Busulfan/melphalan/antithymocyte globulin followed by unrelated donor cord blood transplantation for treatment of infant leukemia and leukemia in young children: the Cord Blood Transplantation study (COBLT) experience

Incidence, Risk Factors, Characteristics, and Outcome of Chronic Graft Versus Host Disease in Children Undergoing Haploidentical Peripheral Blood Stem Cell Transplant With Post-transplant Cyclophosphamide

AIM

Chronic graft versus host disease (cGVHD) is a major cause of morbidity postallogeneic peripheral blood stem cell transplant (PBSCT). There is paucity of literature describing incidence, risk factors, characteristics, and outcome of cGVHD in children undergoing haploidentical PBSCT with post-transplant cyclophosphamide (PTCy). Here, we describe our experience from our center regarding the same.

METHODS

All children who underwent haploidentical PBSCT with PTCy between January 2016 and December 2021 at our center and survived beyond day+100 post-transplant were included in this retrospective study. Conditioning regimens used were: Thiotepa-Fludarabine-Cyclophosphamide with 2 Gy single fraction total body irradiation, Thiotepa-Busulfan-Fludarabine, Fludarabine-total body irradiation and Fludarabine-Melphalan. Peripheral blood was used as stem cell source in all patients. GVHD prophylaxis was PTCy 50 mg/kg on day +3 and +4, Mycophenolate mofetil and Calcineurin inhibitors. Clinical and laboratory data was electronically retrieved and analyzed based on National Institute of Health Consensus Criteria-2014 at regular intervals. Impact of various patient, donor, and transplant-related factors on development of cGVHD were analyzed. Incidence of relapse, event free survival (EFS) and overall survival (OS) were calculated and compared between cGVHD and no cGVHD groups. Patients with rejection were excluded from risk factor analysis for cGVHD but were considered for survival analysis.

RESULTS

Fifty-one children included in this study. Median age of transplant of our cohort was 7.5 years with male:female=1.6:1. Eight patients had rejection with autologous recovery. History of acute GVHD (aGVHD) was present in 15/51 (Grade III to IV in 7/51). cGVHD developed in 19/51 patients (mild-9/51, moderate-6/51, and severe-4/51). Skin was the most common organ involved (100%) followed by gastrointestinal tract (47.4%), liver (36.8%), eyes (21%), lungs (21%), mouth (15.7%), and joints (5.2%). Advanced donor age (>30 y) and previous aGVHD were found to be significantly associated with increased risk of developing cGVHD. At last follow-up, complete response and partial response of cGVHD was seen in 6/19 and 4/19 patients, respectively. Overall mortality was 15/51 (cause of mortality was relapse of cancer 8/15, cGVHD-3/15, other 4/15). EFS and OS of full cohort was 55% and 70.6%, respectively. Compared with patients without cGVHD, patients with cGVHD demonstrated a lower relapse (18.2% vs. 40%, P =0.2333), higher EFS (68.4% vs. 53.1%, P =0.283), and higher OS (73.7% vs. 68.8%, P =0.708).

CONCLUSION

Incidence of cGVHD was high in children undergoing haploidentical PBSCT with PTCy. Other than PBSC graft source; donor age and previous aGVHD were the risks factors for development of cGVHD. Patients with cGVHD had lower incidence of relapse translating into better survival but this difference was not statistically significant.

Current Prophylaxis and Treatment Approaches for Acute Graft-Versus-Host Disease in Haematopoietic Stem Cell Transplantation for Children With Acute Lymphoblastic Leukaemia

Acute graft-versus-host disease (aGvHD) continues to be a leading cause of morbidity and mortality following allogeneic haematopoietic stem cell transplantation (HSCT). However, higher event-free survival (EFS) was observed in patients with acute lymphoblastic leukaemia (ALL) and grade II aGvHD vs. patients with no or grade I GvHD in the randomised, controlled, open-label, international, multicentre Phase III For Omitting Radiation Under Majority age (FORUM) trial. This finding suggests that moderate-severity aGvHD is associated with a graft-versus-leukaemia effect which protects against leukaemia recurrence. In order to optimise the benefits of HSCT for leukaemia patients, reduction of non-relapse mortality-which is predominantly caused by severe GvHD-is of utmost importance. Herein, we review contemporary prophylaxis and treatment options for aGvHD in children with ALL and the key challenges of aGvHD management, focusing on maintaining the graft-versus-leukaemia effect without increasing the severity of GvHD.

Hematopoietic Stem Cell Transplantation to Treat Leukodystrophies: Clinical Practice Guidelines from the Hunter's Hope Leukodystrophy Care Network

The leukodystrophies are a heterogeneous group of inherited diseases characterized by progressive demyelination of the central nervous system leading to devastating neurologic symptoms and premature death. Hematopoietic stem cell transplantation (HSCT) has been successfully used to treat certain leukodystrophies, including adrenoleukodystrophy, globoid leukodystrophy (Krabbe disease), and metachromatic leukodystrophy, over the past 30 years. To date, these complex patients have primarily been transplanted at a limited number of pediatric centers. As the number of cases identified through pregnancy and newborn screening is increasing, additional centers will be required to treat these children. Hunter's Hope created the Leukodystrophy Care Network in part to create and standardize high-quality clinical practice guidelines to guide the care of affected patients. In this report the clinical guidelines for the care of pediatric patients with leukodystrophies undergoing treatment with HSCT are presented. The initial transplant evaluation, determination of patient eligibility, donor selection, conditioning, supportive care, and post-transplant follow-up are discussed. Throughout these guidelines the need for early detection and treatment and the role of the partnership between families and multidisciplinary providers are emphasized.

