Single Cord Blood Transplantation Research Articles

Lymphocyte Crossmatch Testing or Donor HLA-DP and -DQ Allele Typing Effectiveness in Single Cord Blood Transplantation for Patients With Anti-HLA Antibodies Other Than Against HLA-A, -B, -C, and -DRB1

Anti-human leukocyte antigen (HLA) antibodies other than those against HLA-A, -B, -C, and DRB1 are a risk factor for engraftment delay and failure, especially in cord blood transplantation (CBT). The primary objective of this study was to assess the impact of the presence of anti-HLA antibodies on CBT and to evaluate the utility of lymphocyte crossmatch testing or additional HLA-DP and -DQ typing of CB units in improving transplant outcomes. We retrospectively assessed the engraftment rates and transplant outcomes of 772 patients who underwent their first CBT at our hospital between 2012 and 2021. Donors were routinely typed for HLA-A, -B, -C, and-DRB1 alleles, and the anti-HLA antibodies of recipients were screened before donor selection in all cases. Among patients who had antibodies against other than HLA-A, -B, -C, and DRB1 (n = 58), lymphocyte crossmatch testing (n = 32) or additional HLA-DP/-DQ alleles typing of CB (n = 15) was performed to avoid the use of units with corresponding alleles. The median patient age was 57 years (16 to 77). Overall, 75.7% had a high-risk disease status at transplantation, 83.5% received myeloablative conditioning regimens, and >80% were heavily transfused. Two hundred twenty-nine of the 772 recipients (29.6%) were positive for anti-HLA antibodies. There were no statistical differences in the number of infused CD34-positive cells between the anti-HLA antibody-positive and the anti-HLA antibody-negative patients. Of the 229 patients with anti-HLA antibodies, 168 (73.3%) had antibodies against HLA-A, -B, -C, and-DRB1 (Group A), whereas 58 (25.3%) had antibodies against HLA-DP, HLA-DQ, or -DRB3/4/5 with or without antibodies against HLA-A, -B, -C, and -DRB1 (Group B). No patients in both Groups A and B exhibited donor-specific anti-HLA antibodies against HLA-A, -B, -C, and -DRB1. The neutrophil engraftment rate was lower in patients with anti-HLA antibodies than in those without antibodies (89.9% versus 94.1%), whereas nonrelapse mortality (NRM) before engraftment was higher in antibody-positive patients (9.6% versus 4.9%). In patients who received 2 or more HLA allele-mismatched CB in the host-versus-graft (HVG) direction (n = 685), the neutrophil engraftment rate was lower in the anti-HLA antibody-positive recipients than in the antibody-negative recipients with significant differences (88.8% versus 93.8%) (P = .049). Similarly, transplant outcomes were worse in the antibody-positive patients with respect to 2-year overall survival (OS) (43.1% versus 52.3%) and NRM (44.0% versus 30.7%) than in the antibody-negative patients. In contrast, the results of Group B were comparable to those of the antibodies-negative patients, while the results of Group A were statistically worse than the antibody-negative patients in terms of all engraftment rate (88.6%), OS (34.2%), and NRM (49.0%). The presence of anti-HLA antibodies negatively impacts engraftment, NRM, and OS in CBT. However, HLA-DP/-DQ allele typing of CB units or lymphocyte crossmatch testing could be useful strategies to overcome poor engraftment rates and transplant outcomes, especially in patients with anti-HLA antibodies against HLA-DP, HLA-DQ, or -DRB3/4/5.

Comparison of long-term outcomes after first HLA-mismatched unrelated donor transplantation with single unrelated cord blood transplantation using reduced-intensity or reduced-toxicity conditioning

BackgroundNo comparative data have shown significant survival differences between HLA-mismatched unrelated donor (MMUD) transplantation and cord blood (CB) transplantation, each with reduced-intensity/reduced-toxicity conditioning (RIC/RTC). However, advances in graft-versus-host disease (GVHD) prophylaxis might help update current strategies. MethodsWe retrospectively compared the outcomes of first allogeneic hematopoietic cell transplantation from MMUDs (n = 15) or single unrelated CB (n = 35) after RIC/RTC. ResultsThe median age was 60 years. The MMUD group had a numerically lower 100-day incidence of grade III–IV acute GVHD (7% vs. 29%, P = 0.079) and non-relapse mortality (0% vs. 40%, P = 0.12). Eight MMUD recipients received anti-thymocyte globulin, bortezomib, or posttransplant cyclophosphamide for GVHD prophylaxis. They did not develop grade III–IV acute GVHD. The MMUD group had significantly better 5-year overall survival than the CB group (62% vs. 31%, P = 0.021), although relapse rates were similar. A multivariable analysis and sensitivity analysis also showed trends toward higher overall survival in the MMUD group. ConclusionMMUD with better GVHD prophylaxis might be preferred over CB in patients with older age and comorbidities.

Influence of interruption of oral mycophenolate mofetil for graft-versus-host disease prophylaxis on outcomes after single cord blood transplantation

Influence of interruption of oral mycophenolate mofetil for graft-versus-host disease prophylaxis on outcomes after single cord blood transplantation

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

AbstractTo 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.

