Occurrence of graft-versus-host disease increases mortality after umbilical cord blood transplantation for acute myeloid leukaemia: a report from Eurocord and the ALWP of the EBMT

Single vs double umbilical cord blood transplantation in acute leukemia: Systematic review and meta-analysis

BACKGROUND AND AIMS

Umbilical cord blood transplantation (UCBT) has emerged as a promising treatment option for patients with acute leukemia needing hematopoietic stem cell transplantation. Both single (sUCBT) and double cord blood units (dUCBT) demonstrate potential benefits, but studies comparing their effectiveness have shown mixed results. This meta-analysis aimed to determine the comparative safety and efficacy of sUCBT versus dUCBT in acute leukemia patients.

METHODS

Electronic databases were systematically examined to identify relevant studies comparing single vs double UCBT published until November 2023. Nine studies involving 3864 acute leukemia patients undergoing UCBT were included. Outcomes analyzed were acute graft-versus-host disease (GVHD), chronic GVHD, relapse, non-relapse mortality, leukemia-free survival and overall survival. Pooled risk ratios (RR) with 95% confidence intervals (CI) were calculated using a random effects model.

RESULTS

The risk of Grade II-IV acute GVHD (RR 1.55, 95% CI 1.19-2.03) and Grade III-IV acute GVHD (RR 1.25, 95% CI 1.07-1.46) were significantly higher with dUCBT. Relapse risk was lower with dUCBT (RR 0.57, 95% CI 0.38-0.88) while overall survival favored sUCBT (RR 1.25, 95% CI 1.06-1.46). No significant differences were observed for chronic GVHD, non-relapse mortality or leukemia-free survival.

CONCLUSION

Both single and double UCBT have potential as effective treatments for acute leukemia. The choice of treatment should consider various factors, including the risk of GVHD, relapse, and mortality. More research, especially randomized trials, is needed to provide definitive guidance on the optimal use of single and double unit UCBT in patients with acute leukemia.

Reconstitution of double-negative T cells after cord blood transplantation and its predictive value for acute graft-versus-host disease

BACKGROUND

With an increasing number of patients with hematological malignancies being treated with umbilical cord blood transplantation (UCBT), the correlation between immune reconstitution (IR) after UCBT and graft-versus-host disease (GVHD) has been reported successively, but reports on double-negative T (DNT) cell reconstitution and its association with acute GVHD (aGVHD) after UCBT are lacking.

METHODS

A population-based observational study was conducted among 131 patients with hematological malignancies who underwent single-unit UCBT as their first transplant at the Department of Hematology, the First Affiliated Hospital of USTC, between August 2018 and June 2021. IR differences were compared between the patients with and without aGVHD.

RESULTS

The absolute number of DNT cells in the healthy Chinese population was 109 (70-157)/μL, accounting for 5.82 (3.98-8.19)% of lymphocytes. DNT cells showed delayed recovery and could not reach their normal levels even one year after transplantation. Importantly, the absolute number and percentage of DNT cells were significantly higher in UCBT patients without aGVHD than in those with aGVHD within one year ( F = 4.684, P = 0.039 and F = 5.583, P = 0.026, respectively). In addition, the number of DNT cells in the first month after transplantation decreased significantly with the degree of aGVHD increased, and faster DNT cell reconstitution in the first month after UCBT was an independent protective factor for aGVHD (HR = 0.46, 95% confidence interval [CI]: 0.23-0.93; P = 0.031).

CONCLUSIONS

Compared to the number of DNT cells in Chinese healthy people, the reconstitution of DNT cells in adults with hematological malignancies after UCBT was slow. In addition, the faster reconstitution of DNT cells in the early stage after transplantation was associated with a lower incidence of aGVHD.

Cord blood transplantation for adult mature lymphoid neoplasms in Europe and Japan

ABSTRACT

To clarify the different characteristics and prognostic factors of cord blood transplantation (CBT) in adult patients with lymphoid neoplasms in Europe and Japan, we conducted a collaborative study. Patients aged 18-75 years receiving their first CBT (Europe: single CBT, n = 192; double CBT, n = 304; Japan: single CBT, n = 1150) in 2000-2017 were analyzed. Fewer patients with Hodgkin lymphoma (Europe vs Japan, 26% vs 5%), and older patients (≥50 years) (39% vs 59%) with a higher refined disease risk index (rDRI) (high-very high: 49% vs 14%) were included in the Japanese registry. High-very high rDRI was associated with inferior overall survival (OS) (vs low rDRI, Europe: hazard ratio [HR], 1.87; P = .001; Japan: HR, 2.34; P < .001) with higher progression/relapse risks. Total body irradiation (TBI)-containing conditioning contributed to superior OS both in Europe (vs TBI-reduced-intensity conditioning [RIC], non-TBI-RIC: HR, 1.93; P < .001; non-TBI-Myeloablative conditioning [MAC]: HR, 1.90; P = .003) and Japan (non-TBI-RIC: HR, 1.71; P < .001; non-TBI-MAC: HR 1.50, P = .007). The impact of HLA mismatches (≥2) on OS differed (Europe: HR, 1.52; P = .007; Japan: HR, 1.18; P = .107). CBT for lymphoid neoplasms, especially in those with high rDRI showed poor outcomes despite all the different characteristics in both registries. TBI should be considered in conditioning regimens to improve these outcomes. The different impacts of HLA mismatches call attention to the fundamental differences among these populations.

