The primary goal of the Phase III SCATE trial is to compare 30 months of alternative therapy (hydroxyurea) to standard care (observation) in children with sickle cell anemia and conditional (170 - 199cm/sec) Transcranial Doppler (TCD) velocities. For the alternative regimen (hydroxyurea) to be declared superior to the standard treatment regimen (observation), the hydroxyurea-treated group must have a three-fold reduction in the incidence of conversion to abnormal TCD velocities (≥ 200 cm/sec), compared to the standard treatment arm.
Results from previous studies confirm an increased risk of stroke among children with conditional TCD velocities. In addition, studies suggest that patients who were on observation alone, converted from conditional TCD (moderate risk category) to an abnormal TCD (with a much higher risk for primary stroke) within 30 months of initial identification of the conditional TCD velocity; this conversion led to initiation of chronic and indefinite transfusions in all cases. Preliminary data suggests that the risk of conversion to abnormal TCD velocities will be lower for subjects with conditional TCD velocities on hydroxyurea by at least three-fold. This important difference in conversion risk rate suggests that an alternative treatment could have a substantial and beneficial impact on patients with elevated TCD velocities. An alternative treatment could protect the brain of patients with SCA and conditional TCD velocities who are at increased risk for stroke. The avoidance of chronic blood transfusions would be a great benefit for all children with sickle cell disease, especially those in developing countries where the blood supply may be less safe (in comparison with that in the US) or unavailable, and very costly.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
38
Hydroxyurea will be administered once daily, in either capsule form (300mg, 400mg, or 500mg) or as a liquid formulation (100mg/ml). Dosing will commence at 20 mg/kg/day. Dose escalation will occur in 5 mg/kg/day increments, adjusting every 8 weeks unless hematological toxicity occurs.
St. Jude Children's Research Hospital
Memphis, Tennessee, United States
Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti (HEMORIO)
Centro, Rio de Janeiro, Brazil
Tropical Medicine Research Institute, University of the West Indies (UWI)
Mona, Kingston, Jamaica
Conversion to Abnormal Maximum TAMV
The primary endpoint of the SCATE trial is the cumulative incidence of conversion to abnormal maximum TAMV (time-averaged mean velocity) measured by transcranial doppler (TCD) ultrasonography. Subjects must have conditional velocities at baseline, defined as 170 - 199 cm/sec, which indicate moderate stroke risk. Abnormal velocities are defined as ≥ 200 cm/sec, which indicate high stroke risk. The number of conversions from conditional velocities to abnormal velocities in each treatment arm will be compared as the primary outcome.
Time frame: 30 months
Serial TCD Velocities
This secondary outcome measure will be the highest TAMV obtained in specific arteries. Serial TCD velocities are measured throughout the SCATE trial and will be compared to the baseline value.
Time frame: 30 months
Cumulative Incidence of Neurological Events
The cumulative incidence of neurological events as a secondary endpoint, which include both stroke and non-stroke neurological events, will be determined over the treatment period for both standard and alternative arms.
Time frame: 30 months
Cumulative Incidence of Non-Neurological Events
The cumulative incidence of non-neurological sickle cell-related events, including vaso-occlusion and splenic sequestration, will be estimated over the treatment period for both standard and alternative arms.
Time frame: 30 months
Quality of Life
Standard Quality of Life measure will be taken during specific time points, as well as one newly-developed Sickle Cell Disease Quality of Life measure.
Time frame: 30 months
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