Prospective screening and treatment study for children with Sickle Cell Anemia and increased stroke risk living in the Dominican Republic.

SACRED involves a three-part study design, as outlined below, to include (1) initial TCD evaluation phase; (2) longitudinal TCD evaluation; and (3) treatment if warranted.

1. The initial evaluation portion of SACRED will involve obtaining TCD examinations on children with SCA between ages 3-15 years, who are followed at Hospital Infantil Robert Reid Cabral in Santo Domingo to evaluate their risk of stroke. Up to 500 patients will be enrolled. All patients, including those who are already on hydroxyurea and transfusion therapy (whether for stroke or other clinical indications), will be included to obtain a one-year cross-sectional description of TCD velocities in this patient population. Patients who are already on therapy and identified to have elevated TCD velocities will be eligible for the treatment portion of SACRED as a conditional or elevated velocity would suggest that their present therapy was not optimized.
2. In the longitudinal portion of SACRED, all enrolled children will undergo yearly TCD examination. The goal of serial examination is to help define the natural history of cerebrovascular disease, specifically to determine the incidence of new conditional or abnormal velocities. The goal is to obtain a total of 3 TCD examinations per enrolled patient, regardless of treatment status.
3. In the treatment phase of SACRED, those children with TCD velocities between 170-199 cm/sec will be eligible for protocol-directed hydroxyurea therapy. Most participants will initiate hydroxyurea treatment but those who are already on hydroxyurea and have conditional velocities will receive dose optimization. Participants will be followed until a common study termination date, defined as 3 years from the first treatment. Participants with abnormal TCD velocities ≥200 cm/sec will commence with transfusion therapy per current practice guidelines at the clinical site. Patients already on transfusion therapy identified to have conditional velocities will also be eligible for hydroxyurea and those with abnormal velocities may require re-calculation of transfusion dosing.

Inclusion Criteria:

• Pediatric participants with severe forms of sickle cell anemia (HbSS or HbSβ° thalassemia)
• Age: between 3.0 and 15.0 years at the time of enrollment
• Parent or guardian willing and able to provide informed consent
• Ability to comply with study related treatments, evaluations, and follow-up

There are no exclusion criteria applicable to the TCD screening portion of SACRED.

For participants with conditional TCD velocities, the following criteria will disqualify them from the treatment phase of SACRED:

Exclusion Criteria:

• Known medical condition making participation ill-advised (e.g., acute or chronic infectious disease including HIV, known allergy to hydroxyurea therapy, or malignancy)

• Abnormal historical laboratory values (most recent pre-enrollment values):

  1. Anemia: Hemoglobin concentration < 6.0 gm/dL
  2. Reticulocytopenia: Absolute reticulocyte count < 100 x 10˄9/L with a hemoglobin concentration < 8.0 gm/dL
  3. Neutropenia: Absolute neutrophil count (ANC) < 1.0 x 10˄9/L
  4. Thrombocytopenia: Platelet count < 80 x10˄9 /L
  5. Known abnormal renal function (serum creatinine >2X upper limit for age AND ≥ 1.0 mg/dL)

• Pregnancy (for post-menarchal females only)