Outcomes of graft failure after umbilical cord blood transplantation in acute leukemia: a study from Eurocord and the Acute Leukemia Working Party of the EBMT

Graft failure has remained a limitation of umbilical cord blood transplantation (CBT). Here, we assessed the outcomes of patients who experienced graft failure after CBT. Inclusion criteria were patients (age ≥ 18 years) experiencing graft failure after unrelated CBT (single or double) between 2005 and 2016, for acute myelogenous leukemia (AML) or acute lymphoblastic leukemia (ALL), no prior allogeneic or autologous transplantation, no other stem cell product. The study included 87 patients. At 1-year, cumulative incidence of relapse and nonrelapse mortality (NRM) was 35% and 37%, respectively. One-year overall survival (OS) and progression-free survival (PFS) was 40% and 29%, respectively. Forty-six patients underwent a salvage second transplantation with 1-year and 2-year OS and PFS from second transplantation 41% and 34% for OS, and 37% and 34% for PFS, respectively. In multivariate analysis, complete remission (CR) at CBT (HR = 0.45, 95% CI 0.25-0.83, P = 0.01) and reduced-intensity conditioning (HR = 0.51, 95% CI 0.29-0.91, P = 0.023) were associated with better OS. In conclusion, in this retrospective study, we observed that approximately one-quarter of patients experiencing graft failure after CBT remained alive without relapse 2 years later.

Controversies and expectations for the prevention of GVHD: A biological and clinical perspective

Severe acute and chronic graft versus host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation. Historically, cord blood and matched sibling transplantation has been associated with the lowest rates of GVHD. Newer methods have modified the lymphocyte components to minimize alloimmunity, including: anti-thymocyte globulin, post-transplant cyclophosphamide, alpha/beta T cell depletion, and abatacept. These agents have shown promise in reducing severe GVHD, however, can be associated with increased risks of relapse, graft failure, infections, and delayed immune reconstitution. Nonetheless, these GVHD prophylaxis strategies have permitted expansion of donor sources, especially critical for those of non-Caucasian decent who previously lacked transplant options. This review will focus on the biologic mechanisms driving GVHD, the method by which each agent impacts these activated pathways, and the clinical consequences of these modern prophylaxis approaches. In addition, emerging novel targeted strategies will be described. These GVHD prophylaxis approaches have revolutionized our ability to increase access to transplant and have provided important insights into the biology of GVHD and immune reconstitution.

Comparison of HLA-mismatched unrelated donor transplantation with post-transplant cyclophosphamide versus HLA-haploidentical transplantation in patients with active acute myeloid leukemia

HLA-haploidentical allogeneic hematopoietic stem cell transplantation (Haplo-HCT) is frequently used as treatment for patients with active acute myeloid leukemia (AML). Here, we investigated whether 9/10 HLA-mismatched unrelated donor transplantation (MMUD-HCT) with post-transplant cyclophosphamide (PTCy) is an adequate alternative. Inclusion criteria in this retrospective registry study consisted of adult patients, first HCT with a Haplo donor or MMUD between 2010 and 2020 using PTCy as graft-versus-host disease (GVHD) prophylaxis, and primary refractory or relapsed disease. MMUD patients were pair-matched 1 to 2 with Haplo-recipients. A total of 73 MMUD patients met the inclusion criteria. Their data were compared to those of 146 Haplo patients in a matched-pair analysis. Median follow-up was 27 months in MMUD patients and 36 months in Haplo recipients. Two-year incidences of relapse and non-relapse mortality (NRM) were 40% and 18% in MMUD patients, respectively, versus 50% (P = 0.23) and 24% (P = 0.18) in Haplo recipients. Two-year leukemia-free survival (LFS) and overall survival (OS) was 42% and 46% in MMUD recipients, respectively, versus 26% (P = 0.1) and 28% (P = 0.061) in Haplo-patients. In conclusions, in AML patients with active disease at transplantation, MMUD-HCT results in at least comparable outcomes to Haplo-HCT when PTCy is applied.

