Reduced incidence of GVHD without increase in relapse with low-dose rabbit ATG in the preparative regimen for unrelated bone marrow transplants in CML

Outcomes of allogeneic haematopoietic stem cell transplantation for patients with severe aplastic anaemia using the porcine antilymphocyte globulin-containing conditioning regimen

Antithymocyte globulin (ATG) is widely used for allogeneic haematopoietic stem cell transplantation (allo-HSCT) in severe aplastic anaemia (SAA). Only rabbit-ATG (r-ATG) and porcine-antilymphocyte globulin (p-ALG) are available in China, but the p-ALG-containing conditioning regimen for allo-HSCT in SAA has seldom been reported. In this study, we retrospectively evaluated the outcomes of 41 SAA patients receiving allo-HSCT with a p-ALG-containing conditioning regimen in our transplantation centre. All patients engrafted, and no death during conditioning was observed. The actuarial 3-year overall survival (OS) rates were 95.1 ± 3.4%. The actuarial 3-year disease-free survival (DFS) rates were 85.0 ± 5.7%. Acute graft-versus-host disease (aGVHD) predicted inferior OS (p < 0.05). The interval from diagnosis to transplantation for more than 100 days predicted an inferior DFS rate (p < 0.05) and a higher graft rejection/poor graft function (GR/PGF) rate (p < 0.01). In conclusion, the p-ALG-containing regimen showed satisfactory effects and safety in allo-HSCT for SAA patients. P-ALG could be a potential alternative preparation for r-ATG in SAA allo-HSCT.

Low-Dose Anti-T Lymphoglobulin as Prophylaxis for Graft-versus-Host Disease in Unrelated Donor Transplantations for Acute Leukemias and Myelodysplastic Syndromes

Chronic graft-versus-host disease (cGVHD) is a major complication after stem cell transplantation (HSCT). Several randomized studies already demonstrated that anti-T lymphoglobulin (ATLG) is effective in preventing GVHD after myeloablative unrelated and HLA-identical sibling transplants. However, the issue of doses and the potential increase of relapses still remain unsolved. Here we report data on 190 patients with acute leukemia and myelodysplastic syndrome who underwent an unrelated HSCT with low-dose ATLG (15 to 30 mg/kg) given at an earlier timing (days -6 to -2). HSCT was performed from HLA 10/10 (n = 62, 33%), 9/10 (n = 91, 48%), 8/10 (n = 30, 16%), and <8/10 (n = 7, 4%) identical unrelated donor. Peripheral blood was the stem cell source in 42% (n = 80). Median follow-up was 51 months. Grades II to IV and III to IV acute GVHD were 26% and 9%, respectively, and 2-year overall and moderate to severe cGVHD were 23% and 14%, respectively. The 3-year incidences of relapse and nonrelapse mortality were 26% and 18%, respectively. The rates of 3-year overall survival (OS), disease-free survival (DFS), and GVHD-free and relapse-free survival (GRFS) were 60%, 56% and 44%, respectively. Factors such as younger donor, good performance status, and early disease were associated with better outcome in terms of OS, DFS, and GRFS. Our data indicate that doses of ATLG lower that those used in randomized clinical trials can be used for GVHD prevention, even in the adult setting, without clear increases in relapse and infections; these findings need to be further validated by a prospective randomized study.

Blood concentration of cyclosporine during early post-transplant period may have influence on the occurrence of chronic graft versus host disease in patients who received allogeneic hematopoietic stem cell transplantation

Introduction

It has rarely been studied that how the blood level of CsA affect the incidence of chronic GVHD after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Methods

A total of 183 patients who underwent allo-HSCT from an HLA-matched or haplo matched family donors between 2006 and 2014 were reviewed.

