Bone marrow versus mobilized peripheral blood stem cell graft in T-cell-replete haploidentical transplantation in acute lymphoblastic leukemia

Haploidentical hematopoietic cell transplantation as a platform for natural killer cell immunotherapy

An innovative approach is crucially needed to manage relapse after allogeneic hematopoietic cell transplantation (HCT) in patients with advanced hematological malignancies. This review explores key aspects of haploidentical HCT with post-transplant cyclophosphamide, highlighting the potential and suitability of this platform for natural killer (NK) cell immunotherapy. NK cells, known for their unique abilities to eliminate cancer cells, can also exhibit memory-like features and enhanced cytotoxicity when activated by cytokines. By discussing promising results from clinical trials, the review delves into the recent major advances: donor-derived NK cells can be expanded ex vivo in large numbers, cytokine activation may enhance NK cell persistence and efficacy in vivo, and post-HCT NK cell infusion can improve outcomes in high-risk and/or relapsed myeloid malignancies without increasing the risk of graft-versus-host disease, severe cytokine release syndrome, or neurotoxicity. Looking ahead, cytokine-activated NK cells can be synergized with immunomodulatory agents and/or genetically engineered to enhance their tumor-targeting specificity, cytotoxicity, and persistence while preventing exhaustion. The ongoing exploration of these strategies holds promising preliminary results and could be rapidly translated into clinical applications for the benefit of the patients.

Bone marrow versus peripheral blood allogeneic haematopoietic stem cell transplantation for haematological malignancies in adults

BACKGROUND

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is an established treatment option for many malignant and non-malignant haematological disorders. Peripheral blood stem cells represent the main stem cell source in malignant diseases due to faster engraftment and practicability issues compared with bone marrow stem cells. Since the early 2000s, there have been many developments in the clinical field. Allo-HSCT using haploidentical family donors (haplo-HSCT) has emerged as an alternative for people who do not have human leukocyte antigen (HLA)-matched siblings or unrelated donors. In addition, the introduction of new methods and strategies in allo-HSCT, such as the use of post-transplant cyclophosphamide (PT-Cy), better donor selection, the more frequent administration of anti-thymocyte globulins (ATGs), but also improved management of side effects such as graft-versus-host disease (GvHD) and infection, have impacted outcomes after allo-HSCT. In addition, as transplant indications and strategies continue to adapt in line with novel research findings, the effect of the stem cell source on post-transplant outcomes is unclear. For our analysis, we considered peripheral blood stem cells as the standard graft source for adults with haematological malignancies. This is an update of a review first published in 2014.

OBJECTIVES

To assess the effect of bone marrow transplantation versus peripheral blood stem cell transplantation in adults with haematological malignancies with regard to overall survival, disease-free survival, incidence of non-relapse or transplant-related mortality, incidence of extensive chronic graft-versus-host disease (GvHD), incidence of acute GvHD grades III to IV, incidence of overall chronic GvHD, and quality of life.

SEARCH METHODS

For this update we searched CENTRAL, MEDLINE, Embase, and two trials registries on 2 November 2022 with no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing bone marrow transplantation (BMT) with peripheral blood stem cell transplantation (PBSCT) in adults (aged ≥ 18 years) with haematological malignancies.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies and extracted data. We evaluated risk of bias using the original Cochrane risk of bias tool (RoB 1), and we evaluated the certainty of the evidence using the GRADE approach.

MAIN RESULTS

The updated search identified no new studies for inclusion. We found two additional reports relating to a previously included study; they provided new data on quality of life and infection rates after transplantation. As these are clinically relevant outcomes, quality of life was added to the summary of findings table (replacing acute GvHD II to IV), and rate of infection was added to our list of secondary outcomes. We included nine RCTs with a total of 1521 participants. Overall, the risk of bias in the included studies was low. Median participant age across studies ranged from 21 to 45 years, and studies took place in Canada, the USA, New Zealand, Brazil, Australia, Egypt, and across Europe. Bone marrow transplantation (BMT) compared with peripheral blood stem cell transplantation (PBSCT) likely results in little to no difference in overall survival (hazard ratio (HR) for all-cause death 1.07, 95% CI 0.91 to 1.25; 6 studies, 1330 participants; moderate-certainty evidence). There may be little to no difference between BMT and PBSCT in terms of disease-free survival (HR for disease recurrence or all-cause death 1.04, 95% CI 0.89 to 1.21; 6 studies, 1225 participants; low-certainty evidence) and non-relapse or transplant-related mortality (HR 0.98, 95% CI 0.76 to 1.28; 3 studies, 758 participants; low-certainty evidence). BMT compared with PBSCT likely results in lower rates of extensive chronic GvHD (HR 0.69, 95% CI 0.54 to 0.90; 4 studies, 765 participants; moderate-certainty evidence) and overall chronic GvHD (HR 0.72, 95% CI 0.61 to 0.85; 4 studies, 1121 participants; moderate-certainty evidence). BMT compared with PBSCT may reduce the incidence of acute GvHD grades III to IV, although the 95% CI of the HR is also compatible with no effect (HR 0.75, 95% CI 0.55 to 1.02; 3 studies, 925 participants; moderate-certainty evidence). Evidence from two trials that used different quality of life assessment instruments suggests that BMT compared with PBSCT may be associated with higher quality of life five years after transplantation.

AUTHORS' CONCLUSIONS

Moderate-certainty evidence suggests little to no difference in overall survival following allo-HSCT using bone marrow versus peripheral blood stem cells (the current clinical standard stem cell source). Low-certainty evidence suggests little to no difference between the stem cell sources in terms of disease-free survival and non-relapse or transplant-related survival. BMT likely reduces the risk of extensive chronic GvHD and overall chronic GvHD compared with PBSCT. Evidence from two RCTs suggests that BMT compared with PBSCT may result in higher long-term quality of life, possibly due to the lower chronic GvHD incidence. With this update, we aimed to supply the most recent data on the choice of stem cell source for allo-HSCT in adults by including new evidence published up to November 2022. We identified no new ongoing studies and no new RCTs with published results. Further research in this field is warranted.

