Cost-effectiveness and clinical outcomes of double versus single cord blood transplantation in adults with acute leukemia in France

Umbilical Cord Blood Hematopoietic Cells: From Biology to Hematopoietic Transplants and Cellular Therapies

Umbilical cord blood (UCB) is a rich source of hematopoietic stem and progenitor cells that are biologically superior to their adult counterparts. UCB cells can be stored for several years without compromising their numbers or function. Today, public and private UCB banks have been established in several countries around the world. After 35 years since the first UCB transplant (UCBT), more than 50,000 UCBTs have been performed worldwide. In pediatric patients, UCBT is comparable to or superior to bone marrow transplantation. In adult patients, UCB can be an alternative source of hematopoietic cells when an HLA-matched unrelated adult donor is not available and when a transplant is urgently needed. Delayed engraftment (due to reduced absolute numbers of hematopoietic cells) and higher costs have led many medical institutions not to consider UCB as a first-line cell source for hematopoietic transplants. As a result, the use of UCB as a source of hematopoietic stem and progenitor cells for transplantation has declined over the past decade. Several approaches are being investigated to make UCBTs more efficient, including improving the homing capabilities of primitive UCB cells and increasing the number of hematopoietic cells to be infused. Several of these approaches have already been applied in the clinic with promising results. UCB also contains immune effector cells, including monocytes and various lymphocyte subsets, which, together with stem and progenitor cells, are excellent candidates for the development of cellular therapies for hematological and non-hematological diseases.

Higher survival following transplantation with a mismatched unrelated donor with posttransplant cyclophosphamide-based graft-versus-host disease prophylaxis than with double unit umbilical cord blood in patients with acute myeloid leukemia in first complete remission: A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

The best donor option for acute myeloid leukemia (AML) patients lacking an HLA-matched donor has remained intensively debated. We herein report the results of a large retrospective registry study comparing hematopoietic cell transplantation (HCT) outcomes between double-unit umbilical cord blood transplantation (dCBT, n = 209) versus 9/10 HLA-matched unrelated donor (UD) with posttransplant cyclophosphamide (PTCy)-based graft-versus-host disease (GVHD) prophylaxis (UD 9/10, n = 270) in patients with AML in first complete remission (CR1). Inclusion criteria consisted of adult patient, AML in CR1 at transplantation, either peripheral blood stem cells (PBSC) from UD 9/10 with PTCy as GVHD prophylaxis or dCBT without PTCy, transplantation between 2013 and 2021, and no in vivo T-cell depletion. The 180-day cumulative incidence of grade II-IV acute GVHD was 29% in UD 9/10 versus 44% in dCBT recipients (p = .001). After adjustment for covariates, dCBT recipients had a higher non-relapse mortality (HR = 2.35, 95% CI: 1.23-4.48; p = .01), comparable relapse incidence (HR = 1.12, 95% CI: 0.67-1.86; p = .66), lower leukemia-free survival (HR = 1.5, 95% CI: 1.01-2.23; p = .047), and lower overall survival (HR = 1.66, 95% CI: 1.08-2.55; p = .02) compared with patients receiving UD 9/10 HCT. In summary, our results suggest that transplantation outcomes are better with UD 9/10 with PTCy-based GVHD prophylaxis than with dCBT for AML patients in CR1. These data might support the use of UD 9/10 with PTCy-based GVHD prophylaxis over dCBT in AML patients lacking an HLA-matched donor.

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.

Healthcare Resource Utilization and Cost Associated with Allogeneic Hematopoietic Stem Cell Transplantation: A Scoping Review

This scoping review summarizes the evidence regarding healthcare resource utilization (HRU) and costs associated with allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study was conducted in accordance with the Joanne Briggs Institute methodology for scoping reviews. The PubMed, Embase, and Health Business Elite Electronic databases were searched, in addition to grey literature. The databases were searched from inception up to November 2022. Studies that reported HRU and/or costs associated with adult (≥18 years) allo-HSCT were eligible for inclusion. Two reviewers independently screened 20% of the sample at each of the 2 stages of screening (abstract and full text). Details of the HRU and costs extracted from the study data were summarized, based on the elements and timeframes reported. HRU measures and costs were combined across studies reporting results defined in a comparable manner. Monetary values were standardized to 2022 US Dollars (USD). We identified 43 studies that reported HRU, costs, or both for allo-HSCT. Of these studies, 93.0% reported on costs, 81.4% reported on HRU, and 74.4% reported on both. HRU measures and cost calculations, including the timeframe for which they were reported, were heterogeneous across the studies. Length of hospital stay was the most frequently reported HRU measure (76.7% of studies) and ranged from a median initial hospitalization of 10 days (reduced-intensity conditioning [RIC]) to 73 days (myeloablative conditioning). The total cost of an allo-HSCT ranged from $63,096 (RIC) to $782,190 (double umbilical cord blood transplantation) at 100 days and from $69,218 (RIC) to $637,193 at 1 year (not stratified). There is heterogeneity in the reporting of HRU and costs associated with allo-HSCT in the literature, making it difficult for clinicians, policymakers, and governments to draw definitive conclusions regarding the resources required for the delivery of these services. Nevertheless, to ensure that access to healthcare meets the necessary high cost and resource demands of allo-HSCT, it is imperative for clinicians, policymakers, and government officials to be aware of both the short- and long-term health resource requirements for this patient population. Further research is needed to understand the key determinants of HRU and costs associated with allo-HSCT to better inform the design and delivery of health care for HSCT recipients and ensure the quality, safety, and efficiency of care.

