The source of donor cells for haematopoietic stem cell transplants (HSCT) in children with AML does not appear to affect relapse rates, leukaemia-free survival or overall survival.
An international study of 317 children who received HSCT between 2005 and 2015 at one of eight institutions including the Kids Cancer Centre in Sydney, found there were alternatives to the standard matched sibling donor (MSD).
In the 24 Australian patients in the study, 11 received cells from umbilical cord blood (UCB), eight from a MSD, four from double umbilical cord blood (dUCB) and one from a matched unrelated donor (MUD).
The study found all sibling recipients were fully HLA matched to their donor versus 92% of MUD recipients, 29% of single UCB recipients and 18% of dUCBs.
The median follow-up on the patients was almost five years from HSCT.
Overall the likelihood of a leukaemia relapse was 22% and the adjusted leukaemia-free survival was 57% with no difference between the groups based on the source of stem cells.
Overall survival across the full cohort was 63%.
“MSD recipients fared equally well when compared with MUD and UCB, but had a superior survival compared with dUCB,” the study authors wrote in the journal Blood Advances.
However they said survival does not completely describe a successful post-HSCT outcome.
Acute graft versus host disease (aGVHD) was lowest in recipients of MSD grafts (24%) compared to 43% for MUD, 52% for UCB and 56% for dUCB.
Chronic GVHD-free leukaemia free survival – a composite endpoint incorporating quality of life – was 44% with MSD, 49% with UCB, 44% with dUCB and a poorer 29% with MUD.
“Our multicentre retrospective analysis also showed no difference in relapse rates among the various donor sources. This may reflect transplant in an era in which donor source has less of an effect either because of changing indications for allogeneic transplant in AML, or more recently, because MRD-based timing of transplantation likely affects relapse rates.”
“Although other endpoints (LFS, OS and engraftment rates) were equivalent among the various cell sources, the cGVHD-LFS endpoint better reflects the optimal post-HSCT outcome. According to these results, UCB is an excellent alternative cell source if an MSD is lacking.”