Outcome of human umbilical cord blood stem cell transplantation (CBT) for acute myeloid leukemia in patients achieving first complete remission after one versus two induction courses: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT)

We compared transplantation outcomes of adult patients with AML that underwent cord blood transplantation (CBT) in CR1 following 1 versus 2 induction courses. Study included 325 patients, 243 (75%) with 1 and 82 (25%) with 2 induction courses. Engraftment was lower for patients achieving CR1 after 1 vs. 2 induction courses: 91% vs. 99% (p = 0.02). Incidence of acute GVHD was similar, 38% and 36% (p = 0.81), as was 2-year chronic GVHD at 23.4% and 27.5%, respectively (p = 0.65). Two-year non-relapse mortality (NRM), relapse incidence (RI), leukemia-free survival (LFS), overall survival (OS) and GVHD-free, relapse-free survival (GRFS) were not statistically different between patients achieving CR1 with 1 vs. 2 induction courses with 23% vs. 24% (p = 0.87), 25% vs. 30% (p = 0.4), 52% vs. 46% (p = 0.3), 59% vs. 50% (p = 0.2), and 44% vs. 41% (p = 0.66), respectively. Results were confirmed by multivariable analysis, NRM (hazard ratio (HR) = 1.1; 95% CI, 0.6-1.8, p = 0.7), RI (HR = 1.4; 95% CI, 0.9-2.3, p = 0.1), LFS (HR = 1.3; 95% CI, 0.9-1.8, p = 0.2), OS (HR = 1.3; 95% CI, 0.9-1.9, p = 0.1), and GRFS (HR = 1.1; 95% CI, 0.8-1.5, p = 0.5). Overall, outcomes of AML patients undergoing CBT in CR1 achieved after 1 or 2 induction courses are similar.

The impact of GVHD on outcomes after adult single cord blood transplantation in European and Japanese populations

The impact of GVHD and graft-versus-leukemia effect in unrelated cord blood transplantation (UCBT) is controversial. In the Eurocord/ALWP EBMT and JSTCT/JDCHCT collaborative study, we evaluated the impact of GVHD on UCBT outcomes in Japanese and European registries. A total of 3,690 adult patients with acute leukemia who received their first single UCBT were included. A multivariate analysis of overall survival (OS) revealed a positive impact of grade II acute GVHD compared with grade 0-I GVHD, in the Japanese cohort (hazard ratio (HR), 0.81; P = 0.001), and an adverse impact in the European cohort (HR, 1.37; P = 0.007). A negative impact of grade III-IV acute GVHD on OS was observed regardless of registries. In the analysis of relapse, a positive impact of grade II acutes GVHD compared with grade 0-I GVHD was observed only in the Japanese cohort, regardless of disease risk. The positive impact of limited chronic GVHD on OS was observed only in the Japanese cohort. In conclusion, a positive impact of mild GVHD after a single UCBT was observed only in the Japanese cohort. This could explain the ethnic difference in UCBT outcomes and might contribute to the preference usage of UCBT in Japan.

Impact of donor types on reduced-intensity conditioning allogeneic stem cell transplant for mature lymphoid malignancies

We retrospectively compared the outcomes of reduced-intensity conditioning (RIC) transplantation from matched related donors (MRD; n = 266), matched unrelated donors (MUD; n = 277), and umbilical cord blood (UCB; n = 513) for mature lymphoid malignancies. The 3-year overall survival rates for the MRD, MUD, and UCB groups were 54%, 59%, and 40%, respectively (P < 0.001). Multivariate analysis showed no differences in survival between the MRD group and the MUD or UCB group. However, survival was significantly affected by the conditioning regimen and graft-versus-host disease (GVHD) prophylaxis in the UCB group, but not in the MRD and MUD groups. Notably, multivariate analysis showed that the risk of overall mortality in the UCB recipients who received the optimal conditioning regimen and GVHD prophylaxis (n = 116) was lower than that in the MRD group (relative risk [RR], 0.69; P = 0.03) and tended to be lower than that in the MUD group (RR, 0.75; P = 0.09). Our results suggest that UCB transplantation performed with the optimal conditioning regimen and GVHD prophylaxis is highly effective. Moreover, UCB is readily available. Thus, UCB transplantation with the optimal conditioning regimen and GVHD prophylaxis is preferable to MUD transplantation when MRD are not available in the setting of RIC transplantation for mature lymphoid malignancies.

