Haploidentical vs. unrelated allogeneic stem cell transplantation for acute lymphoblastic leukemia in first complete remission: on behalf of the ALWP of the EBMT

Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in Patients Aged 70 Years and Older: A Systematic Review and Meta-Analysis

Allogeneic hematopoietic cell transplantation (allo-HCT) is a potential cure for many hematological malignancies. Historically, older adults were not considered eligible for allo-HCT due to increased toxicity and mortality concerns. This systematic review and meta-analysis aim to explore the outcomes of allo-HCT in patients aged 70 years or older. Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a comprehensive literature search was performed on PubMed, Cochrane Register of Controlled Trials, and Clinicaltrials.gov using MeSH terms and keywords for "Hematopoietic Stem Cell Transplantation" AND "Outcome Assessment" from the date of inception to June 30, 2024. Our search produced 102 articles. After excluding irrelevant and review articles during primary and secondary screening, eight original studies reporting outcomes of allo-HCT in patients aged 70 years or older were included. The survival data were retrieved from Kaplan-Meier (KM) curves using an online plot digitizer tool to calculate the overall survival (OS) and disease-free survival (DFS). The pooled KM curves were plotted and analyzed using the "MetaSurvival" package of R software version 4.2.1. Proportions and 95% confidence intervals (CIs) were extracted as well. A total of 2519 patients aged 70 years or older with allo-HCT were included in the analysis. The included patients' age ranged from 70 to 84 years, and 68% were male. Median follow-up was 23.2 (0.4 to 122.5) months. The combined median OS was 14.84 months (95% CI: 11.61 to 19.50), with OS rates at 6, 12, 24, and 36 months of 71.8%, 54.5%, 41.9%, and 34.9%, respectively. The estimated pooled mean OS was 28.62 months (95% CI: 23.41 to 31.44). The pooled median DFS was 10.54 months (95% CI: 7.93 to 14.17), with DFS rates at 6, 12, 24, and 36 months of 61.5%, 47.5%, 37%, and 30.6%, respectively. The estimated pooled mean DFS was 24.45 months (95% CI: 18.30 to 23.74). The relapse rate ranged from 28% to 55.6%, while non-relapsed mortality ranged from 5.6% to 42%. The acute graft versus host disease (GvHD) incidence varied from 9.3% to 32%, while chronic GvHD rates ranged from 10% to 43%. Allo-HCT provides promising outcomes for patients aged 70 or older with transplant-eligible diseases. Disease progression, followed by infections, is the leading cause of mortality, underscoring the need for improved post-transplant care, including optimized GvHD regimens and strategies to reduce infection risk.

Impact of the Type of Tyrosine Kinase Inhibitor (imatinib or dasatinib) Used Before allo-HCT on Outcome of Patients with Philadelphia-Positive Acute Lymphoblastic Leukemia. A Study on Behalf of the Acute Leukemia Working Party of the EBMT

The use of tyrosine kinase inhibitors (TKIs) during induction and consolidation, followed by allogeneic hematopoietic cell transplantation (allo-HCT), is a standard of care for patients with Philadelphia (Ph)-positive acute lymphoblastic leukemia (ALL). The goal of this study was to compare results of allo-HCT according to the type of TKI used pre-transplant, either imatinib, dasatinib or both. This was a retrospective, registry-based analysis including adult patients with Ph-positive ALL treated with allo-HCT between years 2010-2022. The analysis included 606 patients pre-treated with imatinib, 163 with dasatinib and 94 with both imatinib and dasatinib. Allo-HCTs were performed in first complete remission from either unrelated (56%), matched sibling (36%) or haploidentical donors (8%). Relapse incidence at 2 years was 26% in the imatinib group and 21% in the dasatinib group and 19% in the imatinib + dasatinib group (P = .06) while non-relapse mortality was 19%, 15%, and 23%, respectively (P = .37). No significant differences were found for leukemia-free survival (55% vs. 63% vs. 58%, P = .11) and overall survival (72% vs. 76% vs. 65%, P = .32). The incidence of grade 2-4 acute graft-versus-host disease (GVHD) and chronic GVHD was comparable across study groups, while the incidence of grade 3-4 acute GVHD was significantly increased for patients pre-treated with dasatinib alone (20%) than in the imatinib group (10%) or imatinib + dasatinib group (13%) (P = .002). On multivariate analysis a chance of GVHD and relapse-free survival (GRFS) was significantly decreased while the risk of grade 3-4 acute GVHD was increased for the dasatinib compared to imatinib group (hazard ratio, HR = 1.27, P = .048 and HR = 2.26, P = .0009, respectively). This study provides no evidence for the advantage of one TKI over another in terms of LFS and OS. However, the use of dasatinib is associated with increased risk of severe acute GVHD and decreased GRFS.

Comparison of Long-Term Outcomes of Double Unit Cord Blood Versus Haploidentical Donor Transplantation in Adult Patients With Acute Lymphoblastic Leukemia Regarding KIR-Ligand Mismatch

BACKGROUND

Haploidentical donor transplantation (HIDT) or cord blood transplantation (CBT) are common alternatives for patients lacking human-leukocyte antigen (HLA)-matched donors. In addition to the donor source, NK cell alloreactivity due to HLA-mismatch setting may affect outcomes in alternative-donor hematopoietic cell transplantation (HCT). However, a limited number of studies have evaluated their impacts in adult acute lymphoblastic leukemia (ALL).

OBJECTIVES

We aimed to assess the effects of donor source and KIRL-MM on outcomes of alternative-donor HCT, with a special focus on adult ALL.

STUDY DESIGN

We retrospectively compared clinical outcomes between HIDT (n=47) and double unit CBT (DCBT) (n=134). Patients received fludarabine and busulfan-based reduced toxicity conditioning before HIDT, and TBI-based myeloablative conditioning before DCBT. KIR ligands were determined using a web-based calculator. For DCBT, donor KIR ligand groups were defined by the dominant CB unit after engraftment.

RESULTS

After a median follow-up of 39.4 months, DCBT showed higher 3-year non-relapse mortality (NRM) (22.8% vs. 9.0%, p=0.038), whereas the cumulative incidence of relapse (CIR) was significantly higher in HIDT (47.9% vs. 18.9%, p<0.001). Estimated disease-free survival (DFS) was comparable (DCBT 58.5% vs. HIDT 44.3%, p=0.106). GVH direction KIRL-MM showed lower incidence of acute GVHD in both HIDT and DCBT. However, GVH direction KIRL-MM was associated with poorer DFS (37.2% vs. 66.0%, p=0.008) only in the DCBT subgroup, mostly due to specifically higher NRM rate (35.0% vs 18.4%, p=0.057).

CONCLUSION

Our study supports the usefulness of DCBT in the HIDT-dominant era and suggests potential ways to improve survival outcomes of DCBT.

Transplant in ALL: who, when, and how?

Allogeneic hematopoietic stem cell transplantation (allo-HCT) remains a cornerstone in the treatment of high-risk acute lymphoblastic leukemia (ALL), yet optimal patient selection is challenging in the era of rapidly changing modern therapy. Refined molecular characterization allows for better risk assessment, sparing low-risk patients from allo-HCT toxicity while identifying those who may benefit from intensified approaches. Measurable residual disease (MRD) has emerged as a powerful predictor of relapse irrespective of treatment strategy, challenging the necessity of transplant in MRD-negative patients. Further, expanded donor options, particularly haploidentical transplantation coupled with reduced intensity conditioning, have extended the applicability of allo-HCT to a broader range of patients. Finally, immunotherapies and targeted treatments are increasingly integrated into both initial and relapsed treatment protocols yielding deep remission and allowing for successful transplant in patients with a history of advanced disease. In this review, we provide an overview of the contemporary role of transplant in adult patients with ALL, focusing on indications for allo-HCT in first remission, optimal sequencing of transplant with novel therapies, and advancements in donor selection and conditioning regimens.

Comparing transplant outcomes in ALL patients after myeloablative conditioning in mismatch-related or unrelated donor settings

The optimal myeloablative conditioning regimen for ALL patients undergoing hematopoietic cell transplant (HCT) with an alternative donor is unknown. We analyzed HCT outcomes ALL patients (n = 269) who underwent HCT at our center from 2010 to 2020 in complete remission (CR) after FTBI-etoposide and CNI-based GvHD prophylaxis for matched donor HCT (ETOP-package; n = 196) or FTBI-Fludarabine and post-transplant cyclophosphamide (PTCy)-based prophylaxis for HLA- mismatched (related or unrelated) donors (FLU-package; n = 64). Patients in FLU-package showed a significant delay in engraftment (p < 0.001) and lower cumulative incidence (CI) of any and extensive chronic GVHD (p = 0.009 and 0.001, respectively). At the median follow up of 4.6 years (range 1-12 years); non-relapse mortality, overall or leukemia-free survival and GVHD-free/relapse-free survival were not significantly impacted by the choice of conditioning. However, in patients at CR2 or with measurable residual disease (MRD+), there was a trend towards higher relapse after FLU-package (p = 0.08 and p = 0.07, respectively), while patients at CR1 regardless of MRD status had similar outcomes despite the package/donor type (p = 0.9 and 0.7, respectively). Our data suggests that FLU-package for alternative donors offers comparable outcomes to ETOP-package for matched donor HCT to treat ALL. Disease status and depth of remission at HCT were independent predictors for better outcomes.

Outcome of Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Acute Lymphoblastic Leukemia: Results of a Single-Center Study

BACKGROUND

Despite the adoption of pediatric-like chemotherapy protocols, the introduction of new immunotherapies and a better understanding of the oncogenic landscape, the outcome for adult patients with acute lymphoblastic leukemia (ALL) remain substantially dismal. The aim of the present study was to evaluate the outcome in terms of survival in a cohort of adult patients with ALL who received allogeneic hematopoietic stem cell transplantation (alloSCT) between 2013 and 2023.

