Gene therapy shows positive results for patients with haemophilia

Skåne University Hospital is presently the sole hospital in the Nordic region to have performed gene therapy treatment for haemophilia. In recent years, the hospital has participated in three international studies—one for haemophilia A and two for haemophilia B. The findings reveal a significant enhancement in the blood's coagulation ability, resulting in an improved quality of life for patients.

"All seven patients we have treated have responded to the treatment and we have not seen any serious side effects. The treatment protects the patients from bleeding and they avoid having to treat themselves with around 100 syringes per year," says Jan Astermark, senior consultant in haematology and coagulation at Skåne University Hospital and professor at Lund University.

Not all patients can be guaranteed an ideal response to the treatment. A well-functioning liver is a crucial prerequisite for achieving positive outcomes. Additionally, patients must be capable of adhering to certain restrictions, such as abstaining from alcohol entirely for an extended period.

"The treatment works in the absolute majority of patients who then have several years of mild or even no tendency to bleed at all. They feel that they now have a life like everyone else," says Jan Astermark.

Earlier this year, the initial study on haemophilia B treatment was published in the New England Journal of Medicine.

“The European Medicines Agency has already approved the virus vector employed in the study, and in August of last year, a virus vector received approval for haemophilia A treatment. The ongoing processes involve seeking routine use approvals from the respective national medicine authorities in each country”, Jan Astermark says.

While awaiting approvals, the healthcare system is making preparations for how to organise when it comes to providing gene therapy treatment. Considerations include determining the number of hospitals in the country that will offer the treatment and outlining collaborations among hospitals in the Nordic region.

"The treatments have so far only been given within the framework of studies. We are preparing at Skåne University Hospital to test another viral vector for haemophilia A and we have started discussions about future studies where we intend to use the gene scissors CRISPR-Cas9. With current treatments we add healthy genes, but with the gene scissors we would go in and repair existing genes," says Jan Astermark.

Jan Astermark and his colleagues also conduct follow-ups on previously treated patients to expand knowledge about the long-term effects of the treatment and identify any potential side effects.

"We cannot be completely sure that no side effects will occur in the long term, but so far there are no signals to indicate that this is the case. I feel secure that we do not expose the patients to any unjustified risk, but it is important to have long-term contact and dialogue with the patients."

Facts: Haemophilia

• Haemophilia, an umbrella term encompassing hereditary diseases that cause individuals to bleed more easily than healthy individuals, primarily refers to the congenital form of bleeding disorder inherited via the female sex chromosome. It predominantly affects males.
• The condition arises due to a defective gene responsible for producing either factor 8 (haemophilia A) or factor 9 (haemophilia B), resulting in a lack of the necessary coagulation factor for blood clotting. Haemophilia severity varies, ranging from mild to moderate to severe, with the latter showing no residual factor activity.
• Approximately 1,000 Swedes have some form of classic haemophilia.
• Thanks to available medications, most people with haemophilia can lead relatively normal lives, although regular and frequent injection treatments are required to reduce or prevent bleeding. In some cases, complications may arise in the form of antibodies.
• Individuals with haemophilia require additional treatment during surgical procedures and must exercise extra caution to prevent injuries that could trigger bleeding, as the current substitution treatment fails to normalise their coagulation levels.