Hematopoietic cell transplants in resource-poor countries: challenges and opportunities

INTRODUCTION

Numbers of hematopoietic cell transplants continue to increase globally but most of this activity is in resource-rich countries. Limitations to increasing transplant activity in resource-poor countries include lack of sophisticated personnel and infrastructure, complexity in identifying and accessing donors, unavailability of some new drugs and high cost.

AREAS COVERED

We searched the biomedical literature for hematopoietic cell transplants and resource-rich and resource-poor countries. Recent advances which potentially make transplants more accessible in resource-poor countries include: (1) outpatient transplants; (2) grafts stored at 4°C; (3) less intensive pretransplant conditioning; (4) use of generic drugs; (5) less complex and costly donor access; and (6) increased collaboration with transplant centers in resource-rich countries.

EXPERT OPINION

We reviewed publications on the limitations and solutions discussed above. Paradoxically, most data we analyzed originate from resource-rich countries. We found no convincing epidemiological data to support a recent increased transplant rate in resource-poor countries yet but hope to see increases soon.

Principles of cost-effectiveness studies and their use in haematology

Health economics is about providing the population with the maximum health possible under budget constraint. The most common method to present the result of an economic evaluation is the calculation of the incremental cost-effectiveness ratio (ICER). It is defined by the difference in cost between two possible technologies, divided by the difference in their effect. It represents the amount of money required to gain one additional unit of health for the population. Economic evaluations are based upon 1) medical evidence of the health benefits of technologies and 2) the value of resources used to achieve these health benefits. An economic evaluation is one type of information that can be used by policy makers, in combination with data on organisation, financing, and incentives to decide on the adoption of innovative technologies.

Comparing cord blood transplantation and matched related donor transplantation in non-remission acute myeloid leukemia

Cord blood transplantation (CBT) is an alternative donor transplantation method and has the advantages of rapid availability and the possibility of inducing a more potent graft-versus-leukemia effect, leading to a lower relapse rate for patients with non-remission relapse and refractory acute myeloid leukemia (R/R AML). This study aimed to investigate the impact of CBT, compared to human leukocyte antigen-matched related donor transplantation (MRDT). This study included 2451 adult patients with non-remission R/R AML who received CBT (1738 patients) or MRDT (713 patients) between January 2009 and December 2018. Five-year progression-free survival (PFS) and the prognostic impact of CBT were evaluated using a propensity score (PS) matching analysis. After PS matching, the patient characteristics were well balanced between the groups. The five-year PFS was 25.2% (95% confidence interval [CI]: 21.2-29.5%) in the CBT group and 18.1% (95% CI: 14.5-22.0%) in the MRDT group (P = 0.009). The adjusted hazard ratio (HR) was 0.83 (95% CI: 0.69-1.00, P = 0.045); this was due to a more pronounced decrease in the relapse rate (HR: 0.78, 95% CI: 0.69-0.89, P < 0.001) than an increase in the NRM (1.42, 1.15-1.76, P = 0.001). In this population, CBT was associated with a better 5-year PFS than MRDT after allogeneic HSCT.

Improved Therapeutic Approaches are Needed to Manage Graft-versus-Host Disease

Allogeneic haematopoietic stem cell transplantation (alloHSCT) offers a potentially curative therapy for patients suffering from diseases of the haematopoietic system but requires a high level of expertise and is both resource intensive and expensive. A frequent and life-threatening complication is graft-versus-host disease (GvHD). Acute GvHD (aGvHD) generally causes skin, gastrointestinal and liver symptoms, but chronic GvHD (cGvHD) has a different pathophysiology and may affect nearly every organ or tissue of the body. In Europe, GvHD prophylaxis is generally a calcineurin inhibitor in combination with methotrexate, with high-dose systemic steroids used for advanced GvHD treatment. Between 39% and 59% of alloHSCT patients will develop aGvHD and around 36–37% will develop cGvHD. Steroid response decreases with increasing disease severity, which in turn leads to an increase in non-relapse mortality. GvHD imposes a financial burden on healthcare systems, significantly increasing post-alloHSCT costs. Increased GvHD disease severity magnifies this. Balancing immunosuppression to control the GvHD whilst maintaining a degree of immunocompetence against infection is critical. European GvHD guidelines acknowledge the lack of evidence to support a standard second-line therapy, and improved long-term outcomes and quality-of-life (QoL) remain an unmet need. Evidence generation for potential treatments is challenging. Issues to overcome include choice of comparator (extensive off-label usage); blinding; selection of relevant patient-reported outcome measures (PROMs); and rarity of the condition, which may infeasibly increase timescales to achieve clinical and statistical relevance.