Results

The average monthly CsA blood concentration (CsA^avr, ng/ml) was calculated in each patient: 0-1, 1-2, and 2-3 months after allo-HSCT. CsA^avr at the first month showed significant association with the occurrence of moderate to severe cGVHD in multivariate analysis adjusted for gender, age, total body irradiation, anti-thymocyte globulin, acute GVHD ≥ grade 2 and CsA^avr levels of other periods. The risk of cGVHD development was lowest in patients with CsA^avr of 200-250 ng/ml when compared to those with CsA^avr of ≥ 250 or < 200 ng/ml (p=0.003).

Conclusions

CsA level between 200 and 250 mg/ml during the first month after transplantation was significantly associated with the decreased risk of moderate to severe cGVHD.

In-vivo or ex-vivo T cell depletion or both to prevent graft-versus-host disease after hematopoietic stem cell transplantation

INTRODUCTION

Hematopoietic stem cell transplantation (HSCT) represents a widely accepted therapeutic strategy for the treatment of hematologic disorders which are otherwise considered incurable. Alloreactive T cells infused with the stem cell inoculum may generate graft-versus-host disease (GVHD) representing one the most relevant obstacles to the successful outcome of patients receiving allogeneic HSCT. Areas covered: In this review, the authors provide an overview of the most recent approaches of T-cell depletion (TCD) including ex-vivo αβ+ TCD and in-vivo TCD with anti-thymocyte globulin (ATG). Expert opinion: Ex vivo depletion of donor T-cells prevents both acute and chronic GVHD without the need for any additional posttransplant immunological prophylaxis either in haploidentical HSCT and HLA matched transplants. Three prospective trials evaluating the efficacy of ATG in matched unrelated donor transplant recipients demonstrated that ATG reduces the incidence of both acute and chronic GVHD without a significant increase of relapse rate, and similar results have been reported in the setting of blood stem cell grafts from matched sibling donors.

Myeloablative, but not Reduced-Intensity, Conditioning Overcomes the Negative Effect of Flow-Cytometric Evidence of Leukemia in Acute Myeloid Leukemia

Stringent complete remission (CR) in acute myeloid leukemia (AML) requires the absence of both morphologic and flow cytometric evidence of disease. We have previously shown that persistent AML detected by flow cytometry (FC+) before reduced-intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (alloHCT) was associated with significantly increased relapse, shorter disease-free survival (DFS), and poorer overall survival (OS), independent of morphologic blast count. We evaluated the effect of FC status on outcomes of alloHCT for AML after either myeloablative conditioning (MAC) or RIC regimens in 203 patients (MAC, n = 80, and RIC, n = 123) with no morphologic evidence of persistent AML pretransplant on marrow biopsy. The allografts included 130 umbilical cord blood (UCB) and 73 sibling donors. We performed central review of pretransplant standard sensitivity FC to identify detectable FC+. Twenty-five patients were FC+, including 15 (18.7%) receiving MAC and 10 (8.1%) RIC alloHCT. Among RIC patients FC+ was associated with significantly inferior relapse, DFS, and OS (multiple regression HR, 3.8; 95% CI, 1.7 to 8.7; P < .01 for relapse; HR, 2.9; 95% CI, 1.4 to 5.9; P < .01 for DFS; and HR, 3.4; 95% CI, 1.7 to 7; P < .01 for OS). In contrast, FC+ status was not associated with relapse or decreased OS after MAC. These data suggest that MAC, but not RIC, overcomes the negative effect of pretransplant FC+ after sibling or UCB alloHCT. Therefore, a deeper pretransplant leukemia-free state is preferred for those treated with RIC.

