A pioneering new treatment for the blood clotting disorder haemophilia B, developed in a trial led by Southampton’s Dr Rashid Kazmi, has been approved in the USA.
When most people cut themselves, clotting factors in their blood mix with blood cells called platelets to form a clot which naturally stops the bleeding. People with haemophilia B do not have enough clotting factor IX in their blood, so bleed for longer than usual.
The main preventative treatment (or prophylactic therapy) for haemophilia B is regular infusions of clotting factor IX. While this is effective, it has a large impact on patients’ lives.
This new treatment is the first gene therapy to be approved by the US Food and Drug Administration (FDA) for haemophilia B patients. A one-time infusion raises factor IX levels, keeps them high and reduces bleeding for years.
The evidence to support its approval came from a clinical trial led by Southampton’s Dr Rashid Kazmi. Five patients took part and were dosed at the NIHR Southampton Clinical Research Facility.
Avoiding the need for lifelong infusions
Haemophilia B is a rare disorder caused by a single gene defect, resulting in insufficient production of factor IX. People with the condition are particularly vulnerable to bleeds in their joints, muscles, and internal organs, leading to pain, swelling, and joint damage. It can be life-threatening.
Current treatments include strict, lifelong infusion schedules to top up their factor IX. This new gene therapy, HEMGENIX, instead allows people living with haemophilia B to produce their own factor IX.
Life-changing results
In the ongoing HOPE-B clinical trial, HEMGENIX (etranacogene dezaparvovec-drlb) reduced the rate of annual bleeds. This allowed 94 percent of patients treated with it (51 out of 54) to discontinue their previous factor IX preventative treatment.
The results showed HEMGENIX allowed patients to produce a mean factor IX activity of 39 percent at six months and 36.7 percent at 24 months post infusion. Seven to 18 months post-infusion, the mean adjusted annualized bleeding rate for all bleeds was reduced by 54 percent compared to the six-month lead-in period on factor IX prophylactic replacement therapy.
The trial is being led by Dr Rashid Kazmi, Consultant Haematologist at University Hospital Southampton. He said:
“In the clinical trials we witnessed gene therapy bringing a momentous change to our patients. The availability of this treatment outside clinical trials is fantastic news – for the patients, doctors and nurses.
“Knowing that they no longer need to have regular treatment has enormous effect on various aspects of the life of patients. This expands their choices of deciding where to live, what profession to choose and gives them the liberty of engaging in activities that would not have been possible for them previously. In many ways it gives them a new identity and they experience the world in a different way – they develop a different psychology.”
Next steps for NHS approval
FDA approval marks an important step towards this treatment becoming available to UK patients with haemophilia B. They have approved HEMGENIX 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.
The multi-year clinical development program for HEMGENIX was led by uniQure (Nasdaq: QURE). Sponsorship of the clinical trials transitioned to global biotechnology company CSL after it acquired global rights to commercialize the treatment. CSL Behring, a CSL business, will make HEMGENIX available for eligible people with haemophilia B as soon as possible.
“As part of our promise to patients, CSL is committed to delivering innovative and groundbreaking solutions to address unmet medical needs, and we are proud to introduce the next wave of breakthrough medicines for people living with haemophilia B,” said Paul Perreault, CSL’s Chief Executive Officer and Managing Director.
“We recognize and thank all trial participants, scientists and investigators - without whom this important achievement would not have been possible - and look forward to seeing the positive impact of HEMGENIX on the haemophilia B community.”
HEMGENIX is still currently under assessment by other regulatory agencies. To become available on the NHS, it must first be approved by The National Institute for Health and Care Excellence (NICE).
Dr Kazmi adds: “We will wait for NICE approval and are hopeful that, given the safety, efficacy, and immensely positive impact on patients’ life, it will be made available soon.”