Allogeneic transplantation from HLA-matched sibling or partially HLA-mismatched related donors for primary refractory acute leukemia.

Allogeneic transplantation is successful in a minority of patients with primary refractory acute leukemia (PRAL). An HLA-matched sibling donor (MSD) is available only in 30-40% of the patients, whereas a partially mismatched related donor (PMRD) is available for most. We compared the outcome of 24 MSD (median age 24 years) and 19 PMRD (median age 34 years; P = 0.04) allograft recipients with PRAL. All MSD patients received non-T cell-depleted marrow whereas all PMRD patients received partially T cell-depleted marrow. All evaluable PMRD patients and 90% of the evaluable MSD patients attained CR. Six patients in each group with recurrent/persistent disease died. Ten PMRD (3-year probability 70%) and 14 MSD (3-year probability 63%) patients died of treatment-related causes. At the last follow-up, three PMRD (18-50 months; 3-year probability 14%) and four MSD (20-166 months; 3-year probability 20%) patients were alive and well. We conclude that allogeneic transplantation is a viable therapeutic option for PRAL. PMRD transplantation is a reasonable alternative in patients with no MSD, and results in similar outcome. In terms of identifying a donor and harvesting cells, a PMRD transplant is significantly quicker than an unrelated donor transplant - a point of great practical importance in the setting of failed induction chemotherapy where time is of the essence.