METHODS

This was a single-center observational retrospective study including all consecutive adult patients with ALL who received an alloSCT between April 2013 and April 2023 at the Stem Cell Transplant Center AOU Città della Salute e della Scienza of Torino. The primary endpoints were overall survival (OS), graft-versus-host disease (GVHD) Relapse-Free Survival (GRFS), Leukemia-Free Survival (LFS) and cumulative incidence (CI) of Non-Relapse Mortality (NRM).

RESULTS

The 4-year OS and LFS were 63.4% and 48.1%, respectively, and the 1-year GRFS was 42.9%. The 1-year CI of bloodstream infections (BSI), invasive fungal infections and NRM were 38%, 7% and 18.4%, respectively. Multivariate analysis showed that the use of total body irradiation (TBI), a time interval from diagnosis to alloSCT 7 months and female gender were factors significantly associated with better OS. Relapse of the underlying malignancy and BSI were the main causes of death.

CONCLUSION

Our study suggests that alloSCT from a matched sibling donor (MSD) and alternative donors may be considered an effective tool for patients with ALL achieving a CR.

Donor matters: Donor selection impact on hematopoietic stem cell transplantation outcomes in Hispanic patients with B-cell acute lymphocytic leukemia: Insights from a myeloablative HSCT study

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is a pivotal treatment for high-risk acute lymphocytic leukemia (ALL), although limited by suitable human leukocyte antigen (HLA)-matched sibling donors (MSD). This study evaluates the impact of donor selection on outcomes in post-HSCT Hispanic B-cell ALL patients.

METHODOLOGY

This single-center retrospective study evaluates outcomes in 88 adult Hispanic B-cell ALL patients who underwent haploidentical, MSD, or MUD myeloablative HSCT between 2013 and 2023.

RESULTS

Compared to Haploidentical transplants, MSD exhibited worse cumulative incidence of relapse (CIR) (HR = 3.39; P = 0.014) and disease-free survival (DFS) (HR = 2.44; P = 0.048) whereas MUD outcomes did not differ. This effect persisted even when controlling for pre-HSCT stage and Minimal residual disease (MRD) status. In addition, Ph-like was a significant predictor of worse DFS (HR = 3.60; P=0.014) and CIR (HR = 2.97; P=0.035) on multivariate analysis. Older donor age correlated with worse GVHD-free, relapse-free survival (GRFS) in haploidentical transplants (HR = 1.05; P=0.036).

CONCLUSION

Our data highlights improved outcomes with younger, haploidentical donors among Hispanic B-cell ALL patients undergoing myeloablative HSCT. This underscores the importance of donor selection in optimizing outcomes for ALL patients.

How I treat newly diagnosed acute lymphoblastic leukemia

Treatment algorithms differ for adult patients with Philadelphia-negative (Ph-) and Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL). For Ph- ALL intensive induction-consolidation chemotherapy using "pediatric-inspired" protocols is a standard of care. Allogeneic hematopoietic cell transplantation (allo-HCT) from either an HLA-matched sibling, unrelated or haploidentical donor should be considered for patients with high estimated risk of relapse. Inadequate response at the level of measurable residual disease (MRD) is the strongest adverse prognostic factor. Patients with B-ALL and detectable MRD should be treated with blinatumomab. In the future, the use of blinatumomab and/or inotuzumab ozogamycin in addition to first-line chemotherapy may become a new standard of care reducing the role of allo-HCT. For patients with Ph+ ALL, tyrosine kinase inhibitors (TKI) are the most important components of treatment protocols, while the intensity of chemotherapy may be reduced. Allo-HCT is recommended for all patients treated with imatinib along with low-intensity chemotherapy. Results of phase-II studies using front-line dasatinib or ponatinib in sequence or in combination with blinatumomab are very promising. Such a strategy may allow the avoidance of systemic chemotherapy. The future role of allo-HCT in this context appears uncertain.

Comparison of Infectious Complications in Patients Receiving High-Dose Cyclophosphamide as GvHD Prophylaxis After Transplantation From A 9/10 HLA-Matched Unrelated Donor with Standard GvHD Prophylaxis After Transplant From A Fully Matched Related Donor

Background

The aim of this study was to evaluate whether cyclophosphamide administered after allogeneic stem cell transplantation (ASCT) from 9/10 HLA-Matched Unrelated Donors (MMUD) increases the rates of bacterial, fungal, viral infections, complications (hemorrhagic cystitis (HC)), and infection-related mortality compared to allogeneic stem cell transplantation from matched related donors (MRD).

Methods

This is a retrospective multicenter study. 45 MMUD ASCT patients who received posttransplant cyclophosphamide+methotrexate+calcineurin inhibitor compared with 45 MRD ASCT patients who received methotrexate+calcineurin inhibitor.

Results

Although there was a statistically significant prolongation of neutrophil engraftment time in the PTCy arm, there was no statistically significant difference in bacterial infection frequencies between the groups (PTCy; 9 (20%), control; 8 (17.8%), p=0.778). The distribution of CMV infection in the first 100 days was similar (p=0.827), but the distribution of CMV infection rate between the 100th and 365th days was observed more frequently in the control group (p=0.005). HC rates and their grades were similar in both groups (PTCy; 4 (8.8%), control; 6 (13.3%) p=0.502). The rates of VZV infection and invasive aspergillosis were similar in the PTCy and control groups (13.3% in the PTCy and 17.8% in the control group p=0.561). There is also no statistically significant difference in survival analysis (OS, LFS, GRFS, RI, IRM, NRM) between groups. However, the incidence of cGVHD was significantly higher in the control group (P=0.035).

Conclusions

The addition of PTCy to standard GvHD prophylaxis in MMUD ASCT does not lead to an increase in CMV reactivation, bacterial infections, invasive fungal infection, viral hemorrhagic cystitis, or mortality.

Combining post-transplant cyclophosphamide with antithymocyte globulin for graft-versus-host disease prophylaxis in hematological malignancies

In search of an ideal partner or alternative to conventional immunosuppressive agents, rabbit anti-thymocyte globulin (ATG) and, more recently, post-transplant cyclophosphamide (PT-Cy) have both emerged as valid and efficient options for preventing graft-versus-host disease (GvHD). To further reduce the risk of GvHD, strategies combining ATG and PT-Cy have recently been investigated. In a haploidentical setting, retrospective studies suggest that combining PT-Cy and ATG may result in a lower incidence of chronic GvHD without increasing the risks of infection or relapse, when compared to PT-Cy without ATG. In haploidentical or unrelated donor settings, adding reduced doses of PT-Cy to ATG may reduce the risk of acute and chronic GvHD and improve survival, particularly GvHD-free, relapse-free survival (GRFS), when compared to ATG without PT-Cy. Overall, the combination of PT-Cy and ATG is a safe and promising approach for patients with hematological malignancies undergoing allogeneic hematopoietic stem cell transplantation (HSCT).

Second haploidentical stem cell transplantation (HAPLO-SCT2) after relapse from a first HAPLO-SCT in acute leukaemia-a study on behalf of the Acute Leukaemia Working Party (ALWP) of the European Society for Blood and Marrow Transplantation (EBMT)

For patients with acute myeloid and lymphoblastic leukaemia (AML/ALL) lacking a matched sibling or unrelated donor, haploidentical stem cell transplantation (HAPLO-SCT) is increasingly used. However, available data on the treatment of relapse after HAPLO-SCT, including feasibility and efficacy of a second HAPLO-SCT (HAPLO-SCT2), is scarce. Hence, adults with AML/ALL, that had undergone HAPLO-SCT2 without ex-vivo manipulation after haematologic relapse from HAPLO-SCT1 were selected for a retrospective registry analysis. Eighty-two patients (AML, n = 63, ALL, n = 19, median follow-up: 33 months) were identified. Engraftment rate was 87%. At day +180, cumulative incidences of acute GvHD II-IV°/chronic GvHD were 23.9%/22.6%, respectively. Two-year overall survival/leukaemia-free survival (OS/LFS) were 34.3%/25.4%; 2-year non-relapse mortality (NRM) and relapse incidence (RI) were 17.6% and 57%. Leukaemia was the most frequent cause of death. Separated by disease, 2-year OS/LFS/NRM/RI were 28.7%/22.3%/16.2%/61.6% in AML, and 55.3%/38.4%/23.5%/38.2% in ALL patients. In a risk-factor analysis among patients with AML, stage at HAPLO-SCT1 and HAPLO-SCT2, and interval from HAPLO-SCT1 to relapse significantly influenced outcome. Our data demonstrate that HAPLO-SCT2 is a viable option in acute leukaemia relapse after HAPLO-SCT1. Engraftment, toxicity, risk factors and long-term outcome are comparable to data reported after allo-SCT2 in a matched donor setting.

Effects of isolated central nervous system involvement evaluated by multiparameter flow cytometry prior to allografting on outcomes of patients with acute lymphoblastic leukemia

Introduction

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a major strategy to cure patients with acute lymphoblastic leukemia (ALL). The aim of this study was to evaluate whether isolated flow cytometry (FCM)-positive central nervous system (CNS) involvement before allo-HSCT is clinically significant.

Methods

The effects of isolated FCM-positive CNS involvement prior to transplantation on the outcomes of 1406 ALL patients with complete remission (CR) were retrospectively investigated.

