Inclusion Criteria:  Participants with severe hemophilia A. All age groups (less than [<] 12 and greater than [>] 12 years of age). Participant with greater than equal to (>=) 150 documented exposure days (EDs).  Treated with Adynovate:  Having a PK analysis done/data available for post-hoc modeling Having recorded clinical outcomes analysis: for > 6 months Treated with a SHL/EHL-FVIII product for at least six months before switching to Adynovate To qualify for the secondary objective participants will need to have a WAPPS study performed on Adynovate and on the SHL/EHL-FVIII they were treated before switching.  Exclusion Criteria:  Any participant who meets any of the following criteria will not qualify for entry into the study: Participants with only on-demand Factor VIII (FVIII) use. Current presence of FVIII inhibitory antibodies. (Participants with a history of inhibitors, if any, will be considered for a sensitivity analysis). Diagnosis of other inherited or acquired hemostatic defect other than hemophilia A.