HEMATOPOIETIC STEM CELL TRANSPLANTATION IN SEVERE PEDIATRIC SICKLE CELL DISEASE: OUTCOME AND LONG-TERM COMPLICATIONS, SAUDI EXPERIENCE AT KING FAISAL SPECIALIST HOSPITAL, RIYADH, SAUDI ARABIA

HCT in in Severe Pediatric Sickle Cell Disease

Background

Hematopoietic stem transplantation (HSCT), from matched related donors (MRD) is offered as a curative therapeutic option in children with Sickle cell disease (SCD).

Objective

We wanted to assess the outcome and long terms complications observed in children undergoing HSCT at a single transplant center in Saudi Arabia.

Patients and Methods

One-hundred and twenty nine children were transplanted for severe Sickle cell disease (SCD), consecutively during 2006 to 2020 at our center. Main transplant indication was cerebral vasculopathy in 57 (43%) followed by recurrent vaso-occlusive crisis (VOC) in 47 (36%). Median age at transplant was 9.1 years (range, 1.5-13.9 years). All patients received myeloablative conditioning with Busulfan, Cyclophosphamide and Anti T-Lymphocyte Globulin (Grafalon®): BU/CY/ATG in 114 (88.4%), BU/CY in 13 (10%) and other in 2 (2%). Bone marrow was the main stem cell source in 123 (95%).

Results

All patients showed granulocyte engraftment. Acute graft-versus-host-disease (aGVHD) and chronic GVHD was observed in 26 (20%) and 12 (9%) patients, respectively. At median follow-up of 4.36 years (range, 0.13-15.5 years), 10-year overall survival (OS) and event free survival (EFS) of 94% and 91% was observed. The OS and EFS were significantly better in patients receiving BU/CY/ATG when compared to BU/CY (OS: 97.4%±1.5%, vs. 76.2%±12.1 P=0.003 and EFS: 94.7%±2.1% vs. 76.2%±12.1%, P=0.019).

Conclusion

HSCT for children with sickle cell disease from fully match siblings offers the best outcome using myeloablative conditioning. However, significant toxicities were observed secondary to myeloablative regimens, in particular long-term complications, which demands exploring the use of less toxic regimens.