The European Commission has granted conditional marketing authorisation for CSL’s Hemgenix (etranacogene dezaparvovec), the first one-time gene therapy for severe and moderately severe haemophilia B (congenital Factor IX deficiency) in adults without a history of Factor IX inhibitors.
In an ongoing clinical trial, the drug reduced the rate of annual bleeds with a single infusion by 64% by delivering a functional gene that acts as a blueprint for coagulation Factor IX, a protein important for blood clotting.
People living with haemophilia B currently require lifelong treatment of intravenous infusions of Factor IX to maintain sufficient levels, which can have a significant impact on their quality of life and wellbeing.
According to the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP), there is ‘an unmet medical need for new therapeutic approaches that might free patients from the burden of frequent infusions, or episodically at the time of a bleeding event’.
“This approval marks an important step forward in the treatment of haemophilia 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 Professor Wolfgang Miesbach, Head of Coagulation Disorders at the Comprehensive Care Center, University Hospital of Frankfurt.
Sustained and durable effect
The European Commission’s decision follows the CHMP’s positive opinion in December 2022, based on findings from the pivotal HOPE-B trial, the largest gene therapy trial in haemophilia B to date.
These findings showed that haemophilia B patients treated with Hemgenix demonstrated stable and durable increases in mean Factor IX activity levels (with a mean Factor IX activity of 36.9%) which led to an adjusted annualised bleed rate (ABR) reduction of 64%.
Following infusion of Hemgenix, 96% of 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.
The HOPE-B study 24-month analysis continued to show a sustained and durable effect of Hemgenix.
The multi-year clinical development of Hemgenix was led by uniQure and sponsorship of the clinical trials transitioned to CSL after it licensed global rights to commercialise the treatment. The treatment was approved by the US Food and Drug Administration in November 2022.