Younger unrelated donors may be preferable over HLA match in the PTCy era: a study from the ALWP of the EBMT.

ABSTRACT: There is a paucity of information on how to select the most appropriate unrelated donor (UD) in hematopoietic stem cell transplantation (HSCT) using posttransplant cyclophosphamide (PTCy). We retrospectively analyzed the characteristics of 10/10 matched UDs (MUDs) and 9/10 mismatched UDs (MMUDs) that may affect transplant outcomes in patients with acute myeloid leukemia (AML) in first or second complete remission (CR1 or CR2). The primary end point was leukemia-free survival (LFS). Overall, 1011 patients were included with a median age of 54 years (range, 18-77). Donors had a median age of 29 years (range, 18-64); 304 (30%) were females, of which 150 (15% of the whole group) were donors to male recipients, and 621 (61%) were MUDs; 522 (52%) had negative cytomegalovirus (CMV-neg) serostatus, of which 189 (19%) were used for CMV-neg recipients. Donor age older than 30 years had a negative impact on relapse (hazard ratio [HR], 1.38; 95% confidence interval [CI], 1.06-1.8), LFS (HR, 1.4; 95% CI, 1.12-1.74), overall survival (HR 1.45; 95% CI, 1.14-1.85) and graft-versus-host disease (GVHD) free, relapse-free survival (HR, 1.29; 95% CI, 1.07-1.56). In addition, CMV-neg donors for CMV-neg recipients were associated with improved LFS (HR, 0.74; 95% CI, 0.55-0.99). The use of MMUD and female donors for male recipients did not significantly impact any transplant outcomes. For patients undergoing HSCT from a UD with PTCy for AML, donor age <30 years significantly improves survival. In this context, donor age might be prioritized over HLA match considerations. In addition, CMV-neg donors are preferable for CMV-neg recipients. However, further research is needed to validate and refine these recommendations.

Posttransplant cyclophosphamide versus anti-thymocyte globulin versus combination for graft-versus-host disease prevention in haploidentical transplantation for adult acute myeloid leukemia: A report from the European Society for Blood and Marrow Transplantation Acute Leukemia Working Party.

BACKGROUND: The optimal choice for graft-versus-host disease (GVHD) prophylaxis in haploidentical stem cell transplantation (haplo-SCT) remains debatable. Posttransplant cyclophosphamide (PTCy) and anti-thymocyte globulin (ATG) are two common strategies, but little is known about their combination. METHODS: Using the European Society for Blood and Marrow Transplantation (EBMT) registry, the authors identified 3649 adult patients with acute myeloid leukemia (AML) who underwent haplo-SCT in complete remission between 2007 and 2021 at 260 EBMT-participating centers who received either PTCy (n = 2999), ATG (n = 358), or combination prophylaxis (n = 292). Cord blood transplants, combined bone marrow and peripheral grafts, and transplants with ex vivo graft manipulation were excluded. Median follow-up was 31.8 months. RESULTS: On multivariate analysis, adjusting for patient age and performance status, disease status at transplant, cytogenetic risk, conditioning intensity, stem cell source, female-to-male graft, and donor and patient CMV status, we present the following. Compared to PTCy, ATG had a higher risk of nonrelapse mortality (hazard ratio [HR], 1.6; p = .003), worse leukemia-free survival (HR, 1.4; p = .002), overall survival (HR, 1.49; p = .0009), and GVHD-free and relapse-free survival (HR, 1.29; p = .012). The combination of PTCy and ATG, however, led to significantly reduced rates of grade 2-4 (HR, 0.51; p = .0003) and grade 3-4 (HR, 0.5; p = .018) acute GVHD and did not affect any transplant outcomes compared to PTCy without ATG. CONCLUSION: The authors conclude that ATG alone is a less effective prophylaxis strategy compared to PTCy, however, the combination of PTCy and ATG is superior to either monotherapy. They propose that this combination could be considered a potential new standard of care for GVHD prophylaxis in haplo-SCT for AML.

Prognostic impact of number of induction courses to attain complete remission in patients with acute myeloid leukemia transplanted with either a matched sibling or human leucocyte antigen 10/10 or 9/10 unrelated donor: An Acute Leukemia Working Party European Society for Blood and Marrow Transplantation study.

