Outcomes of Hematopoietic Cell Transplantation in Acute Promyelocytic Leukemia – a Single Institution Experience.

Outcomes of patients with acute promyelocytic leukemia (APL) have improved; however, a significant number of patients still relapse despite receiving all-trans-retinoic acid (ATRA) and arsenic-based therapies. We present single institution outcomes of autologous (auto) and allogenic (allo) hematopoietic cell transplantation (HCT) in patients with relapsed APL. Outcomes in patients with relapsed APL who underwent either auto- or allo- HCT at Moffitt Cancer Center from 1990 to 2018 were reviewed utilizing the clinical data obtained from BMT Research & Analysis Information Network (BRAIN). Survival data were analyzed using Kaplan-Meier estimates. Autologous HCT Cohort: A total of 15 received auto-HCT with a median age at HCT of 39 (range, 21-60) years. Only 3/8 patients with known disease risk at time of diagnosis had high risk disease (high=3, low=5). Disease status at HCT were first complete remission (CR1) in 5 (33%) and CR2 in 10 (67%). All 8 patients who had minimal residual disease evaluation had negative PCR for PML-RARA. The median progression-free survival (PFS) for auto HCT was 12.9 (95% confidence interval (CI): 1.2-24.8) years. With a median follow up of 45.1 months for surviving patients, overall survival (OS) for auto HCT was 12.9 (95%CI: 0-27.8) years. A total of 9 patients received allo HCT with a median age at HCT of 43 (range, 22-56) years. All six patients with known disease risk at time of diagnosis were either intermediate (n=2) or high risk disease (n=4). Disease status at allo HCT was CR2 in 1, CR3 in 6, and two had refractory disease. Two patients had prior auto HCT. 5/6 patients who had minimal residual disease evaluation had negative PCR for PML-RARA. Donor type was HLA-identical sibling=5; one antigen-mismatched sibling=1; HLA-matched unrelated donor=2; related haploidentical=1. Conditioning regimen intensity was myeloablative in six and reduced intensity in three of the patients. Six patients received tacrolimus-based graft-versus-host disease (GVHD) prophylaxis. The median PFS for allo HCT was 11.9 (95%CI: 0-24.1) months. With a median follow up of 48.2 months for surviving patients, OS for allo HCT was 14.2 (95%CI: 6.5-21.9) months. In our single center analysis, auto HCT resulted in a durable remission and prolonged survival. Outcomes after allo HCT were suboptimal primarily due to their heavily pretreated condition and chemotherapy resistant disease. [ABSTRACT FROM AUTHOR]