A Research Study Looking at Long-term Treatment With Mim8 in People With Haemophilia A (FRONTIER 4)

Arm 1 & 2:

Inclusion Criteria:

1. Informed consent obtained before any study related activities. Study relatedactivities are any procedures that are carried out as part of the study, includingactivities to determine suitability for the study.

2. Male or female with diagnosis of congenital haemophilia A based on medical records.

3. Ongoing participation in study NN7769-4513, NN7769-4514, NN7769-4516, or NN7769-4728at the time of transfer. Participant should qualify either of the followingcriteria:

4. Participant from study NN7769-4513, who has participated in the extension partof the study for at least 12 weeks prior to enrolment in study NN7769-4532, or,

5. Participant has completed the end of treatment visit for study NN7769-4514,NN7769-4516 or NN7769-4728.

6. Participant and/or participant's parent(s)/participant's Legally acceptablerepresentative (LAR) willingness and ability to comply with scheduled visits andstudy procedures, including the completion of diary.

Exclusion Criteria:

1. Any disorder, except for conditions associated with haemophilia A, which in theinvestigator's opinion might jeopardise participant's safety or compliance with theprotocol.

2. Participant who has discontinued or been withdrawn from studies NN7769-4513,NN7769-4514, NN7769-4516, or NN7769-4728.

3. Previous participation in this study. Participation is defined as signed informedconsent.

4. Female who is pregnant, breast-feeding or intends to become pregnant.

5. Female of child-bearing potential and not using a highly effective contraceptivemethod (highly effective contraceptive measures or as required by local regulationor practice).

6. Participation (i.e., signed informed consent) in any interventional, clinical study (except from study NN7769-4513, NN7769-4514, NN7769-4516, or NN7769-4728) of anapproved or non-approved investigational medicinal product.

7. Any planned major surgery, during part 1 of the study.

8. Mental incapacity, unwillingness to cooperate, or a language barrier precludingadequate understanding and cooperation.

Arm 3:

Inclusion criteria

1. Informed consent obtained before any study-related activities. Study-relatedactivities are any procedures that are carried out as part of the study, includingactivities to determine suitability for the study.

2. Male or female with diagnosis of congenital severe haemophilia A (endogenous FVIIIactivity less than (<) 1 percentage [%]) with or without FVIII inhibitors based onmedical records.

3. Aged <1 year at the time of signing informed consent.

4. Body weight greater than or equal to (≥) 3.2 kilograms at the time of signinginformed consent.

5. previously untreated patients (PUPs) or minimally treated patients (MTPs) (i.e., upto 5 days of exposure to haemophilia-related treatment such as plasma-derived FVIII,recombinant FVIII, fresh frozen plasma, cryoprecipitate, or whole blood products).

6. Full-term pregnancy (gestational age ≥37 weeks).

7. Participant's parent(s)/LAR(s) willingness and ability to comply with scheduledvisits and Arm 3 (infant) procedures, including the completion of diary and patientreported outcome (PRO) questionnaire.

8. Participants <3 months of age must show no signs of active intracranial haemorrhageat screening. This is confirmed by cranial ultrasound performed according to localpractice and regardless of delivery method.

9. Receipt of vitamin K prophylaxis (as per local standard practice).

10. Availability of historical results in medical records for: a. activated partial thromboplastin time (aPTT) b. FVIII levels.

11. Availability of historical results in medical records or pre-dose sample taken for:

12. fibrinogen

13. haematology parameters

14. biochemistry parameters (aspartate aminotransferase (AST) and/or alanineaminotransferase (ALT), bilirubin and creatinine).

Exclusion criteria

1. Known or suspected hypersensitivity to trial product or related products.

2. Previous participation in study 4532. Participation is defined as signed informedconsent.

3. Participation (i.e., signed informed consent) in any interventional clinical studywith receipt of the last dose within 6 months (or 5 half-lives of theinvestigational medicinal product, whichever is shorter) before planned enrolment.

4. Exposure to non-factor haemostatic products for bleeding prophylaxis within 6 months (or 5 half-lives of the medicinal product, whichever is shorter) before plannedenrolment.

5. Known congenital or acquired coagulation disorders other than haemophilia A.

6. Other conditions (e.g., autoimmune disease) or laboratory abnormality that mayincrease the risk of bleeding or thrombosis, as evaluated by the investigator. Anydisorder, except for conditions associated with haemophilia A, that in theinvestigator's opinion might jeopardise the participant's safety or compliance withthe protocol.

7. Lack of adequate parental/legally acceptable representative (LAR) support to enter accurately and timely information regarding treatment and bleeding episodes into an (electronic) diary.

8. Previous or current treatment for thromboembolic disease (with the exception of previous catheter-associated thrombosis for which anti-thrombotic treatment is not currently ongoing) or signs of thromboembolic disease.

9. Any planned major surgery, during part 1 of Arm 3 (infant). For definition of major surgery.

10. Immune tolerance induction planned to take place after treatment initiation.

11. Hepatic dysfunction defined as AST and/or ALT greater than (>) 3 times the upper limit of normal (ULN) combined with total bilirubin >1.5 times the ULN.

12. Serum creatinine above 1.5 times the ULN.