Stroke Prevention With Hydroxyurea Enabled Through Research and Education (SPHERE)

Hydroxyurea treatment will be provided to reduce stroke risk. Hydroxyurea treatment will be started at a fixed dose of 20.0 ± 5.0 mg/kg/day, followed by escalation to maximum tolerated dose (MTD).

"TCD examination on children with SCA between ages 2 and 16 years of age will be completed to evaluate their risk of stroke.~For children with elevated velocities at initial screening or at 1 Year who receive hydroxyurea therapy, TCD examinations will occur every 6 ± 2 months."

TCD examination on children with SCA between ages 2 and 16 years of age will be completed to evaluate their risk of stroke. TCD examination for all participants will occur at initial screening, at Year 1 (12 ± 3 months), and Year 2 (24 ± 3 months). Children with normal TCD velocities at initial screening will undergo repeat TCD 12 months after enrolment. If the TCD at 12 months has changed to an elevated velocity (conditional or abnormal), the child can begin study treatment (Hydroxyurea).