ABSTRACT
In our single-center study, 357 myeloma and lymphoma patients between 2009 and 2019 were mobilized with granulocyte colony-stimulating factor (G-CSF 7.5 µg/kg bid for four days) plus a fixed dose of 24 mg Plerixafor when indicated (Plerixafor Group, n = 187) or G-CSF alone (G-CSF Group, n = 170). The target CD34 cell yields were ≥2.0 × 106 CD34+ cells/kg in lymphoma and ≥4.0 × 106 CD34+ cells/kg in myeloma patients to enable putative second transplants in the latter. There were no significant differences in engraftment kinetics or transfusion requirements between the Plerixafor Group and the control group in the myeloma cohort, with lymphoma patients not requiring Plerixafor showing significantly faster neutrophil recovery, a trend to faster platelet recovery, and a significantly lower need for platelet transfusions, probably due to the significantly lower number of CD34-positive cells re-transfused. While in myeloma patients the outcome (overall survival, progression-free survival) following autologous stem cell transplantation (ASCT) was similar between the Plerixafor Group and the control group, hard to mobilize lymphoma patients had significantly poorer progression-free survival (47% vs. 74% at 36 months after ASCT, p = 0.003) with a trend also to poorer overall survival (71% vs. 84%). In conclusion, while there seem to be no differences in stemness capacity and long-term engraftment efficiency between the Plerixafor and the G-CSF Group in lymphoma as well as myeloma patients, poor mobilizing lymphoma patients per se constitute a high-risk population with a poorer outcome after ASCT. Whether disease characteristics and/or a more intense or stem cell-toxic pre-mobilization chemo-/radiotherapy burden in this cohort are responsible for this observation remains to be shown in future studies.
ABSTRACT
Acute lymphoblastic leukemia (ALL) is a rare hematological malignancy characterized by proliferation and accumulation of premature lymphoid blasts. Depending on risk factors, the survival of acute lymphoblastic leukemia has significantly improved over the last decades. During the last years, measurable residual disease (MRD) assessment has evolved into one of the most sensitive markers for prognosis and risk of relapse. For this reason, measurable residual disease detection and monitoring count as standard evaluation in patients with acute lymphoblastic leukemia. Allogeneic stem cell transplantation is still the recommended treatment option for patients with high and highest risk profiles as well as for relapsed or refractory settings. The increased understanding of the pathomechanism and heterogeneity of acute lymphoblastic leukemia has led to the development of several novel therapeutic opportunities such as tyrosine-kinase inhibitors, antibody-based therapies and CAR-T cells with the aim of improving clinical outcomes. Furthermore, the major advances in disease understanding of ALL have led to the identification of different subgroups and better disease stratification. Even though novel therapy targets are constantly developed, acute lymphoblastic leukemia remains a challenging and life-threatening disease. To improve the historically unsatisfying result in therapy of adult acute lymphoblastic leukemia many clinical trials have recently been initiated to determine the optimum combination regimens of novel and old agents for adult acute lymphoblastic leukemia.
ABSTRACT
The contribution of natural killer (NK) cells to graft-versus-malignancy (GVM) effects following hematopoietic stem cell transplantation (HSCT) remains uncertain, particularly in the HLA-identical setting. A model considering missing HLA ligands to the donor's inhibitory killer cell immunoglobulin-like receptor (KIR), termed the missing KIR ligand model, has been established in T cell depleted bone marrow transplantation (BMT), but lacks validity in other cohorts with different treatment characteristics. We hypothesized that the impact of missing KIR ligands on relapse-free survival (RFS) and overall survival (OS) in T cell replete peripheral blood SCT (PBSCT) differs from that in the T cell depleted BMT setting, and retrospectively evaluated 100 consecutive, HLA-identical sibling transplantations for hematologic malignancies. In addition to KIR ligand status, we considered the donors' activating KIRs and grafted NK, T, and CD34(+) cell doses. Our findings demonstrate noninferiority for OS (P = .005) and RFS (P = .002) for the heterozygous HLA-C group KIR ligand status (C1/2; n = 47) compared with patients missing either C1 or C2 (n = 53). Similarly, OS (P = .031) and RFS (P = .034) of Bw4-positive patients was noninferior to that of patients missing a Bw4 ligand to KIR3DL1. By multivariate analysis, C1/2 heterozygous patients had a favorable risk ratio (RR) for relapse (RR = 0.28; P = .003), RFS (RR = 0.56; P = .046), and acute graft-versus-host disease grade II-IV (RR = 0.36; P = .05). Following reduced-intensity conditioning (RIC), but not standard-intensity conditioning, myeloablative (MA) transplantation, a grafted NK cell dose above the median (3.4 x 10(7)/kg) was associated with a lower risk of relapse (RR = 0.57; P = .003) and improved survival (RR = 0.78; P = .03). Overall, our findings support a role for NK alloreactivity in HLA-identical HSCT, but argue against a favorable impact of missing KIR ligands in the given setting. We conclude that the mechanism favoring the missing KIR ligand constellation in T cell depleted BMT may not operate in T cell replete PBSCT. The reasons for this differential effect remain unresolved.
