Unrelated cord blood (UCB) transplant may yield high cure rates in children and young adults with leukemic disease, according to a study published in Biology of Blood and Marrow Transplantation.

In a French prospective, randomized study, researchers compared the 3-year overall survival, relapse risk, and disease-free survival of patients transplanted with single- or double-unit UCB.  Outcomes were also assessed based on patients’ pretransplant minimum residual disease (MRD) levels.

Each transplant group (single-UCB and double-UCB) was divided according to MRD level. In the single-UCB group, 24 patients were MRD+ and 32 patients were MRD-; in the double-UCB group, 19 patients were MRD+ and 40 patients were MRD-. Of 115 patients who had MRD assessment before their conditioning regimen, 72 (63%) were MRD- (defined as less than 10-4). All patients were younger than 35 years old, and among the groups, gender was balanced.

The overall survival probability was 69.1 ± 4.4% and was not affected by pretransplant MRD level: 70.7 ± 5.4% in MRD- patients, 71.1 ± 9.4% in MRD+ patients where MRD was between 10-4 and 10-3, and 58.8 ± 11.9% in MRD+ patients where MRD was at least 10-3 patients.

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Patients who were MRD+ and had not received antithymocyte globulin during their conditioning regimen had significantly lower risk of relapse (0% vs 35.3 ± 12.1%, P =.019), higher disease-free survival (91.7 ± 8% vs 56.6 ± 12.7%, P =.025), and higher overall survival (91.7 ± 8% vs 57.8 ± 12.2%, P =.027) when receiving double-unit compared with single-unit treatment.

For patients who were MRD-, no differences were found between the single- and double-unit treatments.

The authors concluded that “even in case of positive pretransplant MRD, UCB transplantation in children and young adults with acute leukemia results in a high cure rate and that a double-unit strategy may enhance graft-vs-leukemia effect and survival in these patients.”

Reference

1. Balligand L, Galambrun C, Sirvent A, et al. Single-unit versus double-unit umbilical cord blood transplantation in children and young adults with residual leukemic disease [published online October 29, 2018]. Biol Blood Marrow Transplant. doi: 10.1016/j.bbmt.2018.10.016