Long-term Study Evaluating Joint Health in People With Haemophilia A Receiving Real-world Prophylactic Treatment With Efanesoctocog Alfa

You might be able to join this study if you have haemophilia A, whether you are male or female. You must already be taking, or about to start taking, the medicine efanesoctocog alfa as prescribed by your doctor. This prescription should have been made within the last six months, or at the time you join the study, and for at least 12 months you should have been on some kind of haemophilia treatment before starting efanesoctocog alfa.

It's important that you are willing and able to attend study visits and keep records of any bleeding episodes you might have. If you are part of a special group within the study, you would also need to agree to have annual ultrasound scans of your ankles, elbows, and knees.

However, you cannot join if you have acquired haemophilia A (which means your body started making antibodies against your clotting factor later in life rather than being born with the condition) or other blood clotting problems, or if you've had a positive test for FVIII inhibitors (which are antibodies that can stop your haemophilia medicine from working) in your medical records when you started efanesoctocog alfa. You also can't take part if you are currently in another clinical study that involves a new or experimental medicine.

If you decide to take part in this study, your journey will start with a visit to the hospital during one of your regular appointments. At this first visit, the team will check to make sure the study rules fit with your health situation. You will need to give your permission by signing a form that fully explains what’s involved.

After that, you will have follow-up visits at the hospital every year. These visits will involve checks on your joint health, using special assessments and questionnaires where you share how you feel about your health. You might also have ultrasound scans of your joints if you're part of a specific group within the study. The study will ask you to keep a simple paper diary to record any bleeding episodes you might have.

You will continue to take efanesoctocog alfa as prescribed by your own doctor, as this study is about how the medicine works in a real-life setting, not about testing a new treatment. You will be part of the study for either 24 or 36 months, depending on when you join. You will stay in the study as long as you continue to take efanesoctocog alfa prophylaxis, and your doctor thinks it’s appropriate.