Molecular monitoring of BCR-ABL transcripts after allogeneic stem cell transplantation for chronic myeloid leukemia

The monitoring of minimal residual disease (MRD) through low sensitivity real-time (RT) polymerase chain reaction (PCR) analysis of BCR-ABL transcripts allows early detection of chronic myeloid leukemia (CML) relapse after allogeneic hematopoietic stem cell transplantation (HSCT). The introduction of more sensitive techniques, such as RT quantitative (Q)-PCR, may lead to an overestimation of the risk of CML relapse. In this study, we reviewed the results of peripheral blood RT Q-PCR in CML patients who underwent allogeneic HSCT from 1983 to 2007. In our laboratory, RT Q-PCR analysis was routinely performed since 2002. Eighty-seven of 189 patients had available RT Q-PCR data; 63 patients had at least 3 RT Q-PCR analyses assessable. Fifty-two of 63 patients (83%) had, at least once, detectable transcript levels, but with an BCR-ABL/ABL ratio <.1% defined as <MR3 (molecular remission <0,1%), whereas 11 (17%) had persistent undetectable BCR-ABL transcripts. Six of 52 patients with <MR3 relapsed, defined as BCR-ABL transcript numbers >.1% confirmed by the finding of Ph+ cells in bone marrow. No patients with persistent undetectable transcripts relapsed (P = .19). Relapse did not correlate with the number of occurrences of <MR3 or with the time to the first <MR3 result. Finally, of 46 patients with detectable transcripts who did not relapse, 35 had undetectable transcripts at last contact. RT Q-PCR analysis had low specificity (19%) and low positive predictive value (12%) in predicting relapse of CML patients after allogeneic HSCT. Our data suggest that detection of low BCR-ABL transcript levels by RT Q-PCR analysis has a poor accuracy in defining the risk of CML relapse and should not be considered as the unique indication to treatment. Fluctuation of BCR-ABL transcripts levels is common as late as ≥10 years posttransplantation, possibly suggesting the long-term persistence of CML stem cells.

ATG prevents severe acute graft-versus-host disease in mismatched unrelated donor hematopoietic cell transplantation

Severe acute graft-versus-host disease (aGVHD) remains a major source of morbidity and mortality following mismatched unrelated donor hematopoietic cell transplantation (HCT). Through a retrospective analysis, we investigated the efficacy of GVHD prophylaxis with rabbit anti-thymocyte globulin (ATG) 7.5 mg/kg (1 mg/kg given on day -3, then 3.25 mg/kg/day on days -2 and -1 before stem cell infusion) followed by standard tacrolimus plus methotrexate in a consecutive series of 45 HLA partially matched unrelated donor HCT recipients. The cumulative incidence of grade III-IV aGVHD was 11% by 100 days (95% confidence interval [CI] 5%-25%). Moderate to severe chronic GVHD (per NIH consensus criteria) was 19% (95% CI 10%-36%) at 1 year, and 28% (95% CI 16%-48%) at 2 years. With a median follow-up time for surviving patients of 12 months (range: 5-39 months), overall survival was 55% (95% CI 39%-71%) at 1 year, and 45% (95% CI 27%-63%) at 2 years. Nonrelapse mortality was 11% (95% CI 5%-25%) by 100 days post-HCT, 26% (95% CI 16%-44%) by 1 year, and 30% (95% CI 18%-50%) by 2 years. The cumulative incidence of primary disease relapse was 23% (95% CI 13%-41%) at 1 year, and 33% (95% CI 20%-56%) by 2 years after HCT. Cytomegalovirus (CMV) infection or reactivation varied according to recipient and donor CMV serostatus. Epstein-Barr Virus (EBV) reactivation occurred in 54% (95% CI 40%-71%) of patients. Preemptive rituximab therapy was administered for EBV reactivation, however, posttransplant lymphoproliferative disorder was diagnosed in 5 (11%) cases, and was fatal in 1. A regimen of ATG 7.5 mg/kg total ending on day -1 effectively decreased the occurrence of grade III-IV aGVHD and severe chronic GVHD.

Fludarabine/i.v. BU conditioning regimen: myeloablative, reduced intensity or both?

