A Study to Learn How Safe the Study Treatment BAY94-9027 is and How it Affects the Body in Previously Treated Children Aged 7 to Less Than 12 Years With Severe Hemophilia A, a Genetic Bleeding Disorder That is Caused by the Lack of a Protein Called Clotting Factor 8 (FVIII) in the Blood

Researchers are looking for a better way to treat hemophilia A. Hemophilia A is a genetic disorder where the body does not create enough of a protein called clotting factor 8 (FVIII) present in the blood. People with hemophilia A may bleed for a long time from minor wounds, have painful bleeding into joints, or have internal bleeding. In severe hemophilia A (clotting factor 8 levels less than 1%) bleedings are more likely to happen.

In this study researchers want to learn more about the treatment called BAY94-9027. BAY94-9027 is an injectable medicine used to replace missing clotting factor 8. In BAY94-9027 the clotting factor 8 has been pegylated (combined with a substance called polyethylene glycol (PEG)). This is to make the treatment last longer in the body so that less injections are required. BAY94-9027 is already available for the prevention and treatment of bleeding in adults and children who are 12 years and older. BAY 94-9027 is also called Jivi.

BAY94-9027 is not yet available for children aged 7 to less than 12 years. One potential specific risk of pegylated drugs is that proteins in the blood called antibodies are built. These may attach to the pegylation part of the drug and this in turn may lead to allergic reactions and the drug not working as well as it should during first 4 infusions. In studies that have been done so far, this has been seen in some children younger than six years, but not in 29 children aged 6 to less than 12 years treated with BAY94-9027. Further safety information related to how the body reacts to BAY94-9027 is however still needed for this age group.

The main purpose of this study is to learn how safe BAY94-9027 is (safety) and how it affects the body (tolerability) in previously treated children with severe hemophilia A who are between 7 to less than 12 years. To answer this question, the researchers will study information about two medical problems of special interest, if allergic reactions occur (also called hypersensitivity) and if the drug is not working as well as it should (also called loss of efficacy) during the first 4 infusions.

Allergic reactions may range from mild local reactions to widespread effects such as shortness of breath, skin rashes and low blood pressure. Only allergic reactions related to the study treatment will be considered.

The assessment if loss of efficacy occurred will be based on the occurrence of bleeding, the clotting factor 8 level in blood after injection called recovery, clotting factor 8 inhibitor tests and measurement of antibodies against the PEG.

The study has two parts, A and B. Part A takes 6 months and part B takes 18 months. In part A the participants will receive two injections of BAY94-9027 per week. In part B, the number of injections may be decreased, with up to five days between the injections. The participants in this study will visit the study site around 14 times and will have 15 phone visits. In part A, visit 1 is for screening. Visits 2 to 5 take place twice a week for two weeks. Visit 6 two weeks after visit 5, visits 7 to 10 take place monthly with visit 11 six weeks after visit 10. In part B, site visits will occur on month 9, 12, 18 and 24 and phone calls every month between the site visits. The participants' and their caregivers will record in an electronic patient diary information about when the study treatment was given and bleeding episodes that have happened.

During the study, the study doctors and their team will

• take blood samples,

• do physical examinations,

• review the participants' electronic diary

• ask questions about the participants' quality of life,

• ask the participants questions about how they are feeling and what adverse events they are having An adverse event is a medical problem that happens during the study. Doctors keep track of all adverse events that happen in study, even if they do not think the adverse events might be related to the study treatments.