Sickle Cell Disease and CardiovAscular Risk - Red Cell Exchange Trial (SCD-CARRE) (SCD-CARRE)

  • End date
    Apr 30, 2026
  • participants needed
  • sponsor
    Gladwin, Mark, MD
Updated on 18 September 2022
anti-thymocyte globulin
hemoglobin s
blood transfusion
sickle hemoglobin
exchange transfusion


The SCD-CARRE trial is a Phase 3, prospective, randomized, multicenter, controlled, parallel two-arm study aimed to determine if automated exchange blood transfusion and standard of care administered to high mortality risk adult SCD patients reduces the total number of episodes of clinical worsening of SCD requiring acute health care encounters (non-elective infusion center/ER/hospital visits) or resulting in death over 12 months as compared with standard of care.


As patients with sickle cell disease (SCD) live to adulthood, the chronic impact of sustained hemolytic anemia and episodic vaso-occlusive events take their toll, with the progressive development of cardiopulmonary organ dysfunction. This culminates in the development of pulmonary hypertension, left ventricular diastolic heart disease, dysrhythmia, chronic kidney disease and sudden death, all major cardiovascular complications of SCD for which there are no approved or consensus therapies. The risk of having pulmonary hypertension and diastolic heart disease can be non-invasively assessed by laboratory tests (NT-proBNP) and Doppler-echocardiography (estimated pulmonary artery systolic pressure). A recent meta-analysis of approximately 6000 patients with SCD demonstrated that patients with elevated tricuspid regurgitant jet velocity (TRV), which is an Doppler-echocardiographic measurement that estimates the pulmonary artery systolic pressure, walked an estimated 30.4 meters less in a 6 minute walk test than those without elevated TRV, and elevated TRV was associated with high mortality (hazard ratio of 4.9). In two large registry cohorts of adult patients with SCD, the investigators found that approximately 20% of the adult SCD population have high values for both biomarkers, defined as a TRV ≥ 2.5 meters per second AND a NT-proBNP ≥ 160 pg/mL, and that the 12-month mortality rate is 7.9% in this group as compared to 0.5% in patients with normal TRV or NT-proBNP values, with a risk ratio for hospitalization of 1.6. This suggests that a simple screening profile of TRV and NT-proBNP can identify about 20% of patients with SCD at the highest risk of death and hospitalization.

Given the increased mortality and early loss of functional capacity associated with cardiovascular disease in SCD adults, it is important to test effective therapeutic interventions in such patients. Red blood cell transfusions are administered by either simple or exchange transfusion, the latter removes the patients blood and replaces it with transfused red blood cells. Exchange transfusions have proven effective for acute treatment of almost all SCD complications, including severe acute chest syndrome, stroke, splenic or hepatic sequestration, and multi-organ failure, and are also used chronically for stroke prevention and recurrent acute chest syndrome. In this study the investigators hypothesize that monthly exchange transfusion will limit disease progression, improve exercise capacity, and prevent interval episodes of vaso-occlusive painful crisis and the acute chest syndrome that acutely increases pulmonary pressures and cause right heart failure.

The investigators propose to perform a clinical trial to evaluate the effects of automated exchange blood transfusion on patient morbidity and mortality, compared to standard of care among 150 adult high risk SCD patients. The trial will leverage existing coordinating center infrastructure at the University of Pittsburgh and will involve 22 experienced clinical sites. Despite the safety and wide utilization of erythrocytapheresis in adult patients with SCD, there is no consensus or quality efficacy data on its use to improve outcomes in our aging high-risk SCD patients with progressive end-organ dysfunction.

Condition Sickle Cell Disease
Treatment Standard of Care, Red Blood Cell
Clinical Study IdentifierNCT04084080
SponsorGladwin, Mark, MD
Last Modified on18 September 2022


Yes No Not Sure

Inclusion Criteria

Age 18 years or older
Diagnosis of SCD: homozygous sickle cell disease, hemoglobin-SC, Sβ-thalassemia, hemoglobin-SO or hemoglobin-SD
Patients not on a chronic exchange transfusion program for at least 2 months
If patients are on hydroxyurea, glutamin, or selectin inhibitors the doses must be stable for at least 2 months prior to randomization
Any one of the following vasculopathy biomarker clinical results (a, b, c, d, or e) measured in the 13 months before randomization that indicates a high-risk patient
Both a TRV 2.5-2.9 m/sec and NT-proBNP plasma level ≥ 160 pg/mL
TRV ≥ 3.0 m/sec
Chronic kidney disease (CKD) due to SCD with macroalbuminuria (albumin creatinine ratio (ACR) >300 mg/g) on 2 occasions, or proteinuria (protein creatinine ratio >30 mg/mmol) on 2 occasions, or estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 calculated on 2 occasions
Both a mean pulmonary artery pressure (PAP) by right heart catheterization 20-24 mmHg and NT-proBNP plasma level ≥ 160 pg/mL
Mean PAP by right heart catheterization ≥ 25 mmHg
Written informed consent obtained from patient to participate in the trial

Exclusion Criteria

RBC alloimmunization resulting in inability of blood bank to obtain compatible components for chronic exchange transfusions
Previous history of hyper-hemolysis syndrome
Previous history of severe transfusion reaction resulting in renal failure or due to serious complications such as hypotension or respiratory distress
More than 10 vaso-occlusive episodes in the past 12 months requiring admission to a hospital to receive treatment
Religious objection to receiving blood transfusion
Diagnosis of ischemic stroke within the past 6 months
Clinical evidence of liver failure or advanced cirrhosis or any co-existing medical condition that in the Investigator's judgement will substantially increase the risk associated with the patient's participation in the trial
Women of childbearing potential who have a positive pregnancy test at baseline
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