Clinical researchers at Barts Health NHS Trust and Queen Mary University of London have found that one year on from a single treatment with a gene therapy drug, participants with hemophilia A  are showing normal levels of the previously missing protein, and effectively curing them.

A single infusion of the gene therapy drug showed improved levels of the essential blood clotting protein Factor VIII, with 85% of patients achieving normal or near-normal Factor VIII levels even many months after treatment. The ' transformational ' results have particular significance as the first successful gene therapy for hemophilia A.  

The trial saw patients across England injected with a copy of the missing gene , which allows their cells to produce the missing clotting factor . Following patients for up to nineteen months, tests show that they had not had patients in the trial now have normal or near normal levels of the previous missing factor and all patients have been able to stop their previous regular treatment.

The team will now hold further tests widening participants globally to include people in the USA, Europe, Africa and South America. Professor Pasi continued: "Incredibly exciting is the potential for a significant change in how hemophilia is treated globally A single dose of medication that can dramatically improve the lives of patients across the world is an amazing prospect."


Jake Omer, 29 lives in Billericay and is married with two children, aged 3 years and a baby of 5 weeks. Diagnosed at two years old, I have had frequent injections of factor VIII to prevent bleeds ever since. Before he was treated with the gene therapy, Jake would wake up early before work to inject three times a week as well as injecting whenever he had an injury to stop the bleeding.

As a result of repeated bleeding Jake has arthritis in his ankles. His father is a Turk-Cypriot and his family could never travel to visit relatives in case he needed medical care as the facilities would not have been available.

Jake said: "The gene therapy has changed my life I have hope for my future The arthritis in my ankles meant I used to worry how far I would be able to walk once I turned 40. At 23 I struggled to run 100m to catch a bus; now at 29 I'm walking two miles every day which I just could not have done before having the gene therapy treatment.