Real-world study of direct medical and indirect costs and time spent in healthcare in patients with chronic graft versus host disease

Chronic graft versus host disease (cGVHD) is a debilitating and costly complication following haemopoietic stem cell transplantation (HSCT). This study describes the economic burden associated with cGVHD. Direct costs associated with specialised healthcare utilisation (inpatient admissions and outpatient visits), as well as indirect costs associated with sickness absence-associated productivity loss were estimated in patients who underwent allogeneic HSCT in Sweden between 2006 and 2015, linking population-based health and economic registers. To capture the period of chronic GVHD, patients were included who survived > 182 days post-HSCT (start of follow-up), and cGVHD was classified based on patient treatment records to correct for any diagnosis underreporting. Patients were classified as 'non-cGVHD' if they received no immunosuppressive treatment, 'mild cGVHD' if they received only systemic corticosteroid treatment or immunosuppressive treatment, or 'moderate-severe cGVHD' if they received extracorporeal photopheresis (ECP) only, corticosteroid treatment and immunosuppressive treatment, or systemic corticosteroid treatment and ECP treatments. Patients with moderate-severe cGVHD spent more time in healthcare, had higher healthcare resource costs and higher sickness absence-related productivity loss compared to patients with non- or mild cGVHD. The cumulative total costs during the first 3 years of follow-up were EUR 14,887,599, EUR 20,544,056, and EUR 47,811,835 for non-, mild, and moderate-severe groups, respectively. The long-term costs incurred with cGVHD following HSCT continue to be very high and significantly impacted by cGVHD severity. This study adds real-world health resource and economic insight relevant for policy-makers and healthcare providers when considering the clinical challenge of balancing immunosuppression to reduce cGVHD.

Hematopoietic Cell Transplantation in the Treatment of Newly Diagnosed Adult Acute Myeloid Leukemia: An Evidence-Based Review from the American Society of Transplantation and Cellular Therapy

The role of hematopoietic cell transplantation (HCT) in the management of newly diagnosed adult acute myeloid leukemia (AML) is reviewed and critically evaluated in this evidence-based review. An AML expert panel, consisting of both transplant and nontransplant experts, was invited to develop clinically relevant frequently asked questions covering disease- and HCT-related topics. A systematic literature review was conducted to generate core recommendations that were graded based on the quality and strength of underlying evidence based on the standardized criteria established by the American Society of Transplantation and Cellular Therapy Steering Committee for evidence-based reviews. Allogeneic HCT offers a survival benefit in patients with intermediate- and high-risk AML and is currently a part of standard clinical care. We recommend the preferential use of myeloablative conditioning in eligible patients. A haploidentical related donor marrow graft is preferred over a cord blood unit in the absence of a fully HLA-matched donor. The evolving role of allogeneic HCT in the context of measurable residual disease monitoring and recent therapeutic advances in AML with regards to maintenance therapy after HCT are also discussed.

Optimizing Preparative Regimen for Umbilical Cord Blood Transplantation in Adult Acute Leukemia Patients: Acute Lymphoblastic Leukemia Requires Myeloablative Conditioning but Not Acute Myeloid Leukemia

Cord blood transplantation (CBT) is a valuable alternative to bone marrow transplantation in adults without readily available donors. We conducted this study to investigate the feasibility of CBT for adult patients with acute leukemia with regards to impact of different conditioning and graft-versus-host disease (GVHD) prophylaxis regimens on clinical outcomes. From 16 centers in Korea, 41 acute myeloid leukemia (AML) and 29 ALL (acute lymphoblastic leukemia) patients undergoing CBT were enrolled. For AML patients, the neutrophil engraftment was observed in 87.5% of reduced intensity conditioning (RIC) and 72.0% of myeloablative conditioning (MAC) (p = 0.242). The median RFS was 5 months and OS 7 months. Conditioning regimen did not affect relapse free survival (RFS) or overall survival (OS). GVHD prophylaxis using calcineurin inhibitors (CNI) plus methotrexate was associated with better RFS compared to CNI plus ATG (p = 0.032). For ALL patients, neutrophil engraftment was observed in 55.6% of RIC and 90.0% of MAC (p = 0.034). The median RFS was 5 months and OS 19 months. MAC regimens, especially total body irradiation (TBI)-based regimen, were associated with both longer RFS and OS compared to other conditioning regimens. In conclusion, individualized conditioning regimens will add value in terms of enhancing safety and efficacy of CBT.

Cord blood research, banking, and transplantation: achievements, challenges, and perspectives

The first hematopoietic transplant in which umbilical cord blood (UCB) was used as the source of hematopoietic cells was performed in October 1988. Since then, significant achievements have been reported in terms of our understanding of the biology of UCB-derived hematopoietic stem (HSCs) and progenitor (HPCs) cells. Over 40,000 UCB transplants (UCBTs) have been performed, in both children and adults, for the treatment of many different diseases, including hematologic, metabolic, immunologic, neoplastic, and neurologic disorders. In addition, cord blood banking has been developed to the point that around 800,000 units are being stored in public banks and more than 4 million units in private banks worldwide. During these 30 years, research in the UCB field has transformed the hematopoietic transplantation arena. Today, scientific and clinical teams are still working on different ways to improve and expand the use of UCB cells. A major effort has been focused on enhancing engraftment to potentially reduce risk of infection and cost. To that end, we have to understand in detail the molecular mechanisms controlling stem cell self-renewal that may lead to the development of ex vivo systems for HSCs expansion, characterize the mechanisms regulating the homing of HSCs and HPCs, and determine the relative place of UCBTs, as compared to other sources. These challenges will be met by encouraging innovative research on the basic biology of HSCs and HPCs, developing novel clinical trials, and improving UCB banking both in the public and private arenas.