Results

Patients were classified into isolated FCM-positive CNS involvement (n=31), cytology-positive CNS involvement (n = 43), and negative CNS involvement (n = 1332) groups. Among the three groups, the 5-year cumulative incidence of relapse (CIR) values were 42.3%, 48.8%, and 23.4%, respectively (P<0.001). The 5-year leukemia-free survival (LFS) values were 44.7%, 34.9%, and 60.8%, respectively (P<0.001). Compared with the negative CNS group (n=1332), the 5-year CIR of the pre-HSCT CNS involvement group (n=74) was higher (46.3% vs. 23.4%, P<0.001], and the 5-year LFS was inferior (39.1% vs. 60.8%, P<0.001). Multivariate analysis indicated that four variables, T-cell ALL, in second complete remission or beyond (CR2+) at HSCT, pre-HSCT measurable residual disease positivity, and pre-HSCT CNS involvement, were independently associated with a higher CIR and inferior LFS. A new scoring system was developed using the following four variables: low-risk, intermediate-risk, high-risk, and extremely high-risk groups. The 5-year CIR values were 16.9%, 27.8%, 50.9%, and 66.7%, respectively (P<0.001), while the 5-year LFS values were 67.6%, 56.9%, 31.0%, and 13.3%, respectively (P<0.001).

Conclusion

Our results suggest that ALL patients with isolated FCM-positive CNS involvement are at a higher risk of recurrence after transplantation. Patients with pre-HSCT CNS involvement had higher CIR and inferior survival outcomes.

Outcomes of allogeneic or autologous stem cell transplantation followed by maintenance chemotherapy in adult patient with B-ALL in CR1 with no detectable minimal residual disease

Autologous haematopoietic stem cell transplantation (auto-HSCT) as a treatment for B-cell acute lymphoblastic leukaemia (B-ALL) has been rigorously debated in recent years. We retrospectively analysed the outcomes of 355 adult patients with B-ALL in first complete remission who had received auto-HSCT or allogeneic HSCT (allo-HSCT) in our centre. The treatment efficacy was evaluated from a model stratified on the risk classification and minimal residue disease (MRD) status after three chemotherapy cycles. Auto-HSCT demonstrated comparable 3-year overall survival (OS) (72.7% vs. 68.5%, p = 0.441) and leukaemia-free survival rates (62.8% vs. 56.1%, p = 0.383) compared to allo-HSCT for patients with negative MRD, while the advantage of lower non-relapse mortality (1.5% vs. 25.1%, p < 0.001) was offset by a higher cumulative incidence of relapse (CIR) rates (35.7% vs. 18.9%, p = 0.018), especially in high-risk patients. For patients at high risk and with positive MRD, there was a lower trend of 3-year OS (50.0% vs. 66.0%, p = 0.078) and significantly higher CIR rates (71.4% vs. 39.1%, p = 0.018) in auto-HSCT. However, no significant interaction was observed in the tests. In conclusion, auto-HSCT appears to be an attractive treatment for patients with negative MRD after three chemotherapy cycles. For MRD-positive patients, allo-HSCT may be a more effective treatment.

Haploidentical Versus Matched Sibling Donor Hematopoietic Stem Cell Transplantation for Adult Patients With Relapsed/Refractory Acute Lymphoblastic Leukemia: A Study From the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

The results of haploidentical stem cell transplantation (haploHCT) for patients with acute lymphoblastic leukemia (ALL) transplanted in active disease remain largely unknown. We retrospectively analyzed adult patients with R/R ALL who underwent haploHCT or matched sibling donor (MSD-HCT) as a first transplantation between 2012 and 2020. The analysis comprised 274 patients, 94 had a haploHCT, and 180 had an MSD-HCT. The median follow-up was 32 months. The median age was 33 (range 18-76) and 37 (18-76) years in the haplo- and MSD-HCT groups, respectively. Post-transplant cyclophosphamide (PTCy) was used in 88% of haploHCT and in 4% of the MSD-HCT group. Graft-versus-host disease grade III-IV was higher in haploHCT than in the MSD-HCT group (18% versus 9%; P = 0.042). The 2-year chronic (c) graft-versus-host disease rates were 17% versus 33% (hazard ratio [HR] = 0.56; P = 0.14), respectively. By multivariate analysis, relapse incidence, and leukemia-free survival were not significatively different between the transplant groups, while nonrelapse mortality (NRM) was significantly higher (25% versus 18% at 2 years; HR = 2.03; P = 0.042) and overall survival (OS) lower (22% versus 38% at 2 years; HR = 1.72; P = 0.009) in the haploHCT group compared with the MSD-HCT group. We conclude that the 2-year OS of R/R ALL patients undergoing MSD transplants is significantly better than in haploHCT with a higher NRM in the latter.

SOHO State of the Art Updates and Next Questions: Novel Transplant and Post-Transplant Options in Acute Lymphoblastic Leukemia

Allogeneic hematopoietic cell transplantation (alloHCT) is a potentially curative treatment approach for patients with high-risk acute lymphoblastic leukemia (ALL). Despite development of several novel therapies targeting B-cell ALL, alloHCT continues to play an essential role in management, but the identification of patients who are most likely to benefit from alloHCT in first or subsequent remissions continues to evolve. Broader donor options, including haploidentical donors and umbilical cord blood, have enabled alloHCT for more patients, but improvements in front-line therapy and increasing use of high-sensitivity measurable residual disease (MRD) quantification continue to modify the calculus for selecting which patients require transplantation. MRD quantification has become increasingly important as a prognostic indicator, as well as a trigger for therapeutic intervention, since the achievement of MRD negative complete remission is well-established to be associated with improved transplant outcomes. ALL remains the only malignancy with approved therapy for MRD positivity after achievement of remission, and use of Blinatumomab in this setting currently appears to be most effective when used as a bridge-to-transplant, rather than a destination or purely consolidative therapy. Expanding options for those with relapsed/refractory disease, including chimeric antigen receptor (CAR)-T cells, also render more patient in suitably deep remissions to enable alloHCT with a high likelihood of success. It remains unclear whether CAR-T cell therapies may obviate the need for alloHCT in some patients, and currently available data suggest there remains a role for alloHCT after CAR-T. Together, these therapeutic advances appear to be improving post-transplant outcomes. Nevertheless, more remains to be studied regarding how to optimize use of available and emerging cellular and immune modulating therapies to maximize the likelihood of long-term post-alloHCT remission in high-risk ALL.

Impact of donor kinship on non-T-cell depleted haploidentical stem cell transplantation with post transplantation cyclophosphamide for acute leukemia: From the ALWP of the EBMT

Non-T-cell depleted haploidentical hematopoietic cell transplantation (Haplo-HCT) is a unique transplantation setting in which several donors are available. We assessed the impact of donor kinship on outcome of Haplo-HCT with post-transplantation cyclophosphamide in a cohort of 717 acute leukemia patients. We compared sibling with parent donors in patients ≤45 years, and child with sibling donors in patients >45 years. Donor kinship was not associated with worse outcomes in multivariate analysis. For patients ≤45 years, the hazard ratio (HR) for leukemia-free survival (LFS), overall survival (OS), relapse incidence (RI), and chronic graft-versus-host disease (cGVHD) was 0.87 (p = 0.75), 1.19 (p = 0.7), 0.52 (p = 0.19), and 0.99 (p = 0.97) for parents versus siblings, respectively, and for patients >45 years the HR was 0.93 (p = 0.8), 0.98 (p = 0.94), 1.3 (p = 0.53), and 0.98 (p = 0.95) for children versus siblings, respectively. Univariate incidence of acute GVHD grade II-IV was significantly higher in patients transplanted from siblings versus children (p = 0.002). Factors associated with inferior outcome were advanced disease and earlier transplant. In patients ≤45 years, acute lymphocytic leukemia and peripheral blood stem cell graft were additional prognostic factors for OS. We did not find a significant impact of donor kinship on transplantation outcome when analyzing by age group (≤45 and >45 years).

Favorable outcomes of allogeneic hematopoietic stem cell transplantation with fludarabine-bendamustine conditioning and posttransplantation cyclophosphamide in classical Hodgkin lymphoma

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for patients with relapsed and refractory classic Hodgkin lymphoma (rrHL). However, the optimal conditioning regimen and GVHD prophylaxis for rrHL remain undetermined. The aim of this study was to investigate outcomes of allo-HSCT with a fludarabine plus bendamustine (FluBe) conditioning regimen and GVHD prophylaxis with posttransplantation cyclophosphamide (PTCY) in patients with rrHL.

METHODS

Allo-HSCT results in 58 adult patients with rrHL were analyzed retrospectively.

RESULTS

Three-year overall survival and event-free survival were 81% (95% CI 65-91) and 55% (95% CI 38-72), respectively. The cumulative incidence of relapse (CIR) at 3 years was 33% (95% CI 13-51). The cumulative incidence of aGVHD grade II-IV and severe aGVHD grade III-IV was 36% (95% CI 22-48) and 22% (95% CI 9-33), respectively. The cumulative incidence of cGVHD was 32% (95% CI 17-45), including moderate or severe cGVHD in 17% (95% CI 4-28). Patients who developed aGVHD after allo-HSCT had significantly lower CIR (24% vs 49%, p = 0.004). The use of PBSC as a graft source also significantly reduced CIR (4% vs 61%, p = 0.002).

CONCLUSIONS

FluBe-PTCY allo-HSCT facilitates favorable outcomes, low toxicity, and mortality in rrHL.

