A Research Study Looking at How Safe it is to Switch From Emicizumab to Mim8 in People With Haemophilia A (FRONTIER 5)

Prior treatment

• Previous participation in this study. Participation is defined as signed informed consent.
• Previous or current thromboembolic disease or events (with the exception of previous catheter associated thrombosis for which anti-thrombotic treatment is not currently ongoing) or risk of thromboembolic disease, as evaluated by investigator.
• Receipt of FVIII gene therapy at any time.
• Ongoing or planned immune tolerance induction therapy.
• Minor or major surgery planned to take place after screening and during the 26-week treatment period.

Other illness

• Any disorder, which in the investigator's opinion might jeopardise the participant's compliance with the protocol or safety, including ongoing Adverse Events (AEs) associated with emicizumab.
• Known congenital or acquired coagulation disorders other than haemophilia A.
• Known or suspected hypersensitivity to study intervention, related products, any constituents of the product or to other monoclonal antibodies.

Lab values

• Neutralising antibodies towards emicizumab have been detected or, for patients adherent to emicizumab therapy, are suspected based on clinical and laboratory assessments.
• Hepatic dysfunction defined as aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) greater than (\>) 3 times the upper limit combined with total bilirubin \>1.5 times the upper limit measured at screening.
• Renal impairment defined as estimated glomerular filtration rate (eGFR) lesser than or equal to (≤) 30 milliliter per minute per 1.73 square meter (mL/min/1.73 m\^2) for serum creatinine measured at screening.
• Other conditions (e.g. autoimmune disease) or laboratory abnormality that may increase risk of bleeding or thrombosis as evaluated by the investigator.

Other

• Participation (i.e., signed informed consent) in any interventional, clinical study, with the exception of emicizumab, with receipt of the last dose within 8 weeks (or 5 half-lives of the investigational medicinal product \[IMP\], whichever is longer) before screening.
• Female who is pregnant, breast-feeding or intends to become pregnant or is of childbearing potential and not using highly effective contraceptive method.
• Mental incapacity, unwillingness to cooperate, or a language barrier precluding adequate understanding and cooperation.

• Informed consent obtained before any study-related activities. Study-related activities are any procedures that are carried out as part of the study, including activities to determine suitability for the study.
• Male or female with diagnosis of congenital haemophilia A of any severity based on medical records.
• Age 12 years or above at the time of signing the informed consent.
• Participants treated with emicizumab once-weekly (QW), once every two weeks (Q2W), or once every four weeks (Q4W) according to the label for at least 8 weeks prior to screening.
• Participants choosing to discontinue emicizumab treatment and switch to Mim8 QW, Q2W, or once-monthly (QM) treatment for 26 weeks from start of treatment (Visit 2).
• Participant and/or caregiver willingness and ability to comply with scheduled visits and study procedures, including the completion of an electronic diary and patient-reported outcomes (PRO) questionnaires.