Durable Chimerism and Long-Term Survival after Unrelated Umbilical Cord Blood Transplantation for Pediatric Hemophagocytic Lymphohistiocytosis: A Single-Center Experience

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder of immune dysregulation characterized by fever, hepatosplenomegaly, cytopenias, central nervous system disease, increased inflammatory markers, and hemophagocytosis. Currently, allogeneic hematopoietic stem cell transplantation is the only curative approach for patients with HLH, with reported survival ranging from 50% to 70% with myeloablative conditioning (MAC) regimens. However, donor availability and transplantation-related mortality associated with conventional MAC are major barriers to success. Unrelated umbilical cord blood transplantation (UCBT) provides a readily available alternative donor source for patients lacking matched related donors. Accordingly, we report the results of UCBT in 14 children treated between 1998 and 2016. All children received standard HLH chemotherapy before UCBT. The median age at diagnosis was 2.7 months (range, .8 to 10.4) and at transplantation was 7.5 months (range, 3.8 to 17). Ten patients received MAC with busulfan/cyclophosphamide/etoposide /antithymocyte globulin (ATG) (n = 5), busulfan/cyclophosphamide /ATG (n = 4), or busulfan /melphalan/ATG (n = 1). Four patients received reduced-toxicity conditioning (RTC) with alemtuzumab/fludarabine/melphalan/hydroxyurea ± thiotepa. Cord blood units were mismatched at either 1 (n = 9) or 2 (n = 5) loci and delivered a median total nucleated cell dose of 11.9 × 10⁷/kg (range, 4.6 to 27.9) and CD34⁺ dose of 3.1 × 10⁵/kg (range, 1.1 to 6.8). The cumulative incidence of neutrophil engraftment by day 42 was 78.6% (95% confidence interval [CI], 42.9% to 93.4%) with a median of 19 days (range, 13 to 27), and that for platelet (50,000) engraftment by day 100 was 64.3% (95% CI, 28.2% to 85.7%) with a median of 51 days (range, 31 to 94). Six patients developed either grade II (n = 5) or grade IV (n = 1) acute graft-versus-host disease (GVHD); no extensive chronic GVHD was seen. Ten patients (71.4%) are alive and well at a median of 11.2 years after transplantation (range, .85 to 18.25), 9 of whom maintain sustained full donor chimerism after a single UCBT, whereas 1 patient with autologous recovery after first UCBT with RTC has achieved full donor chimerism after a second UCBT with MAC. This series demonstrates that, in combination with standard HLH therapy, UCBT after MAC or RTC conditioning can provide long-term survival with durable complete donor chimerism comparable to that of conventional donors. UCBT should be considered for patients with HLH lacking a fully matched related or unrelated adult donor.

Different aspects of stem cell procedures in children with poor responding AML: when is HSCT the best answer?

Acute myeloid leukemia in children is a heterogeneous disease with different morphological and cytogenetic features. New diagnostic tools and treatments, improved supportive care and the use of genomic tissue typing in selecting donors for hematopoietic stem cell transplantation (HSCT) adds to increased survival rates. Candidates to HSCT in first complete remission are patients with cytogenetic or molecular unfavorable prognostic markers, or blasts >15% after first induction. The use of minimal residual disease can also identify children benefiting from HSCT in first complete remission and the patients post HSCT with signs of relapse. The outcome and cure rate of acute myeloid leukemia, still remains poor and new diagnostic tools and treatments strategies need to be evaluated. In this management perspective, future management of novel minimal residual disease tools are discussed, conditioning therapies, as well as different transplantation procedures including haplo-transplantation and haplo-identical natural killer cell transplantation, but also altered graft-versus-host-disease treatments.

Long-term cancer-free survival after infusion of autologous cord blood cells for rejection-unrelated cord blood graft after myeloablative conditioning for t-MDS: a case report

Autologous cord blood transplantations are rarely applied in patients with hematologic as well as metastatic solid cancers since contamination of malignant clones is a concern. We report a case of therapy-related myelodysplasia after metastatic neuroblastoma who suffered from graft rejection and life-threatening infections after a myeloablative unrelated cord blood transplantation. The patient experiences long-term survival, free from leukemia/neuroblastoma after infusion of autologous cord blood cells. It suggests that autologous cord blood transplantation after high dose therapy might be a curative strategy for certain hematologic or metastatic solid cancers.

