An Observational Research Study of the Health of Joints in People With Haemophilia Taking the Medicine Esperoct

This observational study is following men with moderate-to-severe haemophilia A who are switching to (or have recently switched to) Esperoct, a factor VIII replacement therapy used to prevent bleeding episodes. The study tracks joint health over time to see whether Esperoct helps preserve or improve joint function in patients with haemophilia. It does not involve any experimental treatments — patients simply continue their prescribed care while researchers collect health data. You may be eligible if: - You are male and 18 years of age or older - You have been diagnosed with severe (FVIII activity below 1%) or moderate (FVIII activity 1–5%) haemophilia A - You have recently switched or are about to switch to Esperoct for prophylactic (preventive) treatment - Your decision to use Esperoct was made independently from this study - You have baseline joint health data available from within 2 months before or 1 month after your switch You may NOT be eligible if: - You have previously participated in this study - You previously stopped Esperoct treatment - You were receiving Esperoct on-demand (not as regular prophylaxis) - You have a language barrier or cognitive impairment that prevents participation - You participated in a clinical trial within the 30 days before switching to Esperoct Talk to your doctor to see if this trial is right for you.