INTRODUCTION: For the majority of patients with acute myeloid leukemia (AML) an allogeneic stem cell transplant (SCT) in first complete remission (CR) is preferred. However, whether the number of courses required to achieve CR has a prognostic impact is unclear. It is unknown which factors remain important in patients requiring more than one course of induction to attain remission. METHODS: This Acute Leukaemia Working Party study from the European Society for Blood and Marrow Transplantation identified adults who received an allograft in first CR from either a fully matched sibling or 10/10 or 9/10 human leucocyte antigen (HLA)-matched unrelated donor (HLA-A, HLA-B, HLA-C, HLA-DR, or HLA-DQ). Univariate and multivariate analyses were undertaken to identify the prognostic impact of one or two courses of induction to attain CR. RESULTS: A total of 4995 patients were included with 3839 (77%) patients attaining a CR following one course of induction chemotherapy (IND1), and 1116 patients requiring two courses (IND2) to attain CR. IND2 as compared to IND1 was a poor prognostic factor in a univariate analysis and remained so in a multivariate Cox model, resulting in an increased hazard ratio of relapse (1.38; 95% confidence interval [CI], 1.16-1.64; p = .0003) and of death (1.27; 95% CI, 1.09-1.47; p = .002). Adverse prognostic factors in a multivariate analysis of the outcomes of patients requiring IND2 included age, FLT3-ITD, adverse cytogenetics, and performance status. Pretransplant measurable residual disease retained a prognostic impact regardless of IND1 or IND2. CONCLUSION: Initial response to chemotherapy as determined by number of courses to attain CR, retained prognostic relevance even following SCT in CR.

Higher survival following transplantation with a mismatched unrelated donor with posttransplant cyclophosphamide-based graft-versus-host disease prophylaxis than with double unit umbilical cord blood in patients with acute myeloid leukemia in first complete remission: A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

The best donor option for acute myeloid leukemia (AML) patients lacking an HLA-matched donor has remained intensively debated. We herein report the results of a large retrospective registry study comparing hematopoietic cell transplantation (HCT) outcomes between double-unit umbilical cord blood transplantation (dCBT, n = 209) versus 9/10 HLA-matched unrelated donor (UD) with posttransplant cyclophosphamide (PTCy)-based graft-versus-host disease (GVHD) prophylaxis (UD 9/10, n = 270) in patients with AML in first complete remission (CR1). Inclusion criteria consisted of adult patient, AML in CR1 at transplantation, either peripheral blood stem cells (PBSC) from UD 9/10 with PTCy as GVHD prophylaxis or dCBT without PTCy, transplantation between 2013 and 2021, and no in vivo T-cell depletion. The 180-day cumulative incidence of grade II-IV acute GVHD was 29% in UD 9/10 versus 44% in dCBT recipients (p = .001). After adjustment for covariates, dCBT recipients had a higher non-relapse mortality (HR = 2.35, 95% CI: 1.23-4.48; p = .01), comparable relapse incidence (HR = 1.12, 95% CI: 0.67-1.86; p = .66), lower leukemia-free survival (HR = 1.5, 95% CI: 1.01-2.23; p = .047), and lower overall survival (HR = 1.66, 95% CI: 1.08-2.55; p = .02) compared with patients receiving UD 9/10 HCT. In summary, our results suggest that transplantation outcomes are better with UD 9/10 with PTCy-based GVHD prophylaxis than with dCBT for AML patients in CR1. These data might support the use of UD 9/10 with PTCy-based GVHD prophylaxis over dCBT in AML patients lacking an HLA-matched donor.

Complex karyotype but not other cytogenetic abnormalities is associated with worse posttransplant survival of patients with nucleophosmin 1-mutated acute myeloid leukemia: A study from the European Society for Blood and Marrow Transplantation Acute Leukemia Working Party.

