GRFS and CRFS in alternative donor hematopoietic cell transplantation for pediatric patients with acute leukemia

Prognostic impact of the conditioning intensity on outcomes after allogeneic transplantation for MDS with low blasts: a nationwide retrospective study by the adult MDS working group of the Japan Society for Transplantation and Cellular Therapy

Poor prognostic factors, such as transfusion dependency and chromosomal risk, need to be considered in the indication of allogeneic hematopoietic cell transplantation (allo-HCT) for patients harboring myelodysplastic syndromes with less than 5% marrow blasts (MDS-Lo). We analyzed the post-transplant outcomes of 1229 MDS-Lo patients who received myeloablative (MAC)(n = 651), reduced-intensity (RIC)(n = 397), and non-myeloablative conditioning (NMAC) regimens (n = 181). The multivariate analysis revealed that the RIC group had better chronic graft-versus-host disease (GVHD)- and relapse-free survival (CRFS) (P = 0.021), and GVHD- and relapse-free survival (GRFS) than the MAC group (P = 0.001), while no significant differences were observed between the NMAC and MAC groups. In the subgroup analysis, the MAC group has better overall survival (P = 0.008) than the RIC group among patients with an HCT-comorbidity index (HCT-CI) score of 0, while the RIC group had better overall survival (P = 0.029) than the MAC group among those with an HCT-CI score ≥3. According to the type of conditioning regimen, total body irradiation 12 Gy-based MAC regimen showed better OS and CRFS than the other MAC regimen, and comparable outcomes to the RIC regimen. In conclusion, the RIC and NMAC regimens are promising options for MDS-Lo patients in addition to the MAC regimen.

Immunology of cord blood T-cells favors augmented disease response during clinical pediatric stem cell transplantation for acute leukemia

Allogeneic hematopoietic stem cell transplantation (HSCT) has been an important and efficacious treatment for acute leukemia in children for over 60 years. It works primarily through the graft-vs.-leukemia (GVL) effect, in which donor T-cells and other immune cells act to eliminate residual leukemia. Cord blood is an alternative source of stem cells for transplantation, with distinct biological and immunological characteristics. Retrospective clinical studies report superior relapse rates with cord blood transplantation (CBT), when compared to other stem cell sources, particularly for patients with high-risk leukemia. Xenograft models also support the superiority of cord blood T-cells in eradicating malignancy, when compared to those derived from peripheral blood. Conversely, CBT has historically been associated with an increased risk of transplant-related mortality (TRM) and morbidity, particularly from infection. Here we discuss clinical aspects of CBT, the unique immunology of cord blood T-cells, their role in the GVL effect and future methods to maximize their utility in cellular therapies for leukemia, honing and harnessing their antitumor properties whilst managing the risks of TRM.

Allogeneic transplantation of bone marrow versus peripheral blood stem cells from HLA-identical relatives in patients with myelodysplastic syndromes and oligoblastic acute myeloid leukemia: a propensity score analysis of a nationwide database

Bone marrow (BM) and granulocyte colony-stimulating factor-mobilized peripheral blood stem cells (PBSC) are used as grafts from HLA-identical-related donors for adults with myelodysplastic syndrome (MDS). To assess the impact of graft sources on post-transplant outcomes in MDS patients, we conducted a retrospective analysis of a nationwide database. A total of 247 and 280 patients underwent transplantation with BM and PBSC, respectively. The inverse probability of treatment weighting (IPTW) methods revealed that overall survival (OS) was comparable between BM and PBSC (P = .129), but PBSC transplantation was associated with worse graft-versus-host disease (GVHD)-free/relapse-free survival (GRFS) (hazard rate [HR], 1.24; 95% confidence intervals [CIs], 1.00-1.53; P = 0.049) and chronic GVHD-free and relapse-free survival (CRFS) (HR, 1.29; 95% CIs, 1.13-1.73; P = 0.002) than BM transplantation. In the propensity score matched cohort (BM, n = 216; PBSC, n = 216), no significant differences were observed in OS and relapse; 3-year OS rates were 64.7% and 60.0% (P = 0.107), while 3-year relapse rates were 27.1% and 23.5% (P = 0.255) in BM and PBSC, respectively. Three-year GRFS rates (36.6% vs. 29.2%; P = 0.006), CRFS rate (37.7% vs. 32.5%; P = 0.003), and non-relapse mortality rates (13.9% vs. 21.1%; P = 0.020) were better in BM than in PBSC. The present study showed that BM transplantation provides a comparable survival benefit with PBSC transplantation and did not identify an enhanced graft-versus-MDS effect to reduce the incidence of relapse in PBSC transplantation.