Comparison of Graft Acquisition and Early Direct Charges of Haploidentical Related Donor Transplantation versus Umbilical Cord Blood Transplantation

Alternative donor allogeneic hematopoietic cell transplants (HCTs), such as double umbilical cord blood transplants (dUCBT) and haploidentical related donor transplants (haplo-HCT), have been shown to be safe and effective in adult patients who do not have an HLA-identical sibling or unrelated donor available. Most transplant centers have committed to 1 of the 2 alternative donor sources, even with a lack of published randomized data directly comparing outcomes and comparative data on the cost-effectiveness of dUCBT versus haplo-HCT. We conducted a retrospective study to evaluate and compare the early costs and charges of haplo-HCT and dUCBT in the first 100 days at 2 US transplant centers. Forty-nine recipients of haplo-HCT (at 1 center) and 37 with dUCBT (at another center) were included in the analysis. We compared graft acquisition, inpatient/outpatient, and total charges in the first 100 days. The results of the analysis showed a significantly lower cost of graft acquisition and lower total charges (for 100-day HCT survivors) in favor of haplo-HCT. Importantly, to control for the obvious shortcomings of comparing costs at 2 different transplant centers, adjustments were made based on the current (2018) local wage index and inflation rate. In the absence of further guidance from a prospective study, the cost analysis in this study suggests that haplo-HCT may result in early cost savings over dUCBT and may be preferred by transplant centers and for patients with more limited resources.

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.

Prevention of relapse after allogeneic hematopoietic cell transplantation by donor and cell source selection

Allogeneic hematopoietic cell transplantation (HCT) is the most established form of cancer immunotherapy and has been successfully applied for the treatment and cure of otherwise lethal neoplastic blood disorders. Cancer immune surveillance is mediated to a large extent by alloreactive T and natural killer (NK) cells recognizing genetic differences between patient and donor. Profound insights into the biology of these effector cells has been obtained over recent years and used for the development of innovative strategies for intelligent donor selection, aiming for improved graft-versus-leukemia effect without unmanageable graft-versus-host disease. The cellular composition of the stem cell source plays a major role in modulating these effects. This review summarizes the current state-of the-art of donor selection according to HLA, NK alloreactivity and stem cell source.

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.

What compatibility in 2017 for the haematopoietic stem cell transplantation?

The diversification of potential donors to perform stem cell allografts now enables to propose a compatible graft cell source adapted to the different clinical situations. Transplants with a geno-identical sibling donor, otherwise with the most HLA-compatible unrelated donor, remain the first-line solutions. Alternative transplants allow to graft patients having no donors in international registries, owing to the rarity of their HLA typing. They are carried out with fairly incompatible grafts and are therefore limited by the existence in the recipient of preformed anti-HLA antibodies which predispose to their rejection. The simple prevention of acute Graft-versus-host disease in haplo-identical transplants, as well as the availability of donors, explain why they have very often replaced placental stem cell transplants. These latter remain useful for pediatric patients or in the absence of family donors.

Advances in umbilical cord blood cell therapy: the present and the future

INTRODUCTION

Umbilical cord blood (UCB), previously seen as medical waste, is increasingly recognized as a valuable source of cells for therapeutic use. The best-known application is in hematopoietic stem cell transplantation (HSCT), where UCB has become an increasingly important graft source in the 28 years since the first umbilical cord blood transplantation (UCBT) was performed. Recently, UCB has been increasingly investigated as a putative source for adoptive cell therapy. Areas covered: This review covers the advances in umbilical cord blood transplantation (UCBT) to overcome the limitation regarding cellular dose, immunological naivety and additional cell doses such as DLI. It also provides an overview regarding the progress in adoptive cellular therapy using UCB. Expert opinion: UCB has been established as an important source of stem cells for HSCT. Successful strategies to overcome the limitations of UCBT, such as the limited cell numbers and naivety of the cells, are being developed, including novel methods to perform in vitro expansion of progenitor cells, and to improve their homing to the bone marrow. Promising early clinical trials of adoptive therapies with UCB cells, including non-immunological cells, are currently performed for viral infections, malignant diseases and in regenerative medicine.