In the 2022 European LeukemiaNet classification, patients with nucleophosmin 1 (NPM1)-mutated acute myeloid leukemia (AML) were classified in the adverse-risk category in the presence of high-risk cytogenetics (CG). Nonetheless, the impact of various CG aberrations on posttransplant outcomes remains to be unraveled. This registry study analyzed adult patients with NPM1-mutated de novo AML who underwent their first allogeneic hematopoietic cell transplantation in the first complete remission from 2005 to 2021. A total of 3275 patients were identified, 2782 had normal karyotype, 493 had chromosomal aberrations including 160 with adverse-risk CG, 72 patients had complex karyotype (CK), and 66 monosomal karyotype (MK). Overall, 2377 (73%) patients had FLT3-ITD. On univariate analysis, only FLT3-ITD, minimal/measurable residual disease (MRD) positivity and CK, but not abnormal CG, affected posttransplant outcomes. On multivariable analysis, CK was associated with lower overall survival (OS) (hazard ratio [HR] 1.72, p = .009). In the subgroup of 493 patients with aberrant CG, the 2-year leukemia-free survival (LFS) and OS were around 61% and 68%, respectively. On multivariable analysis for this subgroup, CK and MRD positivity were associated with increased risk of relapse (HR 1.7, p = .025; and 1.99, p = .003 respectively) and worse LFS (HR 1.62, p = .018; and 1.64, p = .011 respectively) while FLT3-ITD, MK, or other CG abnormalities had no significant effect. Importantly, CK negatively affected OS (HR 1.91, p = .002). In the first complete remission transplant setting, CK was found as the only cytogenetic risk factor for worse outcomes in NPM1-mutated AML. Nevertheless, even for this subgroup, a significant proportion of patients can achieve long-term posttransplant survival.

Lower relapse incidence with haploidentical versus matched sibling or unrelated donor hematopoietic cell transplantation for core-binding factor AML patients in CR2: A study from the Global Committee and the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

Allogeneic hematopoietic cell transplantation (allo-HCT) is recommended for core-binding factor mutated (CBF) AML patients achieving second complete remission (CR2). However, approximately 20% of patients may relapse after transplant and donor preference remains unclear. We compared in this EBMT global multicenter registry-based analysis the allo-HCT outcomes using either haploidentical (Haplo), matched siblings donors (MSD), or 10/10 matched unrelated donors (MUD). Data from 865 de novo adult CBF AML patients in CR2 receiving allo-HCT in 227 EBMT centers from 2010 to 2022 were analyzed, in which 329 MSD, 374 MUD, and 162 Haplo-HCTs were included. For the entire cohort, 503 (58%) patients were inv(16)/CBFB-MYH11 and 362 patients (42%) were t(8;21)/RUNX1-RUNX1T1 AML. On multivariate analysis, Haplo-HCT was associated with a lower Relapse Incidence (RI) compared to either MSD (hazard ratio [HR] = 0.56, 95% CI 0.32-0.97; p < .05) or MUD (HR = 0.57, 95% CI: 0.33-0.99, p < .05). No significant difference was observed among the 3 types of donors on LFS, OS and GRFS. CBF-AML with t(8;21) was associated with both higher RI (HR = 1.79, 95% CI 1.3-2.47; p < .01) and higher NRM (HR = 1.58, 95% CI 1.1-2.27; p < .01) than CBF-AML with inv(16), which led to worse LFS, OS and GRFS. To conclude, for CBF-AML patients in CR2, Haplo-HCTs were associated with a lower RI compared to MSD and MUD allo-HCTs. There was no difference on LFS, OS or GRFS. CBF AML patients with inv(16) had a better progonosis than those with t(8;21) after allo-HCT in CR2.

Comparable relapse incidence after unrelated allogeneic stem cell transplantation with post-transplant cyclophosphamide versus conventional anti-graft versus host disease prophylaxis in patients with acute myeloid leukemia: A study on behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

