The effect of intensity of conditioning regimen on the outcome of HSCT in children with sickle cell disease

Abstract

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) provides a cure for patients with sickle cell disease (SCD). This study describes the effect of conditioning regimen intensity on HSCT outcomes among children younger than 14 years with SCD. Methods:Transplants from HLA-matched related donors (MRD) and unrelated donors (MUD) using either myeloablative conditioning (MAC) regimens or reduced intensity conditioning (RIC) regimens were considered. Event-free survival (EFS) was the primary endpoint. Secondary endpoints included overall survival (OS) and occurrence of GVHD.Results: 48 SCD patients underwent HSCT, 45 (93.8%) patients had MRD, 1 (2.1%) had 9/10 related donor, and 2 (4.1%) had MUD. The median age at transplant was 8.6 years (range, 3.1-13.8). Conditioning regimens were myeloablative (MAC) in 41 (85.4%) patients and of reduced intensity in 7 (14.6%) patients. EFS at 2 years was 100% among MAC group compared to 29% in the RIC group (p < .001). The median follow-up was 43.4 months (range 26.8-134). All events in the RIC group were secondary graft failure. However, OS was 100% in both groups at 2 years. Acute GVHD II-IV was diagnosed in 2 (4.1%) patients. Chronic GVHD occurred in 2 (4.1%) patients.GVHD did not occur in patients who underwent MUD HSCT.Conclusions: MAC in children with SCD is well tolerated and associated with an excellent outcome for HLA-matched HSCT in SCD. There was a high rate of secondary graft failure with the use of RIC. Future studies are needed to optimize RIC regimens in HSCT of children with SCD.

Comparing between HLA‐matched sibling donor allogenic HSCT and non‐sibling matched related donor allogenic HSCT outcome in pediatric patients; single center retrospective study

“…The median neutrophil engraftment was 19 (11–44) days in the NS‐MRD group and 20 (11–36) days in the MSD group. One patient in each group with sickle cell anemia had primary graft failure whom received (RIC) regimen: Fludarabine, Melphalan, and ATG per local clinical trial 16 . One patient in the MSD group underwent second transplant and did very well.…”

“…One patient in each group with sickle cell anemia had primary graft failure whom received (RIC) regimen: Fludarabine, Melphalan, and ATG per local clinical trial. 16 (SCID) who did not receive conditioning in the NS-MRD group also had graft failure. Mixed chimerism, defined as donor cells<90% was seen in less than 30% of the group; however, all of them are stable and the patients remain disease free.…”