Optimal Practices in Unrelated Donor Cord Blood Transplantation for Hematologic Malignancies

Unrelated donor cord blood transplantation (CBT) results in disease-free survival comparable to that of unrelated adult donor transplantation in patients with hematologic malignancies. Extension of allograft access to racial and ethnic minorities, rapid graft availability, flexibility of transplantation date, and low risks of disabling chronic graft-versus-host disease (GVHD) and relapse are significant advantages of CBT, and multiple series have reported a low risk of late transplantation-related mortality (TRM) post-transplantation. Nonetheless, early post-transplantation morbidity and TRM and the requirement for intensive early post-transplantation management have slowed the adoption of CBT. Targeted care strategies in CBT recipients can mitigate early transplantation complications and reduce transplantation costs. Herein we provide a practical "how to" guide to CBT for hematologic malignancies on behalf of the National Marrow Donor Program and the American Society of Blood and Marrow Transplantation's Cord Blood Special Interest Group. It shares the best practices of 6 experienced US transplantation centers with a special interest in the use of cord blood as a hematopoietic stem cell source. We address donor search and unit selection, unit thaw and infusion, conditioning regimens, immune suppression, management of GVHD, opportunistic infections, and other factors in supportive care appropriate for CBT. Meticulous attention to such details has improved CBT outcomes and will facilitate the success of CBT as a platform for future graft manipulations.

Cord blood transplant for acute myeloid leukaemia

Umbilical cord blood is a haematopoietic progenitor cell source for patients with acute myeloid leukaemia (AML), other haematological malignancies and metabolic diseases who can be cured by allogeneic haematopoietic cell transplantation, but who do not have a human leucocyte antigen compatible related or unrelated donor. Although the first cord blood transplants were done in children, there are currently more cord blood transplants performed in adults. In this review, we explore the history of umbilical cord blood transplantation, paediatric and adult outcome results, and novel trends to improve engraftment and reduce infection. Umbilical cord blood transplantation cures approximately 30-40% of adults and 60-70% of children with AML. Controversial issues, including the use of double versus single cord blood units for transplantation, optimal cord blood unit selection, infection prophylaxis, conditioning regimens and graft versus host disease prophylaxis, will be reviewed. Finally, comparison to other graft sources, cost, access to care, and the ideal graft source are discussed.

High Disease-Free Survival with Enhanced Protection against Relapse after Double-Unit Cord Blood Transplantation When Compared with T Cell-Depleted Unrelated Donor Transplantation in Patients with Acute Leukemia and Chronic Myelogenous Leukemia

Double-unit cord blood (DCB) grafts are a rapidly available stem cell source for adults with high-risk leukemias. However, how disease-free survival (DFS) after DCB transplantation (DCBT) compares to that of unrelated donor transplantation (URDT) is not fully established. We analyzed 166 allograft recipients (66 8/8 HLA-matched URDT, 45 7/8 HLA-matched URDT, and 55 DCBT) ages 16 to 60 years with high-risk acute leukemia or chronic myelogenous leukemia (CML). URDT and DCBT recipients were similar except DCBT recipients were more likely to have lower weight and non-European ancestry and to receive intermediate-intensity conditioning. All URDT recipients received a CD34(+) cell-selected (T cell-depleted) graft. Overall, differences between the 3-year transplantation-related mortality were not significant (8/8 URDT, 18%; 7/8 URDT, 39%; and DCBT, 24%; P = .108), whereas the 3-year relapse risk was decreased after DCBT (8/8 URDT, 23%; 7/8 URDT, 20%; and DCBT 9%, P = .037). Three-year DFS was 57% in 8/8 URDT, 41% in 7/8 URDT, and 68% in DCBT recipients (P = .068), and the 3-year DFS in DCBT recipients was higher than that of 7/8 URDT recipients (P = .021). In multivariate analysis in acute leukemia patients, factors adversely associated with DFS were female gender (hazard ratio [HR], 1.68; P = .031), diagnosis of acute lymphoblastic leukemia (HR, 2.09; P = .004), and 7/8 T cell-depleted URDT (HR, 1.91; P = .037). High DFS can be achieved in adults with acute leukemia and CML with low relapse rates after DCBT. Our findings support performing DCBT in adults in preference to HLA-mismatched T cell-depleted URDT and suggest DCBT is a readily available alternative to T cell-depleted 8/8 URDT, especially in patients requiring urgent transplantation.

Risk Factors for Acute and Chronic Graft-versus-Host Disease after Allogeneic Hematopoietic Cell Transplantation with Umbilical Cord Blood and Matched Sibling Donors

Allogeneic hematopoietic cell transplantation is often complicated by graft-versus-host disease (GVHD). We analyzed the incidences and risk factors for acute (aGVHD) and chronic GVHD (cGVHD), and their impact on disease relapse and survival, among recipients of single umbilical cord blood (sUCB, n = 295), double umbilical cord blood (dUCB, n = 416), and matched sibling donor (MSD, n = 469) allografts. The incidences of grades II to IV aGVHD and chronic GVHD among dUCB, sUCB, and MSD were 56% and 26%, 26% and 7%, 37% and 40%, respectively. Development of aGVHD had no effect on relapse, nonrelapse mortality, or overall survival among cord blood recipients, but it was associated with worse nonrelapse mortality and survival in MSD recipients. Development of cGVHD was only associated with lower relapse in dUCBT. In multivariate analysis of GVHD incidence, age > 18 years was associated with higher incidence of aGVHD and cGVHD across all cohorts. In both UCB cohorts worse HLA match and prior aGVHD were associated with higher risks of aGVHD and cGVHD, respectively. Nonmyeloablative conditioning limited the risk of aGVHD compared with myeloablative conditioning in dUCB recipients. Cyclosporine A and mycophenolate mofetil as GVHD prophylaxis lowered the risk of cGVHD, compared with steroids with cyclosporine A, among sUCB recipients. This large contemporary analysis suggests distiinct risks and consequences of GVHD for UCB and MSD recipients. Limiting the severity of aGVHD remains important in all groups. Increasing the cord blood inventory or developing strategies that reduce the cell-dose threshold and thereby increase the chance of identifying an adequately dosed, better HLA-matched sUCB unit may further limit risks of aGVHD after UCB transplantation.