Increased risk of gastrointestinal acute GVHD following the addition of melphalan to busulfan/cyclophosphamide conditioning

Risk factors associated with the development of aGVHD in the gastrointestinal tract have not been studied in depth. We retrospectively assessed 25 pediatric patients with MDS and JMML and compared the treatment outcome of two different conditioning regimens. Seventeen children (68%) underwent conditioning with busulfan (Bu), cyclophosphamide (Cy), and melphalan (Mel) and eight children (32%) with Bu and Cy. Gastrointestinal aGVHD stages II-IV (day 0-100) were observed in 47% (eight of 17) of the patients in the BuCyMel group and in none (0 of 8) in the BuCy group (p < 0.05). In patients who developed gastrointestinal aGVHD stages III-IV, a 24-h variation in the Bu concentration with a nighttime peak was noted. HC and liver aGVHD stages II-IV were observed in 47% (eight of 17) and 35% (six of 17) after BuCyMel conditioning and in 0% (0 of 17) and 12.5% (one of eight) after BuCy conditioning. The overall survival rate was 53% (nine of 17) in the BuCyMel group and 62.5% (five of eight) in the BuCy group. In conclusion, the addition of melphalan to the BuCy conditioning regimen resulted in severe gastrointestinal complications and did not improve overall survival.

Umbilical cord blood transplantation: a maturing technology

The use of umbilical cord blood (CB) as a source of hematopoietic progenitor cells for patients with high-risk hematologic disorders receiving allogeneic hematopoietic cell transplantations (HCTs) has increased significantly. Single-institution and registry studies have shown a decreased relapse rate and an increased transplantation-related mortality rate with similar overall survival rates after allogeneic HCT with CB compared with other donor sources. The transplantation of double CB units has overcome the dose limitation inherent in a single CB unit and thus has markedly extended the use of CB to larger children and adults. Similarly, the use of reduced intensity conditioning in the CB transplantation setting has allowed the treatment of older patients who would be unable to tolerate the myeloablative regimens used in the original CB transplantation protocols.

Insights and hopes in umbilical cord blood stem cell transplantations

Over 20.000 umblical cord blood transplantations (UCBT) have been carried out around the world. Indeed, UCBT represents an attractive source of donor hematopoietic stem cells (HSCs) and, offer interesting features (e.g., lower graft-versus-host disease) compared to bone marrow transplantation (BMT). Thereby, UCBT often represents the unique curative option against several blood diseases. Recent advances in the field of UCBT, consisted to develop strategies to expand umbilical stem cells and shorter the timing of their engraftment, subsequently enhancing their availability for enhanced efficacy of transplantation into indicated patients with malignant diseases (e.g., leukemia) or non-malignant diseases (e.g., thalassemia major). Several studies showed that the expansion and homing of UCBSCs depends on specific biological factors and cell types (e.g., cytokines, neuropeptides, co-culture with stromal cells). In this review, we extensively present the advantages and disadvantages of current hematopoietic stem cell transplantations (HSCTs), compared to UBCT. We further describe the importance of cord blood content and obstetric factors on cord blood selection, and report the recent approaches that can be undertook to improve cord blood stem cell expansion as well as engraftment. Eventually, we provide two majors examples underlining the importance of UCBT as a potential cure for blood diseases.

Comparison of pre-cryopreserved and post-thaw-and-wash-nucleated cell count on major outcomes following unrelated cord blood transplant in children

Engraftment and OS after umbilical CBT is highly dependent on the TNC. The contribution of the wash step to cell loss and ultimately the dose of cells available for transplant is not well described. To investigate the amount of cell loss after washing and its impact on major outcomes compared to pre-cryopreserved TNC, we analyzed data from patients prospectively enrolled on a National Heart, Lung and Blood Institute sponsored cord blood transplant study between 1999 and 2003. There were 310 patients ≤18 yr of age with malignant (N = 218) or non-malignant (N = 92) disease enrolled on this trial. Only single CBU were used. All CBU were thawed and washed using an identical process. The median TNC after thawing and washing (PTW) was 5.43 × 10(7) /kg (79% recovery of cells). The cumulative incidence of neutrophil engraftment was significantly higher in patients receiving a PTW TNC ≥2.5 × 10(7) /kg (p = 0.01). The cumulative incidence of TRM was higher among patients receiving post-thaw-and-wash TNC <2.5 × 10(7) /kg (p = 0.039). In conclusion, receiving a PTW TNC of <2.5 × 10(7) /kg resulted in worse neutrophil engraftment and increased transplant-related mortality compared to a PTW TNC of ≥2.5 × 10(7) /kg.

The Cord Blood Apgar: a novel scoring system to optimize selection of banked cord blood grafts for transplantation (CME)

BACKGROUND

Engraftment failure and delays, likely due to diminished cord blood unit (CBU) potency, remain major barriers to the overall success of unrelated umbilical cord blood transplantation (UCBT). To address this problem, we developed and retrospectively validated a novel scoring system, the Cord Blood Apgar (CBA), which is predictive of engraftment after UCBT.

STUDY DESIGN AND METHODS

In a single-center retrospective study, utilizing a database of 435 consecutive single cord myeloablative UCBTs performed between January 1, 2000, to December 31, 2008, precryopreservation and postthaw graft variables (total nucleated cell, CD34+, colony-forming units, mononuclear cell content, and volume) were initially correlated with neutrophil engraftment. Subsequently, based on the magnitude of hazard ratios (HRs) in univariate analysis, a weighted scoring system to predict CBU potency was developed using a randomly selected training data set and internally validated on the remaining data set.

