Treatment of Adult Patients With Hemoglobin SC Disease (SCYTHE)

Patients will be recruited from the patient population followed at the Texas Children's Cancer and Hematology Centers (TCC/HC)/Baylor College of Medicine (BCM) and the University of Texas Houston Hematology Center. To be eligible to participate in this study, patients must have HbSC disease, have experienced a sickle cell disease related complication, or have a score of 80 or lower on the AdultQLTM Sickle Cell Disease Module 3.0. This questionnaire will be offered to all patients with HbSC seen in our clinic that consent to this study. Patients must also agree to clinic visits every two months, and to phlebotomy, or blood removal after 6 months on the study if they meet criteria for phlebotomy. If the patient is a sexually active female, they will be offered birth control. If the patient chooses not to initiate effective birth control, they will be tested at their scheduled visit with a urine pregnancy test. If the patient becomes pregnant they will be removed from the study. Patients will be assessed in clinic every two months after starting treatment. Hydroxyurea will be started at 10 mg/kg/day, and increased by 5 mg/kg/day if needed to a maximum tolerated dose (MTD) of 35/mg/day. The most common side effect of the drug is a drop in infection fighting cells, or white blood cells, so the medication will be started at a low dose and the dose will be increased only if it is safe to do so. After 6 months at MTD on the study, patients will be evaluated for their response to hydroxyurea. If they have not reached their MTD after 6 months their time on the study will be increased to allow for 6 months observation at MTD. The minimum time the patients will be on the study is 12 months after starting hydroxyurea therapy with an option to participate in a 2 year observation study following the end of the study. If the patients have had minimal or no benefit from the medication, monthly phlebotomy will be added to their treatment regimen, at 7-10 ml/kg. The first phlebotomy volume will be 7 ml/kg, but may be increased to 10 ml/kg to obtain the target Hb of 9-10 g/dL. Patients will remain on hydroxyurea and phlebotomy for six months. If their Hb is less than or equal to 9.0 g/dL on their phlebotomy visit, phlebotomy will not be performed and their phlebotomy visits will be spaced every 2 months. Patients time on the study will be increased to allow for 6 months observation to ensure that there is no late harmful effects. The minimum time patients will be on the study is 18 months after starting phlebotomy with an option to participate in a 2 year observation study following the end of the study. Patients will be asked to allow the investigators to review information from their medical records at the start of the study, and throughout the study. If the patient would like to participate in the two year follow-up, their records will be reviewed during that period as well.