Novel Gene Therapy Can Reduce The Need For Weekly Injections In Haemophilia Patients

Haemophilia is a rare genetic disorder in which the blood does not clot due to a lack of clotting factors or blood clotting proteins. It is a sex-linked disorder usually seen in men compared to women as most women act as a carrier. There are two types of haemophilia; haemophilia A and haemophilia B. Haemophilia A or classic haemophilia is caused by low levels of clotting factor 8, while Haemophilia B or Christmas Disease is caused by deficiency of clotting factor 9. As haemophilic patients have fewer or no clotting factors, they are at a high risk of bleeding.

Previous studies have shown that haemophilia B is clinically less severe than A. However, 85 percent of the total haemophiliacs suffer from type A, while the rest have type B. Usually, when an unaffected person bleeds, platelets (blood cells) reach the damage site and form clots to prevent excessive bleeding. But, this does not happen in haemophilia patients. Hence, they need to inject blood clotting factors intravenously (in the vein) every one or two weeks to reduce blood loss.

To cure severe haemophilia B, researchers have come up with new gene therapy, FLT180a, that can help normalize levels of clotting factor 9. During the 26th week of trials, they found that a single shot of FLT180a significantly increased the production of clotting proteins from the liver in 9 out of 10 patients with moderately severe or severe haemophilia. This decreased the requirement for regular injections in them and provided long-lasting effects by correcting faults in their genes.

“Removing the need for haemophilia patients to regularly inject themselves with the missing protein is an important step in improving their quality of life,” said Pratima Chowdary, UCL professor and lead study author. “The long-term follow up study will monitor the patients for the durability of expression and surveillance for late effects.”

Patients had to take immune-suppressing drugs in ongoing trials for several weeks to months, so their immune systems didn’t reject the therapy. However, some adverse effects were reported in one patient due to FLT180a use. He experienced abnormal clots in his blood because of excessive therapy doses.

“Gene therapy is still a young field that pushes the boundaries of science for people with severe genetic diseases,” said Amit Nathwani, study co-author and UCL professor. “The new trial adds to the growing body of evidence that gene therapy has the potential to free patients from the challenges of having to adhere to lifelong therapy or could provide treatment where none exists today.”

The research has been published in the New England Journal of Medicine.