Infusion of UM171-Expanded Cord Blood Led to Excellent Survival in Patients with High-Risk Leukemias: Results from Two Independent Phase II Studies

Background: Cord blood transplant (CBT) recipients experience delayed hematopoietic recovery and an increased risk of non-relapse mortality (NRM). UM171 is a small molecule that expands hematopoietic stem and progenitor cells (HSPC). An initial phase I-II clinical trial of a single UM171-expanded CBT was associated with low NRM and excellent long-term outcomes. (S Cohen et al. Lancet Haematology 2020). With the primary goal of generating increased numbers of HSPC to supplement a conventional single cord blood (CB) graft, we tested the same approach exclusively in high and very high-risk patients with acute leukemias/myelodysplastic syndromes (MDS). Methods: Between 2019 and 2022, two single independent prospective phase II studies were conducted in Montreal, at the Maisonneuve Rosemont Hospital and in Seattle, at the Fred Hutchinson Cancer Center. Primary objectives were safety/NRM and progression free survival at 2-years post-transplant. Only patients with high and very-high risk acute myeloid leukemia (AML), acute lymphoid leukemia (ALL) and MDS were eligible. Patients were required to have adequate organ function and comorbidity index as defined by the transplant center. Patients received a single UM171 7-day expanded and cryopreserved CB after either a myeloablative or mid-intensity conditioning regimen. All patients received tacrolimus and mycophenolate mofetil for GVHD prophylaxis. Results: A total of 52 patients were enrolled (31 in Montreal and 21 in Seattle) with 2 patients not receiving the UM171 expanded product and therefore removed from the final analysis. Patient's characteristics are shown in Table 1. The median age was 44 years (range 19-66) and weight 78 kg (range, 44-145). Twenty-eight patients (54%) were either in a no complete response (CR) status or in ≥CR2, ten (19%) were p53+ and 17 (33%) were second or third transplants. Forty patients (77%) received a 5/8 HLA-matched CB unit and the median of CD34+ cells infused was 4.7 10 6/Kg (0.9-7.5). All patients engrafted (ANC &amp;gt;500 10^ 9/L for 2 consecutive days) at a median of 17 days (range, 9-39 days). The median time to platelet recovery (&amp;gt;20 x 10^ 9/L) was 37 days (range 24-116). With a median follow-up of 24 months (range 0.7 - 39), the probability of 2-year overall survival (OS) and progression-free survival (PFS) was 67% (95% CI, 54-82) and 63% (95% CI, 50-79). OS for second/third transplants and p53+ patients was 64% (95% CI, 43-96) and 40 (95% CI, 19-86), PFS was 51 % (95% CI, 29-87) and 40 (95% CI, 19-86), respectively. At 2 years, the cumulative incidence of NRM was 19% (95% CI, 8-31) while the incidence of relapse was 18% (95% CI, 6-29). The incidence of grade II-IV and III-IV acute GVHD was 69% (95% CI, 56−82%) and 16% (95% CI, 6−27%). The rate of moderate/severe chronic GVHD was 7% (95% CI,1−15%) and translated in an incidence of a chronic-relapse-free-survival of 55% (95% CI, 42−72%). Of note, Kaplan-Meier analysis of all clinical outcomes showed no difference for patients treated in Montreal and Seattle, and results were similar for both centers (Figure 1). Conclusions: The results of 2 independent Phase II clinical studies demonstrated that infusion of a UM171 single CBT led to excellent clinical outcomes in patients with high and very-high risk malignancies including patients with p53+ mutation. We also observed encouraging results for patients undergoing second/third transplants (33% of the entire cohort). Clinical outcomes were similar between the two Transplant Centers. Based on these positive results, a multicenter randomized clinical trial is currently in the planning stage.

Single CBT As 2nd Allo-SCT Is Promising for Selected Patients with Relapsed Hematopoietic Malignancies

Background: Hematopoietic malignancies that relapse after allogeneic stem cell transplantation (allo-SCT) generally have a poor prognosis, and there is no standard treatment. Second allo-SCT is a potentially curative treatment, but many patients do not receive 2nd allo-SCT at the best time because of the long preparation time for transplantation, and even if they do, treatment-related complications and relapse of the underlying disease often lead them to fatal outcomes. Umbilical cord blood is considered to be a promising source of 2nd allo-SCT because of its short preparation time, rapid and high graft-versus Leukemia (GVL) effect after transplantation, and better response to GVHD treatment compared to other donor sources. Therefore, we investigated the usefulness of cord blood transplantation for relapsed hematopoietic malignancies after allo-SCT. Methods: We retrospectively analyzed the outcomes of patients with hematopoietic malignancies who received single cord blood transplantation (CBT) as 2nd allo-SCT for relapse after allo-SCT in Toranomon Hospital between Apr. 1999 and Mar. 2022. We exclude the patients with Eastern Cooperative Oncology Group (ECOG) performance status(PS) of 4. Results: 263 patients were included in this study. There were 179 patients with myeloid neoplasms and 84 with lymphoid neoplasms. Median age was 45 years (range: 18-71). 239 patients were in non-remission and 24 in remission before SCT. Median interval between 1st SCT and 2nd SCT was 293 days (26-4703). Donor sources of 1st allo-SCT were related donor in 80, unrelated donor in 62, and sCBT in 121 patients. 135 patients received myeloablative conditioning for 2nd allo-SCT, and 128 patients underwent reduced intensity-conditioning. About cord blood as the donor source of 2nd allo-SCT, the median total nucleated cell count at cryopreservation was 2.71(×10 7)/kg (1.67-5.85), and median CD34 + cell count at cryopreservation was 0.97(×10 5)/kg (0.25-3.18). Median observation period of survivors was 1726 (122-6286) days after 2nd allo-SCT. Overall survival (OS), non-relapse mortality and relapse at 2-year were 16.7%, 46.9% and 40.6%, respectively. Younger patients (&amp;lt; 50 years) had significantly better OS than older patients (50 years and more), with 2-year OS of 21.5% and 9.9%, respectively (P &amp;lt; 0.001). Patients with good PS (0 and 1) had significantly better survival than those with poor PS(2 and 3), with 2-year OS of 23.4% and 2.4%, respectively (P&amp;lt;0.001). Patients with myeloid malignancies tended to have better survival than those with lymphoid malignancies, with 2-year survival rates of 19.2% and 11.9%, respectively (P=0.341). Patients with longer interval between SCTs (&amp;gt;1 year) had significantly better survival than those with shorter interval (&amp;lt;1 year), with 2-year OS of 23.6% and 11.6%, respectively (P=0.00443). In multivariate analysis, younger age (&amp;lt;50), good PS (0-1), long interval between SCTs(≧1 year) showed a superior OS. In the younger age population, patients with myeloid neoplasms showed a superior OS compared to those with lymphoid neoplasms (2yrOS: 30.3% vs 10.6%, P=0.00318). Furthermore, patients with myeloid neoplasms having good PS and long interval between SCTs showed an extremely high survival rate of 50.5% at 2 years (n=31)(Figure 1). In the elderly population, patients with long interval and good PS showed a relatively good OS of 31.4% at 2 years (n=28)(Figure 2). The type of disease (myeloid vs lymphoid) didn't have a significant influence on OS in this subpopulation (28.1% vs 50.0%, P=0.129). Conclusion: Although the outcomes of CBT as 2nd allo-SCT haven't been satisfactory, there are certain populations, including elderly patients, with favorable OS.

