Study of Decitabine and Tetrahydrouridine (THU) in Patients With Sickle Cell Disease

The purposes of this study are to observe if oral tetrahydrouridine and decitabine can increase fetal hemoglobin levels and improve the symptoms of sickle cell disease, and to monitor how patient's bodies react to oral tetrahydrouridine and decitabine. The overall purpose is to develop disease modifying treatment for sickle cell disease that is less cytotoxic than the current standard of care, and which can directly and more efficiently reactivate fetal hemoglobin levels. The hypothesis is that patients treated with oral tetrahydrouridine and decitabine will have the same chance of severe non-hematologic toxicities as the placebo group. The primary end-point is ≥ grade 3 non-hematologic toxicity. The investigators' hypothesis is that patients in the treatment groups receiving oral THU-decitabine 2X/week over 8 weeks (n=15) will be equivalent to placebo group (n=10) with regards to the chance of ≥ grade 3 non-hematologic toxicity.