Stroke With Transfusions Changing to Hydroxyurea (SWiTCH) 

The purpose of this study is to compare standard therapy (transfusions and chelation) with alternative therapy (hydroxyurea and phlebotomy) for the prevention of secondary stroke and management of iron overload in children with sickle cell anemia (SCA).

Condition	Intervention	Phase
Hemochromatosis Cerebrovascular Accident Anemia, Sickle Cell Hematologic Diseases	Procedure: Red Cell Transfusions  Procedure: Iron Chelation  Drug: Hydroxyurea  Procedure: Phlebotomy	Phase III

Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

Primary Outcomes: Secondary stroke; Management of iron overload (both measured at Month 30)
Secondary Outcomes: Comparisons of growth and development; Frequency of non-stroke neurological and other sickle-related events; Quality of life (all measured at Month 30)
Expected Total Enrollment:  150

Stroke occurs in 10% of children with SCA and has a very high risk of recurrence without therapy. Affected children receive chronic erythrocyte transfusions to prevent a secondary stroke, which are effective but have limited long-term utility due to transmission of infectious agents, erythrocyte alloantibody and autoantibody formation, and iron overload. Transfusion acquired iron overload can cause chronic organ damage with hepatic fibrosis and cirrhosis, poor growth and development, cardiac arrhythmias, and early sudden death in young patients with SCA and stroke. Deferoxamine (Desferal [r]) chelation therapy is difficult to tolerate and leads to non-compliance. An alternative to transfusions for secondary stroke prevention that also addresses the issue of transfusion acquired iron overload is clearly needed. Hydroxyurea can prevent acute vaso-occlusive events in SCA, but its utility for cerebrovascular disease and for the prevention of secondary stroke in SCA is not proven. Pilot data indicate hydroxyurea can prevent stroke recurrence in children with SCA; after transfusions are discontinued, serial phlebotomy reduces iron burden.

DESIGN NARRATIVE:

This is a Phase III randomized clinical trial for children with SCA. The hypothesis is that hydroxyurea and phlebotomy can maintain an acceptable stroke recurrence rate and significantly reduce the hepatic iron burden. The primary aim is to compare standard therapy (transfusions and chelation) with alternative therapy (hydroxyurea and phlebotomy) for the prevention of secondary stroke and management of iron overload. Additional aims include comparisons of growth and development, frequency of non-stroke neurological and other sickle-related events, and quality of life. The use of hydroxyurea for secondary stroke prevention, coupled with removal of excess iron by phlebotomy, would represent a significant improvement in the management of individuals with SCA and stroke. If hydroxyurea is effective for the prevention of secondary stroke, it may also be beneficial for other children with SCA and cerebrovascular disease, including those at risk for primary stroke.

The trial includes approximately 130 children (5.0-18.9 years of age with 65 subjects per treatment arm) with SCA who have had symptomatic cerebral infarctions and have been treated with red cell transfusions for at least 18 months. After completing baseline screening studies, half the participants will be switched to a therapeutic program of hydroxyurea and phlebotomy. Half of the participants will remain on transfusion and chelation. The composite primary endpoint in this study is to compare two modalities of treatment for the prevention of secondary stroke and management of iron overload. The impetus for this trial is the fact that long-term transfusion and chelation therapy in children is difficult, is frequently unsuccessful, and is often complicated by severe symptomatic iron overload, particularly of the heart, lungs, and liver.

Ages Eligible for Study:  5 Years   -   18 Years,  Genders Eligible for Study:  Both

Criteria

Inclusion Criteria:

• Pediatric subjects with severe forms of sickle cell anemia (HbSS, HbSß0 thalassemia, HbSOArab)
• Age range of 5.0-18.9 years, inclusive, at the time of study entry
• Initial (primary) completed overt clinical stroke after the age of one year (12 months) with documented infarction on brain computed tomography (CT) or magnetic resonance imaging (MRI)
• At least 18 months of chronic monthly erythrocyte transfusions since primary stroke
• Transfusional iron overload, defined as a previously documented liver iron concentration (LIC) greater than or equal to 5.0 mg Fe per gram of dry weight liver or serum ferritin greater than or equal to 500 ng/mL on two independent measurements
• Adequate monthly erythrocyte transfusions with average HbS less than or equal to 45% (the upper limit of the established academic community standard) in the 6 months prior to study entry
• Parent or guardian willing and able to provide informed consent with verbal or written assent from the child (less than 18 years of age) or subject willing and able to provide informed consent (older than 18 years of age)
• Ability to comply with study-related treatments, evaluations, and follow-up

Exclusion Criteria:

• Inability to receive or tolerate chronic red blood cell (RBC) transfusion therapy, due to any of the following:

  1. Multiple RBC alloantibodies making cross-matching difficult or impossible
  2. RBC autoantibodies making cross-matching difficult or impossible
  3. Religious objection to transfusions that preclude their chronic use
  4. Non-compliance with transfusions in the 6 months prior to study entry (temporary exclusion)

• Inability to take or tolerate daily oral hydroxyurea, due to any of the following:

  1. Known allergy to hydroxyurea therapy
  2. HIV infection
  3. Cancer
  4. Pregnant or breastfeeding
  5. Previous stem cell transplant or other myelosuppressive therapy

• Clinical and laboratory evidence of hypersplenism, due to any of the following:

  1. Palpable splenomegaly greater than 5 cm below the left costal margin and
  2. Transfusion requirement greater than 250 mL/kg in the 12 months prior to study entry

• Abnormal laboratory values at initial evaluation (temporary exclusion):

  1. Pre-transfusion hemoglobin concentration less than 7.0 gm/dL
  2. White blood cell (WBC) count less than 3.0 x 109/L
  3. Absolute neutrophil count (ANC) less than 1.5 x 109/L
  4. Platelet count less than 100 x 109/L
  5. Serum creatinine more than twice the upper limit for age and greater than 1.0 mg/dL
• Current participation in other therapeutic clinical trials
• Current use of other therapeutic agents for SCA (e.g., arginine, decitabine, magnesium)
• Any condition or chronic illness, such as a positive tuberculin (PPD) test, which in the opinion of the study physician makes study participation ill-advised
• Inability or unwillingness to complete required screening studies, including blood tests, brain MRI/magnetic resonance angiography (MRA), and liver biopsy
• A sibling enrolled in SWiTCH

Please refer to this study by ClinicalTrials.gov identifier  NCT00122980

William Schultz       william.schultz@stjude.org

Study chairs or principal investigators

Ronald W. Helms, PhD,  Principal Investigator,  Rho Federal Systems Division, Inc.   
Russell E. Ware, MD, PhD,  Principal Investigator,  St. Jude Children's Research Hospital   

Study ID Numbers:  227; U01 HL78787; U01 HL78987
Last Updated:  June 30, 2006
Record first received:  July 20, 2005
ClinicalTrials.gov Identifier:  NCT00122980
Health Authority: United States: Federal Government
ClinicalTrials.gov processed this record on 2006-10-10