Prognostic factors impacting post-transplant outcomes in adult T-cell acute lymphoblastic leukemia: a registry-based study by the EBMT acute leukemia working party

T-cell acute lymphoblastic leukemia (T-ALL) predominantly affects individuals in late childhood and young adulthood. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative modality particularly in the setting of poor risk genetics and/or persistent minimal residual disease. Limited studies have directly explored the impact of patient- and transplant-related factors on post-transplant outcomes in T-ALL. Using a large dataset from the European Society for Blood and Marrow Transplantation registry, we identified 1907 adult T-ALL patients (70% male) who underwent their first allo-HSCT in first complete remission (CR1) from matched sibling donors (MSD; 45%), unrelated donors (UD; 43%) or haploidentical donors (12%) between 2010 and 2021. The median age at transplant was 33.4 years (18.1-75). The median follow up was 2.9 years. Most patients underwent total body irradiation (TBI)-based myeloablative conditioning (69%). The 2-year overall survival (OS) was 69.4%, and leukemia -free survival (LFS) was 62.1%. In multivariate analysis, advanced age at transplant negatively affected LFS (for each 10-year increment, HR = 1.11, p = 0.004), GVHD-free, relapse-free survival (GRFS) (HR = 1.06, p = 0.04), OS (HR = 1.12, p = 0.002), and non-relapse mortality (NRM) (HR = 1.23, p < 0.001). More recent years of allo-HSCT were associated with improved GFRS (For each 3-year increment, HR = 0.89, p < 0.001), OS (HR = 0.9, p = 0.02), and decreased NRM (HR = 0.82, p = 0.008). TBI improved LFS. (HR = 0.79, p = 0.02), GRFS (HR = 0.83, p = 0.04), and relapse incidence (RI) (HR = 0.65, p < 0.001). Female-to-male transplant negatively affected GRFS (HR = 1.21, p = 0.02) and OS (HR = 1.23, p = 0.048). In vivo T-cell depletion significantly improved GFRS (HR = 0.74, p < 0.001). This large study identified prognostic factors, such as age at transplant conditioning regimen, in influencing post-transplant in adult T-ALL patients undergoing allo-HSCT. Importantly, a significant improvement over time was noted. These findings hold great promise for new adapted treatment strategies and can serve as a benchmark for future studies in that setting.

Graft-versus-tumor effect of post-transplant cyclophosphamide-based allogeneic hematopoietic cell transplantation

Post-transplant cyclophosphamide (PTCy) is becoming the standard prophylaxis for graft-versus-host disease (GVHD) in HLA-haploidentical allogeneic hematopoietic cell transplantation (allo-HCT) and in HLA-matched allo-HCT. Immune reconstitution in the post-transplant setting may influence the graft-versus-tumor (GVT) effect because PTCy has a profound effect on T cell and natural killer cell functions and their reconstitution after allo-HCT. However, many recent studies have shown that the incidence of relapse after allo-HCT with PTCy is comparable to that after conventional allo-HCT. To further improve the outcomes, it is critical to establish a strategy to maintain or effectively induce the GVT effect when using PTCy as a platform for GVHD prophylaxis. However, there is a paucity of studies focusing on the GVT effect in allo-HCT with PTCy. Therefore, focusing on this issue may lead to the establishment of more appropriate strategies to improve transplantation outcomes without exacerbating GVHD, including novel therapies involving cell modification.

Haploidentical stem cell donor choice for patients with acute myeloid leukemia: a study from the ALWP of the EBMT

ABSTRACT

There is a paucity of information to guide the selection of the most suitable donor in haploidentical (Haplo) hematopoietic stem cell transplantation (HSCT). For this reason, from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation, we conducted a retrospective analysis to evaluate the impact of Haplo donor characteristics on outcomes in patients with acute myeloid leukemia (AML) who received graft-versus-host disease prophylaxis with posttransplant cyclophosphamide (PTCy). The primary end point was graft-versus-host disease (GVHD)-free and relapse-free survival (GRFS). Overall, 2200 patients were included. The median age of donors was 37 years (range, 8-71); 820 (37%) were females, including 458 (21%) who were used for male recipients. In addition, 1631 donors (74%) donated peripheral blood (PB). Multivariable analysis identified certain donor-related risk factors with a detrimental impact on transplant outcomes. The use of PB, older donors' ages (>37 years), and female donors to male recipients negatively affected GRFS. Donor's age and female donor-to-male recipient combination also affected nonrelapse mortality, leukemia-free survival, and overall survival. In conclusion, donor-related variables significantly influence outcomes in patients with AML after Haplo-HSCT with PTCy. When possible, younger donors and male donors for male recipients should be prioritized. The use of bone marrow can additionally prevent GVHD.

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.

