Comparison of cord blood transplantation with unrelated bone marrow transplantation in patients older than fifty years

Guidelines for Adult Patient Selection and Conditioning Regimens in Cord Blood Transplant Recipients with Hematologic Malignancies and Aplastic Anemia

For cord blood transplantation (CBT), appropriate patient and conditioning regimen selection is necessary to achieve long-term disease-free survival. This review aims to provide comprehensive guidelines on these issues using evidence from the literature and experience at dedicated CBT centers. Topics include patient and disease characteristics that make CBT a good or poor choice and a review of outcomes in commonly used conditioning regimens in CBT. This is accompanied with recommendations on regimen intensity based on disease, organ function, and patient performance status and age. In addition, the use of antithymocyte globulin in CBT is discussed, as is the choice of conditioning in aplastic anemia patients who have access to acceptable CB units.

Phase I clinical trial of intra-bone marrow cotransplantation of mesenchymal stem cells in cord blood transplantation

Mesenchymal stem cells (MSCs) have immunomodulatory properties and support hematopoiesis in the bone marrow (BM). To develop a new strategy to not only prevent graft‐vs‐host disease (GVHD) but also to enhance engraftment, a phase I trial of cord blood transplantation (CBT) combined with intra‐BM injection of MSCs (MSC‐CBT) was designed. Third‐party BM‐derived MSCs were injected intra‐BM on the day of CBT. The conditioning regimen varied according to patient characteristics. GVHD prophylaxis was tacrolimus and methotrexate. The primary endpoint was toxicity related to intra‐BM injection of MSCs. Clinical outcomes were compared with those of six controls who received CBT alone. Five adult patients received MSC‐CBT, and no adverse events related to intra‐BM injection of MSCs were observed. All patients achieved neutrophil, reticulocyte, and platelet recoveries, with median times to recoveries of 21, 35, and 38 days, respectively, comparable with controls. Grade II‐IV acute GVHD developed in three controls but not in MSC‐CBT patients. No patients developed chronic GVHD in both groups. At 1 year after transplantation, all MSC‐CBT patients survived without relapse. This study shows the safety of MSC‐CBT, and the findings also suggest that cotransplantation of MSCs may prevent GVHD with no inhibition of engraftment. This trial was registered at the University Hospital Medical Information Network Clinical Trials Registry as number 000024291.

Umbilical cord blood: The promise and the uncertainty

Unfortunately, many patients referred for hematopoietic cell transplant will not have a fully matched related donor, and finding matched unrelated donors through the registry may be difficult, especially if the recipient is not of Northern European descent [N Engl J Med 2014;371:339‐348]. Umbilical cord blood (UCB) has been an available graft source for hematopoietic cell transplant for more than 30 years, since the first UCB transplant was performed in the late 1980s [N Engl J Med 1989;321:1174‐1178]. UCB is readily available, has low immunogenicity, and does not require as strict of human leukocyte antigen (HLA) matching compared to other graft sources [N Engl J Med 2004;351:2265‐2275]. According to data from the Center for International Blood and Marrow Transplant Research (CIBMTR), an estimated 500 patients in the US will have received a UCB transplant in 2018. Since 2014, haploidentical transplants have surpassed UCB transplants performed in the United States (CIBMTR Summary Slides, 2018, available at https://www.cibmtr.org). Increased use of haploidentical transplants has brought to light concerns about UCB transplants, including delayed engraftment and graft failure, increased nonrelapse mortality, increased infection risk, and UCB acquisition costs [Lancet Oncol 2010;11:653‐660; Biol Blood Marrow Transplant 2019;1456‐1464]. These concerns will need to be addressed for UCB to remain a viable option as a graft source for hematopoietic cell transplant. Other promising therapeutic benefits for UCB, in addition to hematopoietic cell transplant, is its use in regenerative medicine and immune modulation, which is currently being evaluated in ongoing clinical trials.

