This clinical trial is focused on studying hemophilia, a condition where blood does not clot properly, leading to excessive bleeding. The study involves children aged 1 to less than 12 years who have severe forms of hemophilia A or hemophilia B. The treatment being tested is called fitusiran, which is given as a solution for injection under the skin. Fitusiran is also known by its code name, SAR439774. The purpose of the study is to confirm the appropriate dose levels of fitusiran for these young patients.
During the study, participants will receive regular doses of fitusiran. The study will monitor how the treatment affects the levels of a protein called antithrombin in the blood, which plays a role in blood clotting. Researchers will also keep track of any side effects that participants might experience and measure the amount of fitusiran in the blood over time. The study aims to ensure that the treatment is safe and effective for children with severe hemophilia.
This trial is open-label, meaning that both the researchers and participants know which treatment is being administered. The study is multinational, involving participants from different countries. The goal is to gather enough information to determine the best dosing strategy for fitusiran in young children with hemophilia, ultimately aiming to improve their quality of life by reducing bleeding episodes.



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