Umbilical cord blood transplantation: Still growing and improving

Umbilical cord blood transplantation (UCBT) has been performed in the clinic for over 30 years. The biological and immunological characteristics of umbilical cord blood (UCB) have been re-recognized in recent years. UCB, previously considered medical waste, is rich in hematopoietic stem cells (HSCs), which are naïve and more energetic and more easily expanded than other stem cells. UCB has been identified as a reliable source of HSCs for allogeneic hematopoietic stem cell transplantation (allo-HSCT). UCBT has several advantages over other methods, including no harm to mothers and donors, an off-the-shelf product for urgent use, less stringent HLA match, lower incidence and severity of chronic graft-vs-host disease (GVHD), and probably a stronger graft-vs-leukemia effect, especially for minimal residual disease-positive patients before transplant. Recent studies have shown that the outcome of UCBT has been improved and is comparable to other types of allo-HSCT. Currently, UCBT is widely used in malignant, nonmalignant, hematological, congenital and metabolic diseases. The number of UCB banks and transplantation procedures increased exponentially before 2013. However, the number of UCBTs increased steadily in Asia and China but decreased in the United States and Europe year-on-year from 2013 to 2019. In this review, we focus on the development of UCBT over the past 30 years, the challenges it faces and the strategies for future improvement, including increasing UCB numbers, cord blood unit selection, conditioning regimens and GVHD prophylaxis for UCBT, and management of complications of UCBT.

Guidelines for the Prevention and Management of Graft-versus-Host Disease after Cord Blood Transplantation

The incidence of graft-versus-host disease (GVHD) after cord blood (CB) transplantation (CBT) is lower than expected given the marked degree of human leukocyte antigen (HLA)-mismatch of CB grafts. While the exact mechanism that underlies this biology remains unclear, it is hypothesized to be due to the low number of mostly immature T-cells infused as part of the graft1,2, and increased tolerance of CB-derived lymphocytes induced by the state of pregnancy. Nevertheless, acute GVHD (aGVHD) is a significant complication of CBT. In contrast, the incidence of chronic GVHD (cGVHD) following CBT is lower than what is observed following matched related or unrelated donor HSC transplantation (HSCT)3-6. This review outlines the guidelines for the prevention and management of acute and chronic GVHD following CBT.

Comparison of long-term outcome for AML patients alive free of disease 2 years after allogeneic hematopoietic cell transplantation with umbilical cord blood versus unrelated donor: a study from the ALWP of the EBMT

Since cord blood transplantation (CBT) has been associated with high graft-versus-leukemia effects and a low incidence of chronic graft-versus-host disease (GVHD), we hypothesized that long-term outcomes might be better in CBT patients than in those given grafts from unrelated donors (UD). Therefore, we performed a landmark study comparing long-term outcomes in acute myeloid leukemia (AML) patients alive and disease-free 2 years after transplantation who received grafts from either CBT or UD. A total of 364 CBT recipients, 2648 UD 10/10 patients and 681 patients given grafts from UD 9/10 were included. Median follow-up was 6.0 years. Five-year leukemia-free survival (LFS) from transplantation was 86% in CBT patients, 84% in UD 10/10 patients (P = 0.36) and 84% in UD 9/10 patients (P = 0.86). On multivariate analysis, donor type had no impact on LFS. Similarly, no impact of donor type was observed on relapse incidence or non-relapse mortality. Factors associated with poorer LFS on multivariate analysis included higher age at transplantation (P < 0.001), male gender (P < 0.001), second complete remission (CR2) versus CR1 (P = 0.05), secondary AML (P = 0.01), antecedent of chronic GVHD (P < 0.001) and poor-risk cytogenetics (P = 0.01). In conclusion, our study shows that long-term outcome for AML patients in CR two years after transplantation is not impacted by donor type.

Impact of detectable measurable residual disease on umbilical cord blood transplantation

The impact of measurable residual disease (MRD) on cord blood transplantation (CBT) outcomes has remained debated. To address this issue, we assessed the impact of measurable MRD at CBT on outcomes in large cohort of patients with acute leukemia. Inclusion criteria included adult patients with acute myeloid (AML) or acute lymphoblastic leukemia (ALL), CBT as first allo-HCT in first or second complete remission (CR) at transplantation, and known MRD status at the time of CBT. Data from 506 patients were included in the analysis. Among them, 317 patients had AML and 189 had ALL. Positive MRD was reported in 169 (33%) patients while the remaining 337 patients were MRD negative at CBT. At 2 years, relapse incidence was 18% in patients with MRD negativity vs 33% in those with MRD positivity at transplantation (P < .001). Two-year leukemia-free survival (LFS) and overall survival (OS) were 57% and 60%, respectively, in MRD negative patients, vs 38% (P < .001) and 48% (P = .004), respectively, in those with MRD positivity. There was no interaction between the impact of MRD on OS and LFS and diagnosis (ie, ALL vs AML), single or double CBT, and reduced-intensity or myeloablative conditioning. On multivariate analysis, MRD positivity was associated with a higher risk of relapse (HR = 1.8, P = .003), comparable non-relapse mortality (P = .44), worse LFS (HR = 1.4, P = .008) and a trend towards worse OS (HR = 1.3, P = .065). In conclusion, these data suggest that novel strategies that are aiming to achieve MRD negativity at CBT are needed for leukemic patients with positive MRD pre-CBT.

