Pretransplantation 5-azacitidine in high-risk myelodysplastic syndrome.

We prospectively evaluated the allogeneic hematopoietic cell transplantation (HCT) outcomes in high-risk myelodysplastic syndrome (MDS) patients who received pretransplantation 5-azacitidine. Twenty-five patients evaluated for allogeneic HCT consult and considered medically eligible for a donor search were enrolled. Azacitidine was administered at 75 mg/m(2) for 5 to 7 days every 4 weeks until a suitable donor was found. A median of 3 (range, 0 to 6) cycles of 5-azacitidine were administered. Preallogeneic HCT responses to 5-azacitidine, based on the International Working Group criteria, were 48% partial response, 33% stable disease, and 19% progressive disease. Four patients did not proceed to allogeneic HCT. Twenty-one patients, a median age of 55 (range, 25 to 67) years, received allogeneic HCT after myeloablative pharmacokinetically targeted i.v. busulfan and fludarabine conditioning regimen. Donors were either HLA-matched related or unrelated, except for 1 mismatch unrelated donor. With a median follow-up of 30 months, 1-year relapse-free and overall survivals were 52% (95% confidence interval [CI], 30% to 71%) and 62% (95% CI, 38% to 79%), respectively. Preallogeneic HCT 5-azacitidine administration was well tolerated and provided reasonable disease control before allogeneic HCT. (Registered at ClinicalTrials.gov as NCT00660400).