RESULTS

The CBA assigns transplanted CBUs three scores: a precryopreservation score (PCS), a postthaw score (PTS), and a composite score (CS), which incorporates the PCS and PTS values. CBA-PCS scores, which could be used for initial unit selection, were predictive of neutrophil (CBA-PCS ≥ 7.75 vs. <7.75, HR 3.5; p < 0.0001) engraftment. Likewise, CBA-PTS and CS scores were strongly predictive of Day 42 neutrophil engraftment (CBA-PTS ≥ 9.5 vs. <9.5, HR 3.16, p < 0.0001; CBA-CS ≥ 17.75 vs. <17.75, HR 4.01, p < 0.0001).

CONCLUSION

The CBA is strongly predictive of engraftment after UCBT and shows promise for optimizing screening of CBU donors for transplantation. In the future, a segment could be assayed for the PTS score providing data to apply the CS for final CBU selection.

Umbilical Cord Blood Transplantation for the Treatment of Hematologic Malignancies

Background

The use of unrelated umbilical cord blood (UCB) has grown as an allogeneic source of hematopoietic cells for transplantation of patients with hematologic malignancies. As the number of UCB transplantation procedures has grown, an increasing number of publications have focused on disease-specific outcomes.

Methods

This review focuses on the outcome data following UCB transplantation in subsets of hematologic malignancies in which experience with this graft source is greater.

Results

Registry and single-institution reports regarding the outcomes of children and adults with acute leukemias after UCB transplantation include many patients, while data on the clinical outcomes of other leukemias are limited due in part to the small number of patients with these diseases. UCB is now routinely used as a source of hematopoietic stem cells (HSCs) in pediatric allogeneic transplantation when a suitable sibling donor is not available. Data also support the use of UCB as an alternative source of HSC for transplantation of patients with hematologic malignancies who lack a more conventional donor. Current data also support UCB for patients who require an allograft in the setting of prospective clinical trials.

Conclusions

Along with safety and feasibility in UCB transplantation, continued study is needed that focuses on issues such as accelerating engraftment, extending access, ensuring quality, and examining outcomes in specific subgroups of patients.

Umbilical cord blood: current status and future directions

Once considered biological waste, umbilical cord blood (UCB) has become an accepted source of haematopoietic stem cells (HSCs). With initial success in the pediatric setting, UCB transplantation continues to gain favor in the adult patient population. Novel approaches to UCB transplantation include use of two units and a variety of graft manipulations. Additional uses for UCB are currently being explored and include applications in regenerative medicine and immunotherapy.

Cord blood transplantation and stem cell regenerative potential

The past 20 years of experience with umbilical cord blood transplantation have demonstrated that cord blood is effective in the treatment of a spectrum of diseases, including hematological malignancies, bone marrow failure, hemoglobinopathies, and inborn errors of metabolism. Cord blood can be obtained with ease and then safely cryopreserved for either public or private use without loss of viability. As compared to other unrelated donor cell sources, cord blood transplantation allows for greater human leukocyte antigen disparity without a corresponding increase in graft-vs.-host disease. Moreover, cord blood has a lower risk of transmitting infections by latent viruses and is less likely to carry somatic mutations than other adult cells. Recently, multiple populations of stem cells with primitive stem cell properties have been identified from cord blood. Meanwhile, there is an increasing interest in applying cord blood mononuclear cells or enriched stem cell populations to regenerative therapies. Accumulating evidence has suggested functional improvements after cord blood transplantation in various animal models for treatments of cardiac infarction, diabetes, neurological diseases, etc. In this review, we will summarize the most recent updates on clinical applications of cord blood transplantation and the promises and limitations of cell-based therapies for tissue repair and regeneration.

Review of chronic graft-versus-host disease in children after allogeneic stem cell transplantation: nursing perspective

This review presents a summary of the research literature related to the incidence and risk factors for chronic graft-versus-host disease in children following allogeneic hematopoietic stem cell transplantation. The range of incidence of chronic graft-versus-host disease in children found in this review was large, from 0% to 46%. Incidence of chronic graft-versus-host disease was influenced by sample size, time posttransplantation, and stem cell source. Characteristics of the person (eg, child's age and gender) and disease/treatment (eg, sources of transplant) are associated with chronic graft-versus-host disease in children after stem cell transplantation. Person and disease/treatment characteristics provide a framework for understanding the factors associated with chronic graft-versus-host disease symptom experiences in children after stem cell transplantation. Timely assessment of presenting chronic graft-versus-host disease symptoms is critical for treatment and prognosis. Nursing interventions should focus on educating children and parents about the signs and symptoms of chronic graft-versus-host disease. The summary of supportive nursing care for children with chronic graft-versus-host disease provides important information to tailor effective management strategies for children with chronic graft-versus-host disease.