Reduced-Intensity versus Myeloablative Conditioning in Cord Blood Transplantation for Acute Myeloid Leukemia (40-60 years) across Highly Mismatched HLA Barriers-On Behalf of Eurocord and the Cellular Therapy & Immunobiology Working Party (CTIWP) of EBMT

The use of myeloablative conditioning (MAC) in umbilical cord blood transplantation (UCBT) has been associated with high nonrelapse mortality (NRM) in patients aged >40 years, especially those having a high HLA disparity, thus limiting wider applications. We hypothesized that the NRM advantage of reduced-intensity conditioning (RIC) and higher graft-versus-leukemia effect associated with greater HLA disparities would expand its use for patients (aged 40 to 60 years) without compromising efficacy and compared outcomes between RIC and MAC regimens. In total, 288 patients aged 40 to 60 years, with de novo acute myeloid leukemia, receiving UCBT with at least 2 HLA mismatches with RIC (n = 166) or MAC (n = 122) regimens were included. As compared to RIC, the MAC cohort included relatively younger patients, having received more single UCBT, with lower total nucleated cell counts and more in vivo T cell depletion. Median time to neutrophil engraftment, infections (bacterial, viral, and fungal), and grade II to IV acute and chronic graft-versus-host disease were similar in both groups. In the multivariate analysis, overall survival (hazard ratio [HR], 0.98; P = .9), NRM (HR, 0.68; P = .2), and relapse (HR, 1.24; P = .5) were not different between RIC and MAC. Refractory disease was associated with worse survival. Outcomes of UBCT for patients aged 40 to 60 years having ≥2 HLA mismatches are comparable after the RIC or MAC regimen.

Soluble Interleukin-2 Receptor Index Predicts Outcomes After Cord Blood Transplantation

BACKGROUND

Our previous study demonstrated that the soluble interleukin-2 receptor (sIL-2R) index, defined as the ratio of serum sIL-2R levels at neutrophil engraftment to that before conditioning, is a biomarker that can predict acute graft-vs-host disease (GVHD) after unrelated bone marrow transplantation. In the present study, we evaluated the significance of the sIL-2R index among patients who underwent cord blood transplantation (CBT).

METHODS

We retrospectively analyzed 31 patients who underwent single-unit CBT as their first transplantation for hematologic malignancies.

RESULTS

The median sIL-2R index was 4.2. The cumulative incidence of grade II to IV acute GVHD was not associated with the sIL-2R index. However, the cumulative incidence of relapse at 3 years after transplantation was significantly lower, with an sIL-2R index ≥ 3.7 than with an index < 3.7 (12.8% vs 50.0%; P = .04). As a result, the probability of overall survival at 3 years after transplantation was significantly higher in the former group than in the latter (79.8% vs 20.0%; P < .01). Only the dose of corticosteroid administered in the pre-engraftment period influenced the sIL-2 index.

CONCLUSION

The sIL-2R index can predict the incidence of relapse and probability of survival after CBT, possibly reflecting a graft-vs-leukemia effect.

Role of antithymocyte globulin in patients with hematologic diseases undergoing umbilical cord blood transplantation: A systematic review and meta-analysis

The role of antithymocyte globulin (ATG) in patients with hematologic diseases undergoing umbilical cord blood transplantation (UCBT) remains controversial. This systematic review and meta-analysis was conducted to comprehensively evaluate this issue. PubMed, Embase, and the Cochrane Library were systematically searched. Clinical studies reporting the impact of ATG- vs non-ATG-containing conditioning regimens on transplantation outcomes were identified. Twenty-five studies were included. ATG significantly prevented grade II-IV and grade III-IV acute graft-vs-host disease (GVHD) (11 studies, 5020 patients, HR: 0.49, 95% CI: 0.42-0.56, P < .001; 5 studies, 5490 patients, HR: 0.60, 95% CI: 0.46-0.80, P < .001) but not chronic GVHD (8 studies, 5952 patients, HR: 0.78, 95% CI: 0.51-1.20, P = .266). However, use of ATG was associated with increased transplantation-related mortality and inferior overall survival (9 studies, 4244 patients, HR: 1.79, 95% CI: 1.38-2.33, P < .001; 8 studies, 5438 patients, HR: 1.96, 95% CI: 1.56-2.46, P < .001). Our study did not recommend routine use of ATG in UCBT. Individualizing the ATG timing and dose based on patient characteristics to retain the prophylactic effects of ATG on GVHD without compromising the survival of UCBT recipients may be reasonable.

