A Phase 2 interventional study of Alemtuzumab and Total Body Irradiation in Sickle Cell Disease, Stem Cell Transplant Complications and Red Blood Cell Disorder, sponsored by University of Calgary. Recruiting at 1 site in Canada. Open to participants aged 1 Year to 19 Years. Per ClinicalTrials.gov, last updated 2026-05-01.
Sponsored by University of Calgary · Phase 2, Interventional, and Treatment
The aim of this study to evaluate the safety and efficacy of a nonmyeloablative conditioning regimen for allogeneic hematopoietic stem cell transplantation (HSCT) in pediatric patients with sickle cell disease (SCD) who have a matched related major ABO-incompatible donor. The nonmyeloablative regimen will use alemtuzumab, total body irradiation (TBI) and sirolimus for immune suppression. This study will expand the access of HSCT for patients with SCD who are currently not eligible because of donor restrictions.
Sickle cell disease (SCD) is a debilitating chronic blood disorder with multi-system end-organ damage that leads to morbidity and early mortality. The only cure for SCD is hematopoietic stem cell transplantation (HSCT), which given the risks with unrelated HSCT, is only an option for a minority of patients who have a matched sibling donor.
In the field of HSCT, blood group ABO incompatibility between donor and recipient is not a contraindication and several studies do not show compromised outcomes. However, in the context of nonmyeloablative (NMA) conditioning and major ABO-incompatibility, when the recipient has existing antibodies to donor red blood cells, pure red cell aplasia (PRCA) may occur.
This phase II pilot study will enroll SCD patients with a matched related major ABO-incompatible donor to determine the safety and efficacy of NMA-HSCT. Biological studies will include a plan to study and monitor red cell engraftment in this population to facilitate early detection and interventional measures to prevent and treat PRCA.
1,103 studies on the registry are indexed under Anemia, Sickle Cell; 235 are open to participants now.
This study's planned enrollment of 12 is below the median of 40 across 750 interventional studies indexed under Anemia, Sickle Cell.
Browse Anemia, Sickle Cell studies →University of Calgary is the lead sponsor of 686 studies on the registry; 189 are open to participants now.
Of its 10 completed or terminated interventional studies of FDA-regulated products, 2 (20%) have results posted.
Counted across the registry records on this site, refreshed daily.
Patients must have sickle cell disease as defined by hemoglobin electropheresis, as follows:
Patients must meet standard eligibility criteria to undergo HSCT, including but not limited to one or more of the following:
Exclusion Criteria:
Non-myeloablative conditioning
Drug: Alemtuzumab · Radiation: Total Body Irradiation · Drug: Sirolimus
Alemtuzumab, Day -7 to -3. Dose: 0.2mg/kg/dose SC once daily x 5 days
Also known as: Campath
TBI 300 cGy on Day -2
Also known as: TBI
Sirolimus is used for GVHD prophylaxis
Incidence of pure red cell aplasia (PRCA)
Clinical definition: reticulocytopenia \< 10x109/L (\< 1%) lasting more than 60 days after HSCT, or Pathological definition: the absence of erythroid precursors in the marrow in the setting of adequate myeloid, lymphoid and megakaryocytic precursors
Time frame: 6 months from enrollment
RBC chimerism measured by peripheral blood flow cytometry
Peripheral blood for RBC chimerism on flow sorted erythroid precursor cells
Time frame: 12 months
RBC chimerism measured by bone marrow BFU-erythroid forming colonies
Bone marrow will be performed between Day +45 and +60
Time frame: 2 months
Primary graft failure
Measured by donor chimerism from peripheral blood and bone marrow
Time frame: 6 weeks
Secondary graft failure
Measured by donor chimerism in peripheral blood and bone marrow
Time frame: 24 months
Disease recurrence
Measured by peripheral blood Hb S level
Time frame: 24 months
Incidence and severity of acute GVHD
Acute GVHD grade will be accessed using modified CIBMTR criteria
Time frame: 100 days
Incidence and severity of chronic GVHD
Chronic GVHD will be accessed using the NIH consensus criteria
Time frame: 24 months
Plan to share: No
No publications or documents are linked to this record.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Calgary