We compared relapse incidence (RI) post-unrelated transplantation with post-transplant cyclophosphamide (PTCy) versus no PTCy graft-versus-host disease (GVHD) prophylaxis, in 7049 acute myeloid leukemia (AML) patients in remission, 707 with PTCy, and 6342 without (No PTCy). The patients in the PTCy group were younger, 52.7 versus 56.6 years (p < .001). There were more 9/10 donors in the PTCy group, 33.8% versus 16.4% (p < .001), and more received myeloablative conditioning, 61.7% versus 50.2% (p < .001). In the No PTCy group, 87.7% of patients received in vivo T-cell depletion. Neutrophil and platelet engraftment were lower in the PTCy versus No PTCy group, 93.8% and 80.9% versus 97.6% and 92.6% (p < .001). RI was not significantly different in the PTCy versus the No PTCy group, hazard ratio (HR) of 1.11 (95% confidence interval [CI] 0.9-1.37) (p = .31). Acute GVHD grades II-IV and III-IV, were significantly lower in the PTCy versus the No PTCy group, HR of 0.74 (95% CI 0.59-0.92, p = .007) and HR = 0.56 (95% CI 0.38-0.83, p = .004), as were total and extensive chronic GVHD, HRs of 0.5 (95% CI 0.41-0.62, p < .001) and HR = 0.31 (95% CI 0.22-0.42, p < .001). Non-relapse mortality (NRM) was significantly lower with PTCy versus the No PTCy group, HR of 0.67 (95% CI 0.5-0.91, p = .007). GVHD-free, relapse-free survival (GRFS) was higher in the PTCy versus the No PTCy group, HR of 0.69 (95% CI 0.59-0.81, p = .001). Leukemia-free survival (LFS) and overall survival (OS) did not differ between the groups. In summary, we observed comparable RI, OS, and LFS, significantly lower incidences of GVHD and NRM, and significantly higher GRFS in AML patients undergoing unrelated donor-hematopoietic stem cell transplantation with PTCy versus No PTCy GVHD prophylaxis.

Posttransplant cyclophosphamide versus antithymocyte globulin in patients with acute lymphoblastic leukemia treated with allogeneic hematopoietic cell transplantation from matched unrelated donors: A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

BACKGROUND: The aim of this study was to compare two immunosuppressive strategies, based on the use of either rabbit antithymocyte globulin (ATG) or posttransplant cyclophosphamide (PTCY), as a prophylaxis of graft-versus-host disease (GVHD) for patients with acute lymphoblastic leukemia (ALL) in first complete remission who underwent hematopoietic cells transplantation from matched unrelated donors. METHODS: Overall, 117 and 779 adult patients who received PTCY and ATG, respectively, between the years 2015 and 2020 were included in this retrospective study. The median patient age was 40 and 43 years in the PTCY and ATG groups, respectively, and 37% and 35% of patients, respectively, had Philadelphia chromosome-positive ALL. RESULTS: In univariate analysis, the cumulative incidence of acute and chronic GVHD did not differ significantly between the study groups. The cumulative incidence of relapse at 2 years was reduced in the PTCY group (18% vs. 25%; p = .046) without a significant impact on nonrelapse mortality (11% vs. 16% in the ATG group; p = .29). The rates of leukemia-free survival (LFS) and overall survival were 71% versus 59%, respectively (p = .01), and 82% versus 74%, respectively (p = .08). In multivariate analysis, the receipt of ATG compared with PTCY was associated with a reduced risk of extensive chronic GVHD (hazard ratio, 0.54; 95% confidence interval, 0.3-0.98; p = .04) and an increased risk of low LFS (hazard ratio, 1.57; 95% confidence interval, 1.01-2.45; p = .045). CONCLUSIONS: The receipt of ATG compared with PTCY, despite the reduced risk of extensive chronic GVHD, is associated with inferior LFS in adults with ALL who undergo hematopoietic cell transplantation from 10/10 human leukocyte antigen-matched unrelated donors. These findings warrant verification in prospective trials.

Impact of measurable residual disease on outcomes of unrelated donor haematopoietic cell transplantation with post-transplant cyclophosphamide in AML in first complete remission.

Pre-transplant measurable residual disease (MRD) predicts relapse and outcome of allogeneic haematopoietic cell transplantation (allo-HCT). The impact of MRD on the outcomes of post-transplant cyclophosphamide (PTCy)-based allo-HCT from a matched unrelated donor (UD) is unknown. This study assessed the impact of MRD in acute myeloid leukaemia (AML) in the first complete remission (CR1). A total of 272 patients (MRD negative [MRD-], n = 165; MRD positive [MRD+], n = 107) with a median follow-up of 19 (range: 16-24) months were studied. The incidence of grades II-IV and grades III-IV acute GVHD at day 180 was 25.2% and 25% (p = 0.99), and 10.6% and 6.8% (p = 0.29), respectively, and 2-year chronic GVHD was 35% and 30.4% (p = 0.96) in MRD+ and MRD- cohorts, respectively. In multivariate analysis, MRD+ status was associated with a higher incidence of relapse (RI) (hazard ratio [HR] = 2.56, 95% CI: 1.39-4.72), lower leukaemia-free survival (LFS) (HR = 2.04, 95% CI: 1.23-3.39), overall survival (OS) (HR = 1.83, 95% CI: 1.04-3.25) and GVHD-free, relapse-free survival (GRFS) (HR = 1.69, 95% CI: 1.10-2.58). MRD status did not have a significant impact on non-relapse mortality (NRM), or acute or chronic GVHD risk. Among patients with AML undergoing UD allo-HCT with PTCy, pre-transplant MRD+ status predicted a higher relapse rate, lower LFS, OS and GRFS.