Allogeneic peripheral blood stem cell transplantation with anti-thymocyte globulin versus allogeneic bone marrow transplantation without anti-thymocyte globulin

We compared severe graft-versus-host-disease (GvHD) free and relapse-free survival and other transplantation outcomes of acute myeloid leukemia (AML) patients given bone marrow (BM) without anti-thymocyte globulin (ATG) versus peripheral blood stem cells (PBSC) with ATG after myeloablative conditioning. In the cohort of patients receiving grafts from a human leukocyte antigen (HLA)-matched sibling donor, patients given PBSC with ATG (n=1,021) and those given BM without ATG (n=1,633) presented comparable severe GvHD-free relapse-free survival (GRSF)(hazard ratio [HR]=0.9, 95% confidence interval [CI]: 0.8-1.1, P=0.5) and overall survival (HR=1.0, 95% CI: 0.8-1.2, P=0.8). They had however, a lower incidence of chronic GvHD (cGvHD) (HR=0.7, 95% CI: 0.6-0.9, P=0.01). In the cohort of patients receiving grafts from HLA-matched unrelated donor , patients given PBSC with ATG (n=2,318) had better severe GvHD-free and relapse-free survival (GRFS) than those given BM without ATG (n=303) (HR=0.8, 95% CI: 0.6-0.9, P=0.001). They also had a lower incidence of cGvHD (HR=0.6, 95% CI: 0.5-0.8, P=0.0006) and better overall survival (HR=0.8, 95% CI: 0.6-1.0, P=0.04). In summary, these data suggest that PBSC with ATG results in comparable (in the case of sibling donor) or significantly better (in the case of unrelated donor) severe GRFS than BM without ATG in patients with AML in complete remission receiving grafts after myeloablative conditioning.

Effect of graft-versus-host disease on outcomes after pediatric single cord blood transplantation

The effect of GVHD on transplant outcomes after unrelated cord blood transplantation (UCBT) is not yet fully understood. Pediatric patients aged 0-15 years with acute leukemia or myelodysplastic syndrome who underwent their first UCBT (n = 740) were selected from the Japanese registry. Fifty percent of the patients received a UCB unit containing more than 5.0 × 10⁷/kg total nucleated cells. The occurrence of grade III-IV acute GVHD was associated with a higher risk of non-relapse mortality (NRM, hazard ratio [HR] 4.07, P < 0.001) compared with no acute GVHD. Grade I-II acute GVHD was not associated with NRM. The occurrence of grade I-II or grade III-IV acute GVHD was not associated with a relapse risk. These findings showed that grade I-II acute GVHD carried no survival benefit and grade III-IV acute GVHD had an adverse effect (HR 1.68, P = 0.007). The occurrence of limited chronic GVHD was associated with a low risk of overall mortality (HR 0.60, P = 0.045). Severe acute GVHD should be prevented because of its association with high overall mortality and NRM in pediatric single UCBT. Mild acute GVHD provides no overall benefit. Mild chronic GVHD may be beneficial for survival.

Post transplant cyclophosphamide based haplo-identical transplant versus umbilical cord blood transplant; a meta-analysis

OBJECTIVES

Both haplo-identical transplant (haplo) and umbilical cord transplant (UC) are valuable graft options for patients without available matched relative. Previous studies showed inconsistent outcomes comparing Post transplant Cyclophosphamide based haplo (PTCy-haplo) and UC; therefore, we attempt to compare the studies by mean of meta-analysis.

METHODS

We searched for titles of articles in MEDLINE (PubMed), Cochrane library, EMBASE database and Google scholar that compared transplantation with PTCy-haplo versus UC. We conducted a random-effect meta-analysis of seven studies involving a total of 3434 participants and reported the pooled odd ratios (OR) of acute graft-versus-host disease (aGVHD), chronic graft-versus-host disease (cGVHD), relapse and overall survival (OS) between PTCy-haplo and UC groups.

RESULTS

We found a significantly decreased risk of aGVHD and relapse in the PTCy-haplo group compared to the UC group with a pooled OR of 0.78, 95% Confidence Interval (CI) 0.67-0.92, I2=0%, and 0.74, 95% CI 0.57-0.97, I2=23.9% respectively. We also found a significantly increased rate of cGVHD and OS with a pooled OR of 1.41, 95% CI 1.02-1.95, I2=56.8%, and 1.77, 95% CI 1.1-2.87, I2=82.5%, respectively.

CONCLUSION

Our meta-analysis of clinical trials demonstrated superior outcome from PTCy-haplo group compared to the UC group in terms of decreased rate of aGVHD and relapse as well as the increased rate of OS but inferior in terms of increased cGVHD risk compared to UC transplant.

