Nonmyeloablative stem cell transplant for children with sickle cell disease and incompatible donors

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-AID)

Phase 2 Interventional University of Calgary · NCT03214354

This study is testing a new way to do a stem cell transplant for children with sickle cell disease who have a donor that doesn't perfectly match to see if it can help them get better.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment12 (estimated)
Ages1 Year to 19 Years
SexAll
SponsorUniversity of Calgary Academic / other
Drugs / interventionsalemtuzumab
Locations1 site (Calgary, Alberta)
Trial IDNCT03214354 on ClinicalTrials.gov

What this trial studies

This study evaluates the safety and efficacy of a nonmyeloablative conditioning regimen for hematopoietic stem cell transplantation (HSCT) in pediatric patients with sickle cell disease (SCD) who have a matched related major ABO-incompatible donor. The regimen includes alemtuzumab, total body irradiation, and sirolimus for immune suppression. By expanding access to HSCT for patients previously ineligible due to donor restrictions, this study aims to improve treatment outcomes for SCD. Biological studies will monitor red cell engraftment to facilitate early detection and intervention for potential complications.

Who should consider this trial

Good fit: Ideal candidates are children aged 12 months to 19 years with sickle cell disease and a matched related major ABO-incompatible donor.

Not a fit: Patients who do not have a matched related donor or are outside the specified age range may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could provide a curative treatment option for children with sickle cell disease who have incompatible donors.

How similar studies have performed: Previous studies have shown that ABO incompatibility does not compromise outcomes in HSCT, suggesting this approach may be viable.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Patients must be ≥ 12 months and \< 19 years of age at the time of study enrollment.
* 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)
* Patients must meet standard eligibility criteria to undergo HSCT, including but not limited to one or more of the following:

  * history of repeated (more than 1) bony (vaso-occlusive) crisis
  * 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 with known hypersensitivity to sirolimus, its derivatives or to any of its components.

Where this trial is running

Calgary, Alberta

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Sickle Cell DiseaseStem Cell Transplant ComplicationsRed Blood Cell DisorderPure Red Cell Aplasiasickle cell diseasestem cell transplantred blood cell engraftmentnonmyeloablative
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.