Bone marrow graft versus peripheral blood graft in haploidentical hematopoietic stem cells transplantation: a retrospective analysis in1344 patients of SFGM-TC registry

The use of peripheral blood (PB) or bone marrow (BM) stem cells graft in haploidentical hematopoietic stem cell transplantation with post-transplant cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis remains controversial. Moreover, the value of adding anti-thymoglobulin (ATG) to PTCy is unknown. A total of 1344 adult patients received an unmanipulated haploidentical transplant at 37 centers from 2012 to 2019 for hematologic malignancy. We compared the outcomes of patients according to the type of graft, using a propensity score analysis. In total population, grade II-IV and III-IV acute GVHD (aGVHD) were lower with BM than with PB. Grade III-IV aGVHD was lower with BM than with PB + ATG. All outcomes were similar in PB and PB + ATG groups. Then, in total population, adding ATG does not benefit the procedure. In acute leukemia, myelodysplastic syndrome and myeloproliferative syndrome (AL-MDS-MPS) subgroup receiving non-myeloablative conditioning, risk of relapse was twice greater with BM than with PB (51 vs. 22%, respectively). Conversely, risk of aGVHD was greater with PB (38% for aGVHD II-IV; 16% for aGVHD III-IV) than with BM (28% for aGVHD II-IV; 8% for aGVHD III-IV). In this subgroup with intensified conditioning regimen, risk of relapse became similar with PB and BM but risk of aGVHD III-IV remained higher with PB than with BM graft (HR = 2.0; range [1.17-3.43], p = 0.012).

DNA methylation of hematopoietic stem/progenitor cells from donor peripheral blood to patient bone marrow: implications for allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (AHSCT) is a life-saving treatment for selected hematological malignancies. So far, it remains unclear whether transplanted hematopoietic stem/progenitor cells (HSPCs) undergo epigenetic changes upon engraftment in recipient bone marrow (BM) after AHSCT and whether these changes might be useful in the transplant diagnostics. The purpose of this study was to characterize the whole genome methylation profile of HSPCs following AHSCT. Moreover, the relationship between the observed methylation signature and patient outcome was analyzed. Mobilized peripheral blood (mPB)-HSPCs from seven donors and BM-HSPCs longitudinally collected from transplanted patients with hematological malignancies up to one year from AHSCT (a total of twenty-eight samples) were analyzed using DNA methylation based-arrays. The obtained data showed that DNA methylation of mPB-HSPCs differs between young and adult donors and changes following HSPC engraftment in the BM of recipient patients. Looking at methylation in promoter regions, at 30 days post-AHSCT, BM-HSPCs showed a higher number of differentially methylated genes (DMGs) compared to those of mPB-HSPCs, with a prevalent hyper-methylation. These changes were maintained during all the analyzed time points, and methylation became like the donors after one year from transplant. Functional analysis of these DMGs showed an enrichment in cell adhesion, differentiation and cytokine (interleukin-2, -5 and -7) production and signaling pathways. Of note, DNA methylation analysis allowed to identify a potential "cancer/graft methylation signature" of transplant failure. It was evident in the latest available post-transplant BM-HSPC sample (at 160 days) and surprisingly already in early phase (at 30 days) in patients whose transplant was doomed to fail. Overall, the analysis of HSPC methylation profile could offer useful prognostic information to potentially assess engraftment success and predict graft failure in AHSCT.

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).

Reduced post-transplant cyclophosphamide dose with antithymocyte globulin in peripheral blood stem cell haploidentical transplantation

Post-transplant cyclophosphamide (PT-Cy) is effective for graft-versus-host disease (GVHD) prophylaxis, but it may cause dose-dependent toxicities, particularly in frail patients. Therefore, we compared the outcomes with a reduced PT-Cy total dose (70 mg/kg) to those with the standard PT-Cy dose (100 mg/kg) in haploidentical hematopoietic cell transplantation (HCT) patients aged ≥ 65 years and those with cardiac comorbidities. All consecutive patients with a hematological malignancy receiving peripheral blood stem cells (PBSCs) after a thiotepa-based conditioning with low-dose antithymocyte globulin were included. Thirty-three patients received PT-Cy at 70 mg/kg and 25 at 100 mg/kg. PT-Cy dose reduction did not increase the risk of GVHD and was associated with faster neutrophil and platelet recovery, and lower cumulative incidences of bacteremia (38% versus 72%, p = 0.004) and cardiac complications (12% versus 44%, p = 0.028). At 2 years, GVHD-free, relapse-free survival (GRFS) was higher with the reduced dose compared to the standard dose (60% versus 33%, p = 0.04). In conclusion, reducing PT-Cy total dose to 70 mg/kg is a safe and valid approach for elderly patients and those with cardiac comorbidities underdoing haploidentical HCT with PBSCs and low-dose antithymocyte globulin. The reduced PT-Cy dose was associated with improved hematological count recovery, lower incidence of toxicities, and higher GRFS.

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.

Fludarabine or cyclophosphamide in combination with total body irradiation as myeloablative conditioning prior to allogeneic hematopoietic cell transplantation for acute lymphoblastic leukemia: an analysis by the Acute Leukemia Working Party of the EBMT

In this registry-based study we retrospectively compared outcomes of allogeneic hematopoietic cell transplantation (allo-HCT) for adult patients with acute lymphoblastic leukemia (ALL) following conditioning with total body irradiation (TBI) combined with either cyclophosphamide (Cy) or fludarabine (Flu). TBI 12 Gy + Cy was used in 2105 cases while TBI 12 Gy + Flu was administered to 150 patients in first or second complete remission. In a multivariate model adjusted for other prognostic factors, TBI/Cy conditioning was associated with a reduced risk of relapse (HR = 0.69, p = 0.049) and increased risk of grade 2-4 acute graft-versus-host disease (GVHD, HR = 1.57, p = 0.03) without significant effect on other transplantation outcomes. In a matched-pair analysis the use of TBI/Cy as compared to TBI/Flu was associated with a significantly reduced rate of relapse (18% vs. 30% at 2 years, p = 0.015) without significant effect on non-relapse mortality, GVHD and survival. We conclude that the use of myeloablative TBI/Cy as conditioning prior to allo-HCT for adult patients with ALL in complete remission is associated with lower risk of relapse rate compared to TBI/Flu and therefore should probably be considered a preferable regimen.

Hematopoietic Stem Cell Transplantation Activity in China 2020-2021 During the SARS-CoV-2 Pandemic: A Report From the Chinese Blood and Marrow Transplantation Registry Group

Between 2020 and 2021, 31,525 hematopoietic stem cell transplantations (HSCTs) were reported to the Chinese Blood and Marrow Transplantation Registry Group throughout mainland China. In this report, we describe the activity and current trends for HSCT in China during the SARS-CoV-2 pandemic. In 2020, a total of 13,415 cases of HSCT were reported from 166 transplantation teams, and 75% (10,042 cases) were allogeneic HSCTs. In 2021, a total of 18,110 cases of HSCT were reported from 174 transplantation teams, and 70% (12,744 cases) were allogeneic HSCTs. Haploidentical donor (HID) transplantation accounted for 63% (7977 cases) of allogeneic HSCTs in 2021. The most common indications for allogeneic HSCT for malignant disease were acute myeloid leukemia (37%) and acute lymphoblastic leukemia (23%), and the largest proportion of nonmalignant disease comprised aplastic anemia (13%). The peripheral blood stem cell source accounted for 41% of HIDs and 75% of matched sibling donors. The BuCy-based regimen (57%) was the most popular conditioning regimen for allogeneic HSCT, followed by the BuFlu-based regimen (28%) and total body irradiation-based regimen (11%). This survey provides comprehensive information about the current activities and might benefit clinical physicians' decision planning for HSCT.

Controversies and expectations for the prevention of GVHD: A biological and clinical perspective

Severe acute and chronic graft versus host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation. Historically, cord blood and matched sibling transplantation has been associated with the lowest rates of GVHD. Newer methods have modified the lymphocyte components to minimize alloimmunity, including: anti-thymocyte globulin, post-transplant cyclophosphamide, alpha/beta T cell depletion, and abatacept. These agents have shown promise in reducing severe GVHD, however, can be associated with increased risks of relapse, graft failure, infections, and delayed immune reconstitution. Nonetheless, these GVHD prophylaxis strategies have permitted expansion of donor sources, especially critical for those of non-Caucasian decent who previously lacked transplant options. This review will focus on the biologic mechanisms driving GVHD, the method by which each agent impacts these activated pathways, and the clinical consequences of these modern prophylaxis approaches. In addition, emerging novel targeted strategies will be described. These GVHD prophylaxis approaches have revolutionized our ability to increase access to transplant and have provided important insights into the biology of GVHD and immune reconstitution.

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.

Influence of graft composition in patients with hematological malignancies undergoing ATG-based haploidentical stem cell transplantation

To determine the influence of graft composition in haplo-HSCT, we summarized the long-term consequences of 251 consecutive transplantations from haploidentical donors. For donor-recipient HLA3/6-matched setting, 125 cases used G-CSF-mobilized BM and PBSCs mixtures, while 126 cases only used G-CSF-mobilized PBSCs in HLA4/6-matched transplantation. On the one hand, we wanted to explore the effect of harvests (CD34+ cells and TNCs dosages) on transplantation outcome in the context of haplo-HSCT no matter HLA4/6 or HLA3/6-matched setting. On the other hand, for patients using G-CSF-mobilized BM and PBSCs combination in HLA3/6-matched setting, we attempted to analyze whether TNCs or CD34+ cells from G-CSF-mobilized BM or G-CSF-mobilized PBSCs play the most paramount role on transplantation prognosis. Collectively, patients with hematologic malignancies receiving G-CSF-primed BM and PBSCs harvests had comparable consequences with patients only receiving G-CSF-mobilized PBSCs. Moreover, when divided all patients averagely according to the total amount of transfused nucleated cells, 3-year TRM of the intermediate group (13.06-18.05×10⁸/kg) was only 4.9%, which was remarkably reduced when compared to lower and higher groups with corresponding values 18.3%, 19.6% (P=0.026). The 3-year probabilities of OS and DFS of this intermediate group were 72.6% and 66.5%, which were slightly improved than the lower and higher groups. Most importantly, these data suggest that the transfused nucleated cells from G-CSF-primed BM above than 5.20×10⁸/kg could achieve remarkably lower TRM in haplo-HSCT receiving G-CSF-mobilized BM and PBSCs harvests. These encouraging results suggested that we could improve the efficacy of haplo-HSCT by adjusting the component and relative ratio of transfused graft cells. Nevertheless, the above findings should be confirmed in a randomized prospective comparative research with adequate follow-up.

Comparison of HLA-mismatched unrelated donor transplantation with post-transplant cyclophosphamide versus HLA-haploidentical transplantation in patients with active acute myeloid leukemia

HLA-haploidentical allogeneic hematopoietic stem cell transplantation (Haplo-HCT) is frequently used as treatment for patients with active acute myeloid leukemia (AML). Here, we investigated whether 9/10 HLA-mismatched unrelated donor transplantation (MMUD-HCT) with post-transplant cyclophosphamide (PTCy) is an adequate alternative. Inclusion criteria in this retrospective registry study consisted of adult patients, first HCT with a Haplo donor or MMUD between 2010 and 2020 using PTCy as graft-versus-host disease (GVHD) prophylaxis, and primary refractory or relapsed disease. MMUD patients were pair-matched 1 to 2 with Haplo-recipients. A total of 73 MMUD patients met the inclusion criteria. Their data were compared to those of 146 Haplo patients in a matched-pair analysis. Median follow-up was 27 months in MMUD patients and 36 months in Haplo recipients. Two-year incidences of relapse and non-relapse mortality (NRM) were 40% and 18% in MMUD patients, respectively, versus 50% (P = 0.23) and 24% (P = 0.18) in Haplo recipients. Two-year leukemia-free survival (LFS) and overall survival (OS) was 42% and 46% in MMUD recipients, respectively, versus 26% (P = 0.1) and 28% (P = 0.061) in Haplo-patients. In conclusions, in AML patients with active disease at transplantation, MMUD-HCT results in at least comparable outcomes to Haplo-HCT when PTCy is applied.

Feasibility and Efficacy of Partially Replacing Post-Transplantation Cyclophosphamide with Bendamustine in Pediatric and Young Adult Patients Undergoing Haploidentical Bone Marrow Transplantation

Post-transplantation cyclophosphamide (PT-CY) is the most widely applied graft-versus-host disease (GVHD) prophylaxis regimen in T-cell replete haploidentical bone marrow transplantation (haplo-BMT). Although PT-CY has met with great success in the haplo-BMT arena by suppressing GVHD, patients without acute GVHD have high relapse rates. One strategy to reduce relapse rates being explored by others is a dosage reduction of PT-CY. We have taken a different approach in evaluating whether partially replacing PT-CY with post-transplantation bendamustine (PT-BEN) would be advantageous, an idea based on our preclinical research identifying several beneficial immunomodulatory properties of BEN. We therefore initiated and completed a Phase Ia trial to evaluate the progressive substitution of PT-CY with PT-BEN (ClinicalTrials.gov identifier NCT02996773). We compared outcomes between 13 patients with high-risk hematologic malignancies who received PT-CY/BEN and 31 contemporaneous haplo-BMT recipients treated with the same myeloablative conditioning regimens but receiving only PT-CY. We found that partial replacement of PT-CY with PT-BEN (PT-CY/BEN) on day +4 was well tolerated and associated with significantly earlier trilineage engraftment. We also report favorable trends toward significant improvements on univariate and multivariate analyses with PT-CY/BEN compared with PT-CY with respect to rates of chronic GVHD (hazard ratio [HR], .08; 95% confidence interval [CI], .005 to 1.11; P = .06), and GVHD-free relapse-free survival (GRFS) (HR, .22; 95% CI, .05 to .86; P = .039). Our human trial has now transitioned to Phase Ib, which will further evaluate the safety and potential benefits of PT-CY/BEN. Herein we also expand our pediatric, adolescent, and young adult experience to 31 patients, demonstrating overall survival, progression-free survival, and GRFS at 3 years of 85.6%, 76.1%, and 58.2%, respectively, in a largely racial/ethnic minority cohort. PT-CY/BEN appears to be a promising treatment option that requires further evaluation.

HLA-haploidentical transplantation for relapsed/refractory AML: better LFS with BM than with PBSC in patients ≥ 55 years of age

The best stem cell source for T-cell replete HLA-haploidentical transplantation with post-transplant cyclophosphamide (PTCy) remains to be determined. In this EBMT retrospective study we analyzed the impact of stem cell source on leukemia-free survival (LFS) in adult patients with primary refractory or relapsed acute myeloid leukemia (AML) given grafts from HLA-haploidentical donors with PTCy as graft-versus-host disease (GVHD) prophylaxis. A total of 668 patients (249 bone marrow (BM) and 419 peripheral blood stem cells (PBSC) recipients) met the inclusion criteria. The use of PBSC was associated with a higher incidence of grade II-IV (HR = 1.59, P = 0.029) and grade III-IV (HR = 2.08, P = 0.013) acute GVHD. There was a statistical interaction between patient age and the impact of stem cell source for LFS (P < 0.01). In multivariate Cox models, among patients <55 years, the use of PBSC versus BM resulted in comparable LFS (HR = 0.82, P = 0.2). In contrast, in patients ≥55 years of age, the use of PBSC versus BM was associated with higher non-relapse mortality (NRM) (HR = 1.7, P = 0.01), lower LFS (HR = 1.37, P = 0.026) and lower overall survival (OS) (HR = 1.33, P = 0.044). In conclusions, our data suggest that in patients ≥55 years of age with active AML at HLA-haploidentical transplantation, the use of BM instead of PBSC as stem cell source results in lower NRM and better LFS. In contrast among younger patients, the use of PBSC results in at least a comparable LFS. This article is protected by copyright. All rights reserved.

Infusion of haploidentical HSCs combined with allogenic MSCs for the treatment of ALL patients

Although haploidentical stem cell transplantation (haplo-HSCT) offers almost all acute lymphoblastic leukaemia (ALL) patients an opportunity for immediate transplantation, it exhibits a higher incidence of graft failure and graft versus host disease (GVHD). Mesenchymal stem cells (MSCs) are characterised by their haematopoiesis-promoting and immunomodulatory capacity. Thus, we designed a combination of haplo-HSCT and MSCs for ALL patients. ALL patients (n = 110) were given haploidentical HSCs combined with allogenic MSCs, and ALL patients without MSC infusion (n = 56) were included as controls. The 100-day cumulative incidences of grade ≥2 acute GVHD (aGVHD) and grade ≥3 aGVHD were 40.00% and 9.09% compared to 42.32% (P = 0.79) and 22.79% (P = 0.03) in patients without MSC infusion, respectively. The 3-year cumulative incidences of chronic GVHD (cGVHD) and extensive cGVHD were 22.27% and 10.27% compared to 32.14% (P = 0.19) and 22.21% (P = 0.04) in patients without MSC infusion, respectively. No significant differences in the 3-year relapse incidence, nonrelapse mortality, leukaemia-free survival or overall survival in groups with and without MSC cotransplantation were observed. Multivariate analysis showed that MSC infusion contributed to a lower risk of developing extensive cGVHD. Our data suggested that haplo-HSCT combined with MSCs may provide an effective and safe treatment for ALL patients.

Outcomes of Different Haploidentical Transplantation Strategies from the Taiwan Blood and Marrow Transplantation Registry

BACKGROUND

The two most noteworthy strategies for haploidentical stem cell transplantation (haplo-HSCT) are posttransplantation cyclophosphamide (PTCy) with or without thymoglobulin (ATG) and granulocyte colony stimulating factor-primed bone marrow plus peripheral blood stem cells (GIAC). We aimed to compare these approaches in patients with hematological malignancies.

METHODS

We enrolled 178 patients undergoing haplo-HSCT, including modified GIAC (mGIAC), PTCy without ATG, and PTCy with ATG.

RESULTS

The patients in the mGIAC group had the most favorable platelet and neutrophil engraftment kinetics. Although the grade III-IV acute graft-versus-host-disease (GvHD) rates were similar, those receiving mGIAC had a significantly higher extensive chronic GvHD rate. The patients receiving mGIAC had a similar cumulative incidence of relapse (CIR) to that in the patients receiving PTCy with ATG, but this was lower than that in the patients receiving PTCy without ATG. The patients receiving mGIAC had the lowest nonrelapse mortality (NRM) and the highest overall survival (OS) rates. The differences in CIR, NRM, and OS remained significant when focusing on patients with low/intermediate-risk diseases before haplo-HSCT. Intriguingly, among patients with high/very-high-risk diseases before haplo-HSCT, no differences were observed in the CIR, NRM, OS, or GvHD/relapse-free survival.

CONCLUSION

the mGIAC approach may yield a better outcome in Taiwanese patients with hematologic malignancies, especially for those with low/intermediate-risk diseases.

Validation plan of bone marrow collection, processing and distribution using the failure mode and effect analysis methodology: a technical report

BACKGROUND AIMS

Bone marrow (BM) is commonly used in the pediatric and adult setting as a source of hematopoietic stem cells (HSCs). The standards of the Joint Accreditation Committee of the International Society for Cell & Gene Therapy & European Society for Blood and Marrow Transplantation (JACIE) include specific requirements regarding BM collection, processing and distribution. To run this process, each transplant team develops a series of JACIE-compliant procedures, customizing them with regard to local settings and paths. Moreover, JACIE standards require that transplant teams validate and periodically revise their procedures to keep the entire process under control. In this article, the authors describe the methodology adopted in our center to fulfill the aforementioned JACIE requirements.

METHODS

The authors developed a validation plan based on the failure mode and effect analysis (FMEA) methodology. According to the FMEA approach, the authors carefully revised activities and procedures connected to BM collection, processing and distribution at our institution. The entire process was initially divided into five main phases (assessment of donor eligibility, perioperative autologous blood donation, preparation of BM collection kit, BM harvesting and BM processing and distribution), comprising 17 subphases and 22 activities.

RESULTS

For each activity, one or more failure modes were identified, for a total of 28 failure modes, and a risk priority number (RPN) was then assigned to each failure mode. Although many procedures were validated, others were subjected to substantial changes according to the RPN rating. Moreover, specific indicators were identified for subsequent monitoring to contain the risk of failure of steps emerging as critical at FMEA.

CONCLUSIONS

This is the first study describing use of the FMEA methodology within an HSC transplant program. Shaping the risk analysis based on local experience may be a trustworthy tool for identifying critical issues, directing strict monitoring of critical steps or even amending connected procedures. Overall, the FMEA approach enabled the authors to improve our process, checking its consistency over time.

Case Report: Haploidentical Bone Marrow Transplantation in Two Brothers With Wiskott-Aldrich Syndrome Using Their Father as the Donor

Wiskott-Aldrich syndrome (WAS) is an X-linked genetic disorder with a variable phenotypic expression that includes thrombocytopenia, eczema, and immunodeficiency. Some patients may also exhibit autoimmune manifestations. Patients with WAS are at increased risk of developing malignancies such as lymphoma. Allogeneic hematopoietic cell transplantation remains the only curative treatment. Haploidentical bone marrow transplantation (haplo-BMT) with post-transplant cyclophosphamide (PT-CY) has more recently been applied in WAS. Here, we report two brothers who underwent successful T-cell replete haplo-BMT with PT-CY at ages 9 months and 4 years using their father as the donor. Our myeloablative regimen was well-tolerated with minimal organ toxicity and no acute or chronic graft vs. host disease (GvHD). Haplo-BMT may be considered as a safe and effective option for patients with WAS who do not have available human leukocyte antigen (HLA) matched donors.

Comparison of non-first-degree related donors and first-degree related donors in haploidentical HSCT: a multi-centre retrospective analysis

The transplant outcomes of non-first-degree (NFD) related donors in haploidentical haematopoietic stem cell transplantation (haplo-HSCT) remain unclear. This multi-centre analysis compared NFD and first-degree (FD) related donors in haplo-HSCT using a low-dose anti-T-lymphocyte globulin/G-CSF-mobilised peripheral blood stem cell graft-based regimen. Ninety-nine patients (33 NFD; 66 FD) were included. All patients achieved myeloid and platelet engraftment. The 100-day cumulative incidence (CI) of aGVHD, 2-year CIs of relapse, cGVHD, and NRM, and 2-year probabilities of OS and GRFS were comparable between the two cohorts. In multivariate analysis, donor type (NFD vs. FD) had no impact on OS, PFS, GRFS, incidences of relapse, grade II-IV aGVHD or moderate-severe cGVHD. Older donor age was associated with a higher incidence of grade II-IV aGVHD (HR, 1.64, p = 0.03), moderate-severe cGVHD (HR, 1.92, p = 0.01) and worse GRFS (HR, 1.40, p = 0.02). A lower level of donor-recipient HLA matching was associated with a higher incidence of moderate-severe cGVHD (HR, 4.07, p = 0.02), and disease at complete remission was associated with better OS (HR, 0.21, p = 0.01) and PFS (HR, 0.3, p = 0.03). In conclusion, NFD donors may serve as feasible alternatives when FD donors are not available for haplo-HSCT.