Umbilical cord blood donation: public or private?

Umbilical cord blood (UCB) is a graft source for patients with malignant or genetic diseases who can be cured by allogeneic hematopoietic cell transplantation (HCT), but who do not have an appropriately HLA-matched family or volunteer unrelated adult donor. Starting in the 1990s, unrelated UCB banks were established, accepting donations from term deliveries and storing UCB units for public use. An estimated 730 000 UCB units have been donated and stored to date and ~35 000 UCB transplants have been performed worldwide. Over the past 20 years, private and family banks have grown rapidly, storing ~4 million UCB units for a particular patient or family, usually charging an up-front and yearly storage fee; therefore, these banks are able to be financially sustainable without releasing UCB units. Private banks are not obligated to fulfill the same regulatory requirements of the public banks. The public banks have released ~30 times more UCB units for therapy. Some countries have transitioned to an integrated banking model, a hybrid of public and family banking. Today, pregnant women, their families, obstetrical providers and pediatricians are faced with multiple choices about the disposition of their newborn's cord blood. In this commentary, we review the progress of UCB banking technology; we also analyze the current data on pediatric and adult unrelated UCB, including the recent expansion of interest in transplantation for hemoglobinopathies, and discuss emerging studies on the use of autologous UCB for neurologic diseases and regenerative medicine. We will review worldwide approaches to UCB banking, ethical considerations, criteria for public and family banking, integrated banking ideas and future strategies for UCB banking.

Comparison of outcomes after unrelated cord blood and unmanipulated haploidentical stem cell transplantation in adults with acute leukemia

Outcomes after unmanipulated haploidentical stem cell transplantation (Haplo) and after unrelated cord blood transplantation (UCBT) are encouraging and have become alternative options to treat patients with high-risk acute leukemia without human leukocyte antigen (HLA) matched donor. We compared outcomes after UCBT and Haplo in adults with de novo acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Median follow-up was 24 months. Analysis was performed separately for patients with AML, n=918 (Haplo=360, UCBT=558) and ALL, n=528 (Haplo=158 and UCBT=370). UCBT was associated with delayed engraftment and higher graft failure in both AML and ALL recipients. In multivariate analysis, UCBT was associated with lower incidence of chronic graft-vs-host disease both in the AML group (hazard ratio (HR)=0.63, P=0.008) and in the ALL group (HR=0.58, P=0.01). Not statistically significant differences were observed between Haplo and UCBT for relapse incidence (HR=0.95, P=0.76 for AML and HR=0.82, P=0.31 for ALL), non-relapse mortality (HR=1.16, P=0.47 for AML and HR=1.23, P=0.23 for ALL) and leukemia-free survival (HR 0.78, P=0.78 for AML and HR=1.00, P=0.84 for ALL). There were no statistically differences on main outcomes after unmanipulated Haplo and UCBT, and both approaches are valid for acute leukemia patients lacking a HLA matched donor. Both strategies expand the donor pool for patients in need.

Alternative Donor Allogeneic Hematopoietic Cell Transplantation for Acute Myeloid Leukemia

Allogeneic hematopoietic cell transplantation (alloHCT) provides a potentially curative therapy for patients with high-risk or chemorefractory acute myeloid leukemia (AML). Historically, the applicability of alloHCT has been limited as only 30%-35% of patients have human leukocyte antigen (HLA)-matched siblings and outcomes using other donor types have been markedly inferior due to excess toxicity, graft failure, graft-versus-host disease (GVHD), and consequently non-relapse mortality. Advances in HLA typing, GVHD prophylactic approaches, and other transplantation techniques have successfully addressed these historical challenges. Herein, we review recent alloHCT studies using volunteer unrelated donors, umbilical cord blood units, or HLA-haploidentical donors, specifically focusing on studies that compared outcomes between donor sources. Although none are randomized and most are retrospective, these analyses suggest that current outcomes for AML patients using most alternative donor types are comparable to those seen using HLA-matched siblings.

One-unit versus two-unit cord-blood transplantation for hematologic cancers

BACKGROUND

Umbilical-cord blood has been used as the source of hematopoietic stem cells in an estimated 30,000 transplants. The limited number of hematopoietic cells in a single cord-blood unit prevents its use in recipients with larger body mass and results in delayed hematopoietic recovery and higher mortality. Therefore, we hypothesized that the greater numbers of hematopoietic cells in two units of cord blood would be associated with improved outcomes after transplantation.

METHODS

Between December 1, 2006, and February 24, 2012, a total of 224 patients 1 to 21 years of age with hematologic cancer were randomly assigned to undergo double-unit (111 patients) or single-unit (113 patients) cord-blood transplantation after a uniform myeloablative conditioning regimen and immunoprophylaxis for graft-versus-host disease (GVHD). The primary end point was 1-year overall survival.

