[Place of hematopoietic stem cell transplantation for very high risk acute myeloblastic leukemia and myelodysplastic syndromes (SFGM-TC)]. / Place de l'allogreffe dans les leucémies aiguës myéloblastiques et syndromes myélodysplasiques de très haut risque (SFGM-TC).

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a potentially curative treatment for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). However, these transplants are complicated by a high rate of relapse in very high cytogenetic risk or refractory diseases. The benefit of this therapeutic strategy for these serious malignant hemopathies could therefore be reassessed. As part of the 14th workshop for the harmonization of allograft practices organized by the francophone society of bone marrow transplantation and cellular therapy (SFGM-TC) (SFGM-TC) in Lille in September 2023, the role of allograft for very high risk or refractory AML and MDS was challenged after analysis of published studies.

Directionality of HLA-DP permissive mismatches improves risk prediction in HCT for acute leukemia and MDS.

ABSTRACT: HLA-DP permissive mismatches can be assigned a direction according to their immunopeptidome divergence across core and noncore subsets. Noncore permissive graft-versus-host mismatches show significantly reduced risks of relapse without increased nonrelapse mortality compared with allele-matched pairs.

Human Leukocyte Antigen Mismatching and Survival in Contemporary Hematopoietic Cell Transplantation for Hematologic Malignancies.

PURPOSEHuman leukocyte antigen (HLA) mismatching can reduce survival of patients with blood cancer after hematopoietic cell transplantation (HCT). How recent advances in HCT practice, in particular graft-versus-host disease (GVHD) prophylaxis by post-transplantation cyclophosphamide (PTCy), influence HLA risk associations is unknown.PATIENTS AND METHODSThe study included 17,292 unrelated HCTs with 6-locus high-resolution HLA typing, performed mainly for acute leukemia or related myeloid neoplasms between 2016 and 2020, including 1,523 transplants with PTCy. HLA risk associations were evaluated by multivariable Cox regression models, with overall survival (OS) as primary end point.RESULTSOS was lower in HLA mismatched compared with fully matched transplants (hazard ratio [HR], 1.23 [99% CI, 1.14 to 1.33]; P < .001). This was driven by class I HLA-A, HLA-B, HLA-C (HR, 1.29 [99% CI, 1.19 to 1.41]; P < .001) but not class II HLA-DRB1 and HLA-DQB1 (HR, 1.07 [99% CI, 0.93 to 1.23]; P = .19). Class I antigen-level mismatches were associated with worse OS than allele-level mismatches (HR, 1.36 [99% CI, 1.24 to 1.49]; P < .001), as were class I graft-versus-host peptide-binding motif (PBM) mismatches compared with matches (HR, 1.42 [99% CI, 1.28 to 1.59]; P < .001). The use of PTCy improved GVHD, relapse-free survival compared with conventional prophylaxis in HLA-matched transplants (HR, 0.77 [0.66 to 0.9]; P < .001). HLA mismatching increased mortality in PTCy transplants (HR, 1.32 [1.04 to 1.68]; P = .003) similarly as in non-PTCy transplants (interaction P = .43).CONCLUSIONClass I but not class II HLA mismatches, especially at the antigen and PBM level, are associated with inferior survival in contemporary unrelated HCT. These effects are not significantly different between non-PTCy compared with PTCy transplants. Optimized HLA matching should still be considered in modern HCT.

Long-term exposure and response to azacitidine for post-hematopoietic stem cell transplantation relapse of early T-cell precursor acute lymphoblastic leukemia: a case report and review of the literature.

Adult T-cell acute lymphoblastic leukemia has a poor outcome after relapse. Because the subtype of early T-cell precursor displays characteristics close of those of acute myeloid leukemia, such as epigenetic dysregulation, hypomethylating agents might prove of interest. We describe the case of a patient relapsing 3 months only after allogeneic stem cell transplantation who achieved complete remission on azacitidine, and is still on therapy 9 years later. We discuss the biological background of this very long-term response, underlining the immunological effects of hypomethylating agents, and the perspectives opened by combination of hypomethylating agents with other drugs such as venetoclax.