Prospective evaluation of alternative donor from unrelated donor and cord blood in adult acute leukemia and myelodysplastic syndrome

A prospectively registered observational study was conducted to assess the significance of allogeneic hematopoietic stem cell transplantation from highly HLA-matched unrelated donors (UD) and cord blood (CB) on outcomes in adult acute leukemia (AL) and myelodysplastic syndrome (MDS). Between 2007 and 2015, 231 transplant-eligible patients were registered for a phase 2 study of alternative donor transplantation. After registration, a sufficient time period was given to find appropriate UD. Patients received CB transplantation (CBT) if an appropriate UD was unavailable. In total, 119 patients received CBT (106 AL and 13 MDS) and 91 patients received UD transplantation (UDT) (86 AL and 5 MDS). The median age was 39 years in both groups. The primary objective was overall survival (OS); secondary objectives included cumulative incidences of non-relapse mortality (NRM) and relapse, and disease-free survival. Diagnosis, disease status at transplantation, refined disease risk index, and hematopoietic cell transplant-specific comorbidity index did not differ between UDT and CBT. In multivariate analyses, graft source was not a significant risk factor for all objectives. In adjusted analyses, UDT and CBT showed similar OS, NRM, and relapse in this prospective study. CB can be a comparable alternative stem cell source to UD by achieving a timely transplant.

Role of alternative donor allogeneic hematopoietic stem cell transplantation in patients with intermediate- or poor-risk acute myeloid leukemia in first complete remission

Allogeneic hematopoietic stem cell transplantation (HCT) offers the most effective prevention of relapse and has significant overall survival (OS) benefits for patients with acute myeloid leukemia (AML) in first complete remission (CR1). We conducted a retrospective analysis of a cohort of patients with intermediate- or poor-risk AML. The purpose of the present study was to investigate the role of alternative donors for AML in CR1. We analyzed 1561 patients who underwent HCT from an HLA-matched related donor (MRD), HLA 8/8-matched unrelated donor (MUD), or umbilical cord blood (UCB). The results of a multivariate analysis showed that HCT from UCB (HR = 1.28, 95% CI: 1.07-1.52), age ≥50 years (HR = 1.36, 95% CI: 1.14-1.62), male (HR = 1.42, 95% CI: 1.21-1.66), PS > 1 (HR = 1.68, 95% CI: 1.17-2.42), and poor-risk cytogenetics (HR = 1.53, 95% CI: 1.29-1.81) had an inferior prognostic impact on OS. We conclude that an MUD is the best alternative to an HLA identical MRD for patients with AML in CR1. UCB is an alternative option if neither MRD nor MUD are available, or when patients need to receive urgent HCT for poor-risk AML in CR1.

Phase I study of cord blood transplantation with intrabone marrow injection of mesenchymal stem cells: A clinical study protocol

INTRODUCTION

Delayed hematological recovery, graft failure, and acute graft-versus-host disease (GVHD) still remain major problems in cord blood transplantation (CBT). Mesenchymal stem cells (MSCs) are known to support bone marrow stroma and promote hematopoiesis. Additionally, MSCs possess immunomodulatory properties and are used clinically for the treatment of acute GVHD. Therefore, the use of MSCs to enhance engraftment and prevent GVHD after allogeneic hematopoietic cell transplantation has been explored. Recent clinical trials have shown the feasibility and safety of intravenous cotransplantation of MSCs with cord blood cells in pediatric patients, but not in adult patients, who are at greater risk of graft failure. As for the route of administration of MSCs, direct intrabone marrow injection of MSCs is thought to enhance the engraftment of cord blood cells more than intravenous injection. Based on these background findings, this clinical trial was designed to develop a new strategy to enhance engraftment and prevent GVHD after CBT.

METHODS AND ANALYSIS

This is a single-center, phase I, clinical study to evaluate the safety of CBT combined with intrabone marrow injection of ex vivo expanded MSCs from bone marrow of a third-party donor. Adult patients with hematological disorders are eligible for this study. The target sample size is 5, and the registration period is 3 years. The target dose of MSCs infused is 0.5 × 10 cells/kg of patient body weight. On the day of CBT, MSCs are injected into the intrabone marrow of the patient 4 hours before the infusion of a single cord blood unit. The conditioning regimen varies according to patient age and disease. GVHD prophylaxis consists of a combination of tacrolimus and methotrexate. The primary endpoint of this study is infusional toxicity of MSCs within 14 days after transplantation.