Fludarabine versus cyclophospamide in combination with myeloablative total body irradiation as conditioning for patients with acute myeloid leukemia treated with allogeneic hematopoietic cell transplantation. A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

Total body irradiation (TBI) at a dose of 12 Gy combined with cyclophosphamide (CyTBI12Gy) is one of the standard myeloablative regimens for patients with acute myeloid leukemia (AML) treated with allogeneic hematopoietic cell transplantation (allo-HCT). In clinical practice, cyclophosphamide may be substituted with fludarabine (FluTBI12Gy) to reduce toxicity. We retrospectively compared outcomes of CyTBI12Gy with FluTBI12Gy for patients with AML treated in complete remission (CR) with allo-HCT from either a matched sibling or unrelated donor. Of 1684 adults who met inclusion criteria, 109 patients in each group were included in a matched-pair analysis. The cumulative incidence of relapse at 2 years was 25% in the FluTBI12Gy compared to 28% in the CyTBI12Gy group (p = .44) while non-relapse mortality (NRM) was 17% versus 19%, (p = .89) respectively. The rates of leukemia-free survival and overall survival were 65% versus 54% (p = .28) and 70% versus 60.5% (p = .17). Cumulative incidence of grade 2-4 acute graft-versus-host disease (GVHD) was significantly lower for FluTBI12Gy than CyTBI12Gy (16% vs. 34%, p = .005), while the incidences of grade 3-4 acute GVHD and chronic GVHD did not differ significantly. The probability of GVHD and relapse-free survival was 49% in the FluTBI12Gy and 41% in the CyTBI12Gy group (p = .17). We conclude that for patients with AML treated with allo-HCT in CR, cyclophosphamide may be substituted with fludarabine in a regimen based on TBI at a dose of 12 Gy without negative impact on the efficacy. FluTBI12Gy is associated with reduced risk of grade 2-4 acute GVHD and encouraging survival rates.

Posttransplant cyclophosphamide-based anti-graft-vs-host disease prophylaxis in patients with acute lymphoblastic leukemia treated in complete remission with allogeneic hematopoietic cell transplantation from human leukocyte antigen-mismatched unrelated donors versus haploidentical donors: A study on behalf of the ALWP of the EBMT.

BACKGROUND: Both mismatched unrelated donor (MMUD) and haploidentical (haplo) transplantation are valid options in patients with high-risk acute lymphoblastic leukemia (ALL) lacking a matched donor. METHODS: The study compared the outcomes of adult patients with ALL in complete remission (CR) who underwent 9/10 MMUD versus haplo transplantation with posttransplant cyclophosphamide (PTCy) as graft-vs-host disease (GVHD) prophylaxis in 2010-2020. RESULTS: The study included 781 patients (MMUD, 103; haplo, 678). The median age was 40 (19-73) and 38 (18-75) years, respectively (p = .51). The most frequent immunosuppression agents added to PTCy were mycophenolate mofetil (MMF)/cyclosporine A and MMF/tacrolimus. In vivo T-cell depletion (anti-thymocyte globulin) was administered to 21% and 8% of the transplants, respectively (p < .0001). Neutrophil (absolute neutrophil count >0.5 × 109 /L) recovery was achieved in 97.1% versus 96.7% versus (p = 1) in MMUD and haplo, respectively. Nonrelapse mortality and relapse incidence were not significantly different between MMUD and haplo, hazard ratio (HR) = 1.45 (95% confidence interval [CI], 0.81-2.62; p = .21) and HR = 0.81 (95% CI, 0.52-1.28, p = .38), respectively. HRs for leukemia-free survival, overall survival, and GVHD-free, relapse-free survival were respectively, HR = 1.05 (95% CI, 0.73-1.50, p = .8), HR = 1.17 (95% CI, 0.77-1.76, p = .46), and HR = 1.07 (95% CI, 0.78-1.46, p = .7) for haplo compared to MMUD. Acute (a)GVHD grade 2-4 was significantly higher with haplo, HR = 1.73 (95% CI, 1.08-2.76, p = .023), whereas aGVHD grade 3-4 and chronic GVHD did not differ significantly between the two transplant groups. CONCLUSION: Outcomes of MMUD and haplo transplants with PTCy-based GVHD prophylaxis for ALL patients in CR are similar, apart from a higher incidence of aGVHD with haplo transplants.

