The first gene therapy for adults with haemophilia B has been approved by the US Food and Drug Administration after showing that a single dose of the treatment was able to significantly reduce abnormal bleeding.
Haemophilia B is a genetic disease arising from missing or insufficient levels of blood clotting factor IX, a protein that is needed to produce blood clots to stop bleeding. Symptoms can include prolonged or heavy bleeding after an injury or surgery, or spontaneous bleeding without a clear cause. Most people affected by the disorder are men.