Transcranial Doppler (TCD) With Transfusions Changing to Hydroxyurea

Study Overview
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Brief Summary
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The primary goal of the Phase III TWiTCH trial is to compare 24 months of alternative therapy (hydroxyurea) to standard therapy (transfusions) for pediatric subjects with sickle cell anemia and abnormally high (≥200 cm/sec) Transcranial Doppler (TCD) velocities, who currently receive chronic transfusions to reduce the risk of primary stroke. For the alternative treatment regimen (hydroxyurea) to be declared non-inferior to the standard treatment regimen (transfusions), after adjusting for baseline differences, the hydroxyurea-treated group must have a mean TCD velocity similar to that observed with transfusion prophylaxis.

Detailed Description
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Despite the clear results of the STOP and the follow-up STOP II trials, the use of chronic erythrocyte transfusions for primary stroke prevention in children with Sickle Cell Anemia (SCA) remains controversial for many practicing hematologists, as well as for patients and families. Transfusions have proven clinical efficacy in preventing first stroke in children with SCA and abnormal TCD velocities, but their indefinite use may still be difficult to justifY. The risk of transfusion acquired iron overload is now recognized as a serious consequence of chronic erythrocyte transfusions in children with SCA. After one to two years of monthly transfusions, virtually every patient will have excess hepatic iron deposition that warrants intervention with chelation therapy. The effectiveness of iron chelation has not yet been realized, despite the availability of the oral chelator deferasirox (Exjade®), due to its lack of palatability and increasing recognition of serious drug-related toxicities including renal and hepatic dysfunction. Simply put, indefinite erythrocyte transfusions cannot be viewed as adequate and acceptable long-term therapy for primary stroke prevention in SCA. There is an urgent need to develop an equivalent effective alternative therapy for the prevention of primary stroke in children with SCA, specifically one that better manages iron overload and improves quality of life.

Official Title
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TCD With Transfusions Changing to Hydroxyurea (TWiTCH): A Phase III Randomized Trial to Compare Standard Therapy (Erythrocyte Transfusions) With Alternative Therapy (Hydroxyurea) for the Maintenance of Lowered TCD Velocities in Pediatric Subjects With Sickle Cell Anemia and Abnormal Pre-treatment TCD Velocities

Conditions
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Sickle Cell Anemia

Intervention / Treatment
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* Drug: Hydroxyurea


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Pediatric subjects with severe forms of sickle cell anemia (HbSS, HbSβ0 thalassemia,HbSOArab) Age range of 4.0-15.99 years, inclusive, at the time of enrollment Documented index (pre-treatment) abnormally high TCD Velocity by Transcranial Doppler ultrasonography. An abnormally high index TCD is defined as TCD V greater than or equal to 200 cm/sec, or abnormally high TCDi V greater than or equal to185cm/sec, or TCD maximum V greater than or equal to 250 cm/sec. At least 12 months of chronic monthly erythrocyte transfusions since the index abnormal TCD examination Adequate monthly erythrocyte transfusions with average HbS less than or equal to 45% (the upper limit of the established academic community standard) for the past 6 months before enrollment Parent or guardian willing and able to provide informed consent with verbal or written assent from the child Ability to comply with study related treatments, evaluations, and follow-up Exclusion Criteria: Completed overt clinical stroke or TIA Inability to obtain TCD velocities due to anatomical abnormalities such as a) Inadequate bone windows b) Previous revascularization procedures (e.g., EDAS) Known severe vasculopathy or moya-moya disease on brain MRA Inability to receive or tolerate chronic red blood cell (RBC) transfusion therapy, due to any of the following: a) Multiple RBC alloantibodies making cross-matching difficult or impossible b) RBC autoantibodies making cross-matching difficult or impossible c) Religious objection to transfusions that preclude their chronic use d) Non-compliance with transfusions over the past 6 months before enrollment (temporary exclusion) Inability to take or tolerate daily oral hydroxyurea, including a) Known allergy to hydroxyurea therapy b) Positive serology to HIV infection c) Malignancy d) Current lactation e) Previous stem cell transplant or other myelosuppressive therapy Clinical and laboratory evidence of hypersplenism (temporary exclusions): a) Palpable splenomegaly greater than 5cm below the left costal margin AND b) Transfusion requirement greater than 250 mL/kg over the previous 12 months Abnormal laboratory values at initial evaluation (temporary exclusions): a) Pre-transfusion hemoglobin concentration less than 8.0 gm/dL b) WBC count less than 3.0 x 10^9/L c) Absolute neutrophil count (ANC) less than 1.5 x 10^9/L d) Platelet count less than 100 x 10^9/L e) Serum creatinine more than twice the upper limit for age OR greater than or equal to 1.0 mg/dL Current participation in other therapeutic clinical trials Current use of other therapeutic agents for sickle cell disease (e.g., arginine, decitabine, magnesium). Subjects must have been off hydroxyurea for at least 3- months prior to enrollment. Any condition or chronic illness, such as a positive tuberculin (PPD) test, which in the opinion of the CI makes participation ill-advised. Inability or unwillingness to complete required screening and exit studies, including TCD ultrasonography, brain MRI/MRA, liver MRI and blood tests. A sibling enrolled in TWiTCH Pregnancy or unwillingness to use a medically acceptable form of contraception if sexually active (male OR female).