Additional cytogenetic features determine outcome in patients allografted for TP53 mutant acute myeloid leukemia.

BACKGROUND: The presence of TP53 mutations is associated with an unfavorable outcome in patients allografted for acute myeloid leukemia (AML), leading some to question the benefit of an allogeneic stem cell transplantation (allo-SCT) for this patient group, although this has not been studied in a large cohort. METHODS: A total of 780 patients with AML in first complete remission, with either intermediate- or adverse-risk cytogenetics, whose TP53 mutation status was reported, were included in this study from the European Society for Blood and Marrow Transplantation. RESULTS: Two-year overall survival (OS) was impaired in patients (n = 179) with evidence of a TP53 mutation at diagnosis (35.1%; 95% confidence interval [CI], 26.7-43.7) as compared to the cohort without (n = 601) (64%; 95% CI, 59.1-68.4; P = .001). In patients with mutant TP53 AML with no evidence of either chromosome 17p loss (17p-) and/or complex karyotype (CK) (n = 53, 29.6%), 2-year OS was 65.2% (95% CI, 48.4-77.6). This was not significantly different to patients without TP53 mutations. In patients with mutant TP53 AML with either 17p- and/or CK (n = 126, 70.4%), the OS was lower (24.6%; 95% CI, 16.2-34; P = .001). CONCLUSIONS: In summary, the adverse prognostic effect of TP53 mutations in AML following an allo-SCT is not evident in patients with neither co-occurring 17p- and/or CK, and these data inform decisions regarding allo-SCT in patients with TP53 mutant AML.

Human leukocyte antigen-haploidentical transplantation for relapsed/refractory acute myeloid leukemia: Better leukemia-free survival with bone marrow than with peripheral blood stem cells in patients ≥55 years of age.

The best stem cell source for T-cell replete human leukocyte antigen (HLA)-haploidentical transplantation with post-transplant cyclophosphamide (PTCy) remains to be determined. In this European Society for Blood and Marrow Transplantation 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 = .029) and grade III-IV (HR = 2.08, p = .013) acute GVHD. There was a statistical interaction between patient age and the impact of stem cell source for LFS (p < .01). In multivariate Cox models, among patients <55 years, the use of PBSC versus BM resulted in comparable LFS (HR = 0.82, p = .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 = .01), lower LFS (HR = 1.37, p = .026) and lower overall survival (HR = 1.33, p = .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.

Cytogenetic risk classification maintains its prognostic significance in transplanted FLT3-ITD mutated acute myeloid leukemia patients: On behalf of the acute leukemia working party/European society of blood and marrow transplantation.

FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutational status is a pivotal prognosticator in acute myeloid leukemia (AML) patients and significantly increases the risk of disease relapse. However, it remains unclear whether in FLT3-ITD patients referred for allogeneic stem cell transplantation (allo-SCT), baseline cytogenetics significantly impacts clinical outcome. Using the European Society of Blood and Marrow Transplantation registry, we performed a retrospective analysis of 1631 FLT3-ITD AML patients who underwent allo-SCT with the aim of determining the influence of cytogenetic risk category on patient outcomes. Median patient age was 49 years and median follow-up duration was 36 months. Two-year leukemia-free survival (LFS) and incidence of relapse were 54% and 31.6%, respectively. Non-relapse mortality was experienced by 14.4% with a 2-year overall survival (OS) of 60.1%. On multivariate analysis, LFS was significantly lower in patients with intermediate and adverse risk cytogenetics compared with those with favorable risk cytogenetics, (hazard ratio [HR] = 1.48, 95% confidence interval [CI], 1.06-2.06; p = .02), and (HR = 01.65, 95% CI, 1.13-2.40; p = .009), respectively. OS was significantly lower in patients with adverse risk cytogenetics compared with patients with favorable risk cytogenetics (HR = 1.74, 95% CI, 1.16-2.61; p = .008) with a trend toward lower OS in patients with intermediate risk cytogenetics compared to those with favorable risk cytogenetics (HR = 1.43, 95% CI, 1.00-2.05; p = .052). In addition, adverse risk patients and intermediate risk patients experienced higher relapse rates compared with favorable risk patients (HR = 1.83, 95% CI, 1.13-2.94; p = .013 and HR = 1.82, 95% CI, 1.19-2.77; p = .005). Overall, cytogenetic studies aid in refinement of risk stratification in transplanted FLT3-ITD AML patients.

