Matched sibling donor stem cell transplantation for sickle cell disease: results from the Spanish Group for Bone Marrow Transplantation in Children.

OBJECTIVES The prevalence of sickle cell disease (SCD) in Spain is markedly inferior compared with other European and Mediterranean countries. However, the diagnosis of new patients with SCD is expected to increase. In this multicenter retrospective study we analyze the HSCT results obtained in Spain. METHODS Forty-five patients who underwent a matched sibling donor (MSD) HSCT between 1999 and 2018 were included. Primary endpoint was event-free survival (EFS) and secondary endpoints included acute and chronic graft versus host disease (GVHD) and overall survival (OS). RESULTS Bone marrow was the most frequent stem cell source (93.3%). Most patients received a conditioning regimen based on busulfan and cyclophosphamide (69%). Cumulative incidence of grade III-IV acute GvHD and chronic GvHD were 6.8% (95%CI 2.3%-20.1%) and 5.4% (CI95% 1.38-19-9%), respectively. EFS and overall survival OS at 3 years post HSCT were 89.4% (95%CI 73.9%-95.9%) and 92.1% (95%CI 77.2-97.4%), respectively. All patients aged ≤5 presented 100% EFS and OS. CONCLUSIONS An early referral to HSCT centers should be proposed early in life, before severe complications occur. MSD HSCT should be considered a curative option for all patients aged ≤5 years old and for older pediatric patients who present complications derived from the disease.