UM171 Expanded Cord Blood Transplantation Outcomes Compare Favorably to All Different Stem Cell Sources: An EBMT Registry Case-Control Analysis

Background: Cord blood (CB) transplantation (CBT) has several advantages compared with other graft sources, such as permissive human leucocyte antigen (HLA) mismatches, and low risk of chronic graft-versus-host disease (GVHD) and relapse. However, CBT has fallen into disfavor because of its high risk of non-relapse mortality (NRM) and prolonged hospitalization due to its low cell dose. Furthermore, the need for the rare large cord bloods (CBs) leads to selection of poorly HLA-matched CBs, known to further increase NRM. UM171 is a small molecule that expands hematopoietic stem cells. A phase I-II study of a single UM171-expanded, myeloablative and reduced intensity CBT for patients with high-risk hematologic malignancies who lacked a donor, demonstrated prompt neutrophil engraftment, the ability to use smaller, better HLA-matched CBs, and a low NRM of 5% (Cohen S et al. Lancet Haematol 2020). The aim of the current analysis was to compare outcomes after a UM171 CBT to real-world cohorts of 6 other stem cell sources identified in the European Society for Blood and Marrow Transplantation (EBMT) registry. Methods: This is a retrospective study comparing 22 adults who received a single UM171-expanded CBT in the phase I-II study between 2016-2018, to 6 cohorts of patients allografted from different stem cell sources and reported to the EBMT registry. Control patients were eligible if they had received a myeloablative or reduced intensity allogeneic transplant for a hematologic malignancy in Europe during 2010-2021, were between the ages of 18-65 years, and had a Karnofsky performance status (KPS) score ≥70. The different donor control cohorts were: 1) CB, single or double units, with a calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF) for GVHD prophylaxis, 2) 10/10 HLA-matched unrelated donor (MUD) peripheral blood stem cells (PBSC) with a CNI and MMF or methotrexate (MTX), 3) 10/10 MUD bone marrow (BM) with a CNI and MMF or MTX, 4) 9/10 HLA-MUD BM or PBSC (9/10 UD), 5) T cell replete haploidentical donor (haplo) BM or PBSC, and 6) matched sibling donor (MSD) BM or PBSC. Exclusion criteria included in vitro manipulated grafts and CBT recipients who received anti-thymocyte globulin or alemtuzumab. Patients were directly matched for disease and status at transplant and propensity score matching was used for prior allograft, age, KPS, and conditioning regimen. Endpoints included engraftment, GVHD, NRM, relapse, progression-free survival (PFS), overall survival (OS), and GVHD-free relapse-free survival (GRFS). The EBMT attempted to identify 3 controls for each patient. If no control was identified for a UM171 patient, the latter was excluded from the analysis. Results: Between 17 and 21 UM171 CB patients were compared to 36 to 62 controls depending on the donor group as 1-3 controls could not be identified for each patient (Table 1). Median follow-up for the UM171 group was 36 months and generally longer for the controls. Neutrophil engraftment with UM171 CB was similar to all donor groups except slower for CB and MUD BM. Platelet engraftment was consistently slower for UM171 CB except when compared to conventional CB. The incidence of severe acute GVHD was similar across all donor groups. As there was no severe chronic GVHD in the UM171 group, the latter was associated with less extensive/severe chronic GVHD compared to MUD (PBSC and BM) and MSD. There was a trend towards lower NRM for UM171 CB compared to haplo and 9/10 UD but it did not reach statistical significance. PFS, OS and GRFS were all better with UM171 CB compared to haplo. Finally, GRFS was improved with UM171 CB when compared to MUD PBSC (Figue 1), 9/10 UD, and MSD. Conclusions: This registry matched case-control analysis demonstrated real-word evidence suggesting UM171-expanded CBT recipients have improved outcomes compared to other donor types. More specifically and due to the absence of severe chronic GVHD with UM171 CB, GRFS was better with UM171 CB when compared to other graft sources except for CB and MUD BM. Also, OS and PFS were superior with UM171 CB compared to haplo donors. Limitations of this study included the small number of UM171 patients, the inability to identify controls for each case, and certain missing data for the controls. UM171 expansion of CB appeared to achieve the desired outcome of maintaining benefits of CB while removing its disadvantages. Thus, prospective randomized studies are warranted to confirm these results.