Total body irradiation plus fludarabine versus thiotepa, busulfan plus fludarabine as a myeloablative conditioning for adults with acute lymphoblastic leukemia treated with haploidentical hematopoietic cell transplantation. A study by the Acute Leukemia Working Party of the EBMT

Optimal conditioning for adults with acute lymphoblastic leukemia (ALL) treated with haploidentical hematopoietic cell transplantation (haplo-HCT) and post-transplant cyclophosphamide has not been established so far. We retrospectively compared outcomes for two myeloablative regimens: fludarabine + total body irradiation (Flu-TBI, n = 117) and thiotepa + iv. busulfan + fludarabine (TBF, n = 119). Patients transplanted either in complete remission (CR) or with active disease were included in the analysis. The characteristics of both groups were comparable except for patients treated with TBF were older. In univariate analysis the incidence of non-relapse mortality (NRM) at 2 years was increased for TBF compared to Flu-TBI (31% vs. 19.5%, p = 0.03). There was a tendency towards reduced incidence of relapse after TBF (p = 0.11). Results of multivariate analysis confirmed a reduced risk of NRM using Flu-TBI (HR = 0.49, p = 0.03). In the analysis restricted to patients treated in CR1 or CR2, the use of Flu-TBI was associated with a decreased risk of NRM (HR = 0.34, p = 0.009) but an increased risk of relapse (HR = 2.59, p = 0.01) without significant effect on survival and graft-versus-host disease. We conclude that for haplo-HCT recipients with ALL, Flu-TBI may be preferable for individuals at high risk of NRM while TBF should be considered in cases at high risk of relapse.

PTCy-based Haploidentical vs Matched Unrelated Donor Peripheral Blood HSCT Using Myeloablative Targeted Busulfan-based Conditioning for Pediatric Acute Leukemia

Haploidentical related donor (HRD) is a common alternative donor strategy used when matched sibling or unrelated donors are not available for hematopoietic stem cell transplantation (HSCT). However, there have been no studies comparing HRD HSCT with post-transplant cyclophosphamide (PTCy) and matched unrelated donor (MUD) HSCT with antithymocyte globulin, using similar busulfan-based myeloablative conditioning regimen in pediatric acute leukemia. Here, we compared the outcomes in children and adolescents with high-risk acute leukemia after HRD HSCT with PTCy (n=35) and MUD HSCT (n=45) after targeted busulfan-based myeloablative conditioning using intensive pharmacokinetic monitoring. The median follow-up times of the HRD and MUD groups were 3.7 and 4.6 years, respectively. No engraftment failure was observed in both groups. The cumulative incidence of acute graft-versus-host disease (GVHD) grades II-IV (34.3% versus 48.9%, p=0.142), grades III-IV (2.9% vs. 8.9%, p=0.272), moderate to severe chronic GVHD (11.4% vs. 18.3%, p=0.417), relapse (25.6% vs. 28.0%, p=0.832), and non-relapse mortality (0% vs. 2.2%, p=0.420) were not significantly different between the two groups. The 3-year severe chronic GVHD-free/relapse-free (GRFS), leukemia-free (LFS) and overall survival (OS) rates in the HRD and MUD groups were 62.9% (95% confidence intervals [CI], 45.8%, 80.0%) versus 49.8% (95% CI, 34.9%, 64.7%; p=0.318), 74.4% (95% CI, 58.7%, 90.1%) versus 67.5% (95% CI, 53.4%, 81.6%; p=0.585), and 88.6% (95% CI, 78.0%, 99.2%) versus 83.7% (95% CI, 72.5%, 94.9%; p=0.968), respectively. In a subgroup analysis of acute lymphoblastic leukemia patients (HRD, n=17; MUD, n=26), the 3-year GRFS, LFS, and OS rates of the HRD and MUD groups were 49.4% (95% CI, 24.3%, 74.5%) versus 39.5% (95% CI, 19.7%, 59.3%; p=0.601), 61.8% (95% CI, 37.5%, 86.1%) versus 63.6% (95% CI, 44.4%, 82.8%; p=0.872), and 82.4% (95% CI, 64.4%, 100%) versus 84.2% (95% CI, 70.1%, 98.3%; p=0.445), respectively. In acute myeloid leukemia patients (HRD, n=16; MUD, n=16), the 3-year GRFS, LFS, and OS rates of the HRD and MUD groups were 80.8% (95% CI, 61.2%, 100%) versus 61.9% (95% CI, 37.8%, 86.0%; p=0.326), 87.1% (95% CI, 70.2%, 100%) versus 73.9% (95% CI, 51.8%, 96.0%; p=0.478), and 93.8% (95% CI, 81.8%, 100%) versus 85.6% (95% CI, 67.0%, 100%; p=0.628), respectively. Although the difference was not statistically significant and the number of patients was small, the promising outcomes of HRD HSCT in AML patients were encouraging. Our results demonstrated that HRD HSCT with PTCy using a targeted busulfan-based myeloablative conditioning shows outcomes similar to those of MUD HSCT with antithymocyte globulin. HRD HSCT with PTCy could be a feasible option for pediatric high-risk acute leukemia patients who lack an HLA-matched related or unrelated donor.

Effect of donor characteristics on T cell-replete haploidentical stem cell transplantation over the last 10 years at a single institution

One of the most complex issues with haploidentical stem cell transplantation (haplo-SCT) is donor selection, given that multiple haploidentical donors are often available for a given recipient. To develop evidence-based guidance for donor selection in the setting of anti-thymocyte globulin-based haplo-SCT, we performed a prospective cohort study of 512 patients with haematological malignancies who had haplo-SCT to determine which donor variables were most important in favouring transplant outcomes. Increasing donor age was associated with poorer overall survival (OS) [hazard ratio (HR) 1·08, P = 0·044]. Female donors to male recipients was significantly associated with higher non-relapse mortality (NRM; HR 2·05, P = 0·006). Furthermore, increasing donor age had a higher risk of Grades 3-4 acute graft-versus-host disease (aGVHD; HR 1·17, P = 0·005), female donors to male recipients was associated with a higher risk of Grades 2-4 aGVHD (HR 1·50, P = 0·022). Sibling donors had superior OS, disease-free survival, and NRM than parental donors in patients aged <35 years. However, sibling donors had higher NRM than offspring donors in patients aged ≥35 years. A younger donor, usually a young sibling in younger recipients (aged <35 years) or a young offspring in older patients (aged ≥35 years) and avoiding female donors to male recipients should be preferred when multiple haploidentical donors are available.

Graft-versus-Host Disease Prophylaxis with Post-Transplantation Cyclophosphamide versus Cyclosporine A and Methotrexate in Matched Sibling Donor Transplantation

Cyclosporine A (CSA) and methotrexate (MTX) is the standard graft-versus-host disease (GVHD) prophylaxis regimen for matched sibling donor (MSD) allogeneic hematopoietic cell transplantation (allo-HCT). Recently, post-transplantation cyclophosphamide (PTCy) has been shown to be effective in GVHD prevention. In this registry-based study, we compared outcomes of 118 patients treated with PTCy and 1202 patients with CSA/MTX who underwent MSD allo-HCT for acute myelogenous leukemia. In a matched-pair analysis, PTCy was associated with a higher incidence of relapse at 2 years compared with CSA/MTX (41.1% versus 21.3%; P = .039). The incidences of day +180 grade II-IV acute GVHD and 2-year chronic GVHD were comparable in the PTCy and CSA/MTX arms (25.2% versus 25.4% [P = .90] and 42.6% versus 42.6% [P = .84], respectively). Similarly, 2-year leukemia-free survival (LFS; 54.4% versus 74.32%; P = .052), overall survival (OS; 70.6% versus 79.7%; P = .15), and GVHD-free relapse-free survival (GRFS; 38.1% versus 52.5%; P = .49) were not statistically different in the 2 arms. Our data show that GVHD prophylaxis with PTCy is feasible, resulting in similar incidences of GVHD, GRFS, LFS, and OS as seen with conventional CSA/MTX in patients undergoing allo-HCT from an MSD. The higher rate of relapse observed with PTCy needs further evaluation in a prospective study. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Outcome of Haploidentical Peripheral Blood Allografts Using Post-Transplantation Cyclophosphamide Compared to Matched Sibling and Unrelated Donor Bone Marrow Allografts in Pediatric Patients with Hematologic Malignancies: A Single-Center Analysis

The introduction of post-transplantation cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis has made haploidentical (haplo) hematopoietic stem cell transplantation (HSCT) a common approach in adults, but pediatric experience is limited. Based on the encouraging adult data and with the aim of decreasing the risk of graft failure, our center is increasingly using peripheral blood stem cells (PBSCs) from haplo donors with PTCy. Here we compare outcomes of bone marrow (BM) transplantation with traditional donor choices, including matched sibling donors (MSDs) and 10/10 HLA matched unrelated donors (MUDs), with those of haplo PBSC grafts in pediatric patients with hematologic malignancies. In this retrospective single-center study, the primary endpoint was the comparison of GVHD-free relapse-free survival (GRFS; defined as absence of acute GVHD [aGVHD] grade III-IV, relapse, death, or chronic GVHD [cGVHD] requiring systemic therapy) for the 3 cohorts. Secondary endpoints included overall survival (OS), relapse-free survival (RFS), nonrelapse mortality (NRM), and incidence of aGVHD and cGVHD). A total of 104 consecutive patients underwent first allogeneic (allo)-HSCT for a hematologic malignancy or myelodysplastic syndrome between January 2014 and December 2020 using a haplo family donor (PBSCs; n = 26), an MSD (BM; n = 31), or an MUD (BM; n = 47). Patient demographic and transplantation characteristics were not significantly different across the cohorts, apart from remission status, with the haplo cohort having more patients in third or later complete remission before HSCT (P < .01). The median duration of follow-up for the entire cohort was 573 days. The cumulative incidence of aGVHD (grade II-IV or grade III-IV) was not significantly different among the cohorts; however, the cumulative incidence of cGVHD at 18 months was highest in the MUD cohort (31.7%, versus 10.0% in the MSD cohort and 9.2% in the haplo cohort; P = .02). There were no differences in the 18-month cumulative incidence of relapse or NRM. OS and RFS at 18 months were 80.7% (95% confidence interval [CI], 61.7% to 100%) and 73.8% (95% CI, 55.5% to 98.1%) for the haplo cohort, 83.4% (95% CI, 72.8% to 95.5%) and 70.3% (95% CI, 57.9% to 85.3%) for the MUD cohort, and 80.9% (95% CI, 66.9% to 97.7%) and 66.5% (95% CI, 50.5% to 87.5%) for the MSD cohort, with no statistically significant differences among the cohorts. GRFS at 18 months was 61% (95% CI, 43.3% to 85.9%) for the haplo cohort, 44.6% (95% CI, 31.8% to 62.5%) for the MUD cohort, and 62.1% (95% CI, 45.7% to 84.3%) for the MSD cohort (P = .26). Haploidentical PBSC HSCT with PTCy had comparable outcomes to MSD and MUD BM HSCT and less cGVHD compared with MUD BM HSCT in children. The logistical advantages and lower resource burden of haplo HSCT with PBSCs make it a feasible alternative to MUD HSCT in children with hematologic malignancies. Nonetheless, given that this is a retrospective comparison of transplantation platforms rather than donor types, further prospective studies are warranted. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Haploidentical vs. sibling, unrelated, or cord blood hematopoietic cell transplantation for acute lymphoblastic leukemia

Haploidentical HCT is the preferred alternate donor approach for adults with ALL.

Haploidentical transplantation had similar survival compared with fully HLA-matched donor HCT but with reduced GVHD.

The role of haploidentical hematopoietic cell transplantation (HCT) using posttransplant cyclophosphamide (PTCy) for acute lymphoblastic leukemia (ALL) is being defined. We performed a retrospective, multivariable analysis comparing outcomes of HCT approaches by donor for adults with ALL in remission. The primary objective was to compare overall survival (OS) among haploidentical HCTs using PTCy and HLA-matched sibling donor (MSD), 8/8 HLA-matched unrelated donor (MUD), 7 /8 HLA-MUD, or umbilical cord blood (UCB) HCT. Comparing haploidentical HCT to MSD HCT, we found that OS, leukemia-free survival (LFS), nonrelapse mortality (NRM), relapse, and acute graft-versus-host disease (aGVHD) were not different but chronic GVHD (cGVHD) was higher in MSD HCT. Compared with MUD HCT, OS, LFS, and relapse were not different, but MUD HCT had increased NRM (hazard ratio [HR], 1.42; P = .02), grade 3 to 4 aGVHD (HR, 1.59; P = .005), and cGVHD. Compared with 7/8 UD HCT, LFS and relapse were not different, but 7/8 UD HCT had worse OS (HR, 1.38; P = .01) and increased NRM (HR, 2.13; P ≤ .001), grade 3 to 4 aGVHD (HR, 1.86; P = .003), and cGVHD (HR, 1.72; P ≤ .001). Compared with UCB HCT, late OS, late LFS, relapse, and cGVHD were not different but UCB HCT had worse early OS (≤18 months; HR, 1.93; P < .001), worse early LFS (HR, 1.40; P = .007) and increased incidences of NRM (HR, 2.08; P < .001) and grade 3 to 4 aGVHD (HR, 1.97; P < .001). Haploidentical HCT using PTCy showed no difference in survival but less GVHD compared with traditional MSD and MUD HCT and is the preferred alternative donor HCT option for adults with ALL in complete remission.

Is Post-Transplant Cyclophosphamide the New Methotrexate?

Introducing post-transplant, cyclophosphamide (PT-Cy) graft-versus-host disease (GVHD) prophylaxis in the setting of haploidentical donor transplantation has marked the most important advance in allogeneic hematopoietic cell transplantation (alloHCT) within the past 15 years. The efficacy of this procedure and its simple features have allowed for the significantly widespread application of alloHCT worldwide. Indeed, the procedure's effectiveness in reducing immunological complications in the haploidentical setting has even challenged the status quo use of calcineurin-inhibitor, methotrexate-based GVHD prophylaxis in the setting of HLA-identical donors. Currently, however, prospective clinical trials in support of PT-Cy-based GVHD prophylaxis in the HLA-matched setting are striving to resolve the matter of its potential role. This review will briefly report the overall outcomes of PT-Cy-based GVHD prophylaxis in the haploidentical setting and summarize results obtained in the HLA-identical field. We will present future perspectives at the end of the manuscript.

Allogeneic hematopoietic stem cell transplantation for adult patients with t(4;11)(q21;q23) KMT2A/AFF1 B-cell precursor acute lymphoblastic leukemia in first complete remission: impact of pretransplant measurable residual disease (MRD) status. An analysis from the Acute Leukemia Working Party of the EBMT

Adult B-cell precursor acute lymphoblastic leukemia (BCP-ALL) with t(4;11)(q21;q23);KMT2A/AFF1 is a poor-prognosis entity. This registry-based study was aimed to analyze outcome of patients with t(4;11) BCP-ALL treated with allogeneic hematopoietic stem cell transplantation (alloHSCT) in first complete remission (CR1) between 2000 and 2017, focusing on the impact of measurable residual disease (MRD) at the time of transplant. Among 151 patients (median age, 38) allotransplanted from either HLA-matched siblings or unrelated donors, leukemia-free survival (LFS) and overall survival (OS) at 2 years were 51% and 60%, whereas relapse incidence (RI) and non-relapse mortality (NRM) were 30% and 20%, respectively. These results were comparable to a cohort of contemporary patients with diploid normal karyotype (NK) BCP-ALL with equivalent inclusion criteria (n = 567). Among patients with evaluable MRD pre-alloHSCT, a negative status was the strongest beneficial factor influencing LFS (hazard ratio [HR] = 0.2, p < 0.001), OS (HR = 0.14, p < 0.001), RI (HR = 0.23, p = 0.001), and NRM (HR = 0.16, p = 0.002), with a similar outcome to MRD-negative NK BCP-ALL patients. In contrast, among patients with detectable pretransplant MRD, outcome in t(4;11) BCP-ALL was inferior to NK BCP-ALL (LFS: 27% vs. 50%, p = 0.02). These results support indication of alloHSCT in CR1 for t(4;11) BCP-ALL patients, provided a negative MRD status is achieved. Conversely, pre-alloHSCT additional therapy is warranted in MRD-positive patients.

Predictive Factors for Outcome of First Allogeneic Transplant for Elderly Patients With Acute Lymphoblastic Leukemia

INTRODUCTION/BACKGROUND

The treatment of acute lymphoblastic leukemia (ALL) in patients older than 70 is extremely challenging with dismal outcome. Allogeneic stem cell transplantation (alloHCT) has seen many advancements in the last decades showing benefits in younger ALL patients, but this treatment modality is decreasingly used with increasing age due to high treatment-related mortality.

PATIENTS AND METHODS

We identified 84 ALL patients 70 to 84 years old allografted In 2002 to 2019 from a matched related (23%), unrelated (58%), haploidentical (17%), or cord blood (2%) donor at EBMT participating centers with a median follow-up of 23 months.

RESULTS

The 2-year relapse incidence (RI) and non-relapse mortality were 37% and 28%, respectively, and 2-year leukemia-free survival (LFS), overall survival (OS) and GVHD-free, relapse-free survival (GRFS) were 35%, 39% and 23%, respectively. The strongest predictor of outcome was disease status at transplant whereby patients in first complete remission (CR1) had >50% 2-year OS, reflected in multivariate analysis (MVA) with significant improvement in RI, LFS, and GRFS (HR 0.23, 0.49, and 0.54, respectively). Furthermore, karnofsky score ≥90 reflective of good functional status positively influenced non-relapse mortality in both univariate and MVA (HR 0.37), and interestingly, donor CMV positivity appeared to negatively affect RI, LFS and OS in univariate analysis and RI in MVA (HR 2.87).

CONCLUSION

Our data suggest that alloHCT is an option for elderly ALL patients, particularly those carefully selected and transplanted in CR1 especially if failed or without access to novel non-chemotherapy-based approaches.

Post-transplant cyclophosphamide containing regimens after matched sibling, matched unrelated and haploidentical donor transplants in patients with acute lymphoblastic leukemia in first complete remission, a comparative study of the ALWP of the EBMT

BACKGROUND

There is no information on the impact of donor type in allogeneic hematopoietic stem cell transplantation (HCT) using homogeneous graft-versus-host (GVHD) prophylaxis with post-transplant cyclophosphamide (PTCy) in acute lymphoblastic leukemia (ALL).

METHODS

We retrospectively analyzed outcomes of adult patients with ALL in CR1 that had received HCT with PTCy as GVHD prophylaxis from HLA-matched sibling (MSD) (n = 78), matched unrelated (MUD) (n = 94) and haploidentical family (Haplo) (n = 297) donors registered in the EBMT database between 2010 and 2018. The median follow-up period of the entire cohort was 2.2 years.

RESULTS

Median age of patients was 38 years (range 18-76). Compared to MSD and MUD, Haplo patients received peripheral blood less frequently. For Haplo, MUD, and MSD, the cumulative incidence of 100-day acute GVHD grade II-IV and III-IV, and 2-year chronic and extensive chronic GVHD were 32%, 41%, and 34% (p = 0.4); 13%, 15%, and 15% (p = 0.8); 35%, 50%, and 42% (p = 0.01); and 11%, 17%, and 21% (p = 0.2), respectively. At 2 years, the cumulative incidence of relapse and non-relapse mortality was 20%, 20%, and 28% (p = 0.8); and 21%, 18%, and 21% (p = 0.8) for Haplo, MUD, and MSD, respectively. The leukemia-free survival, overall survival and GVHD-free, relapse-free survival for Haplo, MUD, and MSD was 59%, 62%, and 51% (p = 0.8); 66%, 69%, and 62% (p = 0.8); and 46%, 44%, and 35% (p = 0.9), respectively. On multivariable analysis, transplant outcomes did not differ significantly between donor types. TBI-based conditioning was associated with better LFS.

CONCLUSIONS

Donor type did not significantly affect transplant outcome in patient with ALL receiving SCT with PTCy.

