treatment of hemophilia B, which could be transformative for people who are debilitated by bleeds into their muscles, joints and internal organs, alleviating the burden of lifelong intravenous infusions of Factor IX products,” said Wolfgang Miesbach, MD, PhD, head of coagulation disorders at the University Hospital of Frankfurt, Germany.

The U.S. Food and Drug Administration approved Hemgenix in November 2022, and the therapy is currently under regulatory review in the U.K.

“Data from the HOPE-B study demonstrate the potential of HEMGENIX to remove the need for routine prophylaxis, by providing durable Factor IX activity, as well as improved bleeding outcomes and quality of life for people with hemophilia B,” Miesbach said.

The HOPE-B  trial is due to conclude in March 2025.