Prospective observational study on the first 51 cases of peripheral blood stem cell transplantation from unrelated donors in Japan

The Japan Marrow Donor Program (JMDP) has facilitated unrelated peripheral blood stem cell transplantation (URPBSCT) since 2010. We conducted a prospective multicenter observational study to evaluate the feasibility of such transplantation. Between 2011 and 2014, 51 patients underwent URPBSCT from 8/8 allele-matched donors for hematological malignancies. The median age of the patients was 50 years; 21 had high-risk disease. Myeloablative conditioning regimens were used in 31 patients, and tacrolimus based graft-versus-host disease (GVHD) prophylaxis was used for all patients. The cumulative rate of engraftment was 96%. With a median follow-up period of 610 days for survivors, 100-day and 1-year overall survival rates were 86 and 59%, respectively. The cumulative incidence of non-relapse mortality and relapse at 1 year were 14 and 35%, respectively. The incidence of grade II to IV acute GVHD at 100 days and extensive type of chronic GVHD at 1 year were 25 and 32%, respectively. The probability of overall survival was comparable with that of bone marrow transplantation from HLA matched-unrelated donors in Japan, although the incidence of chronic GVHD was higher. Further follow-up with more patients is clearly warranted to establish the optimal use of URPBSCT together with the approaches of minimizing chronic GVHD.

GvHD prophylaxis after single-unit reduced intensity conditioning cord blood transplantation in adults with acute leukemia

To investigate better GVHD prophylaxis in reduced intensity conditioning umbilical cord blood transplantation (RIC-UCBT), we compared transplant outcomes after UCBT among GvHD prophylaxes using the registry data. We selected patients transplanted for AML or ALL with a calcineurin inhibitor and methotrexate (MTX)/mycophenolate mofetil (MMF) combination. A total of 748 first RIC-UCBT between 2000 and 2012 (MTX+ group, 446, MMF+ group, 302) were included. The cumulative incidence of neutrophil and platelet counts higher than 50 000/μL was significantly better in the MMF+ group (relative risk (RR), 1.55; P<0.001: RR, 1.34; P=0.003, respectively). In multivariate analyses, the risk of grade II-IV and III-IV acute GvHD was significantly higher in the MMF+ group than in the MTX+ group (RR, 1.75; P<0.001: RR, 1.97; P=0.004, respectively). In disease-specific analyses of AML, the risk of relapse of high-risk disease was significantly lower in the MMF+ group (RR, 0.69; P=0.009), whereas no significant difference was observed in the risk of relapse-free and overall survival in high-risk disease. In patients with standard-risk disease, no significant differences were noted in the risk of relapse or survival between the MTX+ and MMF+ groups. Collectively, these results suggest that MMF-containing prophylaxis may be preferable in RIC-UCBT, particularly for high-risk disease.

Alternative Donor Graft Sources for Adults with Hematologic Malignancies: A Donor for All Patients in 2017!

Hematopoietic stem cell transplant (HSCT) is potentially curative for a wide variety of malignant diseases, including acute and leukemias, lymphoma, and myelodysplasia. Choice of a stem cell donor is dependent on donor availability, donor compatibility and health, recipient disease type, and recipient condition. Current sources of stem cell donation for HSCT are matched sibling donors (MSDs), matched unrelated donors (MUDs), 1-antigen mismatched unrelated donors (MMUDs), haploidentical donors (haplo), and umbilical cord blood (UCB) units. Historically, preferred donors for HSCT have been human leukocyte antigen (HLA)-matched sibling donors; however, only about 30% of U.S. patients will have a MSD available. The majority of patients referred for HSCT will require an alternative donor graft: MUD, MMUD, UCB, or haplo. The likelihood of finding a MUD varies depending on the ethnicity of the recipient. White Caucasians of European descent have the greatest chance of finding a MUD. Chances of finding a MUD are significantly less for African-American or Hispanic recipients due to HLA polymorphisms. Therefore, MMUD, UCB, and haplo donor graft sources expand the donor pool for recipients who do not have a MSD or MUD available. Given the variety of different donor stem cell sources available today, nearly every patient who needs an allogeneic HSCT has a potential donor in 2017. All transplant-eligible patients with hematologic malignancies should be evaluated by a transplant center to determine if HSCT is a viable treatment option for their underlying disease process.