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%.

Post-transplantation cyclophosphamide versus antithymocyte globulin in patients with acute myeloid leukemia undergoing allogeneic stem cell transplantation from HLA-identical sibling donors: A retrospective analysis from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation.

BACKGROUND: Graft-versus-host disease (GVHD) is a major complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Addition of antithymocyte globulin (ATG) or post-transplantation cyclophosphamide (PTCY) to standard immunosuppressive agents reduces GVHD in different donor settings. METHODS: We compared the outcomes of adults with acute myeloid leukemia undergoing allo-HSCT from HLA-identical sibling donors after the use of PTCY (n = 197) or ATG (n = 1913). RESULTS: Patients in the PTCY group were younger than those in the ATG group (median age, 47 vs 54 years; P < .01). Peripheral blood was the most frequently used stem cell source, being significantly more frequent in the ATG group than in the PTCY group (95% vs 70% P < .01). The conditioning regimen was more frequently myeloablative in the PTCY group than in the ATG group (59% vs 48%; P < .01). Time to neutrophil engraftment was shorter in the ATG group than in the PTCY group (17 vs 20 days; P < .01). No differences were observed according to the other transplantation outcomes, except for chronic GVHD of all grades and extensive chronic GVHD at 2 years, which were significantly lower in the ATG group compared with the PTCY group (P < .02). CONCLUSION: PTCY is feasible in an HLA-identical sibling setting, and despite similar outcomes, ATG may be associated with lower incidence of chronic GVHD.

Second allogeneic haematopoietic cell transplantation using HLA-matched unrelated versus T-cell replete haploidentical donor and survival in relapsed acute myeloid leukaemia.

Optimal donor choice for a second allogeneic haematopoietic cell transplant (allo-HCT) in relapsed acute myeloid leukaemia (AML) remains unknown. We compared overall survival (OS) using registry data from the Acute Leukemia Working Party (ALWP) of the European Society for Blood and Marrow Transplantation (EBMT) involving 455 adults who received a second allo-HCT from a human leucocyte antigen (HLA)-matched unrelated (MUD) (n = 320) or a haploidentical (n = 135) donor. Eligibility criteria required adults aged ≥18 years who received a second allo-HCT for treating AML relapse between 2005 and 2019. The primary end-point was OS. There was no statistically significant difference in the median (interquartile range) age between the groups, MUD 46 (35-58) versus haploidentical 44 (33-53) years (P = 0·07). The median OS was not different between the MUD and the haploidentical groups (10 vs. 11 months, P = 0·57). Similarly, the 2-year OS was 31% for the MUD and 29% for the haploidentical donor groups. The OS was worse if the procedure was performed with active AML [hazard ratio (HR) 1·42, 95% confidence interval (CI) 1·07-1·89; P = 0·02]. Conversely, a longer time from first allo-HCT to relapse (>13·2 months) was associated with better OS (HR 0·50, 95% CI 0·37-0·69; P < 0·0001). The results of the present analysis limit the ability to recommend one donor type over another when considering a second allo-HCT for relapsed AML. Our findings highlight that best OS is achieved when receiving the second allo-HCT in complete remission.

Posttransplant cyclophosphamide vs antithymocyte globulin in HLA-mismatched unrelated donor transplantation.