Unrelated cord blood transplantation in pediatric patients: a report from Saudi Arabia

In unrelated cord blood (UCB) transplantation, survival has been shown to correlate with the degree of HLA matching. Thus, to extend transplant access to different ethnic backgrounds, many western UCB transplantation banks now encourage donation from non-Caucasians. Until recently, Saudi Arabia did not have a national UCB bank. In this study we report our experience in UCB transplantation in children using units procured from western cord blood banks. A total of 97 children underwent unrelated UCB transplantation at King Faisal Specialist Hospital and Research Center (KFSHRC), of which 95 were of Arab ethnicity. A total of 30 patients had malignant disorders, 25 patients had non-malignant hematological disorders and 42 patients had inborn errors. Conditioning was according to disease, with six patients receiving reduced-intensity regimens. In all, 46 patients received one-Ag-mismatched units and 51 received two-Ag-mismatched units. Engraftment occurred in 93% of patients, the 100-TRM was 15%, acute GVHD developed in 20% of patients and chronic GVHD occurred in 9% of patients. The 5-year OS and EFS estimates were 52 and 43%, respectively. The search for UCB transplantation units for Saudi patients in western banks yielded reasonably compatible units for our patients; the results are consistent with published data. Our data are encouraging for UCB transplant programs in countries in which there are no national UCB transplantation banks.

Optimal management of chronic graft-versus-host disease in children

Chronic graft-versus-host disease (GVHD) is a major complication after allogeneic haematopoietic stem cell transplantation (HSCT). Not only is it the major cause of late mortality in HSCT patients, but it also accounts for significant morbidity. Much of the literature on chronic GVHD has focused on adults. Chronic GVHD is of major importance in children, especially since they have years to live following the complications of chronic GVHD and its therapy. The goal is to review incidence, manifestations, and therapies, especially when applicable to the paediatric population.

Factors affecting mortality following myeloablative cord blood transplantation in adults: a pooled analysis of three international registries

A retrospective analysis was conducted to examine factors affecting early mortality after myeloablative, single-unit cord blood transplantation (CBT) for hematological malignancies in adolescents and adults. Data were collected from the three main CBT registries pooling 514 records of unrelated, single, unmanipulated, first myeloablative allogeneic CBTs conducted in North America or Europe from 1995 to 2005, with an HLA match ≥ 4/6 loci, in patients aged 12-55. Overall 100-day, 180-day and 1-year survival (Kaplan-Meier method) were 56, 46 and 37%, respectively, with no significant heterogeneity across registries. Multivariate analysis showed cell dose < 2.5 × 10⁷/kg (odds ratio (OR) 2.76, P < 0.0001), older age (P = 0.002), advanced disease (P = 0.02), positive CMV sero-status (OR 1.37 P = 0.11), female gender (OR 1.43, P = 0.07) and limited CBT center experience (< 10 records contributed, OR 2.08, P = 0.0003) to be associated with higher 100-day mortality. A multivariate model predictive of 1-year mortality included similar prognostic factors except female gender. Transplant year did not appear as a significant independent predictor. This is the first analysis to pool records from three major CBT registries in the United States and Europe. In spite of some differences in practice patterns, survival was remarkably homogeneous. The resulting model may contribute to better understanding factors affecting CBT outcomes.

Unrelated umbilical cord blood transplantation and immune reconstitution

This review highlights the unique features of immune reconstitution following unrelated cord blood transplantation (UCBT) that lead to heightened risk of infection-related mortality in the early post-UCBT period. There is no evidence that innate immunity is uniquely compromised after UCBT, but the development of antigen-specific cellular immunity is affected by numerical and qualitative deficits, primarily within the first 100 days. Nevertheless, beyond the first few months after UCBT there is no evidence for reduced graft-versus-leukemia (GVL) or anti-viral immunity compared to other hematopoietic cell therapy (HCT) modalities. Novel cellular therapies that are about to enter the clinical setting in the form of natural killer (NK) cell and T-cell therapies in the form of donor lymphocyte infusion (DLI) are also discussed.

Mankind's first natural stem cell transplant

The timing of the umbilical cord clamping at birth is still controversial. In the modern era of medicine, the cord has been clamped early to facilitate resuscitation and stabilization of infants. However, recently delayed cord clamping has been supported by physicians because it allows for the physiological transfer of blood from the placenta to the infant. Many clinical studies have revealed that the delayed cord clamping elevates blood volume and haemoglobin and prevents anaemia in infants. Moreover, since it was known that umbilical cord blood contains various valuable stem cells such as haematopoietic stem cells, endothelial cell precursors, mesenchymal progenitors and multipotent/pluripotent lineage stem cells, the merit of delayed cord clamping has been magnified. In this review, we discuss the advantages and disadvantages of delayed cord clamping at birth. We highlight the importance of delayed cord clamping in realizing mankind's first stem cell transfer and propose that it should be encouraged in normal births.

Cord blood transplantation for haematological malignancies: conditioning regimens, double cord transplant and infectious complications

Growing evidence supports the efficacy of cord blood transplantation (CBT) to treat patients with haematological malignancies, and the number of CBTs is rapidly increasing. Herein, we review considerations regarding conditioning regimens for CBT, the impact of double unit transplantation on CBT outcomes, and data regarding infectious complications following CBT.

Chronic graft-versus-host disease (GVHD) in children

Five-year survival rates for childhood cancer now exceed 80% and with the significant progress made by the transplant community in developing less toxic conditioning regimens and in the treatment of posttransplant complications, allo-hematopoietic stem cell transplantation (HSCT) contributes significantly to that population of long-term survivors. In this context, the acute and long-term toxicities of chronic graft-versus-host disease (cGVHD) have an ever-increasing effect on organ function, quality of life, and survival; patients and families who initially felt great relief to be cured from the primary disease, now face the challenge of a chronic debilitating illness for which preventative and treatment strategies are suboptimal. Hence, the development of novel strategies that reduce and or control cGVHD, preserve graft-versus-tumor effects, facilitate engraftment and immune reconstitution, and enhance survival after allo-HSCT represents one of the most significant challenges facing physician-scientists and patients.

Alternative haematopoietic stem cell sources for transplantation: place of umbilical cord blood

Umbilical cord blood has rapidly become a valuable alternative stem cell source for allogeneic haematopoietic stem cell transplantation. Extensive research over the last 20 years has established the safety and efficacy of umbilical cord blood transplantation in both children and adults with a variety of malignant and non-malignant diseases. This research has clearly shown that this stem cell source has several unique characteristics resulting in distinct advantages and disadvantages when compared to transplantation with unrelated bone marrow or peripheral blood stem cells. This article reviews the most recent literature comparing the outcomes after umbilical cord blood transplantation with other alternative stem cell sources.

Long-term outcome of cord blood transplantation from unrelated donors as an initial transplantation procedure for children with AML in Japan

To assess the outcome of unrelated umbilical cord blood transplantation (UCBT), 141 children with AML who underwent UCBT (39 in first CR (CR1), 33 in CR2, 4 in CR3 and 65 at more advanced stages (not in CR)) were analyzed in a retrospective multicenter study in Japan. Short-term MTX was used for prophylaxis of acute GVHD in 80 cases (57%). The cumulative incidences of neutrophil recovery, platelet recovery and acute GVHD (grades 2-4) were 78.7, 62.4 and 40.1%, respectively, and the 100-day transplantation-related mortality (TRM) was 10.8%. Multivariate analysis showed that an infused CD34(+) cell dose of 1.35 x 10(5) cells per kg or more was associated with favorable neutrophil and platelet recovery, and that short-term MTX was associated with a lower 100-day TRM. The 6-year relapse rate was 38.8% and was associated with disease status. Six-year overall survival was 45.8% (70.4+/-8.3% in CR1, 59.3+/-11.3% in CR2, 75.5+/-21% in CR3 and 20.6+/-6.2% for children with non-CR). We conclude that the results of UCBT are particularly promising for children with a karyotype suggesting a poor prognosis, and for those who receive transplants in CR2 and CR3 after an early relapse.

Busulfan in hematopoietic stem cell transplantation

The development of intravenous busulfan (Bu) and its incorporation in the preparative regimens for allogeneic stem cell transplantation has changed transplantation for myelogenous malignancies. Bypassing the oral route to achieve 100% bioavailability translated into improved control over drug administration, with increased safety and reliability of generating therapeutic Bu levels, maximizing antileukemic efficacy. Bu-nucleoside analog-based conditioning chemotherapy, thus far represented by fludarabine (Flu), is becoming the conditioning chemotherapy regimen of choice for patients with acute myelogenous leukemia (AML) at many transplant centers. The use of busulfan Bu-based conditioning is extending rapidly also to hematopoietic stem cell transplantation (HSCT) for lymphoid malignancies, genetic diseases, and umbilical cord blood transplantation.

Primary graft failure after umbilical cord blood transplant rescued by parental haplocompatible stem cell transplantation

AB Graft failure and aplasia are known complications of umbilical cord blood (UCB) hematopoietic stem cell transplantation (HSCT). In the absence of a second HSCT, graft failure is generally a fatal complication due to overwhelming infection. We describe 2 children with primary graft failure and life-threatening infections after UCB HSCT who were rescued by the use of related haplocompatible T-cell-depleted peripheral blood stem cell transplants. The rapid availability of haplocompatible donors and the brisk neutrophil recovery after haplocompatible peripheral blood stem cell transplant with high numbers of CD34+ cells make this an attractive rescue strategy for patients with graft failure after UCB HSCT.

Update on umbilical cord blood transplantation

PURPOSE OF REVIEW

2008 marks the 20th anniversary of the first use of umbilical cord blood (UCB) as a source of donor cells for hematopoietic stem cell transplantation. In those early days, there was great doubt and skepticism about the utility of UCB as a source of hematopoietic stem cells. Doubts about whether UCB, containing 10-20x fewer cells than bone marrow, had sufficient cells to durably engraft a myeloablated patient and, after demonstration that engraftment occurred with less graft-versus-host disease, whether it would confer graft-versus-leukemia activity were raised.

RECENT FINDINGS

Transplantation with UCB is effective in the treatment of children with hematological malignancies, marrow failure, immunodeficiencies, hemoglobinopathies and inherited metabolic diseases. Transplantation without full human leukocyte antigen matching is possible and, despite a lower incidence of graft-versus-host disease, graft-versus-leukemia is preserved. The number of cells in a single UCB can be limiting, but the use of two UCBs for a single transplant shows promise to overcome this obstacle.

SUMMARY

Cord blood transplantation is now an established field with enormous potential. UCB increases access to transplantation therapy for many patients unable to identify a fully matched adult donor. In the future, it may emerge as a source of cells for cellular therapies focused on tissue repair and regeneration.

Results of the Cord Blood Transplantation Study (COBLT): clinical outcomes of unrelated donor umbilical cord blood transplantation in pediatric patients with hematologic malignancies

Outcomes of unrelated donor cord blood transplantation in 191 hematologic malignancy children (median age, 7.7 years; median weight, 25.9 kg) enrolled between 1999 and 2003 were studied (median follow-up, 27.4 months) in a prospective phase 2 multicenter trial. Human leukocyte antigen (HLA) matching at enrollment was 6/6 (n = 17), 5/6 (n = 58), 4/6 (n = 111), or 3/6 (n = 5) by low-resolution HLA-A, -B, and high-resolution (HR) DRB1. Retrospectively, 179 pairs were HLA typed by HR. The median precryopreservation total nucleated cell (TNC) dose was 5.1 x 10(7) TNC/kg (range, 1.5-23.7) with 3.9 x 10(7) TNC/kg (range, 0.8-22.8) infused. The median time to engraftment (absolute neutrophil count > 500/mm(3) and platelets 50 000/muL) was 27 and 174 days. The cumulative incidence of neutrophil engraftment by day 42 was 79.9% (95% confidence interval [CI], 75.1%-85.2%); acute grades III/IV GVHD by day 100 was 19.5% (95% CI, 13.9%-25.5%); and chronic GVHD at 2 years was 20.8% (95% CI, 14.8%-27.7%). HR matching decreased the probability of severe acute GVHD. The cumulative incidence of relapse at 2 years was 19.9% (95% CI, 14.8%-25.7%). The probabilities of 6-month and 2-year survivals were 67.4% and 49.5%. Unrelated donor cord blood transplantation from partially HLA-mismatched units can cure many children with leukemias. The study was registered at www.clinicaltrials.gov as #NCT00000603.

Unrelated donor umbilical cord blood transplantation for inherited metabolic disorders in 159 pediatric patients from a single center: influence of cellular composition of the graft on transplantation outcomes

Outcomes of 159 young patients with inherited metabolic disorders (IMDs) undergoing transplantation with partially HLA-mismatched unrelated donor umbilical cord blood were studied to investigate the impact of graft and patient characteristics on engraftment, overall survival (OS), and graft-versus-host disease (GVHD). Patients received myeloablative chemotherapy (busulfan, cyclophosphamide, ATG) and cyclosporine-based GVHD prophylaxis. Infused cell doses were high (7.57 x 10(7)/kg) because of the patients' young age (median, 1.5 years) and small size (median, 12 kg). Median follow-up was 4.2 years (range, 1-11 years). The cumulative incidences of neutrophil and platelet engraftment were 87.1% (95% confidence interval [CI], 81.8%-92.4%) and 71.0% (95% CI, 63.7%-78.3%). A total of 97% achieved high (> 90%) donor chimerism. Serum enzyme normalized in 97% of patients with diseases for which testings exist. Grade III/IV acute GVHD occurred in 10.3% (95% CI, 5.4%-15.2%) of patients. Extensive chronic GVHD occurred in 10.8% (95% CI, 5.7%-15.9%) of patients by 1 year. OS at 1 and 5 years was 71.8% (95% CI, 64.7%-78.9%) and 58.2% (95% CI, 49.7%-66.6%) in all patients and 84.5% (95% CI, 77.0%-92.0%) and 75.7% (95% CI, 66.1%-85.3%) in patients with high (80-100) performance score. In multivariate analysis, favorable factors for OS were high pretransplantation performance status, matched donor/recipient ethnicity, and higher infused colony forming units.

A strategy of splitting individual high volume cord blood units into two half subunits prior to processing increases the recovery of cells and facilitates ex vivo expansion of the infused haematopoietic progenitor cells in adults

This study was designed to maximize the recovery of the desirable cell populations contained in the cord blood (CB) freezing bag, in order to optimize donor selection for adolescents and adults. To evaluate this hypothesis, high volume CB units (CBUs) were categorized into three volume collection groups (120-139, 140-159 and >or=160 ml) and were randomly split before volume reduction into two half low volume CBUs; (a) and (b). Using the SEPAX Cell Processing System, all CBUs were standardized to 26 ml. In 128 high volume split CBUs, the WBC, mononuclear cell and CD34+ cell recoveries were significantly higher (P Collapse

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MESH Headings

• Blood Banking/methods
• Blood Cell Count
• Blood Preservation/methods
• Cell Separation/methods
• Cell Survival
• Cord Blood Stem Cell Transplantation/methods
• Female
• Fetal Blood
• Hematopoietic Stem Cells
• Humans

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Affiliation(s)

A C Papassavas Hellenic Cord Blood Bank, Foundation for Biomedical Research, Academy of Athens, Athens, Greece.
V Gioka
T Chatzistamatiou
T Kokkinos
I Anagnostakis
G Gecka
I Redoukas
G Paterakis
C Stavropoulos-Giokas

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Indications and donor selections for allogeneic stem cell transplantation in children with hematologic malignancies

Allogeneic stem cell transplantation (SCT) is the only curative approach for many patients with advanced or high-risk leukemia. Advances in supportive care and management of graft-versus-host disease have resulted in improvements in outcomes of related and unrelated donor SCT, creating controversies as to which strategy might be the optimal therapy for individual patients. This article discusses the indications and donor selection strategies for SCT in patients with malignant hematologic disease.

Allogeneic stem cell transplantation in children with leukemia using human leukocyte antigen-mismatched unrelated donors

Allogeneic HSCT is a curative treatment, when chemotherapy fails, for certain malignant diseases. In Europe, only 15% of the indicated children have an HLA-matched sibling available; in 65-70% of others, HLA allele-matched (9-10/10) UDs can be identified. For the rest, it is necessary to identify other alternative donors (HLA-mismatched family or unrelated cord blood). We present our data of HSCT using HLA partially allele-mismatched (7-8/10) UDs in 24 children with leukemia. Uniform GvHD prophylaxis was used (rATG, CsA and MTX). Acute GvHD grade II was diagnosed in 70.8% of the patients and grade III-IV in 12.5%. Overall incidence of chronic GvHD was 38.7% (extensive in 30%). The probability of EFS was 60.3% (95% CI 35.5-78.1) and OS was 74.9 (95% CI 49.1-88.9). No difference in survival between PBSC and BM recipients was observed. TRM at day + 100 was 4%, and overall was 12.5%. We conclude that used combination of drugs for GvHD prophylaxis is efficient even for patients transplanted with grafts from a HLA-mismatched UDs. It enables stable engraftment, good control of GvHD, full reconstitution of immunity, and is not connected with unacceptable transplant-related mortality.

A scheme for defining cause of death and its application in the T cell depletion trial

The primary cause of death (COD) provides important information in many studies of hematopoietic stem cell transplantation (HSCT). A panel of experts critically assessed the CODs submitted by 15 transplantation centers for 281 patients who died in a randomized multicenter trial of unrelated HSCT. The panel reviewed the CODs reported by the transplantation centers, which used the Center for International Blood and Marrow Transplant Research and National Marrow Donor Program COD reporting form. The panel determined that the existing criteria for primary and contributing CODs lacked sufficient stringency for uniform interpretation. A hierarchy was developed and applied to the T cell depletion project. Using its scheme, the panel reclassified 157 CODs (56%) reported by the transplantation centers. The changes resulted in increased recognition of graft-versus-host disease as the primary COD and a concomitant decrease in attribution of the primary COD to infection. This algorithm promotes consistent assignment of primary and contributing CODs for patients with leukemia or lymphoma who expire after myeloablative allogeneic HSCT.

Expanding the role of umbilical cord blood transplantation

Umbilical cord blood has become a valuable alternative source of haematopoietic stem cells for allogeneic transplantation. However, largely because of the impact of cell dose on engraftment, risk of transplant-related mortality and survival, progress in the field has been largely restricted to children. Nevertheless, substantial clinical experience with umbilical cord blood transplantation clearly establishes its safety and effectiveness in young patients with a variety of malignant and non-malignant diseases. Although less well established in adults, new strategies are now being explored to address the obstacle of cell dose. This article reviews the state of the art and future directions with umbilical cord blood as a source of haematopoietic stem cells for transplantation in both children and adults.

Has stem cell transplantation come of age in the treatment of sickle cell disease?

Currently, hematopoietic SCT (HCT) is the only intervention that can restore normal hematopoiesis to provide a 'cure' in sickle cell disease. Yet, this treatment modality is used sparsely-a total of less than 400 transplants are reported in the Center for International Blood and Marrow Transplant Research database despite 70,000 afflicted in the United States; 88% of transplants are from HLA-matched sibling donors and 84% are <16 years of age at transplant. Overall survival at 3 years is over 90% after HCT in the young but 62% in adult HCT recipients due to increased disease and transplant-related morbidity. The decision and timing of HCT is a dilemma for physicians and families due to the need to consider HCT before severe organ damage in a disease that is generally not fatal in children with adequate supportive care. From the transplant physician's perspective, however, advances in the ability to identify well-matched donors, supportive care and promising conditioning regimens with low toxicity and transplant complications support the development of new HCT trials for sickle cell disease as the risk/benefit ratio can be balanced better. With the recognition of new predictors of early mortality, the anticipation of extensive and expensive life-long medical support, and the poor quality of life despite medical care, the scales tip in favor of HCT. This is prime time for the development of careful unrelated donor HCT trials for sickle cell disease. Research efforts targeting HCT will need to be directed at seeking safe and effective transplant methods applicable to all patients who might derive benefit.

Umbilical cord blood transplantation for myeloid malignancies

PURPOSE OF REVIEW

To review the available data on the outcomes of pediatric and adult patients with acute myeloid leukemia, myelodysplastic syndrome and chronic myelogenous leukemia after umbilical cord blood transplantation.

RECENT FINDINGS

The literature shows that after umbilical cord blood transplantation the relapse rate, disease-free survival and overall survival of patients with myeloid malignancies is similar to other hematopoietic stem cells sources. Disease status at the time of transplantation is found in several studies to be a very important determinant of long-term outcome. Newer strategies such as double umbilical cord blood transplant and utilization of nonmyeloblative conditioning regimens show promising results.

SUMMARY

Umbilical cord blood is a valuable alternative source of hematopoietic stem cells for transplantation of patients with myeloid malignancies who need an allogeneic transplant, but lack a suitable sibling donor.