The is a Phase 3 study for children, ages 0-17 years old, with severe von Willebrand disease (VWD). In this study, the study drug will be used prophylactically for the treatment of bleeding events. Prophylactic treatment means the study drug will be used to prevent or stop a bleed before it happens.
This study is going to look at how safe the study drug is and how well the study drug (recombinant von Willebrand factor (rVWF, vonicog alfa)), works to prevent and control bleeding.

The purpose of this rollover study is to investigate the long-term safety of etavopivat in participants11 months of age and older with SCD or thalassaemia who have completed a treatment period in previous etavopivat studies (parent studies, see Section 4.1). Long-term clinical efficacy measures of etavopivat treatment will also be assessed. This study will also ensure that participants who are benefiting from etavopivat treatment have prolonged access to the drug in the time before it is commercially available in their country.