Long-term Safety and Efficacy of Efanesoctocog Alfa (BIVV001) in Previously Treated Patients With Hemophilia A

This study is open to both men and women who have haemophilia A and have received treatment for it in the past. Some participants will have already taken part in an earlier study for BIVV001, while others will be trying it for the first time. If you're new to BIVV001, you must have severe haemophilia A, which means your natural Factor VIII level is very low (less than 1%). You also need to have been treated for haemophilia A before, for a certain number of days (at least 150 days if you're an adult, or 50 days if you're under 6).

There are also some specific health checks. Your platelet count, which helps with clotting, needs to be at a healthy level. If you have HIV, your CD4 cell count and viral load need to be within certain limits. There are specific groups for new participants, including Chinese participants for one part of the study, and another part for those planning a major surgery soon.

However, you cannot join if you have developed antibodies (called inhibitors) to Factor VIII at a certain level. You also can't be in another study at the same time. If you have serious liver disease, a recent severe infection (other than long-term hepatitis or HIV), or another bleeding disorder alongside haemophilia A, you won't be able to take part. Also, if you've ever had a severe allergic reaction to similar medicines, the study might not be suitable.

If you join this study, you would receive the study medicine, BIVV001, once a week. This would involve regular injections, which often can be done at home after proper training. The aim is for you to receive the medicine for at least 100 days of treatment. You'll have regular hospital visits for check-ups, blood tests, and to make sure everything is going well. These visits will help us monitor your health, how well the medicine is working, and if you experience any side effects. You'll also be asked about your overall quality of life and any bleeding episodes you have.

For those who are new to BIVV001, you might undergo some additional assessments to understand your body's response to the medicine. The study can last for up to four years, but it would end earlier if BIVV001 becomes generally available for purchase in the UK. During the study, you'll need to keep track of any bleeding events and how you use the medicine, often through a diary or mobile app.