Comparative analysis of calcineurin-inhibitor-based methotrexate and mycophenolate mofetil-containing regimens for prevention of Graft-versus-Host Disease after reduced intensity conditioning allogeneic transplantation

The combination of a calcineurin inhibitor (CNI) such as tacrolimus (TAC) or cyclosporine (CYSP) with methotrexate (MTX) or with mycophenolate mofetil (MMF) has been commonly used for graft-versus-host disease (GVHD) prophylaxis after reduced-intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (alloHCT), but there are limited data comparing efficacy of the 2 regimens. We evaluated 1564 adult patients who underwent RIC alloHCT for acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia (CML), and myelodysplastic syndrome (MDS) from 2000 to 2013 using HLA-identical sibling (matched related donor [MRD]) or unrelated donor (URD) peripheral blood graft and received CYSP or TAC with MTX or MMF for GVHD prophylaxis. Primary outcomes of the study were acute and chronic GVHD and overall survival (OS). The study divided the patient population into 4 cohorts based on regimen: MMF-TAC, MMF-CYSP, MTX-TAC, and MTX-CYSP. In the URD group, MMF-CYSP was associated with increased risk of grade II to IV acute GVHD (relative risk [RR], 1.78; P < .001) and grade III to IV acute GVHD (RR, 1.93; P = .006) compared with MTX-TAC. In the URD group, use of MMF-TAC (versus MTX-TAC) lead to higher nonrelapse mortality. (hazard ratio, 1.48; P = .008). In either group, no there was no difference in chronic GVHD, disease-free survival, and OS among the GVHD prophylaxis regimens. For RIC alloHCT using MRD, there are no differences in outcomes based on GVHD prophylaxis. However, with URD RIC alloHCT, MMF-CYSP was inferior to MTX-based regimens for acute GVHD prevention, but all the regimens were equivalent in terms of chronic GVHD and OS. Prospective studies, targeting URD recipients are needed to confirm these results

Impact of T Cell Dose on Outcome of T Cell-Replete HLA-Matched Allogeneic Peripheral Blood Stem Cell Transplantation

Data on whether the T cell dose of allogeneic peripheral blood stem cell (PBSC) products influences transplantation outcomes are conflicting. Using the Center for International Blood and Marrow Transplant Research database, we identified 2736 adult patients who underwent first allogeneic PBSC transplantation for acute leukemia or myelodysplastic syndrome between 2008 and 2014 using an HLA-matched sibling donor (MSD) or an 8/8-matched unrelated donor (MUD). We excluded ex vivo and in vivo T cell-depleted transplantations. Correlative analysis was performed between CD3+ T cell dose and the risk of graft-versus-host-disease (GVHD), relapse, nonrelapse mortality (NRM), disease-free survival (DFS), and overall survival (OS). Using maximum likelihood estimation, we identified CD3+ T cell dose cutoff that separated the risk of acute GVHD (aGVHD) grade II-IV in both the MSD and MUD groups. A CD3+ T cell dose cutoff of 14 × 107 cells/kg identified MSD/low CD3+ (n = 223) and MSD/high CD3+ (n = 1214), and a dose of 15 × 107 cells/kg identified MUD/low CD3+ (n = 197) and MUD/high CD3+ (n = 1102). On univariate analysis, the MSD/high CD3+ group had a higher cumulative incidence of day +100 aGVHD grade II-IV compared with the MSD/low CD3+ group (33% versus 25%; P = .009). There were no differences between the 2 groups in engraftment rate, risk of aGVHD grade III-IV or chronic GVHD (cGVHD), NRM, relapse, DFS, or OS. The MUD/high CD3+ group had a higher cumulative incidence of day +100 aGVHD grade II-IV compared with the MUD/low CD3+ group (49% versus 41%; P = .04). There were no differences between the 2 groups in engraftment rate, risk of severe aGVHD or cGVHD, NRM, relapse, DFS, or OS. Multivariate analysis of the MSD and MUD groups failed to show an association between CD3+ T cell dose and the risk of either aGVHD grade II-IV (P = .10 and .07, respectively) or cGVHD (P = .80 and .30, respectively). Subanalysis of CD4+ T cells, CD8+ T cells, and CD4+/CD8+ ratio failed to identify cutoff values predictive of transplantation outcomes; however, using the log-rank test, the sample size was suboptimal for identifying a difference at this cutoff cell dose. In this registry study, the CD3+ T cell dose of PBSC products did not influence the risk of aGVHD or cGVHD or other transplantation outcomes when using an MSD or an 8/8-matched MUD. Subset analyses of CD4+ and CD8+ T cell doses were not possible given our small sample size