Bone Marrow versus Peripheral Blood Grafts for Haploidentical Hematopoietic Cell Transplantation with Post-Transplantation Cyclophosphamide

In the coronavirus disease 19 (COVID-19) pandemic era, the number of haploidentical hematopoietic cell transplantations (HCTs) with peripheral blood (PB) grafts increased significantly compared with HCTs with bone marrow (BM) grafts, which may be associated with adverse outcomes. We compared outcomes of HCT in BM graft and PB graft recipients age ≥18 years with hematologic malignancies who underwent T cell- replete haploidentical HCT and received graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide, tacrolimus, and mycophenolate mofetil. Among the 264 patients, 180 (68%) received a BM graft and 84 (32%) received a PB graft. The median patient age was 50 years in both groups. The majority (n = 199; 75%) received reduced-intensity conditioning. The rate of acute leukemia or myelodysplastic syndrome was higher in the BM graft recipients compared with the PB graft recipients (85% [n = 152] versus 55% [n = 46]; P < .01). The median times to neutrophil and platelet engraftment and the incidence of grade II-IV and grade III-IV acute GVHD (aGVHD) were comparable in the 2 groups. Among the patients with grade II-IV aGVHD, the rate of steroid-refractory aGVHD was 9% (95% confidence interval [CI], 5% to 18%) in the BM group versus 32% (95% CI, 19% to 54%) in the PB group (hazard ratio [HR], 3.7, 95% CI, 1.5 to 9.3; P = .006). At 1 year post-HCT, the rate of chronic GVHD (cGVHD) was 8% (95% CI, 4% to 13%) in the BM group versus 22% (95% CI, 14% to 36%) in the PB group (HR, 3.0; 95% CI, 1.4-6.6; P = .005), and the rate of systemic therapy-requiring cGVHD was 2.5% (95% CI, 1% to 7%) versus 14% (95% CI, 7% to 27%), respectively (HR, 5.6; 95% CI, 1.7 to 18; P = .004). The PB group had a significantly higher risk of bacterial and viral infections, with no appreciable advantage in the duration of hospitalization, immune reconstitution, relapse, nonrelapse mortality, or survival. Our data suggest a benefit of the use of BM grafts over PB grafts for haplo-HCT.

Outcomes after Haploidentical Hematopoietic Cell Transplantation with Post-Transplantation Cyclophosphamide: A Systematic Review and Meta-Analysis Comparing Myeloablative with Reduced-Intensity Conditioning Regimens and Bone Marrow with Peripheral Blood Stem Cell Grafts

Haploidentical hematopoietic cell transplantation (haplo-HCT) with post-transplantation cyclophosphamide (PTCy) may be the sole available curative option for several hematologic malignancies. However, the best choice of conditioning regimen and graft source has not been established. This study was conducted to compare myeloablative conditioning (MAC) regimens with reduced-intensity conditioning (RIC) regimens and peripheral blood stem cell (PBSC) grafts with bone marrow (BM) grafts in the haplo-HCT setting with PTCy. We performed a systematic review and meta-analysis of studies comparing MAC with RIC and PBSC with BM in the haplo-HCT. The search was conducted in PubMed and TRIALS on February 2, 2021, without a date limit. We excluded studies with >30% non-PTCy graft-versus-host disease (GVHD) prophylaxis and >30% nonmalignant diseases. We screened 570 abstracts from PubMed and TRIALS and selected 20 for full-text review and 17 for inclusion in the qualitative and quantitative analyses. For PBSC versus BM grafts, we found no difference in overall survival (OS; hazard ratio [HR], 1.05; P = .61; nPBSC = 1983; nBM = 2124), progression-free survival (PFS; HR, 0.95; P = .52; nPBSC = 2663, nBM = 2769), graft-versus-host disease (GVHD)-free relapse-free survival (GRFS; HR, 1.16; P = .07; nPBSC = 1454; pBM = 1647), or nonrelapse mortality (HR, 1.14; P = .13; nPBSC = 1664; nBM = 1862). Relapse was lower with the use of PBSC grafts (HR, 0.84; P = .001; nPBSC = 2663; nBM = 2769). The rates of acute GVHD (aGVHD) and chronic GVHD (cGVHD) were higher with PBSC grafts (aGVHD grade II-IV: HR, 1.67; P < .001; nPBSC = 2663; nBM = 2802; aGVHD grade III-IV: HR, 1.82; P < .001; nPBSC = 1826; nBM = 2000; cGVHD: HR, 1.46; P = .002; nPBSC = 2686; nBM = 2815). Engraftment was higher with PBSC grafts (HR, 1.27; P < .001; nPBSC = 1461; nBM = 1717). Comparing MAC and RIC, the use of MAC was associated with less relapse (HR, 0.70; P < .001; nMAC = 1929; nRIC = 2662), higher nonrelapse mortality (HR, 1.24; P = .002; nMAC = 2016; nRIC = 2790), but better PFS (HR, 0.86; P = .002; nMAC = 1929; nRIC = 2662). There were no differences between the 2 conditioning regimens in OS (HR, .95; P = .32; nMAC = 2123; nRIC = 3155), GRFS (HR, 0.97; P = .67; nMAC = 1182; nRIC = 1330), grade II-IV aGVHD (HR, 1.01; P = .81; nMAC = 2099; nRIC = 3090), or cGVHD (HR, 1.05; P = .44; nMAC=1929; nRIC = 2662). This analysis shows that the use of BM grafts is associated with comparable outcomes as seen with PBSC grafts despite a lower incidence of GVHD and a higher relapse rate. The use of MAC regimens is associated with improved PFS. These results suggest that for fit patients, MAC remains the optimal conditioning regimen in terms of mortality, and that the use of PBSC grafts may further decrease relapse risk and hasten engraftment, provided that further strategies can be incorporated to decrease GVHD. Prospective comparisons are awaited.