Umbilical cord blood versus unrelated donor transplantation in adults with primary refractory or relapsed acute myeloid leukemia: a report from Eurocord, the Acute Leukemia Working Party and the Cord Blood Committee of the Cellular Therapy and Immunobiology Working Party of the EBMT

The role of umbilical cord blood transplantation (CBT) in acute myeloid leukemia (AML) patients with active disease at allogeneic hematopoietic cell transplantation (allo-HCT) remains poorly investigated. In this study, we compared transplantation outcomes of 2963 patients with primary refractory or relapsed AML given CBT, 10/10 HLA-matched UD, or 9/10 HLA-matched UD allo-HCT from 2004 to 2015 at EBMT-affiliated centers. Neutrophil engraftment and complete remission rates in CBT, UD 10/10, and UD 9/10 recipients were 75 and 48%, 93 and 69%, and 93 and 70%, respectively. In multivariate Cox analyses, in comparison with CBT (n = 285), UD 10/10 recipients (n = 2001) had a lower incidence of relapse (HR = 0.7, P = 0.001), a lower incidence of non relapse mortality (HR = 0.6, P < 0.001), better GVHD-free and leukemia-free survival (GRFS, HR = 0.8, P < 0.001) and better survival (HR = 0.6, P < 0.001). Further, in comparison with CBT, 9/10 UD recipients (n = 677) also had a lower incidence of relapse (HR = 0.8, P = 0.02), a lower incidence of nonrelapse mortality (HR = 0.7, P = 0.008), better GRFS (HR = 0.8, P = 0.01) and better survival (HR = 0.7, P < 0.001). In summary, these data suggest that in AML patients with active disease at transplantation, allo-HCT with UD results in better transplantation outcomes than CBT.

Comparison of Mesenchymal Stromal Cells From Different Origins for the Treatment of Graft-vs.-Host-Disease in a Humanized Mouse Model

Mesenchymal stromal cells (MSCs) have potent immunomodulatory properties that make them an attractive tool against graft- vs.-host disease (GVHD). However, despite promising results in phase I/II studies, bone marrow (BM-) derived MSCs failed to demonstrate their superiority over placebo in the sole phase III trial reported thus far. MSCs from different tissue origins display different characteristics, but their therapeutic benefits have never been directly compared in GVHD. Here, we compared the impact of BM-, umbilical cord (UC-), and adipose-tissue (AT-) derived MSCs on T-cell function in vitro and assessed their efficacy for the treatment of GVHD induced by injection of human peripheral blood mononuclear cells in NOD-scid IL-2Rγ^null HLA-A2/HHD mice. In vitro, resting BM- and AT-MSCs were more potent than UC-MSCs to inhibit lymphocyte proliferation, whereas UC- and AT-MSCs induced a higher regulatory T-cell (CD4⁺CD25⁺FoxP3⁺)/T helper 17 ratio. Interestingly, AT-MSCs and UC-MSCs activated the coagulation pathway at a higher level than BM-MSCs. In vivo, AT-MSC infusions were complicated by sudden death in 4 of 16 animals, precluding an analysis of their efficacy. Intravenous MSC infusions (UC- or BM- combined) failed to significantly increase overall survival (OS) in an analysis combining data from 80 mice (hazard ratio [HR] = 0.59, 95% confidence interval [CI] 0.32–1.08, P = 0.087). In a sensitivity analysis we also compared OS in control vs. each MSC group separately. The results for the BM-MSC vs. control comparison was HR = 0.63 (95% CI 0.30–1.34, P = 0.24) while the figures for the UC-MSC vs. control comparison was HR = 0.56 (95% CI 0.28–1.10, P = 0.09). Altogether, these results suggest that MSCs from various origins have different effects on immune cells in vitro and in vivo. However, none significantly prevented death from GVHD. Finally, our data suggest that the safety profile of AT-MSC and UC-MSC need to be closely monitored given their pro-coagulant activities in vitro.

Cord blood transplantation is associated with good outcomes in secondary Acute Myeloid Leukaemia in first remission

BACKGROUND

We conducted a retrospective survey within the European Society for Blood and Marrow Transplantation (EBMT) registry to assess the outcomes of cord blood transplantation (CBT) in secondary acute myeloid leukaemia (sAML).

METHODS

Inclusion criteria consisted of ≥18 years of age, sAML, first CBT between 2002 and 2016, and either first complete remission (CR) or active disease at CBT.

RESULTS

One hundred forty-six patients met the study inclusion criteria. Status at transplantation was first CR (n = 97), primary refractory sAML (n = 30) or relapsed (n = 19) sAML. Neutrophil engraftment was achieved in 118 patients while the remaining 25 patients (17%) failed to engraft. This includes 13% of patients transplanted in first CR versus 30% of those transplanted with active disease (P = 0.008). Two-year incidences of relapse were 25% in first CR patients versus 36% in those with advanced disease (P = 0.06) while 2-year incidences of nonrelapse mortality were 35% and 49% (P = 0.03), respectively. At 2-year overall survival, leukaemia-free survival and graft-versus-host disease (GVHD)-free relapse-free survival were 42% vs. 19% (P < 0.001), 40% vs. 16% (P < 0.001), and 26% vs. 12% (P = 0.002) in first CR patients versus those with advanced disease, respectively.