RESULTS

Treatment groups were matched for age, sex, self-reported race (white vs. nonwhite), performance status, degree of donor-recipient HLA matching, and disease type and status at transplantation. The 1-year overall survival rate was 65% (95% confidence interval [CI], 56 to 74) and 73% (95% CI, 63 to 80) among recipients of double and single cord-blood units, respectively (P=0.17). Similar outcomes in the two groups were also observed with respect to the rates of disease-free survival, neutrophil recovery, transplantation-related death, relapse, infections, immunologic reconstitution, and grade II-IV acute GVHD. However, improved platelet recovery and lower incidences of grade III and IV acute and extensive chronic GVHD were observed among recipients of a single cord-blood unit.

CONCLUSIONS

We found that among children and adolescents with hematologic cancer, survival rates were similar after single-unit and double-unit cord-blood transplantation; however, a single-unit cord-blood transplant was associated with better platelet recovery and a lower risk of GVHD. (Funded by the National Heart, Lung, and Blood Institute and the National Cancer Institute; ClinicalTrials.gov number, NCT00412360.).

Complete donor T cell chimerism predicts lower relapse incidence after standard double umbilical cord blood reduced-intensity conditioning regimen allogeneic transplantation in adults

Double umbilical cord blood (dUCB) allogeneic transplantation after a low-dose total body irradiation, cyclophosphamide, and fludarabine (TCF)-based reduced-intensity conditioning regimen (RIC) is increasingly used in adults lacking a suitable related or unrelated donor. Currently, there are little data regarding the long-term outcome of CD3(+) T cell chimerism (TCC) in this particular setting. Thirty-six adults with various hematological diseases who received dUCB allogeneic transplants conditioned with TCF were included in this retrospective study. Peripheral blood CD3(+) TCC was considered until day +100 after transplantation to determine the impact of full versus mixed chimerism on long-term outcomes. Twenty-nine and 7 patients were documented with full and mixed CD3(+) TCC, respectively, within the first 100 days after transplantation. With a median follow-up of 36 months, 3 year-overall survival (OS), disease-free survival (DFS), and cumulative incidence of relapse (CIR) were 61%, (95% confidence interval [CI], 43% to 75%); 50% (95% CI, 32.5% to 66%), and 28% (95% CI, 16% to 44%), respectively. In univariate analysis, a full CD3(+) TCC was associated with a better 3-year DFS: 59% (95% CI, 39% to 75.5%) versus 14% (95% CI, 7% to 46%); hazard ratio (HR), .24 (.09 to .65); P = .005 and a lower CIR: 24% (95% CI, 21.5% to 57%) versus 78% (95% CI, 52% to 99%); HR, .18 (.05 to .50); P = .004. In multivariate analysis, a full CD3(+) TCC remained associated with a lower CIR (HR, .17 [.028 to .99]; P = .049). CD3(+) TCC has no impact on graft-versus-host disease and nonrelapse mortality in this study. In conclusion, here, full CD3(+) TCC was independently associated with a lower risk of relapse in adults receiving a dUCB TCF RIC allogeneic transplantation. This highlights the need to develop immunotherapy approaches allowing for early conversion to full chimerism after this type of transplantation.

Human herpesvirus 6 reactivation before engraftment is strongly predictive of graft failure after double umbilical cord blood allogeneic stem cell transplantation in adults

Our main objective was to determine new factors associated with engraftment and single-unit predominance after double umbilical cord blood (UCB) allogeneic stem-cell transplantation. Engraftment occurred in 78% of cases in this retrospective study including 77 adult patients. Three-year overall survival, disease-free survival, relapse incidence, and nonrelapse mortality were 55 ± 6%, 44 ± 6%, 33 ± 5%, and 23 ± 4%, respectively. In multivariate analysis, Human herpesvirus 6 reactivation during aplasia (hazard ratio [HR] = 2.63; 95% confidence interval [CI]: 1.64-4.17; p < 0.001), younger recipient age (<53 years) (HR = 1.97; 95% CI: 1.16-3.35; p = 0.012), and lower human leukocyte antigen matching between the two units (3 of 6 or 4 of 6) (HR = 2.09; 95% confidence interval: 1.22-3.59; p = 0.013) were the three factors independently associated with graft failure. Also, factors independently predicting the losing UCB unit were younger age of the UCB unit (odds ratio [OR] = 1.01; 95% CI: 1-1.02; p = 0.035), lower CD34(+) cell dose contained in the UCB unit (≤ 0.8 × 10(5)/kg) (OR = 2.55; 95% CI: 1.05-6.16; p = 0.04), and presence of an ABO incompatibility between the UCB unit and the recipient (OR = 2.53; 95% CI: 1.15-5.53; p = 0.02). Thus, Human herpesvirus 6 reactivation during aplasia, lower unit-unit human leukocyte antigen matching, and younger UCB unit age, as new unfavorable predictive factors, may represent new parameters to take into account after double UCB allogeneic stem-cell transplantation in adults. These results need to be confirmed prospectively, as they may influence unit selections and patient outcomes.

