ABSTRACT
The optimal myeloablative conditioning (MAC) for patients undergoing haploidentical hematopoietic cell transplantation (haplo-HCT) is unknown. We studied the outcomes of total body irradiation (TBI) vs chemotherapy (CT) based MAC regimens in acute myeloid leukemia (AML) patients. The study included 1008 patients who underwent first haplo-HCT with post-transplant cyclophosphamide, following TBI (N = 89, 9%) or CT (n = 919, 91%) based MAC. Patients in the TBI cohort were younger (median age, 38 vs 47 years, P < .01) and more likely to receive BM graft (57% vs 43%, P = .01). Two-year overall chronic GVHD (cGVHD) incidence was 42% vs 27% (P < .01) and extensive cGVHD incidence was 9% vs 12% (P = .33) in TBI and CT cohorts, respectively. Graft failure was reported in two (2%) TBI- and 65 (7%) CT-MAC recipients (P = .08). Death from veno-occlusive disease was reported in one (3%) TBI and 11 (3%) CT patients who died during the study period. In the multivariate analysis, TBI was associated with increased risk for overall cGVHD (hazard ratio = 1.95, 95% confidence interval:1.2-3.1, P < .01) compared to CT-based MAC. The choice of conditioning regimen did not impact relapse incidence, leukemia-free survival, non-relapse mortality, overall survival or GVHD-relapse-free survival in multivariate analysis. In conclusion, major transplant outcomes were not statistically different between TBI-based MAC and CT-based MAC in patients with AML after haplo-HCT/PTCy.
ABSTRACT
Allogeneic hematopoietic cell transplantation (HCT) is recommended in high-risk patients with T cell acute lymphoblastic leukemia (T-ALL). For patients without an HLA-identical donor, haploidentical (haplo-) HCT is becoming the leading source of stem cell donation. However, data are scarce on predictive factors for outcome in that setting. We identified 122 adults (20% female; median age, 31 years; range, 18 to 68 years) with T-ALL who underwent haplo-HCT with post-transplantation cyclophosphamide (ptCy) between 2010 and 2017. The median duration of follow-up of living patients was 23 months. The 2-year incidences of relapse and nonrelapse mortality were 45% and 21%, respectively. The 2-year leukemia-free survival (LFS), overall survival (OS), and graft-versus-host disease, relapse-free survival (GRFS) were 34%, 42%, and 27%, respectively. The 2-year LFS and OS were highly influenced by disease status at transplantation, being 49% and 55%, respectively, for patients in first complete remission (CR1); 34% and 50%, respectively, for those in second CR (CR2); and 8% and 12%, respectively, for patients with active disease. On multivariate analysis, only disease status was found to affect LFS and OS. Transplantation in CR2 negatively affected LFS, whereas active disease at the time of haplo-HCT negatively affected LFS and OS. In conclusion, haplo-HCT with ptCy produced encouraging results in this challenging disease, particularly when performed in patients in CR. Despite the limitation of the small sample size, our results were not affected by the type of conditioning, calling into question the need for total body irradiation-based myeloablative conditioning in that setting.
