Allogeneic Stem-cell Transplantation from Related and Unrelated Donors in Older Patients with Myeloid Leukemia

Purpose: To improve outcome for older patients with poor-prognosis myeloid malignancies by using allogeneic hematopoietic stem-cell transplantation (alloHSCT) from unrelated and sibling donors after reduced-intensity conditioning (RIC).

Patients And Methods: Nineteen older patients (median age, 64 years; range, 60 to 70 years) with active myeloid malignancies were treated with an RIC regimen that was based on fludarabine, melphalan, and carmustine followed by alloHSCT from matched unrelated (n = 12) or sibling donors (n = 7). Before transplantation, patients had a median of 50% bone marrow blasts (range, 0% to 70%). Graft-versus-host-disease (GvHD) prophylaxis consisted of cyclosporine and mycophenolate mofetil or methotrexate. Eleven of 12 patients with an unrelated donor also received anti-T-lymphocyte globulin (ATG).

Results: Engraftment was successful for all 19 patients. Seventeen assessable patients achieved complete response (CR). Four patients experienced relapse; three achieved CR again after donor lymphocyte infusion (n = 1) or a second alloHSCT (n = 2). Six patients died as a result of relapse (n = 2), GvHD-associated complications (n = 2), or fungal infections (n = 2), resulting in a 1-year nonrelapse mortality rate of 22%. With a median follow-up of 825 days (range, 595 to 1,028 days), 13 of 19 patients are alive, resulting in a 1-year survival rate of 68% (95% confidence interval, 48% to 89%).

Conclusion: In older patients with untreated poor-prognosis leukemia, this RIC regimen combined with alloHSCT sufficiently reduces the leukemic burden, resulting in a high CR rate. When ATG is added, matched unrelated donor transplantation can be performed safely in older patients. For these patients, early transplantation after diagnosis offers a fair chance of cure.