Comparison of Non-Relapse Mortality after Haploidentical Hematopoietic Stem Cell Transplantation with Post-Transplant Cyclophosphamide Versus Single Umbilical Cord Blood Transplantation for Hematologic Disease

Introduction: Unrelated cord blood transplantation (UCBT) and haploidentical stem cell transplantation with post-transplant cyclophosphamide as graft-versus-host disease (GVHD) prophylaxis (PTCy-haplo) are alternative options for patients with hematologic disease lacking a human leukocyte antigen (HLA)-matched donor. Non-relapse mortality (NRM) after UCBT may vary depending on the cord blood CD34+ cell count, but no study has accounted for CD34+ cell count when comparing the outcomes after UCBT and PTCy-haplo. Therefore, we analyzed transplant outcomes after UCBT and PTCy-haplo in patients with hematologic disease from data of a nationwide registry that included cord blood CD34+ cell count. Methods: Patients with hematologic disease receiving first UCBT or PTCy-haplo between 2014 and 2020 were identified from the nationwide registration data of the Japanese Data for Hematopoietic Cell Transplantation. Acute GVHD-related mortality was defined as death caused primarily by GVHD or occurred secondary to GVHD, and infection-related mortality as death due to graft failure or infection but not acute GVHD. Patients treated by UCBT were stratified by the median CD34+ cell count for comparison (0.84 × 10 5/kg). Results: A total of 7,499 patients were enrolled and classified into 3 groups: PTCy-haplo (n = 1,142), UCBT with high CD34+ cell count (UCB-H; ≥ 0.84 × 10 5/kg, n = 3,185), and UCBT with low CD34+ cell count (UCB-L; &amp;lt; 0.84 × 10 5/kg, n = 3,172). Patients in the PTCy-haplo group were slightly younger than UCB-H and UCB-L patients (median age: 54 vs. 56 and 55 years). The PTCy-haplo group also included a greater proportion of males than the UCB-H group (62.4% vs. 50.0%) but not the UCB-L group (64.2%). A greater proportion of PTCy-haplo patients had a PS score of 0 (53.2% vs. 46.2% and 45.6%), a hematopoietic cell transplantation-specific comorbidity index of 0 (57.6% vs. 52.7% and 54.4%) and donor-specific anti-HLA antibody (2.7% vs. 1.0% and 1.6%), received reduced-intensity conditioning (58.0% vs. 40.5% and 41.6%), calcineurin inhibitor with mycophenolate mofetil (88.5% vs. 38.6% and 38.4%), and underwent transplantation in the later period (82.0% vs. 54.6% and 50.7%). There were no significant differences in disease-risk index between groups. At 2 years post-transplantation, NRM and overall survival (OS) were significantly better in the PTCy-haplo group than the UCB-H and UCB-L groups (NRM: 18.8% vs. 21.6% and 25.3%, P &amp;lt; 0.001; OS: 56.2% vs. 53.3% vs. 49.6%, P &amp;lt; 0.001). Neutrophil engraftment rate at 42 days was also significantly higher in the PTCy-haplo group than the UCB-H and UCB-L groups (93.7% vs. 87.5% and 82.9%, P &amp;lt; 0.001). The PTCy-haplo group less frequently developed grade II-IV (26.4% vs. 37.3% and 34.4%, P &amp;lt; 0.001) and III-IV acute GVHD (7.0% vs. 12.2% and 10.5%, P &amp;lt; 0.001). While neither the differences in NRM nor that in OS remained significant between PTCy-haplo and UCB-H groups in multivariable analysis (NRM: hazard ratio [HR], 1.18, 95% confidence interval [CI], 0.99-1.41, P = 0.073; OS: HR, 1.05, 95% CI, 0.94-1.17, P = 0.42), significant differences were maintained between PTCy-haplo and UCB-L groups (NRM: HR, 1.35, 95% CI, 1.13-1.61, P = 0.001; OS: HR, 1.12, 95% CI, 1.00-1.26, P = 0.042). Regarding the cause-specific mortality, infection-related mortality was also significantly lower in the PTCy-haplo group compared to UCB-H and UCB-L groups (8.1% vs. 11.1% and 13.6%, P &amp;lt; 0.001) while GVHD-related mortality did not differ among groups (5.0% vs. 5.2% and 4.9%, P = 0.69). Conclusion: UCBT-H resulted in similar NRM and OS as patients receiving PTCy-haplo, whereas outcomes were worse in UCBT-L. These findings indicate that high CD34+ cell count in cord blood is a critical criterion for alternative donor selection.

Clinical implications of augmented renal clearance after unrelated single cord blood transplantation in adults

Augmented renal clearance (ARC) is a phenomenon characterized by increased renal functionality, which can impact the pharmacokinetics and pharmacodynamics of antimicrobial drugs eliminated by the kidneys. It is a potential concern for infection treatment. Cord blood transplantation (CBT) is primarily impeded by delayed neutrophil recovery and immune reconstitution, thereby increasing susceptibility to infection. However, the clinical implications of ARC following CBT remain unexplored. We retrospectively assessed the influence of ARC on post-transplant outcomes at various time points in 194 adult recipients of single-unit unrelated CBT between 2007 and 2022 at our institution. ARC was observed in 52.9% of patients at 1 day, 39.8% at 15 days, and 26.5% at 29 days post-CBT. ARC was not significantly associated with bloodstream infection, acute graft-versus-host disease, or veno-occlusive disease/sinusoidal obstruction syndrome at any time point. ARC at 1 day, 15 days, and 29 days post-CBT was not significantly associated with overall survival, non-relapse mortality, or relapse rates. These findings suggest that ARC is common in adults during the early stages of CBT, but does not discernibly influence clinical outcomes or post-CBT complications.

Cord blood transplantation for AML: Comparable LFS in patients with de novo versus secondary AML in CR1, an ALWP/EBMT study.