Isocitrate dehydrogenase (IDH) 1 and 2 mutations predict better outcome in patients with acute myeloid leukemia undergoing allogeneic hematopoietic cell transplantation: a study of the ALWP of the EBMT.

Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) mutations have uncertain prognostic implications in AML. We investigate the impact IDH1 and IDH2 mutations in AML patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) in first complete remission (CR1). In total, 1515 adult patients were included, 15.91% (n = 241) carried IDH1 mutation (mIDH1), and 26.27% (n = 398) IDH2 mutation (mIDH2) and 57.82% (n = 876) had no-IDH mutation. NPM1 was frequently encountered with IDH1 mutation (no-IDH group, n = 217, 24.8%, mIDH1, n = 103, 42.7%, mIDH2, n = 111, 27.9%, p < 0.0001). At day 180, the cumulative incidence (CI) of grade II-IV acute graft-versus-host disease (GVHD) was significantly lower in mIDH1 and mIDH2 compared to no-IDH groups (Hazard ratio [HR] = 0.66 (95% CI 0.47-0.91), p = 0.011; HR = 0.73 (95% CI 0.56-0.96), p = 0.025, respectively). In the mIDH1 group, overall survival (OS) was improved compared to no-IDH (HR = 0.68 (95% CI 0.48-0.94), p = 0.021), whereas mIDH2 was associated with lower incidence of relapse (HR = 0.49 (95% CI 0.34-0.7), p < 0.001), improved leukemia free survival (LFS) (HR = 0.7 (95% CI 0.55-0.9), p = 0.004) and OS (HR = 0.74 (95% CI 0.56-0.97), p = 0.027). In the subgroup of NPM1 wild type, only IDH2 was associated with improved outcomes. In conclusion, our data suggest that IDH1 and IDH2 mutations are associated with improved outcomes in patients with AML undergoing allo-HCT in CR1.

Childhood myelodysplastic syndromes: Is cytoreductive therapy useful before allogeneic hematopoietic stem cell transplantation?

For most patients with childhood myelodysplastic syndrome (cMDS), allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative option. In the case of increased blasts (cMDS-IB), the benefit of pretransplant cytoreductive therapy remains controversial. In this multicenter retrospective study, the outcomes of all French children who underwent allo-HSCT for cMDS reported in the SFGM-TC registry between 2000 and 2020 were analyzed (n = 84). The median age at transplantation was 10.2 years. HSCT was performed from matched sibling donors (MSD) in 29% of the cases, matched unrelated donors (MUD) in 44%, haploidentical in 6%, and cord blood in 21%. Myeloablative conditioning was used in 91% of cases. Forty-eight percent of patients presented with cMDS-IB at diagnosis (median BM blasts: 8%). Among them, 50% received pretransplant cytoreductive therapy. Five-year overall survival (OS), cumulative incidence of nonrelapse mortality (NRM), and relapse were 67%, 26%, and 12%, respectively. Six-month cumulative incidence of grade II-IV acute graft-versus-host disease was 46%. Considering the whole cohort, age under 12, busulfan/cyclophosphamide/melphalan conditioning or MUD were associated with poorer 5-year OS. In the cMDS-IB subgroup, pretransplant cytoreductive therapy was associated with a better OS in univariate analysis. This seems to be mainly due to a decreased NRM since no impact on the incidence of relapse was observed. Overall, those data may argue in favor of cytoreduction for cMDS-IB. They need to be confirmed on a larger scale and prospectively.

Hematopoietic stem cell transplantation for DLBCL: a report from the European Society for Blood and Marrow Transplantation on more than 40,000 patients over 32 years.

