Haploidentical Donor Transplantation Is Not Inferior to Identical Sibling Donor for Patients with Chronic Myeloid Leukemia in Blast Crisis

Objectives: Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative therapy for patients with chronic myeloid leukemia (CML) in blast crisis (BC). Haploidentical donors (HID) are immediately available for almost all of them. We compare the outcomes of HID transplantation with those of matched related donor (MRD) transplantation in cohort study.

Methods: We studied 90 T-replete HID (n=67) and MRD (n=23) HSCT for CML-BC patients in our center from Jan 1^st, 2001 to September 30, 2013. After transplantation, patients received tapering immunosupressant or TKI or donor lymphocyte infusion (DLI) or combined therapy as intervention based on BCR-ABL levels.

Results: Of the 86 engrafted patients, 30 received intervention after transplantation. The 1-year cumulative incidence of intervention in HID transplants was significantly lower than in MRD transplants, 24.7% vs. 56.5% (P=.002). At 3 years, overall survival (OS) was similar (60.0% vs. 53.3%), 3-year event-free survival (EFS) higher (35.8% vs. 13.0%; P=.002) in HID transplants. Three-year incidences of transplant related mortality (TRM) and relapse did not significantly differ.

Conclusions: HID transplantation achieves comparable OS with less post-transplant intervention, which is not inferior to MRD in CML-BC patients, and might be regular donors for those who need urgent transplantation.