We investigated whether secondary versus de novo acute myeloid leukaemia (AML) would be associated with poor outcomes in adult acute AML patients in first complete remission (CR1) receiving unrelated cord blood transplantation (CBT). This is a retrospective study from the acute leukaemia working party of the European Society for Blood and Marrow Transplantation. Inclusion criteria included adult at first allogeneic haematopoietic cell transplantation between 2000 and 2021, unrelated single or double unit CBT, AML in CR1, no ex vivo T-cell depletion and no post-transplant cyclophosphamide. The primary end-point of the study was leukaemia-free survival (LFS). A total of 879 patients with de novo (n = 696) or secondary (n = 183) AML met the inclusion criteria. In multivariable analyses, sAML patients had non-significantly different LFS (HR = 0.98, p = 0.86), overall survival (HR = 1.07, p = 0.58), relapse incidence (HR = 0.74, p = 0.09) and non-relapse mortality (HR = 1.26, p = 0.13) than those with de novo AML. Our results demonstrate non-significantly different LFS following CBT in adult patients with secondary versus de novo AML.

Abstract 3 Efficacy of Foscarnet in Preventing HHV6 Encephalitis in Adult Single Cord Blood Transplantation

Abstract Introduction The risk of HHV-6 encephalitis is high in cord blood transplantation (CBT) and the prognosis after encephalitis is poor, but there is no clarity regarding effective prevention methods for HHV-6 encephalitis. Objectives We retrospectively evaluated the effect of foscarnet (FCN) in preventing HHV-6 encephalitis in CBT. Methods We included 184 patients who underwent single CBT at Kyoto University Hospital from 2005 to 2022. For those who developed HHV-6 encephalitis, we calculated cumulative steroid doses from transplantation to the date of encephalitis onset, and for those who did not develop encephalitis, we calculated them to 25 days (the median encephalitis onset). Results Median (range) age was 49 years (18-70 years); 82% used tacrolimus and MMF for GVHD prophylaxis; FCN was used prophylactically or preemptively in 141 patients (77%) to prevent HHV6 encephalitis. FCN was used in 35% of patients from day 7 post-transplant, 20% from the time of HHV-6 reactivation, and 8% after the start of steroid administration. HHV-6 encephalitis occurred in 18 (10%) of 184 patients. The median cumulative steroid dose for those receiving steroids was 4.0 mg/kg. Steroid dose (mg/kg) had a significant effect on the development of encephalitis (HR 1.09, P=0.003); pre-engraftment immune reaction had no significant effect. The ROC curve showed that the cutoff for cumulative steroid dose that best predicted the development of encephalitis was 6.5 mg/kg. FCN prophylaxis showed no significant effect in preventing HHV6 encephalitis in the high-steroid group. However, FCN prophylaxis reduced the incidence of HHV6 encephalitis in the low-steroid group with marginal significance (HR 0.22, P=0.070). Patients who developed encephalitis without HHV6 prophylaxis had a significantly lower survival rate than those who did not develop encephalitis (1yr-OS, 25% vs. 69%). However, those who developed encephalitis during HHV6 prophylaxis did not differ significantly from those who did not develop encephalitis (1yr-OS, 59% vs. 69%) (Figure). Discussion FCN prophylaxis significantly reduced the incidence of encephalitis in the low-dose steroid group, whereas prophylaxis was not effective in the high-dose steroid group. However, prophylactic administration may improve the prognosis after the onset of encephalitis.

Single-unit unrelated cord blood transplantation versus HLA-matched sibling transplantation in adults with advanced myelodysplastic syndrome: A registry-based study from the adult MDS working group of the Japanese society for transplantation and cellular therapy.

Allogeneic hematopoietic stem cell transplantation (HCT) remains the only potential curative therapeutic modality for advanced myelodysplastic syndrome (MDS). Within HCT, the advancement of cord blood transplantation (CBT) procedures has resulted in a drastic expansion of CBT as a donor source for MDS. However, data comparing matched sibling donors (MSDs) HCT with CBT for advanced MDS, which was defined as refractory anemia with an excess of blasts (RAEB)-1 and RAEB-2 according to the World Health Organization classification at the time of HCT, have not been explored. We retrospectively compared survival and other posttransplant outcomes in 999 adult patients with advanced MDS after receiving allogeneic HCT in Japan between 2011 and 2020, using either MSD (n=331) or single-unit unrelated cord blood (UCB) (n=668). In the multivariate analysis, there were no significant differences in overall survival (hazard ratio [HR], 1.10; 95% confidence interval [CI], 0.90-1.34; P=0.347), disease-free survival (HR, 1.01; 95% CI, 0.84-1.23; P=0.845), relapse (HR, 0.88; 95% CI, 0.68-1.15; P=0.370), or non-relapse mortality (HR, 1.15; 95% CI, 0.87-1.50; P=0.310) between MSD recipients and UCB recipients. UCB was significantly associated with lower neutrophil (HR, 0.28; 95% CI, 0.24-0.33; P<0.001) and lower platelet (HR, 0.29; 95% CI, 0.23-0.36; P<0.001) recovery compared to MSD. UCB was significantly associated with a lower incidence of chronic graft-versus-host disease (GVHD) (HR, 0.57; 95% CI, 0.44-0.75; P<0.001) and extensive chronic GVHD (HR, 0.46; 95% CI, 0.32-0.67; P<0.001) compared to MSD. Similar results were observed after adjusting for differences between MSD and UCB recipients by propensity score matching analysis. Our study demonstrated that single CBT and MSD HCT had similar survival outcomes for adult patients with advanced MDS despite the lower hematopoietic recovery in CBT recipients and higher chronic GVHD in MSD recipients.

