OUTCOMES OF UCB TRANSPLANTATION ARE COMPARABLE IN FLT3+ AML: RESULTS OF CIBMTR, EUROCORD AND EBMT COLLABORATIVE ANALYSIS

Allogeneic hematopoietic cell transplantation (HCT) from siblings or unrelated donors (URD) during complete remission (CR) may improve leukemia-free survival (LFS) in FLT3+ acute myeloid leukemia (AML) that has poor prognosis due to high relapse rates. Umbilical cord blood (UCB) HCT outcomes are largely unknown in this population. We found that compared with sibling HCT, relapse risks were similar after UCB (n=126), (HR 0.86, p=0.54) and URD (n=91) (HR 0.81, p=0.43). UCB HCT was associated with statistically higher non-relapse mortality compared with sibling HCT (HR 2.32, p=0.02), but not vs. URD (HR 1.72, p=0.07). All three cohorts had statistically not significant 3-year LFS: 39% (95% CI 30–47) after UCB, 43% (95% CI 30–54) after sibling, and 50% (95% CI 40–60) after URD. Chronic GVHD rates were significantly lower after UCB compared with either sibling (HR 0.59, p=0.03) or URD (HR 0.49, p=0.001). Adverse factors for LFS included high leukocyte count at diagnosis and HCT during CR2. UCB is a suitable option for adults with FLT3+AML in the absence of an HLA-matched sibling and its immediate availability may be particularly important for FLT3+ AML where early relapse is common thus allowing HCT in CR1 when outcomes are best.