In this study, we utilized a conditioning regimen with fludarabine and myeloablative dose i.v. BU (12.8 mg/kg) (FluBU) in 36 adult patients (median age: 44 years, range: 18-61) with myeloid or lymphoid malignancies at standard risk (n=10) or high risk of relapse (n=26), who received an allogeneic hematopoietic SCT (HSCT) from HLA-matched related (n=16) or unrelated (n=20) donors. The source of hematopoietic stem cells was peripheral blood in 28 and marrow in 8 cases. Rabbit-antithymocyte globulin at 7 mg/kg was utilized in 21 patients. Acute GVHD grade II-IV was observed in 19% of the patients (grade III-IV in 14% of patients) and chronic GVHD in 11 of 30 evaluable patients (37%). At median follow-up of 737 days (range: 152-1,737) for alive patients, overall survival rates in standard- and high-risk patients were 80 and 35%, respectively, and event-free survival rates were 70 and 31%, respectively. TRM was 10% in standard-risk and 19% in high-risk patients. Post transplant relapse was observed in 20% standard-risk and in 46% high-risk patients. FluBU conditioning regimen is associated with a limited hematologic and extrahematologic toxicity and with an antitumor activity comparable to other standard myeloablative regimens.

Impact of HLA class I and class II DNA high-resolution HLA typing on clinical outcome in adult unrelated stem cell transplantation after in vivo T-cell depletion with alemtuzumab

Survival after volunteer unrelated donor (VUD) stem cell transplantation (SCT) is influenced by matching for human leucocyte antigens (HLA). We analysed the effects of serological and molecular typing at HLA-A, -B, -C and -DRB1 in 100 patient/VUD pairs from a single transplant centre. Patients received SCT for good risk [chronic myeloid leukaemia in first chronic phase (CML-CP1), n=55] or poor risk (n=45) diseases after myeloablative conditioning and T-cell depletion with alemtuzumab. By serological typing, 70 pairs were fully matched, whereas molecular typing revealed 10 pairs with additional mismatches. The day 100 transplant related mortality was 15%. Acute graft versus host disease (GvHD) grades III-IV occurred in 11%, whilst extensive chronic GvHD in 13% of evaluable patients. There was no statistical difference in GvHD rates between patients who received grafts from fully matched or from mismatched donors. In univariate analysis the disease risk group and CMV seronegativity of recipient and donor were the only significant predictors for survival, with 3-year survival probabilities of 71.2% for CML-CP1 and 28% for poor risk diseases. In the poor risk group, HLA mismatches had a negative impact on survival (p=0.003) and progression free survival (p=0.009) contrary to CML-CP1 patients, in whom HLA mismatches at molecular or serological level did not have any impact.

Fludarabine, cyclophosphamide plus thymoglobulin conditioning regimen for unrelated bone marrow transplantation in severe aplastic anemia

Antithymocyte globulin (ATG) has been used in severe aplastic anemia (SAA) as a part of the conditioning regimen. Among the many kinds of ATG preparations, thymoglobulin had been found to be more effective in preventing GVHD and rejection of organ transplants. As the fludarabine-based conditioning regimens without total body irradiation have been reported to be promising for bone marrow transplantation (BMT) from alternative donors in SAA, thymoglobulin was added to fludarabine and cyclophosphamide conditioning to reduce GVHD and to allow good engraftment in unrelated BMT. Five patients underwent BMT with cyclophosphamide (50 mg/kg once daily i.v. on days -9, -8, -7 and -6), fludarabine (30 mg/m2 once daily i.v. on days -5, -4, -3 and -2) and thymoglobulin (2.5 mg/kg once daily i.v. on days -3, -2 and -1) from HLA-matched unrelated donors. Complete donor type hematologic recovery was achieved in all patients. No serious complication occurred during BMT. Only one patient developed grade I acute GVHD resolved spontaneously. Except for one who had rupture of hepatic adenoma 78 days after BMT, all the other four patients are still alive with median 566 days. Fludarabine, cyclophosphamide plus thymoglobulin conditioning allows for the promising results of good engraftment, tolerable toxicity and minimal GVHD.