Early versus Late Preemptive Allogeneic Hematopoietic Cell Transplantation for Relapsed or Refractory Acute Myeloid Leukemia

Many patients with relapsed or refractory acute myeloid leukemia (AML) do not receive allogeneic hematopoietic cell transplantation (alloHCT) because they are unable to achieve a complete remission (CR) after reinduction chemotherapy. Starting in January 2003, we prospectively assigned patients with AML with high-risk clinical features to preemptive alloHCT (p-alloHCT) as soon as possible after reinduction chemotherapy. High-risk clinical features were associated with poor response to chemotherapy: primary induction failure, second or greater relapse, and first CR interval <6 months. We hypothesized that any residual disease would be maximally reduced at the time of transplant, resulting in the best milieu and most lead time for developing a graft-versus-leukemia effect and in improved long-term overall survival (OS) without excess toxicity. This analysis studied the effect of transplant timing on p-alloHCT in 30 patients with high-risk clinical features of 156 consecutive AML patients referred for alloHCT. We compared early p-alloHCT within 4 weeks of reinduction chemotherapy before count recovery with late p-alloHCT 4 weeks after reinduction chemotherapy with count recovery. OS and progression-free survival (PFS) at 2 years were not significantly different for early versus late p-alloHCT (OS 23% versus 33%, respectively, P > .1; PFS 18% versus 22%, respectively, P > .1). Day 100 and 1-year transplant-related mortality were similar (33.3% versus 22.2%, P > .1; 44.4% versus 42.9%, P > .1, respectively). Preemptive alloHCT allowed 30 patients to be transplanted who would normally not receive alloHCT. Clinical outcomes for early p-alloHCT are similar to those for late p-alloHCT without excess toxicity. Early p-alloHCT is a feasible alternative to late p-alloHCT for maximizing therapy of AML that is poorly responsive to induction chemotherapy.