Comparing transplant outcomes in ALL patients after haploidentical with PTCy or matched unrelated donor transplantation

We compared outcomes of 1461 adult patients with acute lymphoblastic leukemia (ALL) receiving hematopoietic cell transplantation (HCT) from a haploidentical (n = 487) or matched unrelated donor (MUD; n = 974) between January 2005 and June 2018. Graft-versus-host disease (GVHD) prophylaxis was posttransplant cyclophosphamide (PTCy), calcineurin inhibitor (CNI), and mycophenolate mofetil (MMF) for haploidentical, and CNI with MMF or methotrexate with/without antithymoglobulin for MUDs. Haploidentical recipients were matched (1:2 ratio) with MUD controls for sex, conditioning intensity, disease stage, Philadelphia-chromosome status, and cytogenetic risk. In the myeloablative setting, day +28 neutrophil recovery was similar between haploidentical (87%) and MUD (88%) (P = .11). Corresponding rates after reduced-intensity conditioning (RIC) were 84% and 88% (P = .47). The 3-month incidence of grade II-IV acute GVHD (aGVHD) and 3-year chronic GVHD (cGVHD) was similar after haploidentical compared with MUD: myeloablative conditioning, 33% vs 34% (P = .46) for aGVHD and 29% vs 31% for cGVHD (P = .58); RIC, 31% vs 30% (P = .06) for aGVHD and 24% vs 29% for cGVHD (P = .86). Among patients receiving myeloablative regimens, 3-year probabilities of overall survival were 44% and 51% with haploidentical and MUD (P = .56). Corresponding rates after RIC were 43% and 42% (P = .6). In this large multicenter case-matched retrospective analysis, despite the limitations of a registry-based study (ie, unavailability of key elements such as minimal residual disease testing), our analysis indicated that outcomes of patients with ALL undergoing HCT from a haploidentical donor were comparable with 8 of 8 MUD transplantations.

Allogeneic hematopoietic cell transplantation with cord blood versus mismatched unrelated donor with post-transplant cyclophosphamide in acute myeloid leukemia

BACKGROUND

Allogeneic hematopoietic cell transplantation (allo-HCT) using a mismatched unrelated donor (MMUD) and cord blood transplantation (CBT) are valid alternatives for patients without a fully human leukocyte antigen (HLA)-matched donor. Here, we compared the allo-HCT outcomes of CBT versus single-allele-mismatched MMUD allo-HCT with post-transplant cyclophosphamide (PTCy) in acute myeloid leukemia.

METHODS

Patients who underwent a first CBT without PTCy (N = 902) or allo-HCT from a (HLA 9/10) MMUD with PTCy (N = 280) were included in the study. A multivariate regression analysis was performed for the whole population. A matched-pair analysis was carried out by propensity score-based 1:1 matching of patients (177 pairs) with known cytogenetic risk.

RESULTS

The incidence of grade II-IV and grade III-IV acute graft-versus-host disease (GVHD) at 6 months was 36% versus 32% (p = 0.07) and 15% versus 11% (p = 0.16) for CBT and MMUD cohorts, respectively. CBT was associated with a higher incidence of graft failure (11% vs. 4%, p < 0.01) and higher 2-year non-relapse mortality (NRM) (30% vs. 16%, p < 0.01) compared to MMUD. In the multivariate analysis, CBT was associated with a higher risk of, NRM (HR = 2.09, 95% CI 1.46-2.99, p < 0.0001), and relapse (HR = 1.35, 95% CI 1-1.83, p = 0.05), which resulted in worse leukemia-free survival (LFS) (HR = 1.68, 95% CI 1.34-2.12, p < 0.0001), overall survival (OS) (HR = 1.7, 95% CI 1.33-2.17, p < 0.0001), and GVHD-free, relapse-free survival (GRFS) (HR = 1.49, 95% CI 1.21-1.83, p < 0.0001) compared to MMUD. The risk of grade II-IV acute GVHD (p = 0.052) and chronic GVHD (p = 0.69) did not differ significantly between the cohorts. These results were confirmed in a matched-pair analysis.

CONCLUSIONS

CBT was associated with lower LFS, OS, and GRFS due to higher NRM, compared to MMUD allo-HCT with PTCy. In the absence of a fully matched donor, 9/10 MMUD with PTCy may be preferred over CBT.

Outcome of haploidentical versus matched sibling donors in hematopoietic stem cell transplantation for adult patients with acute lymphoblastic leukemia: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Background

Non-T-cell depleted haploidentical hematopoietic stem cell transplantation (HaploSCT) is being increasingly used in acute lymphoblastic leukemia (ALL) with improving patient outcomes. We have recently reported that outcomes of adult patients (pts) with ALL in complete remission (CR) receiving HaploSCT are comparable to unrelated donor transplants. We now compared HaploSCT and matched sibling donor (MSD) transplants in pts with ALL.

Aim

To assess transplantation outcomes of HaploSCT and MSD transplants in pts with ALL in CR.

Methods

We retrospectively analyzed adult patients (≥ 18 years) with ALL who underwent their first allogeneic stem cell transplantation (alloSCT) in first or second CR between 2012 and 2018, either from a T cell replete Haplo or MSD donor, and whose data were reported to the Acute Leukemia Working Party (ALWP) of the European Society for Blood and Marrow Transplantation (EBMT). Multivariate analysis (MVA) adjusting for differences between the groups was performed using the Cox proportional hazards regression model. Propensity score matching was also performed to reduce confounding effects.

Results

The analysis comprised 2304 patients: HaploSCT-413; MSD-1891. Median follow-up was 25 months. Median age was 37 (range 18–75) and 38 (18–76) years in HaploSCT and MSD, respectively. HaploSCT patients were transplanted more recently than those transplanted from MSD (2016 vs 2015, p < 0.0001). A higher rate of HaploSCT was in CR2 (33.4% vs 16.7%, p < 0.0001), respectively, and fewer received myeloablative conditioning (68% vs 83.2%, p < 0.0001). Cytomegalovirus (CMV) seropositivity was lower in HaploSCT patients (22% vs 28%, p = 0.01) and donors (27.1% vs 33%, p < 0.02), and a higher proportion of the HaploSCTs were performed using a bone marrow (BM) graft (46.2% vs 18.6%, p < 0.0001). The 2 groups did not differ with regard to gender, Karnofsky performance status score, ALL phenotype, Philadelphia chromosome (Ph) positivity and pre-alloSCT measurable residual disease (MRD). Graft versus host disease (GVHD) prophylaxis was mainly post-transplant cyclophosphamide (PTCy) based (92.7%) in the HaploSCT setting, while it was mostly pharmacologic in the setting of MSD (18.7% received ATG). Cumulative incidence of engraftment at day 60 was higher in MSD transplants compared to HaploSCT (98.7% vs 96.3%, p = 0.001), respectively. Day 180 incidence of acute (a) GVHD II-IV and III-IV was higher in HaploSCT vs. MSD: 36.3% vs 28.9% (p = 0.002 and 15.2% vs 10.5% (p = 0.005), respectively. Conversely, the 2-year chronic (c) GVHD and extensive cGVHD were 32% vs 38.8% (p = 0.009) and 11.9% vs 19.5% (p = 0.001) in HaploSCT vs MSD, respectively. Main causes of death were leukemia (31.8% vs 45%), infection (33.1% vs 19.7%) and GVHD (16.6% vs 19.7%) for HaploSCT and MSD, respectively. Two-year relapse incidence (RI), non-relapse mortality (NRM), leukemia-free survival (LFS), overall survival (OS) and GVHD-free, relapse-free survival (GRFS) were 26% vs 31.6%, 22.9% vs 13%, 51% vs 55.4%, 58.8% vs 67.4% and 40.6% vs 39% for HaploSCT and MSD, respectively. In the MVA, RI was significantly lower in HaploSCT in comparison with MSD, hazard ratio (HR) = 0.66 (95% CI 0.52–0.83, p = 0.004), while NRM was significantly higher, HR = 1.9 (95% CI 1.43–2.53, p < 0.0001). aGVHD grade II-IV and grade III-IV were higher in HaploSCT than in MSD HR = 1.53 (95% CI 1.23–1.9, p = 0.0002) and HR = 1.54 (95% CI 1.1–2.15, p = 0.011), respectively. Extensive cGVHD was lower in HaploSCT compared with MSD, HR = 0.61 (95% CI 0.43–0.88, p = 0.007), while total cGVHD did not differ significantly, HR = 0.94 (95% CI 0.74–1.18, p = 0.58). LFS, OS and GRFS did not differ significantly between the 2 transplant groups, HR = 0.96 (95% CI 0.81–1.14, p = 0.66); HR = 1.18 (95% CI 0.96–1.43, p = 0.11) and HR = 0.93 (95% CI 0.79–1.09, p = 0.37), respectively. These results were confirmed in a matched-pair analysis.

Conclusions

Outcomes of adult patients with ALL in CR receiving alloSCT from haploidentical donors are not significantly different from those receiving transplants from MSD in terms of LFS, OS and GRFS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-021-01065-7.

Outcome of T-cell-replete haploidentical stem cell transplantation improves with time in adults with acute lymphoblastic leukemia: A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

BACKGROUND

The use of haploidentical hematopoietic cell transplantation (haplo-HCT) with posttransplantation cyclophosphamide prophylaxis is gaining traction in patients with acute lymphoblastic leukemia (ALL).

METHODS

The Acute Leukemia Working Party/European Society for Blood and Marrow Transplantation registry was used to evaluate the outcomes of adult patients with ALL who underwent haplo-HCT during 2011 through 2015 and compared them with the outcomes of those who underwent transplantation during 2016 through 2018.

RESULTS

The analysis consisted of 195 patients, including 79 who underwent transplantation during 2011 through 2015 and 116 who underwent transplantation during 2016 through 2018. Overall, the 2-year leukemia-free survival and relapse incidence rates were 56.5% and 21%, respectively. The 100-day incidence of grade 2 through 4 acute graft-vs-host disease (GVHD) was 34.5%. The rates of nonrelapse mortality (NRM) and overall survival (OS) were 22.5% and 64.7%, respectively. Patients who underwent transplantation during 2016 through 2018 experienced improved rates of leukemia-free survival (64.9% vs 47.3%; P = .019) and OS (75.5% vs 53.5%; P = .006). Patients who underwent transplantation during 2016 through 2018 developed more grade 2 through 4 acute GVHD (42% vs 26.4%; P = .047). The incidence of relapse, GVHD-free/relapse-free survival, grade 3 and 4 acute GVHD, chronic GVHD, and extensive chronic GVHD did not differ significantly between groups. In multivariate analysis, more recently transplanted patients had a significantly reduced risk of NRM (hazard ratio, 0.44; 95% CI, 0.22-0.89; P = .022) and improved OS (hazard ratio, 0.47; 95% CI, 0.26-0.86; P = .014). A comparable analysis of patients who had acute myeloid leukemia during the same timeframes did not reveal any statistically significant differences in any outcomes.

CONCLUSIONS

The outcome of adult patients with ALL who receive posttransplant cyclophosphamide has improved over time, with an impressive 2-year OS of 75% and, most recently, an NRM rate of only 17%.

Exosomes and Obesity-Related Insulin Resistance

Exosomes are extracellular vesicles, delivering signal molecules from donor cells to recipient cells. The cargo of exosomes, including proteins, DNA and RNA, can target the recipient tissues and organs, which have an important role in disease development. Insulin resistance is a kind of pathological state, which is important in the pathogeneses of type 2 diabetes mellitus (T2DM), gestational diabetes mellitus and Alzheimer's disease. Furthermore, obesity is a kind of inducement of insulin resistance. In this review, we summarized recent research advances on exosomes and insulin resistance, especially focusing on obesity-related insulin resistance. These studies suggest that exosomes have great importance in the development of insulin resistance in obesity and have great potential for use in the diagnosis and therapy of insulin resistance.

Haploidentical stem cell transplantation vs matched unrelated donor transplantation in adults with hematologic malignancies: a systematic review and meta-analysis

OBJECTIVES

Haploidentical hematopoietic stem cell transplantation (Haplo-SCT) and matched unrelated donor transplantation (MUD-SCT) are two important options when a matched sibling donor (MSD) is unavailable. Several studies comparing Haplo-SCT and MUD-SCT have reported inconsistent clinical outcomes. Therefore, it is necessary to synthesize the existing evidence regarding outcomes of stem cell transplantations comparing Haplo-SCT with MUD-SCT.

METHODS

We searched for titles of articles in MEDLINE (PubMed), Cochrane library, EMBASE database that compared transplantation with Haplo-SCT versus MUD-SCT. To compare clinical outcomes between Haplo-SCT and MUD-SCT, we performed a meta-analysis of 17 studies and reported the pooled odd ratios (OR) of 6 endpoints including overall survival (OS), progression free survival (PFS), non-relapse mortality (NRM), relapse rate (RR), acute graft-versus-host disease (aGVHD) and chronic graft- versus-host disease (cGVHD).

RESULTS

We found that Haplo-SCT was associated with a comparable OS (pooled OR of 0.99, 95% Confidence Interval (CI) 0.86-1.14), PFS (OR 1.00, 95% CI 0.88-1.15), NRM (OR 0.83, 95% CI 0.65-1.04) and RR (OR 1.08, 95% CI 0.95-1.22) compared to MUD-SCT. We also found a significantly decreased risk of aGVHD (OR 0.74, 95% CI 0.62-0.88) and cGVHD (OR 0.50, 95% CI 0.38-0.66) in Haplo-SCT group.

CONCLUSION

Results of this meta-analysis demonstrates that Haplo-SCT achieves comparable clinical outcomes compared to MUD-SCT in terms of OS, PFS, TRM and RR, but is better than MUD-SCT in terms of decreased aGVHD and cGVHD risk. Haplo-SCT is a valid option for patient needing urgent transplantation.

Improved Outcomes of Haploidentical Hematopoietic Cell Transplantation with Total Body Irradiation-Based Myeloablative Conditioning in Acute Lymphoblastic Leukemia

The optimal myeloablative conditioning (MAC) for patients undergoing haploidentical hematopoietic cell transplantation (haplo-HCT) is unknown. We studied the outcomes of total body irradiation (TBI)-based versus chemotherapy (CT)-based MAC regimens in patients with acute lymphoblastic leukemia (ALL). The study included 427 patients who underwent first haplo-HCT with post-transplantation cyclophosphamide (PTCy), following TBI-based (n = 188; 44%) or CT-based (n = 239; 56%) MAC. The median patient age was 32 years. Fludarabine-TBI (72%) and thiotepa-busulfan-fludarabine (65%) were the most frequently used TBI- and CT-based regimens, respectively. In the TBI and CT cohorts, 2-year leukemia-free survival (LFS) was 45% versus 37% (P = .05), overall survival (OS) was 51% versus 47% (P = .18), relapse incidence (RI) was 34% versus 32% (P = .44), and nonrelapse mortality (NRM) was 21% versus 31% (P < .01). In the multivariate analysis, TBI was associated with lower NRM (hazard ratio [HR], 0.53; 95% confidence interval [CI], 0.33 to 0.86; P = .01), better LFS (HR, 0.71; 95% CI, 0.52 to 0.98; P =.04), and increased risk for grade II-IV acute graft-versus-host disease (GVHD) (HR, 1.59; 95% CI, 1.08 to 2.34; P = .02) compared with CT-based MAC. The type of conditioning regimen did not impact RI, chronic GVHD, OS, or GVHD-free, relapse-free survival after adjusting for transplantation-related variables. TBI-based MAC was associated with lower NRM and better LFS compared with CT-based MAC in patients with ALL after haplo-HCT/PTCy.

Allogeneic HCT for adults with B-cell precursor acute lymphoblastic leukemia harboring IKZF1 gene mutations. A study by the Acute Leukemia Working Party of the EBMT

The presence of IKZF1 gene mutations is associated with poor prognosis of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). The goal of this retrospective study was to evaluate outcome of allogeneic hematopoietic cell transplantation (allo-HCT) in this population. Ninety-five patients transplanted in first (n = 75) or second (n = 20) complete remission (CR) from either HLA-matched sibling (n = 32), unrelated (n = 47) or haploidentical (n = 16) donor were included in the analysis. The probabilities of the overall survival (OS) and leukemia-free survival (LFS) at 2 years were 55% and 47%, respectively. Relapse incidence (RI) was 32% while non-relapse mortality (NRM), 21%. The incidence of grade II-IV acute graft-versus-host disease (GVHD) and chronic GVHD was 34% and 30%, respectively. The probability of GVHD and relapse-free survival (GRFS) was 35%. In a multivariate analysis positive minimal residual disease (MRD) status was associated with decreased chance of LFS (HR = 3.15, p = 0.004) and OS (HR = 2.37, p = 0.049) as well as increased risk of relapse (HR = 5.87, p = 0.003). Disease stage (CR2 vs. CR1) affected all, LFS, OS, GRFS, RI, and NRM. Results of allo-HCT for patients with BCP-ALL and IKZF1 mutations are generally improving, however, individuals with detectable MRD have poor prognosis and require additional intervention prior to transplantation.

Comparison of Haploidentical Bone Marrow versus Matched Unrelated Donor Peripheral Blood Stem Cell Transplantation with Posttransplant Cyclophosphamide in Patients with Acute Leukemia

PURPOSE

Posttransplant cyclophosphamide (PTCy) is increasingly being utilized as a principle GvHD prophylaxis strategy in allogeneic hematopoietic cell transplantation (allo-HCT). A haploidentical (haplo) or matched unrelated donor (UD) is a valid option in the absence of a matched related donor.

EXPERIMENTAL DESIGN

We compared the outcomes of patients with acute leukemia who underwent haplo bone marrow (haplo-BM, N = 401) versus UD mobilized peripheral blood stem cells (UD-PB, N = 192) transplantation in the setting of PTCy.

RESULTS

The median follow-up duration was 36 months in the haplo-BM group and 16.6 months in the UD-PB group, respectively (P < 0.01). Myeloablative conditioning was used in 64.6% and 42.7% of haplo-BM and UD-PB patients, respectively (P < 0.01). Cumulative incidence of neutrophil engraftment at day 30 was 87% in haplo-BM versus 94% in UD-PB, respectively (P = 0.21). In the multivariate analysis, the risk of grade 2-4 acute GvHD (HR = 0.53, P = 0.01) and chronic GvHD (HR = 0.50, P = 0.02) was significantly lower in the haplo-BM group compared with the UD-PB group. There was no significant difference between the study groups with respect to relapse incidence, nonrelapse mortality, leukemia-fee survival, overall survival, or GvHD-free and relapse-free survival.

CONCLUSIONS

The use of a haplo donor with a BM graft resulted in a lower incidence of GvHD compared with a UD-PB stem cell graft in the setting of PTCy for patients with acute leukemia. However, differences in GvHD did not translate into a difference in survival outcomes. Based upon these data, UD-PB or haplo-BM should be considered equally acceptable sources for allo-HCT.