Selection of Cord Blood Unit by CD34+ Cell and GM-CFU Numbers and Allele-Level HLA Matching in Single Cord Blood Transplantation

In Japan, only single-unit cord blood transplantations (CBTs) are typically performed, and their number has increased over the last 23 years, with ongoing improvement in results. In most cases, CBTs with multiple HLA mismatches are used, owing to a low HLA barrier, and lower engraftment rate is a problem that must be overcome. Here, as part of an effort to improve guidelines for the selection and processing of CB units for transplantation, we sought to assess the present status of CBT in Japan and to elucidate factors contributing to the favorable outcomes, focusing in particular on selection by cell components of CB unit and HLA allele matching. We conducted a nationwide study analyzing 13,443 patients who underwent first CBT between in Japan between December 1997 and December 2019 using multivariate regression analysis. Both patient- and transplantation-related variables, such as age and Hematopoietic Cell Transplantation Comorbidity Index, as well as selected CB unit characteristics, were included in the analysis. The interaction analysis elucidated that CB unit selection favoring higher counts of CD34+ cells and granulocyte macrophage colony-forming units (GM-CFU)/kg, but not of total nucleated cells, contributed to improved engraftment after transplantation. Moreover, a higher CD34+ cell dose was associated with improved overall survival (OS). Distinctive HLA allele matching was observed. A 0 or 1 HLA allele mismatch between patient and donor had favorable engraftment and carried significantly lower risks of acute GVHD and chronic GVHD but had a significantly higher leukemia relapse rate, compared with a 3-HLA allele mismatch. HLA-DRB1 mismatches were associated with reduced risk of leukemia relapse. Notably, the number of HLA allele mismatches had no incremental effect on engraftment, acute and chronic GVHD, or relapse incidence. As a result, 5-year overall survival did not differ significantly among patients receiving CB units with 0 to 7 HLA allele mismatches. The main points of CB unit selection are as follows. First, selection according to a higher number of CD34+ cells/kg and then of CFU-GM/kg is recommended to obtain favorable engraftment. A unit with .5 × 105 CD34+ cells/kg is minimally acceptable. For units with a CD34+ cell dose of .5 to 1.0 × 105 cells/kg, applying the parameter of ≥20 to 50 × 103 GM-CFU/kg (66.5% of transplanted CB units in this cohort) is associated with a neutrophil engraftment rate of approximately 90%. A unit with ≥1.0 × 105 CD34+ cells/kg can achieve a ≥90% mean neutrophil engraftment rate. Subsequently, HLA allele matching of HLA-A, -B, -C, and -DRB1 at the 2-field level should be searched for units with 0 or 1 HLA allele mismatch in the host-versus-graft direction for favorable engraftment. Units with 2 to 6 HLA allele mismatches are acceptable in patients age ≥15 years and units with 2 to 4 HLA allele mismatches are acceptable in patients age ≤14 years. Units with HLA-DRB1 and/or -B allele mismatch(es) might not be preferable owing to an increased GVHD risk. Our analysis demonstrates that single-unit CBT with the selection of adequate CD34+/kg and GM-CFU/kg and HLA allele matching showed favorable outcomes in both pediatric and adult patients.

Impact of Allele-Level HLA-Matching on Outcomes after Double Cord Blood Transplantation in Adults with Malignancies.

In single unrelated cord blood transplantation (UCBT), an increasing number of HLA allele mismatches (MM) has been associated with inferior overall survival (OS) attributed to higher transplant-related mortali-ty (TRM). Previous studies on the role of allele-level HLA matching following double UCBT (dUCBT) showed conflicting results. Herein we report the impact of allele-level HLA matching on outcomes of a large dUCBT cohort . We included 963 adults with hematologic malignancies, with available allele-level HLA matching at HLA-A, -B, -C and -DRB1, receiving dUCBT between 2006-2019. Assignment of donor-recipient HLA match was performed considering the unit with the highest disparity with the recipient. 392 patients received dUCBT with 0-3 and 571 with ≥4 allele MM. Day-100 and 4-year TRM were 10% and 23%, for recipients of dUCBT with 0-3 MM compared to 16% and 36% for those with ≥4 MM (HR 1.58, p=.002; and HR 1.54, p=.002), respectively. Higher degree of allele MM was also associated with worse neutrophil recovery and lower incidence of relapse; no significant effect on graft-versus-host disease was observed. Patients receiving units with 0-3 MM had a 4-year OS of 54% versus 43% for those with ≥4 MM (HR 1.40, p=.005). The inferior OS associated with higher HLA disparity was only partially mitigated by increased total nucleated cell doses. Our results confirm that allele-level HLA typing is a significant factor for OS following dUCBT and units with ≥4 MM (≤4/8 HLA-matched) should be avoided if possible.

Effect of Graft-versus-Host Disease on Post-Transplantation Outcomes following Single Cord Blood Transplantation Compared with Haploidentical Transplantation with Post-Transplantation Cyclophosphamide for Adult Acute Myeloid Leukemia

The possibility that HLA mismatches could reduce relapse after alternative HLA-mismatched allogeneic hematopoietic cell transplantation (HCT) is an attractive concept for treating acute myeloid leukemia (AML). However, it remains unclear whether the prognostic effect of graft-versus-host disease (GVHD) on survival differs between recipients of single-unit cord blood transplantation (CBT) and recipients of haploidentical HCT using post-transplantation cyclophosphamide (PTCy-haplo-HCT) for AML. The objective of this retrospective study was to compare the effect of acute GVHD and chronic GVHD on post-transplantation outcomes between recipients of CBT and recipients of PTCy-haplo-HCT. We retrospectively evaluated the effect of acute and chronic GVHD on post-transplantation outcomes following CBT and PTCy-haplo-HCT in adults with AML (n=1981) between 2014 and 2020 using a Japanese registry database. In univariate analysis, the probability of overall survival was significantly greater in patients who developed grade I-II acute GVHD (P < .001, log-rank test) and limited chronic GVHD (P < .001, log-rank test) among CBT recipients, but these effects were not significant among PTCy-haplo-HCT recipients. In multivariate analysis, in which the development of GVHD was treated as a time-dependent covariate, the effect of grade I-II acute GVHD on reducing overall mortality differed significantly between CBT and PTCy-haplo-HCT (adjusted hazard ratio [HR] for CBT, .73, 95% confidence interval [CI], .60 to .87; adjusted HR for PTCy-haplo-HCT, 1.07; 95% CI, .70 to 1.64; P for interaction=.038). Our data demonstrate that grade I-II acute GVHD was associated with a significant improvement in overall mortality in adults with AML receiving CBT but not in recipients of PTCy-haplo-HCT.