Autologous(auto-) and allogeneic(allo-) hematopoietic stem cell transplantation (HSCT) are key treatments for relapsed/refractory diffuse large B-cell lymphoma (DLBCL), although their roles are challenged by CAR-T-cells and other immunotherapies. We examined the transplantation trends and outcomes for DLBCL patients undergoing auto-/allo-HSCT between 1990 and 2021 reported to EBMT. Over this period, 41,148 patients underwent auto-HSCT, peaking at 1911 cases in 2016, while allo-HSCT saw a maximum of 294 cases in 2018. The recent decline in transplants corresponds to increased CAR-T treatments (1117 cases in 2021). Median age for auto-HSCT rose from 42 (1990-1994) to 58 years (2015-2021), with peripheral blood becoming the primary stem cell source post-1994. Allo-HSCT median age increased from 36 (1990-1994) to 54 (2015-2021) years, with mobilized blood as the primary source post-1998 and reduced intensity conditioning post-2000. Unrelated and mismatched allo-HSCT accounted for 50% and 19% of allo-HSCT in 2015-2021. Three-year overall survival (OS) after auto-HSCT improved from 56% (1990-1994) to 70% (2015-2021), p < 0.001, with a decrease in relapse incidence (RI) from 49% to 38%, while non-relapse mortality (NRM) remained unchanged (4%). After allo-HSCT, 3-year-OS increased from 33% (1990-1999) to 46% (2015-2021) (p < 0.001); 3-year RI remained at 39% and 1-year-NRM decreased to 19% (p < 0.001). Our data reflect advancements over 32 years and >40,000 transplants, providing insights for evaluating emerging DLBCL therapies.

Treatment Patterns and Clinical Outcomes of Patients with Moderate to Severe Acute Graft-Versus-Host Disease: A Multicenter Chart Review Study.

Acute graft-versus-host disease (aGVHD) remains a barrier to successful allogeneic hematopoietic stem cell transplantation (HSCT) outcomes. Contemporary comprehensive analyses of real-world clinical outcomes among patients who develop aGVHD post-HSCT are needed to better understand the unmet needs of this patient population. This multicenter, retrospective chart review describes treatment patterns and clinical outcomes among patients (≥18 years old) from Finland, Sweden, and France who developed grades II-IV aGVHD after their first HSCT (January 2016-June 2017). From 13 participating centers, 151 patients were included. The median (Q1, Q3) age at HSCT was 56 (45, 62) years old. One line of aGVHD treatment was received by 47.7%, and the most common first-line treatment was methylprednisolone (alone or in a combination regimen, 74.2%; monotherapy, 25.8%). Among patients treated with methylprednisolone, 79.5% achieved a complete or partial response. The median (Q1, Q3) number of treatment lines was 2.0 (1.0, 3.0). The median (Q1, Q3) time to obtain an aGVHD diagnosis from transplant was 29.5 (21.0, 44.0) days, and 14.5 (7.0, 34.0) days to achieve the best response for 110 evaluable patients. At 6 and 12 months, 53.6% and 49.0%, respectively, achieved a complete response. Chronic GVHD occurred in 37.7% of patients, and aGVHD reoccurred in 26.5%. Following aGVHD diagnosis, mortality rates were 30.0% at 6 months and 37.3% at 12 months. Findings from this study demonstrate a continuing unmet need for new therapies that control aGVHD and improve mortality.

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.

Post-transplant cyclophosphamide versus anti-thymocyte globulin after reduced intensity peripheral blood allogeneic cell transplantation in recipients of matched sibling or 10/10 HLA matched unrelated donors: final analysis of a randomized, open-label, multicenter, phase 2 trial.

The use of post-transplantation cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis is not established after reduced intensity conditioning (RIC) hematopoietic stem cell transplantation (HSCT) from fully matched donors. This was a randomized, open-label, multicenter, phase 2 trial. All patients received a RIC regimen with fludarabine, intravenous busulfan for 2 days (Flu-Bu2), and a peripheral blood stem cell (PBSC) graft from a matched related or 10/10 HLA-matched unrelated donor. Patients were randomly assigned to receive anti-thymocyte globulin (ATG) 5 mg/kg plus standard GVHD prophylaxis or PTCy 50 mg/kg/d at days +3 and +4 plus standard GVHD prophylaxis. The primary endpoint was the composite endpoint of GVHD- and relapse-free survival (GRFS) at 12 months after HSCT. Eighty-nine patients were randomly assigned to receive either PTCy or control prophylaxis with ATG. At 12 months, disease-free survival was 65.9% in the PTCy group and 67.6% in the ATG group (P = 0.99). Cumulative incidence of relapse, non-relapse mortality, and overall survival were also comparable in the two groups. GRFS at 12 months was 54.5% in the PTCy group versus 43.2% in the ATG group (P = 0.27). The median time to neutrophil and platelet count recovery was significantly longer in the PTCy group compared to the ATG group. Except for day +30, where EORTC QLQ-C30 scores were significantly lower in the PTCy compared to the ATG group, the evolution with time was not different between the two groups. Although the primary objective was not met, PTCy is effective for GVHD prophylaxis in patients receiving Flu-Bu2 conditioning with a PBSC graft from a fully matched donor and was well tolerated in term of adverse events and quality of life. This trial was registered at clinicaltrials.gov: NCT02876679.