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%.

G-CSF-Primed Peripheral Blood Stem Cell Haploidentical Transplantation Could Achieve Satisfactory Clinical Outcomes for Acute Leukemia Patients in the First Complete Remission: A Registered Study

G-CSF-mobilized peripheral blood (G-PB) harvest is the predominant graft for identical sibling donor and unrelated donor allogeneic hematopoietic stem cell transplantation (HSCT) recipients, but it was controversial in haploidentical related donor (HID) HSCT. In this registry study, we aimed to identify the efficacy of HID G-PB HSCT (HID-PBSCT) for acute leukemia (AL) patients in first complete remission (CR1). Also, we reported the outcomes for the use of G-PB grafts in comparison with the combination of G-BM and G-PB grafts in HID HSCT recipients. Sixty-seven AL patients in CR1 who received HID-PBSCT were recruited at Institute of Hematology, Peking University. Patients who received haploidentical HSCT using the combination of G-BM and G-PB harvests in the same period were enrolled as controls (n=392). The median time from HSCT to neutrophil and platelet engraftment was 12 days (range, 9-19 days) and 12 days (range, 8-171 days), respectively. The 28-day cumulative incidence of neutrophil and platelet engraftment after HSCT was 98.5% and 95.5%, respectively. The cumulative incidences of grade II-IV and grade III-IV acute graft-versus-host disease (GVHD) were 29.9% (95%CI 18.8-40.9%) and 7.5% (95%CI 1.1-13.8%), respectively. The cumulative incidences of total and moderate-severe chronic GVHD were 54.9% (95%CI 40.9-68.8%) and 17.4% (95%CI 6.7-28.0%), respectively. The cumulative incidences of relapse and non-relapse mortality were 13.9% (95%CI 5.4-22.5%) and 3.4% (95%CI 0-8.1%), respectively. The probabilities of overall survival (OS) and leukemia-free survival (LFS) were 84.7% (95%CI 74.7-94.7%) and 82.7% (95%CI 73.3-92.1%) respectively. Compared with the HID HSCT recipients using the combination of G-BM and G-PB grafts, the engraftments of neutrophil and platelet were both significantly faster for the G-PB group, and the other clinical outcomes were all comparable between the groups. In multivariate analysis, graft types did not influence the clinical outcomes. Overall, for the patients with AL CR1, G-PB graft could be considered an acceptable graft for HID HSCT recipients. This study was registered at https://clinicaltrials.gov as NCT03756675.

Feasibility and Efficacy of CD45RA+ Depleted Donor Lymphocytes Infusion After Haploidentical Transplantation With Post-Transplantation Cyclophosphamide in Patients With Hematological Malignancies

Allogeneic stem cell transplantation from haploidentical donor using post-transplantation cyclophosphamide has been used to cure hematological diseases. Because of slow immunological reconstitution, there is an increased incidence of viral infection. The aim of our study was to prospectively evaluate the efficacy and the feasibility of a CD45RA+ depleted donor lymphocytes infusion (DLI) in terms of reduction of viral infection early after haploidentical transplantation. This a prospective single-center study. We enrolled 23 patients, of whom 19 were evaluable. Graft-versus-host disease (GVHD) prophylaxis was the same for all patients. The primary endpoint was 100-day cumulative incidence of viral infections. The primary endpoint was met, because the 100-day cumulative incidence of viral infection was 32%. The median time from transplantation to first CD45RA+ depleted DLI was 55 days (range, 46-63). 28% of patients had cytomegalovirus reactivation, no patients reactivated human herpesvirus-6; 1 patient developed BK virus related hemorrhagic cystitis. Most of the patients received the planned 3 infusions. Only 1 patient had development of grade 2 acute GVHD, and 2 patients had moderate chronic GVHD. All evaluable patients were off immunosuppressive therapy at last follow-up. The median follow-up was 12 months (range, 3-23), the 1-year overall survival and progression-free survival were 79% and 75%, respectively; the 100-day and 1-year non-relapse mortality were 5% and 12%, respectively. CD45RA+ depleted DLI are feasible in patients treated with haploidentical transplantation. The toxic profile is good with a low risk for development of both acute and chronic GVHD.

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.

Haploidentical transplantation in patients with multiple myeloma making use of natural killer cell alloreactive donors

Disease relapse is an important problem after allogeneic stem cell transplantations in multiple myeloma (MM). To test the hypothesis that natural killer (NK) cell alloreactivity in the setting of a haploidentical stem cell transplantation (haploSCT) can reduce the risk of myeloma relapse, we performed a small prospective phase 2 study in which we transplanted poor-risk MM patients using a killer cell immunoglobulin-like receptor (KIR)-ligand mismatched haploidentical donor. Patients received bone marrow grafts after reduced-intensity conditioning, with post-transplantation cyclophosphamide (PTCY) graft-versus-host-disease (GVHD) prophylaxis. The primary endpoint was 1.5-year progression-free survival (PFS); stopping rules were installed in case interim results made a benefit of 50% PFS at 1.5 years unlikely. After inclusion of 12 patients, of which 9 were evaluable for the primary endpoint, all patients relapsed within a median time of 90 days. All except 1 patient showed engraftment, with a median time to neutrophil recovery of 18 (12–30) days. The study was prematurely terminated based on the predefined stopping rules after the inclusion of 12 patients. With this small study, we show that in chemo-resistant myeloma patients, NK cell KIR-mismatch is not superior to conventional alloSCT. This strategy, however, can serve as a platform for new treatment concepts.

Clinical Trial Registry: NCT02519114