Umbilical cord blood: an undervalued and underutilized resource in allogeneic hematopoietic stem cell transplant and novel cell therapy applications

PURPOSE OF REVIEW

The purpose of this review is to primarily discuss the unwarranted decline in the use of umbilical cord blood (UCB) as a source of donor hematopoietic stem cells (HSC) for hematopoietic cell transplantation (HCT) and the resulting important implications in addressing healthcare inequities, and secondly to highlight the incredible potential of UCB and related birthing tissues for the development of a broad range of therapies to treat human disease including but not limited to oncology, neurologic, cardiac, orthopedic and immunologic conditions.

RECENT FINDINGS

When current best practices are followed, unrelated donor umbilical cord blood transplant (CBT) can provide superior quality of life-related survival compared to other allogeneic HSC donor sources (sibling, matched or mismatched unrelated, and haploidentical) through decreased risks of relapse and chronic graft vs. host disease. Current best practices include improved UCB donor selection criteria with consideration of higher resolution human leukocyte antigen (HLA) typing and CD34+ cell dose, availability of newer myeloablative but reduced toxicity conditioning regimens, and rigorous supportive care in the early posttransplant period with monitoring for known complications, especially related to viral and other infections that may require intervention. Emerging best practice may include the use of ex vivo expanded single-unit CBT rather than double-unit CBT (dCBT) or 'haplo-cord' transplant, and the incorporation of posttransplant cyclophosphamide as with haploidentical transplant and/or incorporation of novel posttransplant therapies to reduce the risk of relapse, such as NK cell adoptive transfer. Novel, non-HCT uses of UCB and birthing tissue include the production of UCB-derived immune effector cell therapies such as unmodified NK cells, chimeric antigen receptor-natural killer cells and immune T-cell populations, the isolation of mesenchymal stem cells for immune modulatory treatments and derivation of induced pluripotent stem cells haplobanks for regenerative medicine development and population studies to facilitate exploration of drug development through functional genomics.

SUMMARY

The potential of allogeneic UCB for HCT and novel cell-based therapies is undervalued and underutilized. The inventory of high-quality UCB units available from public cord blood banks (CBB) should be expanding rather than contracting in order to address ongoing healthcare inequities and to maintain a valuable source of cellular starting material for cell and gene therapies and regenerative medicine approaches. The expertise in Good Manufacturing Practice-grade manufacturing provided by CBB should be supported to effectively partner with groups developing UCB for novel cell-based therapies.

Cytomegalovirus infection may be oncoprotective against neoplasms of B-lymphocyte lineage: single-institution experience and survey of global evidence

Background

Although cytomegalovirus (CMV) is not considered tumorigenic, there is evidence for its oncomodulatory effects and association with hematological neoplasms. Conversely, a number of experimental and clinical studies suggest its putative anti-tumour effect. We investigated the potential connection between chronic CMV infection in patients with B-lymphocyte (B-cell) malignancies in a retrospective single-center study and extracted relevant data on CMV prevalences and the incidences of B-cell cancers the world over.

