Adding Hydroxyurea to Chronic Transfusion for Sickle Cell Anemia Reduces Transfusion Burden: Final Results of the HAT Prospective Trial

Background: Chronic red blood cell (RBC) transfusion is an established therapy to prevent stroke in patients with sickle cell anemia (SCA). Chronic transfusion, however, requires considerable blood resources and has risks so a strategy to decrease transfusion requirements is highly desirable especially given blood shortages. Chronic transfusion also can fail to prevent progressive cerebrovascular disease so further optimization of this therapy is needed. Hydroxyurea has been studied as an alternative to chronic transfusion, but alone it provides inadequate cerebrovascular protection for patients at highest risk for stroke. Combination therapy hydroxyurea and transfusion (HAT) may provide benefits over either therapy alone because each ameliorates the pathology of SCA via different mechanisms. To evaluate the feasibility and impact of HAT on transfusion requirements, we conducted a single-arm clinical trial (NCT03644953).