A Study of Nicotinamide With Oral Tetrahydrouridine and Decitabine to Treat High Risk Sickle Cell Disease

Inclusion Criteria:

• Age 18 years or older.
• Written informed consent provided by the subject before study entry.
• Confirmed sickle cell disease (SCD) as determined by hemoglobin electrophoresis orliquid chromatography.
• Subject is in his/her steady state and not having any acute complication due to SCD (i.e., hospitalization, acute pain, or acute chest syndrome in the past 14 days).
• Weight at least 40kg
• Regular compliance with comprehensive care and previous therapy.
• Symptomatic SCD is defined as having one of following, despite at least 6 months ofhydroxyurea therapy, or refuse to take hydroxyurea for personal reasons: fetalhemoglobin <0.5 g/dL, or 3 or more pain episodes per year requiring parenteralnarcotics, or 1 or more acute chest syndrome episodes, or Hemoglobin <9 g/dL andabsolute reticulocyte count <250,000/mm3.

Exclusion Criteria:

• Inability to give informed consent.
• Experienced severe sepsis or septic shock within the previous 12 weeks.
• Last HU dose was ingested within the previous 4 weeks.
• Currently pregnant or breast-feeding.
• Alanine Aminotransferase (ALT) ≥ 3 times the upper limit of normal or albumin <2.0mg/dL or direct (conjugated) bilirubin ≥ 1.5 mg/dl.
• Serum creatinine >2.9 mg/dL and calculated creatinine clearance <30 mL/min.
• Platelet count >800 x 109/L.
• Absolute neutrophil count <1.5 x 109/L.
• Female of active childbearing potential who is unwilling to use at least one of thetwo following forms of birth control: (i) not having heterosexual sexual contactbeginning at the screening visit and continuing until 4 weeks after the last dose ofdecitabine OR (ii) intrauterine device (IUD).
• Sexually active male who is unwilling to use a condom when engaging in any sexualcontact with a female with child-bearing potential, beginning at the screening visitand continuing until 4 weeks after taking the last dose of THU and decitabine. Thisrequirement applies also to males who have had a successful vasectomy.
• Altered mental status or recurrent seizures requiring anti-seizure medications.
• Moribund or any concurrent disease (e.g., hepatic, renal, cardiac, metabolic) of suchseverity that death within 24 weeks is likely.
• Concurrent diagnosis of malignancy including known Myelodysplastic syndrome, leukemia,or an abnormal karyotype.
• New York Heart Association (NYHA) class III/IV status.
• Eastern Co-operative Oncology Group (ECOG) performance status ≥3.
• Participant is on chronic transfusion therapy
• Known history of illicit drug or alcohol abuse within the past 12 months.
• Other experimental or investigational drug therapy in the past 28 days.
• Taking l-glutamine within the last 28 days
• Being positive for HIV infection