CONCLUSIONS

We report here the first study of CBT in a large cohort of sAML patients. Main observation was that CBT rescued approximately 40% of patients with sAML in first CR.

Development of Pre-Engraftment Syndrome, but Not Acute Graft-versus-Host Disease, Reduces Relapse Rate of Acute Myelogenous Leukemia after Single Cord Blood Transplantation

The different effects of pre-engraftment syndrome (PES) and acute graft-versus-host disease (aGVHD) on outcomes after cord blood transplantation (CBT) are unclear. We retrospectively evaluated the impact of PES and aGVHD on relapse and survival after single-unit CBT in 138 adult patients with hematologic malignancies at our institution between 2004 and 2016. Multivariate analysis demonstrated that development of grade III-IV aGVHD, particularly with gut or liver involvement, significantly contributed to higher nonrelapse mortality (P < .001), but PES and grade II-IV aGVHD did not. In subgroup analyses of underlying disease type, the development of PES had a significant effect on decreased relapse (P = .032) and better disease-free survival (DFS) (P = .046) in patients with acute myelogenous leukemia (AML). These data suggest that PES is associated with a reduced relapse rate and better DFS in AML, indicating that the early immune reaction before neutrophil engraftment may provide a unique graft-versus-leukemia effect after single-unit CBT.

Single- Versus Double-Unit Umbilical Cord Blood Transplantation for Hematologic Diseases: A Systematic Review

Controversial results exist regarding the clinical benefits of single- vs double-unit umbilical cord blood transplantation (UCBT) in patients with hematologic diseases. A systematic review was conducted to evaluate this issue. The PubMed, Embase, and Cochrane Library databases were searched up to May 2018. A total of 25 studies including 6571 recipients were identified. Although double-unit UCB contained higher doses of total nucleated cells and CD34⁺ cells, it offered no advantages over single-unit UCB in terms of hematologic recovery, including the rate and speed of neutrophil and platelet engraftment. Double-unit UCBT was associated with higher incidences of grades II-IV acute and extensive chronic graft-vs-host disease, accompanied by a lower relapse incidence, which may be attributed to a graft-vs-graft effect induced by double-unit UCB. However, transplant-related mortality, disease-free survival, and overall survival were comparable between single- and double-unit UCBT. Although double-unit UCBT confers no clinical advantages over single-unit UCBT, certain patients, such as those at high risk of relapse, might benefit from double-unit UCBT, a possibility that needs to be clarified in future randomized trials.

Impact of Donor Type in Patients with AML Given Allogeneic Hematopoietic Cell Transplantation After Low-Dose TBI-Based Regimen

Purpose: We assessed the impact of donor type in acute myeloid leukemia (AML) patients transplanted with 2 Gy total body irradiation (TBI)-based nonmyeloablative conditioning regimen.Patients and Methods: Data from 1,715 adult patients, with AML in CR1 or CR2 were included in this retrospective survey.Results: Donors consisted either of HLA-matched sibling donors (MSD, n = 701), 10/10 HLA-matched unrelated donors (MUD, n = 611), HLA-haploidentical donors (haplo, n = 112) or single or double umbilical cord bloods (CBT, n = 291). Chronic graft-versus-host disease (GVHD) was less frequent in CBT (28%) and in haplo (30%) patients than in MSD (50%) and MUD (51%) recipients (P < 0.001). Two-year incidence of relapse was 32%, 30%, 34%, and 34% in MSD, MUD, CBT and haplo patients, respectively (P = 0.7). Two-year overall (OS) and GVHD-free relapse-free survival (GRFS) were 59% and 29% in MSD patients, 56% and 39% in CBT recipients, 53% and 23% in MUD recipients, and 43% and 37% in haplo patients, respectively. In multivariate analyses, MUD patients had lower GRFS than MSD patients beyond day 100 (HR 1.3, P = 0.001) while CBT was associated with a better GRFS than MSD beyond day 100 (HR 0.6, P = 0.002).Conclusions: In this large cohort of AML patients transplanted following low-dose TBI-based conditioning, the relapse incidence was not affected by donor type suggesting that the intensity of GVL effects might be comparable with these four transplant approaches. Furthermore, CBT was associated with better GRFS beyond day 100 than MSD while the opposite was observed for MUD. Clin Cancer Res; 24(12); 2794-803. ©2018 AACR.