The use of anti-thymocyte globulin (ATG) has represented the standard of care in graft-versus-host disease (GVHD) prophylaxis in patients undergoing a mismatched unrelated donor (MMUD) transplant. The safety and feasibility of posttransplant cyclophosphamide (PTCY) in this setting have been reported recently, but no study has compared the outcomes of PTCY vs ATG in 9/10 MMUD transplants. Using the registry data of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation, we performed a matched-pair analysis comparing those 2 strategies in a 9/10 MMUD setting. Ninety-three patients receiving PTCY were matched with 179 patients receiving ATG. A significantly lower incidence of severe acute GVHD was observed with PTCY compared with ATG. Recipients of the former also showed higher leukemia-free survival and GVHD/relapse-free survival (GRFS). When performing a subgroup analysis including patients receiving peripheral blood stem cells, being in complete remission, or receiving the same associated immunosuppressive agents, superiority of PTCY over ATG was confirmed. Similar to the haploidentical setting, use of PTCY is an effective anti-GVHD prophylaxis in the 9/10 MMUD transplant. Use of PTCY may also provide better outcomes in long-term disease control. These results need confirmation in large prospective randomized trials.

Post-transplant cyclophosphamide versus anti-thymocyte globulin for graft-versus-host disease prevention in haploidentical transplantation for adult acute lymphoblastic leukemia.

Graft-versus-host disease (GVHD) prophylaxis for unmanipulated haploidentical hematopoietic cell transplantation (haplo-HCT) include post-transplant cyclophosphamide (PTCy) and anti-thymocyte globulin (ATG). Utilizing EBMT registry, we compared ATG versus PTCy based GVHD prophylaxis in adult acute lymphoblastic leukemia (ALL) patients undergoing haplo-HCT. Included were 434 patients; ATG (n=98) and PTCy (n=336). Median follow-up was ~2 years. Baseline characteristics were similar between the groups except that the ATG-group was more likely to have relapsed/refractory ALL (P=0.008), non-TBI conditioning (P<0.001), peripheral blood graft source (P=<0.001) and transplanted at an earlier time-period (median year of HCT 2011 vs. 2015). The 100-day grade II-IV and III-IV acute-GVHD was similar between ATG and PTCy, as was 2-year chronic-GVHD. On multivariate analysis (MVA), leukemia-free survival (LFS) and overall survival (OS) was better with PTCy compared to ATG prophylaxis. Relapse incidence (RI) was lower in the PTCy group (P=0.03), while non-relapse mortality (NRM) was not different. Advanced disease and lower performance score were associated with poorer LFS and OS and advanced disease with inferior GVHD-free/relapse-free survival (GRFS). Peripheral grafts were associated with higher GVHD compared to bone marrow grafts. In ALL patients undergoing unmanipulated haplo-HCT, PTCy for GVHD prevention resulted in lower RI and improved LFS and OS compared to ATG.

Autologous stem cell transplantation for progressive systemic sclerosis: a prospective non-interventional study from the European Society for Blood and Marrow Transplantation Autoimmune Disease Working Party.

Three randomized controlled trials in early severe systemic sclerosis demonstrated that autologous hematopoietic stem cell transplantation was superior to standard cyclophosphamide therapy. This European Society for Blood and Marrow Transplantation multi-center prospective non-interventional study was designed to further decipher efficacy and safety of this procedure for severe systemic sclerosis patients in real-life practice and to search for prognostic factors. All consecutive adult systemic sclerosis patients undergoing a first autologous hematopoietic stem cell transplantation between December 2012 and February 2016 were prospectively included in the study. Primary endpoint was progression free survival. Secondary endpoints were overall survival, non-relapse mortality, response and incidence of progression. Eighty systemic sclerosis patients were included. Median follow-up duration was 24 (6-57) months after stem cell transplantation using cyclophosphamide plus antithymocyte globulins conditioning for all, with CD34+ selection in 35 patients. At 2 years, progression free survival was 81.8%, overall survival was 90%, response was 88.7% and incidence of progression was 11.9%. The 100 days non-relapse mortality was 6.25% (n=5) with four deaths from cardiac event, including three due to cyclophosphamide toxicity. Modified Rodnan skin score and forced vital capacity improved with time (p< 0.001). By multivariate analysis, baseline skin score >24 and older age at transplant were associated with lower progression free survival (Hazard ration 3.32) and 1.77, respectively). CD34+-selection was associated with better response (Hazard ration: 0.46). This study confirms the efficacy of autologous stem cell transplantation in real-life practice for severe systemic sclerosis using non myeloablative conditioning. Careful cardio-pulmonary assessment to identify organ involvement at patient referral, reduced cyclophosphamide doses and CD34+ selection may improve outcomes. The study was registered at ClinicalTrials.gov: NCT02516124.