Donor Type Did Not Influence Transplant Outcome in High-Risk Pediatric ALL

Receipt of stem cell transplantation from an HLA-genoidentical sibling or from an HLA-matched unrelated donor did not significantly affect outcomes among a group of high-risk pediatric patients with acute lymphoblastic leukemia (ALL) from the ALL-SCT-BFM-2003 Trial, study results showed.

In fact, the 4-year event-free survival and relapse incidence were both similar among patients with either sibling or unrelated donors.

“Our data demonstrate excellent event-free survival and overall survival, and low incidence of relapse in children with high-risk ALL after treatment with total body irradiation and etoposide before allogeneic HSCT from HLA-matched siblings or well-matched unrelated donors,” wrote Christina Peters, MD, from St. Anna Children’s Hospital, and colleagues in the Journal of Clinical Oncology.

Peters and colleagues examined the outcomes of 411 children with high-risk ALL who underwent stem cell transplantation in the ALL-SCT-BFM-2003 trial. All patients underwent total-body irradiation and treatment with etoposide. Donors were either HLA-genoidentical siblings (n = 105) or HLA-matched unrelated donors (n = 306) compatible with at least 9 of 10 HLA loci.

No differences were found between the two groups of transplant patients for the 4-year event free survival rate (unrelated 0.67 vs sibling 0.71) or relapse incidence (4-year cumulative incidence, 0.22 for unrelated vs 0.02 for sibling donors). In addition, no differences in event-free survival, overall survival, or relapse incidence was seen between patients with unrelated donors with 9 out of 10 or 10 out of 10 HLA matches.

“Furthermore, no significant differences in outcomes were observed between patients with various degrees of acute GVHD or chronic GVHD,” the researchers wrote. “These data demonstrate that long-term relapse-free survival after HLA-matched unrelated donor-HSCT can be achieved without a high incidence of chronic GVHD, which is a devastating disease for children and adolescents.”

The researchers did find a significant difference in non-relapse mortality at 4 years in favor of the sibling donors (0.10 vs 0.03; P = .017).

“Despite excellent outcomes of HLA-matched unrelated donors-HSCT, our data indicate that matched sibling donors bone marrow transplantation remains superior, which is possibly a result of faster engraftment and more rapid immune reconstitution resulting in fewer severe infections,” the researchers wrote.

However, they still concluded that “HLA-matched unrelated-HSCT could be a standard of care for patients with ALL who have a high risk of relapse and who lack matched sibling donors.”