Prospective Identification of Variables As Outcomes for Treatment (PIVOT): A Phase II Clinical Trial of Hydroxyurea for Children and Adults with HbSC Disease

Introduction: HbSC is a common form of sickle cell disease especially prevalent in West Africa. Despite experiencing similar clinical events as those with sickle cell anemia (HbSS or HbSβ 0 thalassemia), individuals with HbSC disease have received much less attention because disease complications occur less frequently and often manifest later in life. Retrospective reports suggest that hydroxyurea might benefit people living with HbSC disease, but rigorous prospective data are unavailable to describe potential treatment benefits, long-term safety, and appropriate study endpoints. We designed a Phase II clinical trial of hydroxyurea for children and adults with HbSC disease with the following aims: 1) to measure possible laboratory toxicities of hydroxyurea; 2) to assess the clinical effects of hydroxyurea on sickle-related clinical and laboratory parameters; and 3) to identify study endpoints that are suitable for a future definitive Phase III trial of hydroxyurea for HbSC disease.