Unrelated cord blood (UCB) transplant can result in comparable outcomes as matched sibling (MS) donor transplant in adults with B-cell acute lymphoblastic leukemia (B-ALL), according to a retrospective study published in Stem Cell Research & Therapy.

Patients who underwent allogeneic hematopoietic stem cell transplant (HSCT) with UCB had similar relapse rates, relapse-free survival, and overall survival as patients who underwent MS donor HSCT.

This single-center, retrospective study included data from 156 adult patients with B-ALL who underwent HSCT between 2006 and 2020. All patients were in complete remission prior to their transplant.


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At the time of transplant, the median age was 25 years in the UCB group and 34 years in the MS group (P =.002). Conditioning regimens were similar between the groups, with the majority of patients receiving busulfan plus cyclophosphamide or total body irradiation plus cyclophosphamide.

Patients who underwent an MS donor HSCT had faster hematopoietic recovery than patients who underwent UCB HSCT. By day 42, neutrophil engraftment had occurred in 96.5% of patients in the UCB group and 100% of those in the MS group (P <.001). The median time to neutrophil engraftment was 18 days and 11 days, respectively. Platelet engraftment occurred in 86.3% of patients in the UCB group and 100% of those in the MS group (P <.001). The median time to platelet engraftment was 38.5 days and 14 days, respectively.

Overall survival was similar between the groups during the first 700 days (P =.842), but it was longer after 700 days among patients who received UCB transplant (hazard ratio, 7.40; 95% CI, 1.12-48.93; P =.04). Other factors associated with longer survival after 700 days included first compete response and use of a busulfan-containing conditioning regimen.

The 2-year cumulative incidence of non-relapse mortality was 18.7% in the UCB group and 16.3% in the MS group (P =.67). The cumulative incidence of relapse at 2 years was 17.0% and 23.8%, respectively (P =.35). The 5-year disease-free survival (P =.82) and 5-year graft vs host disease (GVHD)-free relapse-free survival (P =.99) were also similar regardless of donor source.

Acute GVHD occurred more frequently in the UCB group than in the MS group. Grade II-IV acute GVHD occurred in 28.3% of patients in the UCB group and 2.3% of those in the MS group (P <.001). Grade III-IV acute GVHD occurred in 14.2% and 2.3%, respectively (P =.03).

The 2-year cumulative incidence of extensive chronic GVHD was higher in the MS group than in the UCB group — 35.3% and 8.0%, respectively (P <.001).

“Our study shows that when treating adult B-ALL patients in complete response, UCB transplant can achieve comparable effects as MS transplant, may provide superior overall survival for patients with long-term survival, and should be considered a good alternative,” the study authors concluded.

Reference

Sun G, Tang B, Song K, et al. Unrelated cord blood transplantation vs. HLA‑matched sibling transplantation for adults with B‑cell acute lymphoblastic leukemia in complete remission: superior OS for patients with long‑term survival. Stem Cell Res Ther. 2022;13:500. doi: 10.1186/s13287-022-03186-3

This article originally appeared on Hematology Advisor