Methods

In the clinical single-center study, prevalence of chronic CMV infection was compared between patients with B-cell leukemia/lymphoma and the healthy controls. Also, global data on CMV seroprevalences and the corresponding country-specific incidences of B- lineage neoplasms worldwide were investigated for potential correlations.

Results

Significantly higher CMV seropositivity was observed in control subjects than in patients with B-cell malignancies (p = 0.035). Moreover, an unexpected seroepidemiological evidence of highly significant inverse relationship between country-specific CMV prevalence and the annual incidence of B-cell neoplasms was noted across the populations worldwide (ρ = −0.625, p < 0.001).

Conclusions

We try to draw attention to an unreported interplay between CMV infection and B-cell lymphomagenesis in adults. A large-scale survey across > 70 countries disclosed a link between CMV and B-cell neoplasms. Our evidence hints at an antagonistic effect of chronic CMV infection against B-lymphoproliferation.

Strategies for Success With Umbilical Cord Haematopoietic Stem Cell Transplantation in Children With Malignant and Non-Malignant Disease Indications

Umbilical Cord blood is an intuitively attractive stem cell source, but its use has declined since it is associated with an increased procedure-related morbidity and transplant related mortality. Some of this reflects that cord blood transplants are more often HLA-mismatched compared to other unrelated donor transplants. The ability to transplant in such a setting, indeed without high rates of chronic Graft versus Host Disease (GVHD), constitutes an advantage compared to other unrelated donor cell sources and there are other advantages specifically associated with cord blood as a donor cell source. These advantages must be weighed against its disadvantage, and we have utilised cord blood preferentially as a donor cell source in certain clinical situations in paediatric medicine. In non-malignant diseases, outcomes in metabolic disease are critically dependent on age at transplant and the enzyme delivered by that transplant, and in cord blood transplantation then the time to transplant can be minimised and the engrafted recipients have higher chimerism that delivers higher enzyme levels. In malignant diseases, studies have described reduced relapse rate and better GVHD-free survival, and so we have prioritised cord as a donor cell source where the risk of relapse is highest, and the effects of higher transplant related mortality is most clearly offset by the reduced relapse rates.

Anti-thymocyte globulin with CsA and MMF as GVHD prophylaxis in nonmyeloablative HLA-mismatched allogeneic HCT

Nonmyeloablative regimens are used for allogeneic hematopoietic cell transplantation (HCT) of older or medically unfit patients, but successful outcome is still hindered by graft-versus-host disease (GVHD), especially in the setting of HLA-mismatched HCT. New GVHD prophylaxis strategies are emerging, including the triple drug strategy, that improve the GVHD-free and relapse-free survival (GRFS). Because the impact of ATG in HLA-mismatched Flu-TBI-based nonmyeloablative HCT has not been investigated, we did a retrospective analysis in three Dutch centers. 67 patients were evaluable, with a median age of 56 years. Overall survival, relapse-free survival and GRFS at 4 years were 52%, 43%, and 38%, respectively. NRM findings and cumulative incidence of relapse at 4 years were 26% and 31%, respectively. At 1-year grade II-IV had occurred in 40% of the patients, and the incidence of moderate-severe chronic GVHD incidence was 16%. Acknowledging the limitations of retrospective analyses, we conclude that the use of ATG for HLA-mismatched truly nonmyeloablative Flu-TBI HCT is feasible and results in acceptable long term outcomes, especially with regards to GRFS. We consider ATG in combination with cyclosporin and mycophenolate mofetil as an alternative for the triple drug strategy that uses sirolimus for GVHD prophylaxis in this particular setting.