Don't forget cord blood in non-remission acute myeloid leukaemia!

Transplantation from haploidentical donors is widely used, with progressive reduction of cord blood (CB) as alternative donor. The paper by Matsuda and colleagues, the largest analysing the outcome in non-remission acute myeloid leukaemia (AML) transplanted with haploidentical donor or CB, suggests that CB is still a viable option when considering allogeneic transplantation for advanced AML. Commentary on: Matsuda et al. Comparison of transplant outcomes between haploidentical transplantation and single cord blood transplantation in non-remission acute myeloid leukaemia: A nationwide retrospective study. Br J Haematol. 2023;201:106-113.

Impact of Allele-Level HLA-Matching on Outcomes after Double Unrelated Cord Blood Transplantation in Adults with Malignant Diseases

Introduction: In single unrelated cord blood transplantation (sCBT), an increasing number of HLA-mismatches (MM) has been associated with inferior overall survival (OS) attributed to higher transplant-related mortality (TRM). These findings have prompted current guidelines to endorse high resolution HLA typing in the selection of CB (cord blood) units, including double CBT (dCBT). However, a comprehensive appraisal of the effect of allele-level HLA matching following dCBT was likely hindered by the relatively small sample sizes in previous studies. Herein we aimed to analyze the impact of allele-level HLA-matching on outcomes of a large cohort of dCBT recipients to improve CB unit selection and further explore the unique dCBT biology. Methods: We included patients ≥18 years-old receiving a dCBT between 2006-2019 with the availability of HLA typing minimally at HLA-A, -B, -C at the antigen-level and HLA-DRB1 at the allele-level for the recipient and both CB units. A validated high-resolution imputation tool, HaploStats, was used to adjudicate allele-level match status for a subset of cord and recipient pairs (n = 173) having only antigen-level typing at HLA-A, -B or -C. A sensitivity analysis for OS was performed excluding imputed cases, and results were unchanged. HLA matching was classified according to the CB unit with the greatest degree of HLA mismatch with the patient, meaning that only the most mismatched unit was considered and that the interunit matching was not considered. Continuous covariates were dichotomized to find an optimal cutoff value by using the Contal-O'Quigley method, except for cryopreserved CD34 and total nucleated cell (TNC) count, whose cutoffs were based on previous findings reported by our group. Pairwise comparisons of the numbers of allele MM showed that receiving units with ≥4 MM had the highest negative impact on OS. Cox and Fine-Gray regression models were built for the different outcomes using the backward elimination method (p<.05 to stay). Results: 963 patients met the eligibility criteria, of which 392 received at least one CB unit with 0-3 allele MM while 571 with ≥4 allele MM. Of those receiving at least one unit with ≥4 allele MM, 18% had a maximum HLA disparity of 5/6 at lower HLA-typing resolution, 69% of 4/6 and 13% of ≤3/6. Median age at dCBT was 49 years old. Acute leukemia and myelodysplastic syndrome (MDS) accounted for 70% of the cases. There was a larger proportion of patients receiving CB units with fewer allele MM after 2012. Other patient-, disease- and CB unit-related characteristics are summarized in Table 1. The day-42 cumulative incidence of neutrophil recovery was 83% (95%CI 81-85). The number of allele MM had no significant impact on neutrophil recovery (≥ 4 MM vs 0-3 MM, multivariate HR 0.94 [0.80-1.11], P=.46). The cumulative incidence of TRM at 4 years was 36% (95% CI 32-40) for patients receiving CB units with ≥4 MM vs. 23% (95% CI 19-28) for those with 0-3 MM (multivariate HR 1.58 [95%CI 1.18-2.11], P=.002] - Fig. 1A). Infectious complications were the most frequent cause of TRM in the group receiving dCBT with ≥ 4 allele MM (40%). Relapse, grade II-IV/III-IV acute and chronic GVHD were not significantly different between the two groups. Patients receiving CB units with 0-3 allele MM had a 4-year survival of 54% (95%CI 49-59) compared to 43% (95%CI 39-47) for those receiving units with ≥4 allele MM (multivariate HR 1.40 [1.11-1.78], P=.005 - Fig. 1B). The inferior OS associated with higher allele HLA disparity was only partially mitigated by increasing the TNC count in multivariate analysis (0-3 MM + TNC ≤ 3.9x10ˆ7/kg vs.0-3 MM + TNC > 3.9x10ˆ7/kg, HR 1.50 [0.97-2.32], P=.07; ≥4 MM + TNC > 4.9x10ˆ7/kg vs. 0-3 MM + TNC > 3.9x10ˆ7/kg, HR 1.42 [1.06-1.89], P=.02; ≥4 MM + TNC ≤ 4.9x10ˆ7/kg vs. 0-3 MM + TNC > 3.9x10ˆ7/kg, HR 1.66 [1.24-2.22], P=<.001 - Fig. 1C). Discussion: Our results confirm that allele-level HLA typing is a significant factor for OS following dCBT. The inferior OS associated with the increasing number of allele-level MM was driven by higher TRM. Selection of CB units with 0-3 allele-level MM is recommended. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Comparison of transplant outcomes between haploidentical transplantation and single cord blood transplantation in non-remission acute myeloid leukaemia: A nationwide retrospective study.

