Stroke Prevention With Hydroxyurea Enabled Through Research and Education (SPHERE): A Prospective Trial to Reduce Primary Stroke in Children With Sickle Cell Anaemia


1 United States site

1 Tanzania site


2 to 16 Years


Phase 2

Study type






Diagnostic Test



About the study

This study will 1) Evaluate the prevalence of elevated (conditional or abnormal) transcranial
Doppler (TCD) velocities in a cross-sectional analysis of children with Sickle Cell Anemia
(SCA) living in Tanzania; 2) Obtain longitudinal data on TCD velocities in this population;
and 3) Measure the effects of hydroxyurea therapy on TCD velocities and associated primary
stroke risk.

participation requirements

– Willingness to sign informed consent

– Willingness to follow all study procedures

– Available for study visits for the duration of the study and no plans to move away
from study center.

– Confirmed diagnosis of Sickle Cell Anemia (SCA) by haemoglobin electrophoresis.

– Able to take oral medication and follow hydroxyurea treatment schedule.

participation restrictions

There are no permanent exclusion criteria for participants to enroll in the screening TCD
portion of SPHERE. Temporary, time-limited exclusion criteria for the screening TCD portion
include the following:

– Febrile illness within the past two weeks. (Temporary Exclusion)

– Hospitalized within the past two weeks. (Temporary Exclusion)

– Transfusion within the past two weeks. (Temporary Exclusion)

Patients who enroll in the screening portion, have a conditional or abnormal TCD, and are
eligible to start hydroxyurea will be excluded from receiving study treatment if they meet
any of the following criteria:

– Abnormal pre-enrolment laboratory values (Temporary Exclusion)

– Known medical condition making participation ill-advised.

– Known allergic reactions to components of hydroxyurea.

– Previous history of stroke.

– Currently pregnant or lactating.


  • Cincinnati, Ohio, United States, Cincinnati Children's Hospital Medical Center, 45229
  • Mwanza, Tanzania, Bugando Medical Centre