Adult cord blood transplant results in comparable overall survival and improved GRFS vs matched related transplant

We compared outcomes among adult matched related donor (MRD) patients undergoing peripheral blood stem cell transplantation and adult patients undergoing double unit cord blood transplantation (CBT) at our center between 2010 and 2017. A total of 190 CBT patients were compared with 123 MRD patients. Median follow-up was 896 days (range, 169-3350) among surviving CBT patients and 1262 days (range, 249-3327) among surviving MRD patients. Comparing all CBT with all MRD patients, overall survival (OS) was comparable (P = .61) and graft-versus-host disease (GVHD) relapse-free survival (GRFS) was significantly improved among CBT patients (P = .0056), primarily because of decreased moderate to severe chronic GVHD following CBT (P < .0001; hazard ratio [HR], 3.99; 95% confidence interval [CI], 2.26-7.04). Among patients undergoing our most commonly used MRD and umbilical cord blood (CB) myeloablative regimens, OS was comparable (P = .136) and GRFS was significantly improved among CBT patients (P = .006). Cumulative incidence of relapse trended toward decreased in the CBT group (P = .075; HR, 1.85; CI 0.94-3.67), whereas transplant-related mortality (TRM) was comparable (P = .55; HR, 0.75; CI, 0.29-1.95). Among patients undergoing our most commonly used nonmyeloablative regimens, OS and GRFS were comparable (P = .158 and P = .697). Cumulative incidence of both relapse and TRM were comparable (P = .32; HR, 1.35; CI, 0.75-2.5 for relapse and P = .14; HR, 0.482; CI, 0.18-1.23 for TRM). Our outcomes support the efficacy of CBT and suggest that among patients able to tolerate more intensive conditioning regimens at high risk for relapse, CB may be the preferred donor source.

Outcomes of Adolescents and Young Adults Compared with Children with Acute Leukemia after Single-Unit Unrelated Cord Blood Transplantation Using Myeloablative Conditioning without Antithymocyte Globulin

BACKGROUND

Although the use of cord blood transplantation (CBT) is becoming more frequent in acute leukemia, considering the relationship between the low stem cell dose and graft failure, whether use of CBT for adolescents and young adults (AYAs) is appropriate remains uncertain.

METHODS

A retrospective registry-based analysis of clinical outcomes and immune reconstitution was conducted for 105 AYAs and 187 children with acute leukemia who underwent single-unit CBT using myeloablative conditioning (MAC) without antithymocyte globulin (ATG).

RESULTS

Outcomes were similar between AYAs and children, except for nonrelapse mortality (NRM) and recovery rates of neutrophils and platelets. The 30-day cumulative incidence of neutrophil engraftment was similar between AYAs and children, but children had faster rates of neutrophil and platelet recovery than AYAs. The median time to neutrophil engraftment was earlier in children than in AYAs (AYAs, 19 days, 95% confidence interval [CI] 17.3-21.7; children, 16 days, 95% CI 13.1-19.5, p = 0.00003). The incidence of platelet recovery on day 120 was higher in children than in AYAs (AYAs, 80%, 95% CI 71-81%; children, 88%, 95% CI 82-92%, p = 0.037). CD34+ cell dose was the only independent factor influencing both neutrophil and platelet recovery. The cumulative incidence of NRM at 2 years was higher among AYAs than among children (AYAs, 27.5%, 95% CI 20-37%; children, 15%, 95% CI 10-21%, p = 0.008). Conditioning regimen was an independent factor influencing NRM. With respect to immune reconstitution, natural killer cell counts quickly recovered to normal levels 1-month post-CBT in both children and AYAs. CD8+ T-cell counts were higher in children than in AYAs at 1 and 3 months post-CBT. CD4+ T-cell counts were similar in both children and AYAs after CBT.

CONCLUSION

AYAs with acute leukemia have outcomes of single-unit CBT using MAC without ATG that are as good as those of children. Thus, single-unit CBT using modified MAC without ATG is an acceptable choice for both AYAs and children who do not have a suitable donor.