Ages Eligible for Study
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Minimum Age: 4 Years
Maximum Age: 15 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Standard Therapy<br>Standard Therapy of monthly transfusions | |
| Experimental: Treatment Arm<br>Hydroxyurea will be provided as capsules or liquid | Drug: Hydroxyurea<br>* Capsules (300 mg, 400 mg, or 500 mg) taken once daily liquid formulation (100 mg/mL)<br>* Other names: Droxia;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in TCD Time-averaged Mean Velocity (TAMV) on the Index Side | The primary endpoint for the TWiTCH trial was the difference between the treatment groups of the maximum TCD TAMV on the index side, calculated from a mixed model. The index side is the side with the higher mean (averaged over baseline evaluations) of the maximum (over arteries on that side) TCD time-averaged velocity. Values of the TAMV on the index site were obtained at clinic visits during baseline and during the treatment period. | Since the study was terminated early, time frame is from beginning of treatment until end of treatment (up to 24 Months). | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| TCD Time-averaged Mean Velocity on the Non-index Side | This secondary endpoint for the TWiTCH trial will be maximum TCD time-averaged mean velocity on the non-index side. The non-index side is the side with the lower mean (averaged over baseline evaluations) of the maximum (over arteries on that side) TCD time-averaged velocity. Values of the secondary endpoint will be obtained at clinic visits during baseline and during the 24-month treatment period. | 24 months | 
| Primary Stroke Events | This secondary outcome measure will compare standard to alternative therapy for primary stroke events (a) primary ischemic stroke; b) primary hemorrhagic stroke | 24 months | 
| Non-stroke Neurological Events | This secondary objective will compare standard to alternative treatment for the incidence of non-stroke neurological events. Data for this outcome will be collected through entry and exit neurological exams. | 24 months | 
| Change of Baseline in Hepatic Iron Overload as Assessed by Serum Ferritin | This secondary objective will compare standard to alternative therapy for hepatic iron overload. | Baseline and 24 months | 
| Effects on Quality of Life | Standard Quality of Life measure will be taken during specific time points as well as one newly developed Sickle Cell Disease-specific test. | 24 months | 
| Functional Status | This outcome will be measured using Barthel Index testing at the beginning, middle, and end of the treatment period. | 24 months | 
| Neuropsychological Decline | This outcome will be measured using standardized neurocognitive tests at baseline and exit. | 24 months | 
| Growth and Development | This outcome will be measured by capturing height and weight monthly and conducting an annual pubertal assessment. | 24 months | 
| Number of Participants With Transfusion Events | This outcome will be recorded on every interval visit form through questions asking whether there have been transfusion complications. Any complication higher than a CTCAE grade 2 event will be reported as a SAE. | 24 months | 
| Number of Participants With Hydroxyurea Toxicities | This measure will be performed on a monthly basis throughout the trial by recording the CBC and retic count. | 24 Months | 
| Number of Participants With Phlebotomy Complications | This outcome will be recorded on every interval visit form through questions asking whether there have been phlebotomy complications. Any complication higher than a CTCAE grade 2 event will be reported as a SAE. | 24 months | 
| Number of Participants With Liver MRI Complications | This outcome will be recorded through questions asking whether there have been Liver MRI complications at baseline, middle, and end of treatment. Any complication higher than a CTCAE grade 2 event will be reported as a SAE. | 24 months | 
| Number of Participants With Serious Adverse Events |  | 24 Months | 
| Change of Baseline in Hepatic Iron Overload as Assessed by Liver Iron Concentration | This secondary objective will compare standard to alternative therapy for hepatic iron overload. | Baseline and 24 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Pediatric patients, Phase III, Sickle cell anemia, Abnormally high Transcranial Doppler velocities., Reduce risk of primary stroke, Chelation therapy