Impact of donor type on long-term graft-versus-host disease-free/relapse-free survival for adult acute lymphoblastic leukemia in first remission

We assessed the impact of donor type on long-term outcomes of allogeneic hematopoietic cell transplantation (HCT) in 440 consecutive adults with acute lymphoblastic leukemia (ALL) in first complete remission (CR1), particularly focusing on the donor type-specific difference in graft-versus-host disease (GVHD)-free/relapse-free survival (GRFS). Donor sources were matched sibling donor (MSD; n = 199), matched unrelated donor (MUD; n = 110), 1-allele-mismatched unrelated donor (1-MMUD; n = 83), and cord blood (CB; n = 48). Cumulative incidence of severe chronic GVHD was 14.8% for MSD-HCT, 30.1% for MUD-HCT, 9.6% for 1-MMUD-HCT, and 4.2% for CBT, respectively (P < 0.001), while no difference was observed in grade III-IV acute GVHD. After a median follow-up of 58.1 months, cumulative incidence of relapse was 26.1% for MSD-HCT, 27.2% for MUD-HCT, 31.2% for 1-MMUD-HCT, and 7.2% for CBT, respectively (P = 0.042). Disease-free survival and overall survival were comparable among all donor sources. However, GRFS for MSD-HCT, MUD-HCT, 1-MMUD-HCT, and CBT was 33.1%, 14.5%, 42.1%, and 50.3%, respectively (P = 0.001). In multivariate analysis, CBT showed a comparable GRFS to MSD-HCT (HR, 0.78; P = 0.290), while MUD-HCT was associated with a poorer GRFS (HR, 1.53; P = 0.002). Given the encouraging GRFS of CBT, our data suggest that CBT remains a valid option for adult ALL in CR1.

Haploidentical HSCT with post transplantation cyclophosphamide versus unrelated donor HSCT in pediatric patients affected by acute leukemia

T-cell replete hematopoietic stem cell transplantation (HSCT) from a haploidentical donor followed by high doses of cyclophosphamide has been demonstrated to provide the best chances of a cure for many children in need of an allograft but who lack both a sibling and an unrelated donor. In this study we retrospectively compared the outcome of pediatric patients undergoing T-replete haploidentical HSCT (Haplo) for acute leukemia with those undergoing transplantation from unrelated HLA-matched donor (MUD) and HLA mismatched unrelated donor (MMUD) from 2012 to 2017 at our Center. Both univariable and multivariable analyses showed similar 5-year overall survival rates for MUD, MMUD, and Haplo patients: 71% (95% CI 56-86), 72% (95% CI 55-90), and 75% (95% CI 54-94), respectively (p = 0.97). Haplo patients showed reduced event-free survival rates compared to MUD and MMUD patients: 30% (95% CI 12-49) versus 70% (95% CI 55-84) versus 53% (95% CI 35-73), respectively (p = 0.007), but these data were not confirmed by a multivariable analysis. Non-relapse mortality (NRM) and relapse incidence (RI) were similar for the three groups. Therefore, our data confirm that Haplo is a suitable clinical option for pediatric patients needing HSCT when lacking both an MUD and an MMUD donor.

Measurable residual disease of acute lymphoblastic leukemia in allograft settings: how to evaluate and intervene

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a curable strategy for acute lymphoblastic leukemia (ALL), especially for adult cases. However, leukemia relapse after allograft restricts the improvement of transplant outcomes. Measurable residual disease (MRD) has been the strongest predictor for relapse after allo-HSCT, allowing MRD-directed preemptive therapy.

AREAS COVERED

This manuscript summarizes the detection of MRD in patients with ALL who undergo allo-HSCT, focusing the effects of positive pre-HSCT MRD and post-HSCT MRD on outcomes as well as MRD-directed interventions.

EXPERT OPINION

Except for MFC and RQ-PCR, other strategies, such as next-generation sequencing and RNAseq, have been developed for MRD determination. Negative effects of positive MRD peri-transplantation on outcomes of ALL patients were observed both in human leukocyte antigen (HLA)-matched sibling donor transplantation and in alternative donor transplantation. Advances have been made in determining the need for transplant according to MRD evaluation after induction or consolidation therapy. A number of approaches, including CAR-T-cell therapy, antibodies (blinatumomab, etc), targeted therapy (imatinib, etc), transplant donor selection, as well as donor lymphocyte infusion and interferon-α, have been successfully used or are promising for peri-transplantation MRD interventions. This progress could lead to the significant improvement of transplant outcomes for ALL patients.

Comparison of haplo-SCT and chemotherapy for young adults with standard-risk Ph-negative acute lymphoblastic leukemia in CR1

Abstract

Human leukocyte antigen (HLA) haploidentical stem cell transplantation (haplo-SCT) as a postremission treatment for standard risk Philadelphia chromosome-negative acute lymphoblastic leukemia (SR Ph-ALL) in the first complete remission (CR1) has not been defined. In this multicenter, phase 3 study (NCT02042690), of the 131 consecutive Ph-ALL young adult patients (YA, aged 18–39 years) without high-risk features who achieved CR1, 114 patients without HLA-matched donors received consolidation with an adult chemotherapy regimen (n = 55) or haplo-SCT (n = 59). In the landmark analysis, haplo-SCT resulted in a lower 2-year cumulative incidence of relapse (CIR, 12.8% vs 46.7%, P = 0.0017) and superior 2-year leukemia-free survival (LFS, 80.9% vs 51.1%, P = 0.0116) and 2-year overall survival (OS, 91.2% vs 75.7 [64.8–93.2] %, P = 0.0408) than chemotherapy. In the time-dependent multivariate analysis with propensity score adjustment, postremission treatment (haplo-SCT vs chemotherapy) was an independent risk factor for the CIR (HR 0.195, 95% CI 0.076–0.499, P = 0.001), LFS (HR 0.297, 95% CI 0.131–0.675, P = 0.003), and OS (HR 0.346, 95% CI 0.140–0.853, P = 0.011). In all subgroups, CIR was lower in haplo-SCT. Myeloablative haplo-SCT with ATG+G-CSF might be one of the preferred therapies for YA patients with standard-risk Ph-ALL.

Trial registration

ClinicalTrials.gov. Registered on 23 January 2014, https://clinicaltrials.gov/ct2/show/NCT02042690

Haploidentical donor is preferred over matched sibling donor for pre-transplantation MRD positive ALL: a phase 3 genetically randomized study

Background

Previous reports suggest a benefit associated with haploidentical donor transplantation (HIDT) compared to matched sibling donor transplantation (MSDT) in certain contexts, and the choice of optimal candidates warrants further investigation.

Methods

We designed a prospective genetically randomized study to evaluate donor options between acute lymphoblastic leukemia (ALL) patients positive for measurable residual disease (MRD) pre-transplantation who underwent HIDT (n = 169) or MSDT (n = 39).

Results

The cumulative incidence of positive MRD post-transplantation was 26% (95% CI, 19–33%) and 44% (95% CI, 28–60%) for HIDT and MSDT, respectively (P = 0.043). Compared to the HIDT cohort, the MSDT cohort had a higher 3-year cumulative incidence of relapse (CIR; 47%, 95% CI, 31–63% vs. 23%, 95% CI, 17–29%; P = 0.006) and lower 3-year probability of leukemia-free survival (LFS; 43%, 95% CI, 27–59% vs. 65%, 95% CI, 58–72%; P = 0.023) and overall survival (OS; 46%, 95% CI, 30–62% vs. 68%, 95% CI, 61–75%; P = 0.039), without a difference in non-relapse-mortality (10%, 95% CI, 1–19% vs. 11%, 95% CI, 6–16%; P = 0.845). Multivariate analysis showed that HIDT is associated with a low CIR (HR = 0.364; 95% CI, 0.202–0.655; P = 0.001) and better LFS (HR = 0.414; 95% CI, 0.246–0.695; P = 0.001) and OS (HR = 0.380; 95% CI, 0.220–0.656; P = 0.001).

Conclusions

HIDT is better than MSDT in view of favorable anti-leukemia activity for patients with pre-transplantation MRD positive ALL. The current study paves the way to determine that haploidentical donors are the preferred choice regardless of available matched sibling donors in a subgroup population.

Trial registration

ClinicalTrials.gov Identifier: NCT02185261. Registered July 9, 2014. https://clinicaltrials.gov/ct2/show/NCT02185261?term=NCT02185261&draw=2&rank=1.

ATIR101 administered after T-cell-depleted haploidentical HSCT reduces NRM and improves overall survival in acute leukemia

Overcoming graft-versus-host disease (GvHD) without increasing relapse and severe infections is a major challenge after allogeneic hematopoietic stem-cell transplantation (HSCT). ATIR101 is a haploidentical, naïve cell-enriched T-cell product, depleted of recipient-alloreactive T cells to minimize the risk of GvHD and provide graft-versus-infection and -leukemia activity. Safety and efficacy of ATIR101 administered after T-cell-depleted haploidentical HSCT (TCD-haplo + ATIR101) without posttransplant immunosuppressors were evaluated in a Phase 2, multicenter study of 23 patients with acute leukemia and compared with an observational cohort undergoing TCD-haplo alone (n = 35), matched unrelated donor (MUD; n = 64), mismatched unrelated donor (MMUD; n = 37), and umbilical cord blood (UCB; n = 22) HSCT. The primary endpoint, 6-month non-relapse mortality (NRM), was 13% with TCD-haplo + ATIR101. One year post HSCT, TCD-haplo + ATIR101 resulted in lower NRM versus TCD-haplo alone (P = 0.008). GvHD-free, relapse-free survival (GRFS) was higher with TCD-haplo + ATIR101 versus MMUD and UCB (both P < 0.03; 1-year rates: 56.5%, 27.0%, and 22.7%, respectively) and was not statistically different from MUD (1 year: 40.6%). ATIR101 grafts with high third-party reactivity were associated with fewer clinically relevant viral infections. Results suggest that haploidentical, selective donor-cell depletion may eliminate requirements for posttransplant immunosuppressors without increasing GvHD risk, with similar GRFS to MUD. Following these results, a randomized Phase 3 trial versus posttransplant cyclophosphamide had been initiated.