Hospital length of stay in the first 100 days after allogeneic hematopoietic cell transplantation for acute leukemia in remission: comparison among alternative graft sources

Several studies have shown comparable survival outcomes with different graft sources, but the relative resource needs of hematopoietic cell transplantation (HCT) by graft source have not been well studied. We compared total hospital length of stay in the first 100 days after HCT in 1577 patients with acute leukemia in remission who underwent HCT with an umbilical cord blood (UCB), matched unrelated donor (MUD), or mismatched unrelated donor (MMUD) graft between 2008 and 2011. To ensure a relatively homogenous study population, the analysis was limited to patients with acute myelogenous leukemia and acute lymphoblastic leukemia in first or second complete remission who underwent HCT in the United States. To account for early deaths, we compared the number of days alive and out of the hospital in the first 100 days post-transplantation. For children who received myeloablative conditioning, the median time alive and out of the hospital in the first 100 days was 50 days for single UCB recipients, 54 days for double UCB recipients, and 60 days for MUD bone marrow (BM) recipients. In multivariate analysis, use of UCB was significantly associated with fewer days alive and out of the hospital compared with MUD BM. For adults who received myeloablative conditioning, the median time alive and out of the hospital in first 100 days was 52 days for single UCB recipients, 55 days for double UCB recipients, 69 days for MUD BM recipients, 75 days for MUD peripheral blood stem cell (PBSC) recipients, 63 days for MMUD BM recipients, and 67 days for MMUD PBSC recipients. In multivariate analysis, UCB and MMUD BM recipients had fewer days alive and out of the hospital compared with recipients of other graft sources. For adults who received a reduced-intensity preparative regimen, the median time alive and out of the hospital during the first 100 days was 65 days for single UCB recipients, 63 days for double UCB recipients, 79 days for MUD PBSC recipients, and 79 days for MMUD PBSC recipients. Similar to the other 2 groups, receipt of UCB was associated with a fewer days alive and out of the hospital. In conclusion, length of stay in the first 100 days post-transplantation varies by graft source and is longer for UCB HCT recipients. These data provide insight into the resource needs of patients who undergo HCT with these various graft sources.

Optimal stem cell source for allogeneic stem cell transplantation for hematological malignancies

Hematopoietic stem cell transplant (HSCT) is a standard treatment for many hematological malignancies. Three different sources of stem cells, namely bone marrow (BM), peripheral blood stem cells (PBSC) and cord blood (CB) can be used for HSCT, and each has its own advantages and disadvantages. Randomized controlled trials (RCTs) suggest that there is no significant survival advantage of PBSC over BM in Human Leukocyte Antigen-matched sibling transplant for adult patients with hematological malignancies. PBSC transplant probably results in lower risk of relapse and hence better disease-free survival, especially in patients with high risk disease at the expense of higher risks of both severe acute and chronic graft-versus-host disease (GVHD). In the unrelated donor setting, the only RCT available suggests that PBSC and BM result in comparable overall and disease-free survivals in patients with hematological malignancies; and PBSC transplant results in lower risk of graft failure and higher risk of chronic GVHD. High level evidence is not available for CB in comparison to BM or PBSC. The risks and benefits of different sources of stem cells likely change with different conditioning regimen, strategies for prophylaxis and treatment of GVHD and manipulation of grafts. The recent success and rapid advance of double CB transplant and haploidentical BM and PBSC transplants further complicate the selection of stem cell source. Optimal selection requires careful weighing of the risks and benefits of different stem cell source for each individual recipient and donor. Detailed counseling of patient and donor regarding risks and benefits in the specific context of the patient and transplant method is essential for informed decision making.

"No wash" albumin-dextran dilution for double-unit cord blood transplantation is safe with high rates of sustained donor engraftment

Washing cord blood (CB) grafts involves product manipulation and may result in cell loss. We investigated double-unit CB transplantation (CBT) using red blood cell (RBC)-depleted units diluted with albumin-dextran in patients with hematologic malignancies. One-hundred thirty-six patients (median age, 43 years; range, 4 to 71; median weight, 69 kilograms (kg); range, 24 to 111) underwent transplantation with a 4/6 to 6/6 HLA-matched graft. Patients ≤ 20 kg were excluded, as they only received washed units. Units were diluted a median of 8 fold to a median volume of 200 mL/unit. The median infused total nucleated cell doses were 2.7 (larger unit) and 2.0 (smaller unit) x 10(7)/kg, respectively, and the median post-thaw recovery was 86%. Units were infused consecutively (median, 45 minutes/unit). While only 17 patients (13%) had no infusion reactions, reactions in the remaining 119 patients were almost exclusively mild-moderate (by CTCAE v4 criteria 12 grade 1, 43 grade 2, 63 grade 3) with only 1 patient (< 1%) having a severe (grade 4) reaction. Moreover, most were easily treated. Grade 2 to 3 hypertension was the most common in 101 (74%) patients. The cumulative incidence of sustained donor-derived neutrophil engraftment was high: 95% in myeloablative and 94% in nonmyeloablative CBT recipients. With appropriate supportive care, double-unit CBT with RBC-depleted grafts infused after albumin-dextran dilution is safe with high rates of engraftment in patients > 20 kg.