Allogeneic haematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for some patients with acute myeloid leukaemia (AML) who are refractory to chemotherapy. Cord blood transplantation (CBT) is a reasonable option in such cases because of its rapid availability. Recently, a growing number of human leucocyte antigen (HLA)-haploidentical related donor HSCTs (haplo-HSCTs) have been performed, although its effectiveness remains undetermined. Using the Japanese nationwide transplantation registry data, we identified 2438 patients aged ≥16 years who received CBT or haplo-HSCT as their first transplant for non-remission AML between January 2008 and December 2018. After 2:1 propensity score matching, 918 patients in the CBT group and 459 patients in the haplo-HSCT group were selected. In this matched cohort, no significant difference in overall survival (OS) was observed between the CBT and haplo-HSCT groups (hazard ratio [HR] of haplo-HSCT to CBT 1.02, 95% confidence interval [CI] 0.89-1.16). Similarly, no significant difference in the cumulative incidence of relapse (HR 1.09, 95% CI 0.93-1.28) or non-relapse mortality (HR 0.94, 95% CI 0.76-1.18). Subgroup analysis showed that CBT was significantly associated with preferable OS in patients receiving myeloablative conditioning. Our data showed comparable outcomes between haplo-HSCT and CBT recipients with non-remission AML.

Unrelated Cord Blood Transplantation in Children, Adolescents, and Young Adults with Acute Leukemia or Myelodysplastic Syndrome: A Retrospective Comparative Study from the French Society for Bone Marrow Transplantation and Cellular Therapy Between Real-World Data and Previously Reported Results of a Randomized Clinical Trial

We previously reported results of a French randomized clinical trial (RCT) comparing the risk of transplantation failure (including transplant-related mortality [TRM], engraftment failure, and autologous recovery) in single and double unrelated cord blood (UCB) transplantation in children and young adults with hematologic malignancies. We concluded that single-UCB transplantation with an adequate cell dose is the standard of care, leading to a 70% two-year overall survival (OS). It remains unclear, however, whether RCT participants have better outcomes than comparable patients not treated in the setting of a clinical trial. We compared the characteristics and outcomes of RCT participants (n=137) to a Francophone population-based registry of patients (real-world [RW] group) fulfilling the eligibility criteria used in our RCT and transplanted with 1 or 2 UCB units after a myeloablative conditioning (MAC) regimen between March 2015 (end of inclusion in the RCT) and February 2019 (n=141). The primary endpoint was the 2-year cumulative incidence (CI) of transplantation strategy failure as defined in our RCT. The 2 groups were comparable in terms of age, disease distribution, hematologic status at transplantation, follow-up, and HLA compatibility. Patients in the RW group were more likely to be transplanted with a single-unit UCB (87.9% versus 49.6%, P< .001) and to receive a radiation-free regimen (39.0% versus 60.6%, P< .001). The 2-year CI of transplantation strategy failure, TRM, and the 2-year probability of OS were similar between the 2 groups, although the relapse risk was higher in the RW group (31.2% ± 7.7% versus 20.4% ± 6.8%, P= .01), resulting in a significantly lower disease-free survival (DFS) (59.2% ± 8.4% versus 69.3% ± 8.0%, P= .047). This difference remained statistically significant only in the group of patients with acute lymphoid leukemia (ALL) who did not receive the conditioning regimen recommended by the RCT (fludarabine 75 mg/m2, total body irradiation 12 Gy, cyclophosphamide 120 mg/kg). The results of our RCT appear to be reproducible in real-world conditions, provided that the same cord blood selection criteria and conditioning regimen are used.

Effect of Multiple HLA Locus Mismatches on Outcomes after Single Cord Blood Transplantation

The effect of single or multiple mismatches at each HLA locus on outcomes after cord blood transplantation (CBT) is controversial. We analyzed the effects of single or multiple HLA locus mismatches on the outcomes after single CBT using Japanese registry data from the Japan Society for Hematopoietic Cell Transplantation. Patients age ≥16 years with acute leukemia and myelodysplastic syndromes who underwent their first CBT between 2003 and 2017 (n=4074) were included. The effect of the number of HLA locus mismatches (0, 1, or 2 for the HLA-A, -B, -C, and -DRB1 loci) on outcomes was analyzed after adjusting for other significant variables. The patient cohort had a median age of 54 years. The median total nucleated and CD34 cell doses were 2.6×107/kg and .8×105/kg, respectively. The number of CBTs with single or double mismatches were 2099 and 292, respectively, for the HLA-A locus, 2699 and 341 for the HLA-B locus, 2555 and 609 for the HLA-C locus, and 2593 and 571 for the HLA-DRB1 locus. Single and double HLA-DRB1 mismatches were associated with a higher risk of grade II-IV acute graft-versus-host disease (GVHD; single: hazard ratio [HR], 1.29, P < .001; double: HR, 1.49, P < .001; P for trend <.001). Single and double mismatches at HLA-DRB1 as well as single mismatches at HLA-A and HLA-B also were associated with grade III-IV acute GVHD. Single and double HLA-B mismatches and double HLA-DRB1 mismatches were associated with a high risk of nonrelapse mortality (NRM). On the other hand, double mismatches at HLA-A or HLA-DRB1 and single mismatches at HLA-B were associated with a lower risk of relapse. HLA-DRB1 double mismatch was associated with high risk of grade II-IV and grade III-IV acute GVHD and NRM but lower risk of relapse. Not only the locus mismatch, but also the number of mismatches, should be considered in cord blood unit selection.