Pre-transplant prognostic factors for patients with high-risk leukemia undergoing an unrelated cord blood transplantation

Scoring system for optimal cord blood unit selection for single cord blood transplantation

BACKGROUND

We conducted a retrospective study to categorize the cord blood unit (CBU)s to identify the optimal units.

METHODS

A total of 8503 adults (female, n = 3592; male, n = 4911) receiving their first single cord blood transplantation (CBT) in 2000-2019 were analyzed. Factors associated with CBUs affecting overall survival (OS) and neutrophil engraftment were selected to create ranked categorization for each outcome, followed by comparison with transplantation using HLA-matched bone marrow (BMT)/peripheral blood stem cell (PBSCT) from unrelated (n = 6052) and related donors (n = 4546).

RESULTS

Sex-mismatch, CD34+ cell and CFU-GM counts were selected in the OS analysis. Considering the strong interaction between sex mismatch and CD34+ cell counts, we analyzed females and males separately. For females, female CBU with CD34+ cell counts {greater than or equal to} 0.5 × 10e5/kg and CFU-GM counts {greater than or equal to} 15 × 10e3/kg offered the best OS (Group I), followed by other groups with any (Groups II-IV) or all (Group V) of the risk factors. Group I consistently showed favorable OS (Group IV: HR1.22, P = 0.027; Group V: HR1.31, P = 0.047), comparable to those of rBMT/PBSCT (OS: HR1.02, P = 0.654) and uBM/PBSCT in patients with higher rDRI (HR1.07, P = 0.353). Male patients lacked significant factors affecting OS. Categorization for neutrophil engraftment consisting of CD34+ cell and CFU-GM counts, sex-mismatch, presence of donor-specific antibodies, and the number of HLA-mismatches was effective but not predicted OS.

CONCLUSION

Our ranked categorizations sufficiently predicted female OS and engraftment. The best-ranked CBUs offered preferable outcomes comparable to conventional BM/PB donors in female but not in male patients.

Momentum of neutrophil recovery using an exponential growth model predicts the prognosis of single cord blood transplantation

INTRODUCTION

After the first appearance of peripheral blood neutrophils, recipients from adult donor sources have a rapid increase in neutrophil recovery, whereas cord blood transplantation (CBT) recipients have a slow increase. However, the momentum of neutrophil recovery after CBT varies widely among individuals, but optimal methods to evaluate the momentum of neutrophil recovery and their clinical impacts are yet to be clarified.

METHODS

We retrospectively examined the prognostic effect of the momentum of neutrophil recovery in the last 7 days until neutrophil engraftment, which was calculated by an exponential growth model, after single CBT following myeloablative conditioning for 207 adults.

RESULTS

Among patients who achieved each hematopoietic lineage recovery by day 100, the momentum of neutrophil recovery, which was represented as a growth constant, was associated with the day of neutrophil engraftment (P < .0001), red blood cell engraftment (P < .0001), and platelet engraftment (P < .0001) using the Spearman's rank correlation coefficient test. More importantly, overall survival was superior with a higher growth constant compared with a lower growth constant (P < .001). In the multivariate analysis, a higher growth constant showed a lower overall mortality compared with a lower growth constant (hazard ratio: 0.48, P = .014).

CONCLUSION

Our data demonstrated that the momentum of neutrophil recovery during the last 7 days before neutrophil engraftment, which was measured using an exponential growth model, was associated not only with hematopoietic recovery but also with a better prognosis after single CBT.

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

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

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.

Unrelated cord blood transplantation: outcomes after single-unit intrabone injection compared with double-unit intravenous injection in patients with hematological malignancies

BACKGROUND

Unrelated cord blood transplantation (UCBT) is associated with delayed hematopoietic recovery. Intrabone injection of cord blood cells (IB-UCBT) and double-UCBT (dUCBT) are designed to circumvent this problem.

METHODS

In a retrospective registry-based analysis, we compared outcomes of 87 IB-UCBT with 149 dUCBT recipients, after myeloablative conditioning regimen adjusting for the differences between the two groups. Median-infused total nucleated cells were 2.5×10/kg for IB-UCBT and 3.9×10/kg for dUCBT (P<0.001).

RESULTS

At day +30, cumulative incidence (CI) of neutrophil recovery was 76% and 62% (P=0.014) with a median time to engraftment of 23 and 28 days (P=0.001), after IB-UCBT and dUCBT, respectively. At day +180, CI of platelets recovery was 74% after IB-UCBT, and 64%, after dUCBT (P=0.003). In multivariate analysis, IB-UCBT was associated with neutrophil and platelets recovery and lower acute graft versus host disease (II-IV) (P<0.01). At 2 years, CI of nonrelapse mortality and relapse incidence were 30% and 25% after IB-UCBT and 34% and 29% after dUCBT, and disease-free survival was 45% and 37%, respectively. However, after landmark analysis at 4.7 months from transplantation, in multivariate analysis, relapse incidence was reduced (P=0.03), and there was a trend for better disease-free survival after IB-UCBT (P=0.09).

CONCLUSION

Both approaches expand the possibility of offering UCBT to patients with hematopoietic malignancies; IB-UCBT is associated with faster myeloid and platelet recovery and lower acute graft versus host disease and may reduce the total cost. However, studies on cost effectiveness are needed to compare both strategies.

Validation of cord blood split products prepared by an automated method

OBJECTIVES

In this study, we studied whether the contents of the two compartments of automatically processed cord blood (CB) units are comparable with respect to cell counts and viability and therefore suitable for clinical therapy.

BACKGROUND

CB-derived stem cells are increasingly used for allogeneic transplantation. Many centres prepare the transplants by automated methods allowing to split the product into two portions.

METHODS

CB was collected at different sites in Germany and transported to a single centre for processing. Before and after cryopreservation laboratory analyses were performed to compare the quality of the two CB segments.

RESULTS

In total, 33 products were processed [mean collection volume: 18·6 ± 1·2 mL (range 15·2-20·2 mL) segment A; mean: 4·7 ± 0·3 mL (range 4·2-5·2 mL) segment B]. CD34+ cell counts, viability of CD34+ cells and many other haematological parameters showed a good comparibility between the two segments. However, lymphocyte counts and results of clonogenic assays were significantly different between the two segments of the split product.

CONCLUSION

We conclude that the preparation of the cord blood unit by the automated process results in a homogenous distribution of stem and progenitor cells. However, our findings show that the clonogenic capacity differs between the two segments.

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.

Algorithm for donor selection in 2011

PURPOSE OF REVIEW

The timing represents a relevant prognostic factor of outcome for patients with hematological malignancies undergoing an allogeneic hematopoietic stem cell transplant (ASCT). In this review, the most recent studies and own transplant center policy on the donor search will be summarized in order to design an algorithm of donor identification driving towards a timely ASCT.

RECENT FINDINGS

Nowadays, volunteer-unrelated, umbilical cord blood and haploidentical-related donors represent the three alternative sources of hematopoietic stem cells for patients who lack a human leukocyte antigen identical sibling, so that an alternative donor can potentially be found for about all patients eligible for an ASCT. To date, all retrospective studies comparing transplants from these alternative donors have shown no substantial differences in terms of final outcome of patients grafted for hematological malignancies. The policy of a widespread search for an alternative donor has been progressively increasing in the past years.

SUMMARY

All patients with hematological malignancy for whom the intention to treatment includes an allogeneic transplant should proceed with a well timed ASCT, whatever the stem cell source. The therapeutic policy following the concept of 'donor versus no donor' should presently be changed according to the concept of 'transplant versus no transplant'.

Concurrent search for unrelated cord and volunteer donor in high-risk acute lymphoblastic leukemia

To assess the effectiveness of the search for an unrelated donor on the outcome of patients with high-risk acute lymphoblastic leukemia, we analyzed prospectively 136 patients who underwent a search for cord blood (CB) and an unrelated volunteer donor (UD) at the same time. The probability of finding a donor was 58.2%, 70.3%, and 75.7% at 3, 6, and 12 months, respectively. The median time to find a donor was 1.8 months for CB and 3.5 months for UD. Of the 99 patients with a donor, 38.4% failed to undergo the transplant because of a relapse observed at a median of 4 months from the start of the search. In univariate analysis, absence of relapse during the search (p < 0.0001) and transplant (p = 0.004) showed a positive impact on long-term survival. In multivariate analysis, relapse during the search remained the key factor affecting survival (p < 0.0001). Since an extension of the search beyond 3 months enables only a slight increase in the probability of finding a donor compared to the increased risk of relapse, the time of the search should not exceed the 3-month time point. The simultaneous search for CB and UD increases the likelihood of performing a timely transplant.

Quality assessment of umbilical cord blood units at the time of transplantation

Total nucleated cell (TNC) count, CD34(+) cell count, colony-forming unit-granulocyte-macrophage (CFU-GM) content, and cell viability impact the outcome of umbilical cord blood (UCB) transplantation. Assessments of unit quality have usually been provided by cord blood banks (CBBs), but it is unclear whether pre-freezing tests or pre-transplant release tests performed by CBBs are reproducible. The aim of this study was to compare the UCB characteristics analyzed at the site of infusion of the UCB with those provided by CBBs. Samples were taken from 54 UCB units for assessment of post-thaw characteristics. TNC counts and CD34(+) cell contents measured at our hospital before infusion showed good correlations with values assessed in pre-freezing tests (r = 0.900 and 0.943, respectively) and pre-transplant release tests (r = 0.829 and 0.930, respectively). Our data reveal that the TNC counts and CD34(+) cell contents determined by pre-freezing and pre-transplant release tests, which are the most important UCB unit selection criteria, accurately reflected the quality of infused UCB units. However, CFU-GM content was poorly correlated (r = 0.560 and 0.606). Correlation of post-thaw cell viabilities measured before infusion and during the pre-transplant release tests was also poor (r = 0.308). We suggest that the TNC count and CD34(+) cell content estimated before cryopreservation and in pre-transplant release tests provided by CBBs are reproducible and can assist the transplant physicians in selection of appropriate UCB units.

Improving outcomes of cord blood transplantation: HLA matching, cell dose and other graft- and transplantation-related factors

The use of unrelated umbilical cord blood (UCB) as an alternative source of haematopoietic stem cells transplantation (HSCT) has been widely used for patients lacking a human leucocyte antigen (HLA) matched donor. One of the disadvantages of using UCB is the limited number of haematopoietic stem cells and, consequently, delayed engraftment and increased risk of early mortality. Many approaches have been investigated in the attempt to improve engraftment and survival. Among those, studies analysing prognostic factors related to patients, disease, donor and transplantation have been performed. Variable factors have been identified, such as factors related to donor choice (HLA, cell dose and others) and transplantation (conditioning and graft-versus-host disease prophylaxis regimens). This review will focus on the interactions between HLA, cell dose and other modifiable factors related to the UCB unit selection and transplantation that may improve outcomes after UCB transplantation.

Relapse risk after umbilical cord blood transplantation: enhanced graft-versus-leukemia effect in recipients of 2 units

Umbilical cord blood (UCB) transplantation is potentially curative for acute leukemia. This analysis was performed to identify risk factors associated with leukemia relapse following myeloablative UCB transplantation. Acute leukemia patients (n = 177; 88 with acute lymphoblastic leukemia and 89 with acute myeloid leukemia) were treated at a single center. Patients received a UCB graft composed of either 1 (47%) or 2 (53%) partially human leukocyte antigen (HLA)-matched unit(s). Conditioning was with cyclophosphamide and total body irradiation with or without fludarabine. The incidence of relapse was 26% (95% confidence interval [CI], 19%-33%). In multivariate analysis, relapse was higher in advanced disease patients (> or = third complete remission [CR3]; relative risk [RR], 3.6; P < .01), with a trend toward less relapse in recipients of 2 UCB units (RR = 0.6; P = .07). However, relapse was lower for CR1-2 patients who received 2 UCB units (RR 0.5; P < .03). Leukemia-free survival was 40% (95% CI, 30%-51%) and 51% (95% CI, 41%-62%) for single- and double-unit recipients, respectively (P = .35). Although it is known that transplantation in CR1 and CR2 is associated with less relapse risk, this analysis reveals an enhanced graft-versus-leukemia effect in acute leukemia patients after transplantation with 2 partially HLA-matched UCB units. This trial was registered at http://clinicaltrials.gov as NCT00309842.

Unrelated cord blood transplantation after myeloablative conditioning in adults with ALL

We analyzed the disease-specific outcomes of adult ALL treated with cord blood transplantation (CBT) after myeloablative conditioning. Between October 2000 and November 2007, 27 adult patients with ALL were treated with unrelated CBT. All patients received four fractionated 12 Gy TBI and chemotherapy as myeloablative conditioning. The median age was 36 years, the median weight was 57 kg and the median number of nucleated cells was 2.47 x 10(7)/kg. All patients received a single and HLA-mismatched cord blood unit. The cumulative incidence of neutrophil recovery at day 30 and platelet recovery at day 200 was 92.6 and 92.3%, respectively. With a median follow-up of 47 months, the probability of EFS at 5 years was 57.2%. The 5-year cumulative incidence of TRM and relapse was 3.7 and 27.4%, respectively. These results suggest that unrelated CBT after myeloablative conditioning could be safely and effectively used for adult patients with ALL.

Association of cord blood platelet characteristics and hematopoietic progenitor cells

BACKGROUND

Total nucleated cell (TNC) dose is associated with neutrophil and platelet (PLT) engraftment after cord blood (CB) transplantation and thus is used for selection of CB for banking. The goal of this study was to evaluate the internal relationships of CB PLT characteristics, TNC, and the hematopoietic progenitor cell (HPC) content of CB units.

STUDY DESIGN AND METHODS

HPC and TNC counts of 167 CB units processed with an automated cell separation system were compared with CB PLT count and mean PLT volume (MPV). Megakaryocyte progenitors (CFU-MK) were cultured from a subset of units (n = 24).

RESULTS

PLT concentration correlated with MPV (r = -0.39), which was also associated with both TNC and total CD34+ cells before and after processing (r = 0.37 and 0.35 and r = 0.41 and 0.42, respectively). In addition, MPV was associated with HPC counts in the CB unit. The p value was less than 0.001 for all associations. PLT count was inversely associated with markers of hematopoietic potential. Median removal of PLTs during processing was 62 percent (range, 40%-84%). All 24 CB units of the subset exhibited CFU-MK growth. In multivariate linear regression analysis, MPV improved prediction of the HPC content of the CB unit compared to prediction with CB volume and nucleated cell concentration only.

CONCLUSION

Mean PLT volume correlated with current markers of CB hematopoietic potential and is potentially useful for evaluating CB collections for banking. The question of the clinical significance of PLT characteristics in CB transplantation remains unanswered.

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.

The impact of post-thaw colony-forming units-granulocyte/macrophage on engraftment following unrelated cord blood transplantation in pediatric recipients

We retrospectively reviewed the engraftment kinetics following unrelated cord blood transplantation (CBT) in association with the post-thaw colony-forming units-granulocyte/macrophage (CFU-GM) number along with the numbers of total nucleated cells (TNC), CD34(+) cells and CD3(+) cells. A total of 71 cord blood units prepared for 53 patients (double-unit CBT in 18 patients) were evaluated. Either the number of infused CFU-GM or CD34(+) cells was significantly lower in patients who failed to achieve engraftment (P=0.028 and 0.005, respectively). Post-thaw CFU-GM, TNC and CD34(+) cells correlated with the speed of neutrophil engraftment (P=0.004, 0.037 and 0.004, respectively), whereas only CFU-GM showed a significant correlation with platelet engraftment (r=-0.385, P=0.024). In double-unit transplants, the number of CFU-GM was the only significant factor predicting engraftment of the predominating unit (P=0.006). We conclude that the post-thaw CFU-GM number is a reliable predictor of rapid engraftment after CBT as well as of the predominating unit in double-unit transplants. Thus, it would be important to perform post-thaw CFU-GM assay on cryopreserved aliquots from several candidate cord blood units in advance before CBT to avoid selecting the unit that might possess a low clonogenic potential.

Posttransplantation Engraftment and Safety of Cord Blood Transplantation with Grafts Containing Relatively Low Cell Doses in Adults

The cell dose of a graft is a critical determinant of hematopoietic recovery and survival following unrelated cord blood transplantation. Most studies have found that the minimum acceptable nucleated cell dose should be between 1.5 X 10(7) and 2.0 X 10(7) nucleated cells per kilogram of body weight to reduce the time to myeloid recovery and increase the probability of engraftment. For some patients who have indications for hematopoietic cell transplants and for whom no other graft source except cord blood is available, it is difficult to decide whether they can receive cord blood grafts containing lower cell doses. In our study, patients who received cord blood grafts containing 1.0 X 10(7) to 2.0 X 10(7) cells/kg (n = 7) exhibited slower neutrophil and platelet recoveries compared with patients who received grafts containing total nucleated cell doses of 2.0 X 10(7) cells/kg and above (n = 93); however, 4 of those low-cell-dose recipients survived with a longer follow-up. Based on these preliminary results, cord blood grafts containing less than 2.0 X 10(7) cells/kg may be useful for cases where no grafts with higher cell doses or other stem cell sources are available.

Factors predicting success or failure associated with common types of transplants

The ability to predict clinical outcomes is essential to accurate medical decision analysis. Many accepted bone marrow transplant related prognostic variables are derived from data that is over 20-years old and may or may not be applicable to current medical practice. This report reviews both older data concerning bone marrow transplantation prognostic factors as well as more current reports. In addition to pretransplant variables, this review examines easily measured post-transplant variables that may affect prognosis, as well as data concerning the cellular component of the infused graft in both allogeneic and autologous transplantation.

Umbilical cord blood transplantation

PURPOSE OF REVIEW

Familiar and unrelated umbilical cord blood is an appealing alternative source of hematopoietic stem cells patients undergoing transplantation for a wide variety of diseases. In the unrelated donor transplant setting, shorter time to transplant, which is particularly relevant to patients requiring urgent transplantation, and tolerance of 1-2 human leukocyte antigen mismatch, which increases the chance of finding a suitable donor, are evident advantages over bone marrow transplantation. The speed of engraftment is slower after cord blood transplantation but it is counterbalanced by a lower incidence of severe graft-versus-host disease. Cell dose and human leukocyte antigen are major factors influencing outcome after umbilical cord blood transplantation.

RECENT FINDINGS

Unrelated donor cord blood transplantation is considered an acceptable option to bone marrow for pediatric transplantation, and recent data in adults point the same way.

SUMMARY

This review describes the recent clinical results of cord blood transplantation and discusses developing research strategies aimed at optimizing this kind of transplantation.