Allogeneic Hematopoietic Cell Transplantation (HCT) for Acute Leukemia in First Relapse or Second Remission.

Allogeneic HCT offers the best chance for long-term survival in patients with acute leukemia after first relapse. A difficult clinical decision for a patient suffering leukemic relapse who has a histocompatible donor is whether to attempt re-induction therapy or proceed directly to HCT. Sixty-five patients with acute leukemia in first relapse or second remission were treated with allogeneic HCT at 3 institutes in Seoul, Korea between Jan 1995 and Sep 2004. We analyzed their post-transplant outcomes and investigated the role of salvage chemotherapy aimed at re-induction of remission before allogeneic HCT. Forty patients received hematopoietic cell graft from a sibling donor, 21 from an unrelated donor, and 2 from a haplo-identical family donor, and 2 received cord blood. Thirteen patients received TBI-based conditioning regimen and 10 received reduced-intensity conditioning regimen. There occurred 34 relapses with 51.3% of 5-y cumulative incidence of relapse (CIR) and there were 22 non-relapse deaths with 34.7% of non-relapse mortality. Probabilities of overall survival and disease-free survival were 20.6% and 14.0% at 5-y, respectively. Multivariate analysis by Gray method for CIR revealed that patients with unfavorable cytogenetics (Philadelphia chromosome-positive or complex karyotype) and those not in remission at the time of HCT had significantly higher CIR (P=0.023 and P=0.031, respectively). Fourteen patients underwent allogeneic HCT after first relapse without salvage chemotherapy aimed at re-induction of remission (“untreated relapse”), 15 patients failed in attempts aimed at re-induction of remission before HCT (“refractory relapse”), and 36 patients attained second remission with salvage chemotherapy before HCT (“second remission”). 5-y CIR for “untreated relapse” (57.1%) was higher than that for “second remission” (42.3%), but lower than that for “refractory relapse” (66.7%). Among patients transplanted in relapse, those with BM blasts ≤ 30% seemed to have lower 5-y CIR than patients in florid relapse (BM blasts > 30%) (57.7% vs. 70.6%). These results do not support the role of salvage chemotherapy aimed at re-induction of remission before allogeneic HCT in patients with acute leukemia after first relapse. At least the patients with early relapse do not appear to receive benefit from salvage chemotherapy before HCT.