Non-myeloablative hematopoietic stem cell transplantation (NST) in the treatment of human malignancies: from animal models to clinical practice

The impact of HLA-matching on reduced intensity conditioning regimen unrelated donor allogeneic stem cell transplantation for acute myeloid leukemia in patients above 50 years-a report from the EBMT acute leukemia working party

Background

Data comparing fully matched and mismatched-unrelated-donor (M- and mM-URD) allogeneic hematopoietic stem cell transplant (allo-SCT) following reduced intensity conditioning regimens for acute myeloid leukemia are limited.

Methods

We retrospectively compared the outcome of 3398 patients above the age of 50 years who underwent 10/10 M-URD (n = 2567), 9/10 (n = 723), or 8/10 (n = 108) mM-URD allo-SCT for acute myeloid leukemia after reduced intensity conditioning regimen between 2000 and 2013. The Kaplan-Meier estimator, the cumulative incidence function, and Cox proportional hazards regression models were used where appropriate.

Results

HLA matching had no impact on engraftment (p = 0.31). In univariate analysis, in comparison to 10/10 M-URD, mM-URD was associated with higher incidence of grade II–IV acute graft-versus-host disease (GVHD) (p = 0.0002), similar rates of chronic GVHD (p = 0.138) but increased incidence of its extensive form (p = 0.047). Compared to 10/10 M-URD, patients transplanted in the first complete remission (CR1) with a 9 or an 8/10 mM-URD had decreased 2-year leukemia free (LFS) (p = 0.005) and overall survivals (OS) (56.7, 46.1, and 50.2 %, respectively, p = 0.005), while outcomes were comparable between all groups for patients transplanted beyond CR1. In multivariate analysis, 9/10 versus 10/10 URD was associated with higher non-relapse mortality (HR 1.34, p = 0.001), similar risk of relapse and chronic GVHD and inferior LFS (HR 1.25, p = 0.0001), and OS (HR 1.27, p = 0.0001). There was no difference in adjusted transplant outcomes between 9/10 and 8/10 mM-URD.

Conclusions

Reduced intensity conditioned allo-SCT with a 10/10 M-URD remains the preferable option for AML patients above the age of 50 years. The use of a 9/10 or an 8/10 mM-URD in patients not having a fully matched donor represents an alternative therapeutic option that should be compared to other alternative donor transplant strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0295-9) contains supplementary material, which is available to authorized users.

WT1-specific CTL cells of recipient origin may exist in the peripheral blood of patients achieving full donor chimerism soon after nonmyeloablative transplantation

This study was performed to assay whether leukemia-associated antigen (LAA)-specific CTLs of recipient origin existed in the blood of patients who achieved full donor chimerism (FDC) soon after nonmyeloablative transplantation (NST). In 15 patients who received haplo-identical NST, WT1(+) CD8(+) CTLs were detected with WT1/HLA-A*0201 pentamer, and the donor-recipient chimerism levels were analyzed by three methods. Results showed that WT1(+) CD8(+) CTLs could be detected in patients with HLA-A*0201 expressing only in recipient, and cells of recipient origin existed in the blood of patients who achieved FDC, which suggested that LAA-specific CTLs of recipient origin may exist in patients achieving FDC soon after NST.

Results of genoidentical hemopoietic stem cell transplantation with reduced intensity conditioning for acute myelocytic leukemia: higher doses of stem cells infused benefit patients receiving transplants in second remission or beyond--the Acute Leukemia Working Party of the European Cooperative Group for Blood and Marrow Transplantation

PURPOSE

Nucleated cell dose is an important and modifiable factor in hematopoietic stem cell transplantation (HSCT), however its association with outcomes in the context of reduced intensity conditioning regimen (RIC) HSCT for adults with acute myelocytic leukemia (AML) is not known.

PATIENTS AND METHODS

From 1998 to 2003, 253 patients with de novo AML, received transplants with RIC and peripheral blood from a genoidentical donor. Median age was 55 years (range, 18 to 72) and the median follow-up was 17 months (range, 2 to 67). One hundred forty one patients received transplants in first remission (CR1), 47 received transplants in second remission (CR2), and 65 patients received transplants in a more advanced phase. Fludarabin-based RIC was used in 91% of patients and low-dose (< 4 Gy) total-body radiation in 23% of patients. The median nucleated and CD34 cell dose infused were 9.1x 10(8)/kg and 5.8x 10(6)/kg, respectively.

RESULTS

Overall, 2-year leukemia-free survival (LFS) was 41% +/- 4% and it was 46% +/- 5% for patients receiving a higher cell dose (> 9.1x 10(8)/kg) and 37% +/- 5% for the remainders (P = .03). Higher cell doses exclusively benefited patients who received transplantations in CR2 or beyond, with LFS of 47 +/- 8 versus 20 +/- 8, with no detectable effect for patients who received transplants in CR1. In a multivariate analysis of the overall patient population, higher nucleated cell dose cells were associated with higher LFS (P = .04), higher incidence of chronic graft-versus-host disease (P = .01), and there was a trend towards a lower relapse incidence (P = .06). Interestingly, CD34+ cell dose was not associated with any outcomes.

CONCLUSION

Nucleated cell dose is an important factor that can be modified to improve results of RIC for patients with AML transplanted later than in CR1.

Comparative outcome of reduced intensity and myeloablative conditioning regimen in HLA identical sibling allogeneic haematopoietic stem cell transplantation for patients older than 50 years of age with acute myeloblastic leukaemia: a retrospective survey from the Acute Leukemia Working Party (ALWP) of the European group for Blood and Marrow Transplantation (EBMT)

Results of reduced intensity conditioning regimen (RIC) in the HLA identical haematopoietic stem cell transplantation (HSCT) setting have not been compared to those after myeloablative (MA) regimen HSCT in patients with acute myeloblastic leukaemia (AML) over 50 years of age. With this aim, outcomes of 315 RIC were compared with 407 MA HSCT recipients. The majority of RIC was fludarabine-based regimen associated to busulphan (BU) (53%) or low-dose total body irradiation (24%). Multivariate analyses of outcomes were used adjusting for differences between both groups. The median follow-up was 13 months. Cytogenetics, FAB classification, WBC count at diagnosis and status of the disease at transplant were not statistically different between the two groups. However, RIC patients were older, transplanted more recently, and more frequently with peripheral blood allogeneic stem cells as compared to MA recipients. In multivariate analysis, acute GVHD (II-IV) and transplant-related mortality were significantly decreased (P=0.01 and P<10(-4), respectively) and relapse incidence was significantly higher (P=0.003) after RIC transplantation. Leukaemia-free survival was not statistically different between the two groups. These results may set the grounds for prospective trials comparing RIC with other strategies of treatment in elderly AML.

Pathogenesis and treatment of graft-versus-host disease after bone marrow transplant

Stem cell transplantation is being used to treat a number of hematologic malignancies as well as hematologic and immune deficiency states. The ages of patients being offered this therapy and the donor marrow sources have been expanded. One persistent problem has been graft-versus-host disease (GVHD). This article reviews the basic biology of GVHD, clinical manifestations of acute and chronic GVHD, prophylaxis and treatment of acute GVHD, and treatment of chronic GVHD.