Randomised controlled trial of conditioning regimen for cord blood transplantation for adult myeloid malignancies comparing high-dose cytarabine/cyclophosphamide/total body irradiation with versus without G-CSF priming: G-CONCORD study protocol

INTRODUCTION

A better long-term quality of life after umbilical cord blood transplantation (CBT) is observed compared with transplants from other alternative donors, whereas graft failure and relapses after CBT are still major issues. To minimise graft failure and relapse after CBT, intensification of conditioning by the addition of high-dose cytosine arabinoside (CA) and concomitant continuous use of granulocyte-colony stimulating factor (G-CSF) are reported to convey a significantly better survival after CBT in some retrospective studies. To confirm the effect of G-CSF plus CA combination, in addition to the standard conditioning regimen, cyclophosphamide (CY)/total body irradiation (TBI), we design a randomised controlled study comparing CA/CY/TBI with versus without G-CSF priming (G-CSF combined conditioned cord blood transplantation [G-CONCORD] study).

METHODS AND ANALYSIS

This is a multicentre, open-label, randomised phase III study that aimed to compare G-CSF+CA/CY/TBI as a conditioning regimen for CBT with CA/CY/TBI. Patients with acute myeloid leukaemia or myelodysplastic syndrome, aged 16-55 years, are eligible. The target sample size is 160 and the registration period is 4 years. The primary endpoint is the 2-year disease-free survival rate after CBT. The secondary endpoints are overall survival, relapse, non-relapse mortality, acute and chronic graft-versus-host disease, engraftment rate, time to neutrophil recovery, short-term adverse events, incidence of infections and causes of death.This study employs a single one-to-one web-based randomisation between the with-G-CSF versus without-G-CSF groups after patient registration. Combination of high-dose CA and CY/TBI in both groups is used for conditioning.

ETHICS AND DISSEMINATION

The study protocol was approved by the central review board, Nagoya University Certified Review Board, after the enforcement of the Clinical Trials Act in Japan. The manuscripts presenting data from this study will be submitted for publication in quality peer-reviewed medical journals. Study findings will be disseminated via presentations at national/international conferences and peer-reviewed journals.

TRIAL REGISTRATION NUMBERS

UMIN000029947 and jRCTs041180059.

T-Cell Replete Myeloablative Haploidentical Bone Marrow Transplantation Is an Effective Option for Pediatric and Young Adult Patients With High-Risk Hematologic Malignancies

Twenty-one pediatric and young adult patients (1.1-24.7 years) with hematologic malignancies underwent myeloablative T-cell replete haploidentical bone marrow transplant (haplo-BMT) between October 2015 to December 2019. Fifty-seven percent of the patients were ethnic or racial minorities. Thirteen patients had B-cell precursor acute lymphoblastic leukemia (B-ALL) with 10 receiving 1,200 cGy fractionated total body irradiation with fludarabine while the remaining 11 patients had targeted dose-busulfan, fludarabine, melphalan conditioning. Graft-vs.-host disease (GvHD) prophylaxis consisted of post-transplant cyclophosphamide (15 patients) or cyclophosphamide and bendamustine (six patients), with all patients receiving tacrolimus and mycophenolate mofetil. Twelve patients were in first or second remission at time of transplant with five in >2nd remission and four with measurable disease. Three patients had failed prior transplants and three CAR-T cell therapies. Only one patient developed primary graft failure but engrafted promptly after a second conditioned T-replete peripheral blood stem cell transplant from the same donor. An absolute neutrophil count of 0.5 × 109/L was achieved at a median time of 16 days post-BMT while platelet engraftment occurred at a median of 30 days. The cumulative incidence of grades III to IV acute GvHD and chronic GvHD was 15.2 and 18.1%, respectively. With a median follow-up of 25.1 months the relapse rate is 17.6% with an overall survival of 84.0% and a progression-free survival of 74.3%. The chronic graft-vs.-host-free relapse-free survival (CRFS) is 58.5% while acute and chronic graft-vs.-host-free relapse-free survival (GRFS) is 50.1%. Myeloablative conditioned T-replete haploidentical BMT is a viable alternative to matched unrelated transplantation for children and young adults with high-risk hematologic malignancies.