This study is for boys and men with Hemophilia A, a condition where blood doesn’t clot properly due to a lack of a protein called Factor VIII (FVIII). Some patients develop FVIII inhibitors, which makes treatment harder. The study is observational, meaning researchers will watch and record information without changing any treatments. It will last up to 5 years. The goal is to see how different treatments work, especially when patients develop these inhibitors. The study will also look at immune tolerance induction (ITI), a way to help the body accept FVIII. The study divides participants into three groups based on their treatment plans: some will receive ITI alone, some with a new medicine called emicizumab, and some will receive emicizumab without ITI. Participants need to give informed consent, which means they agree to take part and understand the study.

• The study is observational, lasting up to 5 years.
• Participants will be placed in one of three treatment groups.
• Participants need to provide informed consent.