Evolving Criteria for Donor Selection for Transplants in Acute Myeloid Leukemia

Background The best donor for a haematopoietic cell transplant in a person with acute myeloid leukaemia (AML) in 1st remission is controversial. Prior data indicate similar outcomes after transplants from HLA-haplotype-matched relatives, HLA-identical siblings and HLA-matched unrelated donors.

Methods We analyzed data from persons with intermediate- or high-risk AML in 1st complete remission (CR1) treated in a prospective, multi-centre study.

Results 602 consecutive subjects received a transplant from an HLA-haplotype-matched relative (N=328) or an HLA-identical sibling (N=274). 4 year leukaemia-free survivals were 78% (95% confidence interval [CI], 73, 83%) and 80% (75, 85%; P=0.39). In multivariate analyses younger donor/recipient age (donor<30y-receipient<30y) was associated with less transplant-related-mortality (TRM) (hazard ratio [HR)=0.25; [0.06, 1.00]; P=0.05) whereas female-to-male transplants (HR=1.93; [1.10, 3.38; P=0.02) and donor-recipient ABO major-mismatch transplants (HR=1.95 [1.12, 3.38; P=0.02) were correlated with higher TRM. A risk score was generated based on donor/recipient age, gender and ABO-incompatibility. The scoring system predicted TRM and survival. TRMs were 5% (3, 7%), 15% (10, 20%) and 20% (4, 36%) for subjects with scores of 0-1, 2 and 3 (trend comparison P<0.001). 4 year survivals were 85% (81, 89%), 77% (71, 83%), and 75% (59, 91%; trend comparison P=0.04).

Conclusions In contrast to the lack of impact of HLA-disparity on transplant outcomes, selection of the best donor needs to consider D/R age, sex and ABO-incompatibility combined together. Our data suggest choosing young, male, ABO match/minor-mismatch donors is reasonable. Transplants from older female-to-male and from ABO major-mismatched donors should probably be avoided.