IMPLICATIONS FOR PRACTICE

The goal of this review is to increase the awareness of oncology practitioners to the availability of alternative donor stem cell transplants for patients with hematologic malignancies. Despite new agents, stem cell transplant remains the only curative therapy for many patients with acute and chronic leukemia, myelodysplasia, and lymphoma. Given the variety of different donor stem cell sources available today, nearly every patient who needs an allogeneic stem cell transplant will have a donor.

Comparison of transplant outcomes from matched sibling bone marrow or peripheral blood stem cell and unrelated cord blood in patients 50 years or older

Older recipient and donor age were associated with higher incidences of severe graft-versus-host disease (GVHD) and mortality after allogeneic hematopoietic stem cell transplantation from matched sibling donors (MSDs) and matched unrelated donors. Since a lower incidence of severe GVHD is advantageous in unrelated cord blood transplantation (CBT), a higher incidence of GVHD using older MSDs could be overcome using cord blood for older patients. We retrospectively analyzed Japanese registration data of 2,091 patients with acute myeloid leukemia, acute lymphoblastic leukemia (ALL), and myelodysplastic syndrome aged 50 years or older who underwent MSD bone marrow transplantation (BMT) (n = 319), MSD peripheral blood stem cell transplantation (PBSCT) (n = 462), or unrelated CBT (n = 1,310) between 2007 and 2012. Median age of MSD was 56 (range, 38-74) years. Compared with CBT, the risk of developing extensive chronic GVHD was higher after BMT (hazard ratio [HR], 2.00; P = 0.001) or PBSCT (HR, 2.38; P < 0.001), and transplant-related mortality was lower after BMT (HR, 0.61; P < 0.001) or PBSCT (HR, 0.63; P < 0.001). Relapse rates were not significant difference between three groups. Although overall mortality was lower after BMT (HR, 0.67; P < 0.001) or PBSCT (HR, 0.75; P = 0.002) compared with CBT, the rates of a composite endpoint of GVHD-free, relapse-free survival (GRFS) were not significant difference between three groups. These data showed that MSDs remain the best donor source for older patients, but CBT led to similar GRFS to BMT and PBSCT.

Recommendations for a standard UK approach to incorporating umbilical cord blood into clinical transplantation practice: an update on cord blood unit selection, donor selection algorithms and conditioning protocols

Allogeneic haemopoietic stem cell transplantation offers a potentially curative treatment option for a wide range of life-threatening malignant and non-malignant disorders of the bone marrow and immune system in patients of all ages. With rapidly emerging advances in the use of alternative donors, such as mismatched unrelated, cord blood and haploidentical donors, it is now possible to find a potential donor for almost all patients in whom an allograft is indicated. Therefore, for any specific patient, the transplant physician may be faced with a myriad of potential choices, including decisions concerning which donor to prioritize where there is more than one, the optimal selection of specific umbilical cord blood units and which conditioning and graft-versus-host disease prophylactic schedule to use. Donor choice may be further complicated by other important factors, such as urgency of transplant, the presence of alloantibodies, the disease status (homozygosity or heterozygosity) of sibling donors affected by inherited disorders and the cytomegalovirus serostatus of patient and donor. We report UK consensus guidelines on the selection of umbilical cord blood units, the hierarchy of donor selection and the preferred conditioning regimens for umbilical cord blood transplantation, with a summary of rationale supporting these recommendations.