A Phase II Pilot Study of Nonmyeloablative Conditioning Hematopoietic Stem Cell Transplantation in Children with Sickle Cell Disease who have a Matched Related Major ABO-Incompatible Donor (Sickle-MAID).


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. Currently, patients with a matched related major ABO-incompatible donor are not eligible for treatment with nonmyeloablative (NMA)-HSCT. 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.


Currently recruiting participants: Yes

Eligible gender: Male, Female, Transgender, Other

Eligible ages: 1 to 19

Inclusion criteria:

Age: Patients must be ≥ 12 months and < 19 years of age at the time of study enrollment.

Diagnosis: Patients must have sickle cell disease as defined by hemoglobin electropheresis, as follows:
• homozygous Hb S disease (HbSS),
• sickle-Hb C disease (HbSC),
• sickle beta-plus-thalassemia (HbS/β+), or
• sickle beta-null-thalassemia (HbS/βo)

Eligibility for HSCT: Patients must meet standard eligibility criteria to undergo HSCT, including but not limited to one or more of the following:
• history of repeated painful episodes (more than 1) including but not limited to bony crisis. Pain may occur in typical sites associated with vaso-occlusive painful events and cannot be explained by causes other than vaso-occlusion mediated by sickle cell disease.
• history of stroke
• elevated transcranial Doppler velocity not eligible for hydroxyurea, as per TWiTCH trial (ie. severe vasculopathy)
• history of acute chest crisis or splenic sequestration crisis
• history of priapism in males
• history of osteonecrosis
• pulmonary hypertension as documented by tricuspid regurgitation jet velocity (TRV) > 2.5 m/s on echocardiogram
• red cell allo-immunization (≥ 2 antibodies) during long term transfusion therapy

Sickle complications should be present despite the use of hydroxyurea, but this is not an absolute requirement, if the treating team considers the patient to be at high risk for further crisis episodes.

Exclusion criteria:

• Patients who are unable to comply with or follow the study protocol.
• Patients who are not followed in either the Edmonton or Calgary hemoglobinopathy programs.
• Patients with known hypersensitivity to sirolimus, its derivatives or to any of its components.


This study is not currently accepting expressions of interest via the website. Please see contact information below.

Additional information

Contact information

Referral to the Alberta Children's Hospital Bone Marrow Transplant Program

Principal investigator:

Tony Truong

Clinical trial: