Comparative analysis of unrelated cord blood transplantation and HLA-matched sibling hematopoietic stem cell transplantation in children with high-risk or advanced acute leukemia

Hematopoietic stem cell transplantation for acute lymphoblastic leukemia: why do adolescents and young adults outcomes differ from those of children? A retrospective study on behalf of the Francophone Society of Stem Cell Transplantation and Cellular Therapy (SFGM-TC)

PURPOSE

In the acute lymphoblastic leukemia (ALL) landscape, adolescents and young adults (AYA) often present high-risk diseases and increased chemotherapy-related toxicity. Studies analyzing the outcomes of AYA after hematopoietic stem cell transplantation (HSCT) are scarce. Our study aimed to compare the outcomes of children and AYA with ALL after HSCT and to determine the factors influencing potential differences.

METHOD

891 patients, from the SFGM-TC registry, aged between 1 and 25 years who received HSCT between 2005 and 2012 were included. The outcomes of AYA were compared to the ones of their younger counterparts.

RESULTS

Five-year OS and GRFS were lower in AYA: 53.1% versus 64% and 36% versus 47% (p = 0.0012 and p = 0.007, respectively). WhileCIR was similar in both groups, 5 year-treatment related mortality was higher in AYA: 19% versus 13% (p = 0.04). The lower GRFS in AYA was mainly explained by a higher chronic graft versus host disease (cGvHD) incidence: 32% versus 19% (p < 0.001). Use of peripheral blood stem cells and use of anti-thymoglobulin appeared to be the main factors impacting cGvHD occurrence in AYA.

CONCLUSION

AYA have worse outcomes than children after HSCT for ALL because of a greater risk of TRM due to cGvHD. HSCT practices should be questioned in this population.

Unrelated cord blood transplantation vs. HLA-matched sibling transplantation for adults with B-cell acute lymphoblastic leukemia in complete remission: superior OS for patients with long-term survival

Background

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an important curative therapy for adult acute lymphoblastic leukemia (ALL). For patients who lack a human leukocyte antigen (HLA)-matched sibling donor, unrelated cord blood (UCB) is an alternative graft option. Previous studies have focused mainly on all T- and B-cell ALL (B-ALL) patients, while data related specifically to adult B-ALL patients after UCB transplantation (UCBT) are scarce.

Methods

We retrospectively compared the outcomes of UCBT and HLA-matched sibling transplantation (MST) in the treatment of adult B-ALL patients in complete remission (CR) at our center. From June 2006 to December 2020, 156 adult B-ALL patients who achieved CR before transplantation were enrolled. The main clinical outcomes of UCBT and MST were analyzed.

Results

Hematopoietic recovery was significantly faster in MST recipients than in UCBT recipients. Higher incidences of grades II-IV and III-IV acute graft-versus host disease (aGVHD) were found in UCBT recipients (P < 0.001 and = 0.03), while a lower incidence of extensive chronic GVHD (cGVHD) was found in UCBT recipients (P < 0.001). The cumulative incidences of 2-year non-relapse mortality (NRM), 2-year relapse, 5-year disease-free survival (DFS) and 5-year GVHD-free relapse-free survival (GRFS) were comparable between MST and UCBT recipients. The overall survival (OS) during the first 700 days was similar between the MST and UCBT groups, while the OS of patients with a survival time of more than 700 days in the UCBT group was better than that in the MST group according to multivariate analysis (P = 0.03).

Conclusions

Our study shows that when treating adult B-ALL patients in CR, UCBT can achieve comparable effects as MST, may provide superior OS for patients with long-term survival, and should be considered a good alternative.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03186-3.

[Unrelated cord blood stem cell transplantation for high-risk/refractory childhood acute myeloid leukemia: a clinical analysis of 160 cases]

Objective: To retrospectively analyze the clinical outcomes of single unrelated cord blood transplantation (UCBT) in children with high risk and refractory acute myeloid leukemia (AML) . Methods: Between June 2008 and December 2018, a total of 160 consecutive pediatric patients with AML received single UCBT (excluding acute promyelocytic leukemia) . Myeloablative conditioning (MAC) regimen were applied. All patients received a combination of cyclosporine A (CsA) and mycophenolate mofetil (MMF) for the prophylaxis of graft -versus- host disease (GVHD) . Results: The cumulative incidence of neutrophil cells engraftment at day +42 and platelet recovery at day +120 was 95.0% (95% CI 90.0%-97.5%) at a median of 16 days after transplantation (range, 11-38 days) and 85.5% (95%CI 83.3%-93.4%) with a median time to recovery of 35 days (range, 13-158) , respectively. Incidence of grades Ⅱ-Ⅳ and Ⅲ-Ⅳ acute GVHD and chronic GVHD were 37.3% (95%CI 29.3%-45.2%) , 27.3% (95%CI 20.0%-35.0%) and 22.4% (95%CI 15.5%-28.7%) , respectively. The transplant-related mortality (TRM) at 360 day was 13.1% (95%CI 8.4%-18.9%) . The 5-year cumulative incidence of relapse was 13.8% (95%CI 8.5%-20.3%) . The 5-year disease-free survival (DFS) and overall survival (OS) were 71.7% (95%CI 62.7%-77.8%) and 72.2% (95%CI 64.1%-78.7%) , respectively. The 5-year GVHD and relapse free survival (GRFS) was 56.1% (95%CI 46.1%-64.9%) . The 5-year cumulative recurrence rates of CR1, CR2, and NR groups were 5.3%, 19.9%, and 30.9% (P=0.001) , and the 5-year OS rates were 79.9% (95%CI 70.3%-86.7%) , 71.1% (95%CI 50.4%-84.4%) and 52.9% (95%CI 33.0%-69.3%) (χ(2)=7.552, P=0.020) , respectively. Conclusions: For pediatric patients with high risk and refractory AML, UCBT is a safe and effective treatment option, and it is favorable to improve the survival rate in CR1 stage.

Comparison of central nervous system relapse outcomes following haploidentical vs identical-sibling transplant for acute lymphoblastic leukemia

To explore the incidence, risk factors, and outcomes of central nervous system (CNS) relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for acute lymphoblastic leukemia (ALL) and to compare the differences in CNS relapse between haploidentical donor HSCT (HID-HSCT) and HLA-identical sibling donor HSCT (ISD-HSCT). We performed a retrospective nested case-control study on patients with CNS relapse after allo-HSCT. The cumulative incidence of CNS relapse was 4.06% after allo-HSCT in ALL, with a significantly poor prognosis. The incidence was 3.91% and 5.36% in HID-HSCT and ISD-HSCT, respectively (p = .227). Among the patients with CNS relapse, the overall survival (OS) at 3 years was 56.2 ± 6.8% in the HID-HSCT subgroup and 76.9 ± 10.2% in the ISD-HSCT subgroup (p = .176). The 3-year cumulative incidence of systemic relapse was also comparable between the two subgroups (HID-HSCT, 40.6 ± 7.4%; ISD-HSCT, 13.3 ± 8.7%, respectively, p = .085). Younger age (p = .045), T-ALL (p = .035), hyperleukocytosis at diagnosis (p < .001), advanced disease stage at transplant (p < .001), pre-HSCT CNS involvement (p < .001), and absence of chronic graft vs host disease (cGVHD) (p < .001) were independent risk factors for CNS relapse after allo-HSCT. In conclusion, CNS relapse was a significant complication after allo-HSCT in ALL and was associated with poor prognosis. The incidences and outcomes were comparable between HID-HSCT and ISD-HSCT.

Alternative donor peripheral blood stem cell transplantation for the treatment of high-risk refractory and/or relapsed childhood acute leukemia: a randomized trial

Background

The high-risk refractory and/or relapsed (R/R) childhood acute leukemia prognosis is poor, and allogeneic stem cell transplantation (allo-HSCT) is the most prudent treatment modality. However, there are limited matched sibling donors (MSDs), and alternative donors (ADs) are the main source for allo-HSCT. Thus, we evaluated the clinical efficacy of AD peripheral allo-HSCT for treating high-risk R/R childhood acute leukemia.

Methods

We assessed 111 children who underwent allo-HSCT at the Affiliated Cancer Hospital of Zhengzhou University between October 2006 and July 2019. The patients were divided in the MSD and AD groups, and their clinical characteristics, complications, and survival rates were compared.

Results

The cumulative incidences of Epstein–Barr virus and cytomegalovirus infections were significantly higher in the AD than in the MSD group (P < 0.001); however, the recurrence and mortality rates were significantly higher in the MSD than in the AD group (P < 0.05). Furthermore, the 5-year disease-free (DFS) (65.2% vs. 43.3%, P = 0.033) and overall survival (OS) rates (71.6% vs. 53.8%, P = 0.053) were significantly higher in the AD than in the MSD group. In the AD group, the grade II–IV acute graft-versus-host disease (aGVHD), donor-recipient ABO compatibility, conditioning regimen, and CMV infection affected the 5-year OS. The grade II–IV aGVHD also affected the 5-year DFS; however, only the donor-recipient ABO compatibility affected the 5-year DFS. The donor MSD (HR: 2.035, 95% confidence interval [CI] 1.057–3.920, P = 0.034) and the grade II–IV aGVHD (HR: 2.914, 95% CI 1.261–6.736, P = 0.012) affected the 5-year DFS of childhood acute leukemia after allo-HSCT, and the grade II–IV aGVHD (HR: 3.016, 95% CI 1.217–7.473, P = 0.017) affected the 5-year OS. Moreover, the donor source (HR: 2.836, 95% CI 1.179–6.823, P = 0.020) and grade II–IV aGVHD (HR: 3.731, 95% CI 1.332–10.454, P = 0.012) were independent predictors of the 5-year DFS, while the latter (HR: 3.524, 95% CI 1.310–10.988, P = 0.030) was an independent predictor of the 5-year OS.

Conclusions

AD-PBSCT was effective for high-risk R/R childhood leukemia and may have better clinical outcomes than MSD-PBSCT; thus, it can be used as first-line treatment for high-risk R/R childhood leukemia.

Partially CD3+-Depleted Unrelated and Haploidentical Donor Peripheral Stem Cell Transplantation Has Favorable Graft-versus-Host Disease and Survival Rates in Pediatric Hematologic Malignancy

Most children who may benefit from stem cell transplantation lack a matched related donor. Alternative donor transplantations with an unrelated donor (URD) or a partially matched related donor (PMRD) carry an increased risk of graft-versus-host-disease (GVHD) and mortality compared with matched related donor transplantations. We hypothesized that a strategy of partial CD3⁺/CD19⁺ depletion for URD or PMRD peripheral stem cell transplantation (PSCT) would attenuate the risks of GVHD and mortality. We enrolled 84 pediatric patients with hematologic malignancies at the Children's Hospital of Philadelphia and the Children's Hospital of Wisconsin between April 2005 and February 2015. Two patients (2.4%) experienced primary graft failure. Relapse occurred in 23 patients (27.4%; cumulative incidence 26.3%), and 17 patients (20.2%) experienced nonrelapse mortality (NRM). Grade III-IV acute GVHD was observed in 18 patients (21.4%), and chronic GVHD was observed and graded as limited in 24 patients (35.3%) and extensive in 8 (11.7%). Three-year overall survival (OS) was 61.8% (95% confidence interval [CI], 50.2% to 71.4%) and event-free survival (EFS) was 52.0% (95% CI, 40.3% to 62.4%). Age ≥15 years was associated with decreased OS (P= .05) and EFS (P= .05). Relapse was more common in children in second complete remission (P = .03). Partially CD3⁺-depleted alternative donor PSCT NRM, OS, and EFS compare favorably with previously published studies of T cell-replete PSCT. Historically, T cell-replete PSCT has been associated with a higher incidence of extensive chronic GVHD compared with limited chronic GVHD, which may explain the comparatively low relapse and NRM rates in our study cohort despite similar overall rates of chronic GVHD. Partial T cell depletion may expand donor options for children with malignant transplantation indications lacking a matched related donor by mitigating, but not eliminating, chronic GVHD.

Current status of umbilical cord blood transplantation in children

The first umbilical cord blood (UCB) transplantation was performed 30 years ago. UCB transplantation (UCBT) is now widely used in children with malignant and non-malignant disorders who lack a matched family donor. UCBT affords a lower incidence of graft-versus-host disease compared to alternative stem cell sources, but also presents a slower immune recovery and a high risk of infections if serotherapy is not omitted or targeted within the conditioning regimen. The selection of UCB units with high cell content and good human leucocyte antigen match is essential to improve the outcome. Techniques, such as double UCBT, ex vivo stem cell expansion and intra-bone injection of UCB, have improved cord blood engraftment, but clinical benefit remains to be demonstrated. Cell therapies derived from UCB are under evaluation as potential novel strategies to reduce relapse and viral infections following transplantation. In recent years, improvements within haploidentical transplantation have reduced the overall use of UCBT as an alternative stem cell source; however, each may have its relative merits and disadvantages and tailored use of these alternative stem cell sources may be the optimal approach.

Comparison of survival outcome between donor types or stem cell sources for childhood acute myeloid leukemia after allogenic hematopoietic stem cell transplantation: A multicenter retrospective study of Study Alliance of Yeungnam Pediatric Hematology-oncology

We compared transplant outcomes between donor types and stem cell sources for childhood acute myeloid leukemia (AML). The medical records of children with AML in the Yeungnam region of Korea from January 2000 to June 2017 were reviewed. In all, 76 children with AML (male-to-female ratio = 46:30) received allogenic hematopoietic stem cell transplantation (allo-HSCT). In total, 29 patients received HSCT from either a matched-related donor or a mismatched-related donor, 32 patients received an unrelated donor, and 15 patients received umbilical cord blood. In term of stem cell sources, bone marrow was used in 15 patients and peripheral blood in 46 patients. For all HSCT cases, the 5-year overall survival (OS) was 73.1% (95% CI: 62.7-83.5) and the 5-year event-free survival (EFS) was 66.1% (95% CI: 54.5-77.7). There was no statistical difference in 5-year OS according to the donor types or stem cell sources (P = .869 and P = .911). There was no statistical difference in 5-year EFS between donor types or stem cell sources (P = .526 and P = .478). For all HSCT cases, the 5-year relapse rate was 16.1% (95% CI: 7.3-24.9) and the 5-year non-relapse mortality (NRM) was 13.3% (95% CI: 5.1-21.5). There was no statistical difference in the 5-year relapse rate according to the donor types or stem cell sources (P = .971 and P = .965). There was no statistical difference in the 5-year NRM between donor types or stem cell sources (P = .461 and P = .470).

Improvement of treatment outcome over 2 decades in children with acute myeloid leukemia

Background

The prognosis of pediatric acute myeloid leukemia (AML) has recently improved. This study aimed to describe the epidemiology, changes in treatment strategies, and improvement of outcomes in Gwangju-Chonnam children with AML over 2 decades.

Methods

Medical records of 116 children with newly diagnosed AML were retrospectively reviewed for demographic characteristics, prognostic groups including cytogenetic risks, treatment protocols, and survival rates over the periods between 1996 and 2005 (Period I, N=53), and 2006 and 2015 (Period II, N=38).

Results

The annual incidence of AML has decreased with reduced pediatric population. The 5-year Kaplan-Meier (K-M) estimated overall survival (OS) and event-free survival (EFS) rates in 110 AML patients were 53.2±5.1% and 43.8±5.1%, respectively. The 5-year OS rate significantly improved during period II (70.3±7.0%) as compared to that during period I (40.0±6.8%) (P =0.001). The 5-year OS was not significantly different among cytogenetic risk groups (P =0.11). Fifty-eight patients underwent hematopoietic stem cell transplantation (HSCT). The K-M 5-year estimated survival for transplanted patients was 53.7±7.0%, while that for chemotherapy-only patients was 30.1±9.1% (P =0.014). Among the prognostic factors, treatment modality was the only independent factor. The chemotherapy-only group had a relative risk of 2.06 for death compared with the transplantation group (P=0.015).

Conclusion

The survival of Korean children with AML has improved to a level comparable with that of developed countries over 2 decades, owing to a change in induction strategy, better supportive care with economic growth, refinement of HSCT techniques including a better selection of patients based on prognostic groups, and stem cell donor selection.

Clinical outcomes of unrelated cord blood transplantation in children with malignant and non-malignant diseases: Multicenter experience in China

This multicenter retrospective study included 184 children with malignant and non-malignant diseases who underwent UCBT between January 1998 and August 2012. The malignant disease group included 101 children with ALL, AML, CML, JMML, and MDS, and the non-malignant disease group included 83 children with PID, β-thalassemia, IMD BMF, and HLH. The median duration to neutrophil and platelet engraftment was 16 and 35 days in the malignant disease group vs 15 and 38 days in the non-malignant disease group. The cumulative incidence of grade II-IV aGVHD and cGVHD was 25.6% and 13.5% in the malignant disease group vs 19.7% and 11.1% in the non-malignant disease group, respectively. The median duration and cumulative incidence of neutrophil and platelet engraftment, and the cumulative incidence of grade II-IV aGVHD and cGVHD were similar between the two groups. Of the 184 pediatric patients, 114 patients survived during a median follow-up period of 14 months (range 4-138). The 5-year OS and DFS were not statistically different between the two groups (56.3% and 46.1% in malignant disease group vs 68.5% and 52.8% in non-malignant disease group). The above results indicate that UCB is a viable source for HSCT for children with malignant or non-malignant diseases, especially in urgent cases.

Transplants of unrelated cord blood or sibling allogeneic peripheral blood stem cells/bone marrow in adolescent and young adults with chronic myeloid leukemia: comparable outcomes but better chronic GVHD-free and relapse-free survival among survivors with cord blood

Adolescent and young adult (AYA) patients with hematological malignancy aged 15 to 39 years are recognized as a separate entity, and the efficacy and safety of unrelated cord blood transplantation (CBT) for chronic myeloid leukemia (CML) in AYA patients has not been reported. From March 2002 to June 2015, total of 106 CML patients received allogeneic hematopoietic cell transplantation (allo-HCT) in our center. Included in the present study were CML patients aged 15 to 39 years who received unrelated CBT or sibling allo-HCT, and 74 consecutive AYA patients with CML enrolled in this analysis. The day-100 cumulative incidences of grade 2–4 aGVHD and grade 3–4 aGVHD were similar following CBT and sibling-PBSCT/BMT. The cumulative incidences of cGVHD and extensive cGVHD were 21.7% and 5.3% in the CBT cohort, which were significantly lower than those in the sibling-PBSCT/BMT cohort (58.0% and 45.5%), respectively (p = 0.046, 0.008). There was no significant difference between the two cohorts in terms of transplant-related mortality (TRM), relapse, and long-term survival (overall survival and leukemia-free survival). The 5-year probability of GVHD-free/relapse-free survival (GRFS) was 47.9% and 33.4% in the CBT and the sibling-PBSCT/BMT cohorts, respectively (p = 0.632); among patients who survived more than 100 days after transplantation (n = 61), the 5-year probability of chronic GVHD-free, relapse-free survival (CRFS) was 66.2% in the CBT cohort, which was significantly higher than that in the sibling-PBSCT/BMT cohort (37.4%) (p = 0.037). Our study suggests that for AYA patients with CML, transplantation using unrelated CB offers comparable outcomes to sibling -PBSCT/BMT, including similar aGVHD, TRM, relapse, and long-term survival; however, from the perspective of quality of life, unrelated CBT have a lower incidence of cGVHD and a higher CRFS among survivors.

European Group for Blood and Marrow Transplantation Risk Score Predicts the Outcome of Patients with Acute Leukemia Receiving Single Umbilical Cord Blood Transplantation

The European Group for Blood and Marrow Transplantation (EBMT) risk score has been implemented as an important tool to predict patient outcomes after allogeneic hematopoietic stem cell transplantation. However, to our knowledge, this score has never been applied in cases of single umbilical cord blood transplantation (sUCBT). We retrospectively analyzed 207 consecutive patients with acute leukemia who received sUCBT at our center between February 2011 and December 2015. The probabilities of 3-year overall survival (OS) and leukemia-free survival (LFS) of the entire cohort were 65.0% and 59.8%, respectively, whereas the cumulative incidences of 3-year nonrelapse mortality (NRM) and relapse rate were 19.5% and 20.3%, respectively. In the univariate analysis, a higher EBMT risk score was associated with worse OS and LFS and higher NRM and relapse rate, ranging from 81.7%, 75.9%, 7.3%, and 15.3%, respectively, for patients with a score of 1 to 43.8%, 44.3%, 31.7%, and 23.9%, respectively, for patients with scores of 4 to 6. Hazard ratios of OS, LFS, and NRM all steadily increased for each additional score point. Importantly, the prognostic value of the EBMT risk score on OS, LFS, NRM, and relapse was maintained in the multivariate analysis. Moreover, considering the univariate analysis results of donor-recipient gender and mismatched allele-level HLA-A, -B, -C, and -DRB1 loci on patient outcomes and the fairly strong interaction between time from diagnosis to sUCBT and disease status, we developed a modified sUCBT-EBMT risk score by using degrees of 8-allele HLA match instead of donor type, donor-recipient gender combination, and time from diagnosis to sUCBT, and found that the modified score could also be used as a predictor for patient outcomes after sUCBT. The EBMT risk score is a good predictor of outcomes of patients with leukemia after sUCBT. The modified sUCBT-EBMT risk score can also be used as a pretransplant risk assessment, but this metric still requires further evaluation with a larger cohort.

Factors Determining the Outcome of Hematopoietic Stem Cell Transplantation in Patients With Acute Lymphoblastic Leukemia at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia

Medical records of 82 patients with acute lymphoblastic leukemia (ALL) who underwent hematopoietic cell transplantation (HCT) at our institution from 2005 to 2011 were reviewed. Forty-five patients were male (54.8%). The median age at HCT was 7.46 years (range, 0.98 to 14.31 y), the median time to HCT after diagnosis was 12.56 months. Ten patients were below the age of 1 year (12%). All patients were in complete remission at the time of HCT. In 83 transplants, 64 patients received HCT from human leukocyte antigen-identical-related donors and 19 from other donors. Stem cell source was bone marrow in 65 (78%) and cord blood in 18 (22%). Five-year overall survival was 58.8% and event-free survival was 54.3%. The cumulative incidence of acute graft versus host disease was 4.8%±2.3% and of chronic graft versus host disease was 8.9%±3.2%. The median time to absolute neutrophil count and platelet recovery was 17 days (range, 12 to 43 d) and 28 days (range, 15 to 98 d), respectively. One patient acquired CMV infection after transplant. No one developed venoocclusive disease, hemorrhagic cystitis, or other complication. Patient's age at diagnosis, sex, donor's human leukocyte antigen status and sex, source of transplant and complete remission status at HCT did not affect overall survival and event-free survival. Our results show a favorable outcome to HCT for acute lymphoblastic leukemia patients comparable to published data, and no single factor was associated with superior outcome.

Decitabine prior to salvaged unrelated cord blood transplantation for refractory or relapsed childhood acute leukemia

No clinical studies have investigated the role of decitabine as a part of the myeloablative conditioning regimen prior to UCBT for refractory or relapsed childhood AL in patients in NR status. The aim of this study was to identify the potential benefits of decitabine as a prior therapy before salvaged unrelated UCBT for refractory or relapsed childhood AL. Eight consecutive patients with childhood refractory/relapsed AL were enrolled in our study between 2013 and 2014. All patients were in NR status before the time of transplant and had features associated with poor outcomes, such as CNSL, MDS-AML, high WBC count at diagnosis, and hypodiploid status (FLT3+/ITD+). Additionally, all patients had one of the following disease statuses: PIF, multiple relapse, or early relapse. All transplants were performed with decitabine as part of the myeloablative conditioning regimen, which was decitabine+Flu/Bu/CY±BCNU or decitabine+Ara-c/BU/CY2±BCNU. A total of seven patients (7 of 8) achieved neutrophil engraftment and platelet engraftment, and one patient experienced primary graft failure. All eight patients (100%) developed PES at a median of 7 days. Three patients developed stage II-IV acute GVHD at a median of 18 days. Additionally, three patients developed chronic GVHD, but it was not extensive in any of those three patients. The median follow-up time after CBT was 19.9 months (range, 9.2-30.7 months). The estimated probability of OS was 75%. Two patients (2 of 8) experienced a testis relapse, and two patients (2 of 8) died. Our experience suggests that the additional application of decitabine as part of the myeloablative conditioning regimen prior to UCBT for refractory or relapsed childhood AL among patients who are not in remission is safe and might be an effective treatment option.

The Impact of Donor Type on Long-Term Health Status and Quality of Life after Allogeneic Hematopoietic Stem Cell Transplantation for Childhood Acute Leukemia: A Leucémie de l'Enfant et de L'Adolescent Study

We compared the long-term impact of donor type (sibling donor [SD] versus matched unrelated donor [MUD] or umbilical cord blood [UCB]) on late side effects and quality of life (QoL) in childhood acute leukemia survivors treated with hematopoietic stem cell transplantation. We included 314 patients who underwent transplantation from 1997 to 2012 and were enrolled in the multicenter French Leucémie de l'Enfant et de L'Adolescent ("Leukemia in Children and Adolescents") cohort. More than one-third of the patients were adults at last visit; mean follow-up duration was 6.2 years. At least 1 late effect was observed in 284 of 314 patients (90.4%). The average number of adverse late effects was 2.1 ± .1, 2.4 ± .2, and 2.4 ± .2 after SD, MUD, and UCB transplantation, respectively. In a multivariate analysis, considering the SD group as the reference, we did not detect an impact of donor type for most sequelae, with the exception of increased risk of major growth failure after MUD transplantation (odds ratio [OR], 2.42) and elevated risk of osteonecrosis after UCB transplantation (OR, 4.15). The adults and children's parents reported comparable QoL among the 3 groups. Adult patient QoL scores were lower than age- and sex-matched French reference scores for almost all dimensions. We conclude that although these patients are heavily burdened by long-term complications, donor type had a very limited impact on their long-term health status and QoL.

Comparison of outcomes after umbilical cord blood and unmanipulated haploidentical hematopoietic stem cell transplantation in children with high-risk acute lymphoblastic leukemia

Allogeneic hematopoietic stem cell transplantation (HSCT) is an effective therapy for children with high-risk acute lymphoblastic leukemia (ALL). Human leukocyte antigen (HLA)-haploidentical HSCT (haplo-HSCT) or umbilical cord blood transplantation (UCBT) are both important alternative sources of stem cells for those without an HLA-identical sibling donor or unrelated matched donor. We aimed to compare the therapeutic effects of single UCBT and unmanipulated haplo-HSCT in high-risk ALL children (n = 129). Hematopoietic recovery was significantly faster in haplo-HSCT recipients than in UCBT recipients. The 2-year cumulative incidences of relapse in the haplo-HSCT and UCBT groups were 16.1% and 24.1%, respectively (p = 0.169). The 2-year cumulative incidences of non-relapse mortality in the haplo-HSCT and UCBT groups were 12.8% and 18.8%, respectively (p = 0.277). The 2-year probabilities of overall survival in the haplo-HSCT and UCBT groups were 82.0% and 69.6%, respectively (p = 0.071), and the 2-year probability of disease-free survival in the haplo-HSCT group was higher than in the UCBT group (71.0% vs. 57.2%, p = 0.040). However, several variables (such as leukocyte count and cytogenetics at diagnosis) were different between the groups, and a possible center effect should also be considered. In addition, only mild and moderate chronic graft-versus-host disease (GVHD) was associated with significantly improved survival compared to those without chronic GVHD in multivariate analysis. Thus, our results show that both unmanipulated haplo-HSCT and UCBT are valid for high-risk ALL children lacking a HLA matched donor, and both strategies expand the donor pool for children in need.

The impact of pre-transplant minimal residual disease on outcome of intensified myeloablative cord blood transplant for acute myeloid leukemia in first or second complete remission

The impact of pretransplant minimal residual disease (MRD) on outcome of myeloablative cord blood transplant (CBT) for acute myeloid leukemia (AML) in complete remission (CR) has not been reported. Seventy-two AML patients were assessed for MRD before CBT, and the majority (84.7%) of these patients received single-unit CBT. All patients received intensified myeloablative conditioning with BUCY2 or TBICY plus high-dose cytarabine, and graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and mycophenolate mofetil. The cumulative incidences of neutrophil and platelet engraftment, acute or chronic GVHD were comparable between MRD-negative and MRD-positive groups. The cumulative incidence of transplant-related mortality (TRM) and relapse did not differ significantly between the two cohorts (25.6% vs. 32.5%, 16.1% vs. 19.2%; p = 0.52, 0.61). There were no apparent differences in 3-year overall survival (OS) (68.9% in MRD-negative group and 57.9% in MRD-positive group, p = 0.31) and 3-year leukemia-free survival (LFS) (62.5% in MRD-negative group and 52.7% in MRD-positive group, p = 0.42) between both groups. The current study suggests that AML patients in morphological CR1 or CR2 who have detectable MRD might benefit from unrelated CBT with intensified myeloablative conditioning.

Comparison of conditioning regimens with or without antithymocyte globulin for unrelated cord blood transplantation in children with high-risk or advanced hematological malignancies

The role and potential efficacy of antithymocyte globulin (ATG) in patients receiving cord blood transplantation (CBT) remain controversial. We retrospectively evaluated the effect of ATG on patient outcomes in 207 children with high-risk or advanced hematological malignancies at 8 child blood disease centers in China. The cumulative incidence of platelet recovery on day 100 was significantly lower in the ATG cohort compared with the non-ATG cohort (77.3% versus 89.8%) (P = .046). There was no significant difference in the incidence of grade II to IV acute and chronic graft-versus-host disease (GVHD), and transplantation-related mortality (TRM) between the 2 groups (P = .76, P = .57, and P = .46, respectively). The incidence of CMV infection was significantly higher among the ATG group compared with that among the non-ATG group (P = .003). The 5-year cumulative incidence of relapse was significantly higher in the ATG cohort (30.7% versus 15.4%) (P = .009). Overall survival in the non-ATG group was slightly higher than that of the ATG cohort (64.1% versus 52.1%, P = .093) and leukemia-free survival in the non-ATG cohort was significantly higher than in the ATG cohort (56.6% versus 37.7%, P = .015). Our study demonstrated that, for high-risk or advanced childhood hematological malignancies receiving unrelated CBT, patients who received conditioning that omitted ATG had a faster platelet recovery, a comparable GVHD and TRM, a significantly lower relapse risk, and an improved long-term survival compared with those patients who received ATG in the conditioning.

Topping it up: methods to improve cord blood transplantation outcomes by increasing the number of CD34+ cells

Cord blood is increasingly recognized for its excellent stem cell potential, lenient matching criteria, instant availability and clinical behavior in transplants when cell dose criteria can be met. However with 1-2 log fewer total (stem cell) numbers in the graft compared with other cell sources, the infused cell dose per kilogram is critical for engraftment and outcome, creating the need for development of stem cell support platforms. The co-transplant platforms of haplo cord and double unit cord blood (DUCB) transplantation are aimed toward increasing stem cell dose. Together with the optimization of reduced-intensity protocols, long-term sustained engraftment using cord blood has become available to most patients, including elderly patients. Haplo cord has a low incidence of both acute and chronic graft-versus-host disease but may require anti-thymocyte globulin ATG for effective neutrophil recovery. DUCB can be performed without anti-thymocyte globulin with excellent immune reconstitution and disease-free survival, but engraftment is considerably slower, and graft-versus-host disease incidence significant. Both haplo-cord and DUCB transplantation appear to both be valid alternatives to matched unrelated donors in adults.