EC approves first gene therapy for adults with haemophilia B

The European Commission (EC) has granted conditional marketing authorisation to CSL’s Hemgenix (etranacogene dezaparvovec) as the first gene therapy for haemophilia B.

Specifically, Hemgenix is indicated for adults with severe or moderately severe haemophilia B without a history of factor IX inhibitors.

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-off, single dose by IV infusion.

The EC’s decision, which follows a recommendation from the Committee for Medicinal Products for Human Use in December, was supported by results from the ongoing HOPE-B trial, the largest gene therapy study of the condition to date.

The results showed that Hemgenix was associated with stable and durable increases in mean factor IX activity levels, leading to an adjusted annualised bleed rate reduction of 64%.

Additionally, 96% of Hemgenix-treated patients discontinued routine factor IX prophylaxis, and mean factor IX consumption was reduced by 97% at 18 months post-treatment, compared to the lead-in period.

Dr Bill Mezzanotte, CSL’s head of research and development and chief medical officer, said: "The approval of Hemgenix in Europe is the essence of great science delivering a medicine that we believe can transform the treatment paradigm for both people living with haemophilia B and the healthcare professionals who treat them.”

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.

The company has already received US approval for Hemgenix in haemophilia, and its UK submission is currently under review.

Lutz Bonacker, senior vice president and general manager of commercial operations Europe at CSL Behring, said: “We now need to work to ensure that as many eligible patients across Europe can access this innovative treatment as possible.”