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).

Pooled allogeneic faecal microbiota MaaT013 for steroid-resistant gastrointestinal acute graft-versus-host disease: a single-arm, multicentre phase 2 trial.

Background: Failure of gastrointestinal acute graft-versus-host disease (GI-aGvHD) to respond to steroid therapy is associated with limited further therapeutic options. We aimed to assess the safety and efficacy of the first-in-human use of the pooled allogeneic faecal microbiota, MaaT013, for the treatment of steroid-refractory GI-aGvHD. Methods: This prospective, international, single-arm, phase 2a study reports clinical outcomes from a 24-patient cohort with grade III-IV, steroid refractory GI-aGvHD treated with the pooled allogeneic faecal microbiota MaaT013. MaaT013 involved pooling faecal matter from 3 to 8 screened donors then transplanting the pooled batches into patients to treat GI-aGVHD. The 24 patients were treated in the HERACLES study (Aug 2018 to Nov 2020) at 26 sites in Europe and an additional 52 patients were treated in a compassionate use/expanded access program (EAP) in France (July 2018 to April 2021). The primary endpoint was GI response at day 28, defined as the proportion of patients with GI-aGvHD who had a complete response (CR) or very good partial response (VGPR). GvHD grading and staging were assessed according to the revised Glucksberg criteria. Adverse events and severe adverse events were monitored for 6 months and 12 months, respectively. The HERACLES study was registered with ClinicalTrials.gov (NCT03359980). Findings: Compared with single donors, MaaT013 is characterised by higher microbial richness and reduced variability across batches. At day 28 (D28), the GI-overall response rate (ORR) was 38% in the prospective population, including 5 complete responses (CR), 2 very good partial responses (VGPR) and 2 partial responses (PR). In the EAP, the GI-ORR was 58% (17 CR, 9 VGPR and 4 PR). The 12-month overall survival (OS) was 25% in the prospective study and 38% in the EAP. Regarding safety, five infectious complications, including 3 sepsis, could not be excluded from being related to the study procedure in HERACLES. Shotgun sequencing analyses of the identified strains suggest that none were found in MaaT013. In the EAP, 18 pharmacovigilance cases were reported among 52 treated patients, including 11 bacteraemia/sepsis. In HERACLES, we observed in stools from responding patients at D28 a higher microbiota richness and increased levels of beneficial bacteria, in particular butyrate producers, along with increased levels of short-chain fatty acid and bile acids. In contrast, stools from non-responding (NR) patients displayed increased levels of pathogenic pro-inflammatory bacteria along with increased systemic inflammatory parameters. Interpretation: Overall, MaaT013 was safe in this population of highly immunocompromised patients and was associated with responses in some patients with GI-aGvHD and deserves further investigation. Funding: MaaT Pharma.

Vitamin C and D supplementation in acute myeloid leukemia.

Recent studies have highlighted the role of vitamin C and D in acute myeloid leukemia (AML). In 2018, we changed our practices to add both vitamins to the supportive care for all consecutive patients with AML undergoing intensive chemotherapy. In this study, we compared the outcomes of patients treated before and after this change in practice. From 2015 to 2020, 431 patients were included, 262 of whom received no supplementation and 169 of whom received vitamin supplementation. Vitamin C and vitamin D was administered from day 10 of chemotherapy until hematologic recovery from induction and consolidation. Most patients presented at diagnosis with low levels of vitamin C and D. Upon recovery from induction, vitamin D levels among the vitamin C/D group significantly increased compared with those at diagnosis, and pretransplant levels were significantly higher in the vitamin C/D group compared with the control group (median of 33 vs 19 ng/mL; P < .0001). During induction, the rates of bacterial or fungal infection, hemorrhage, or macrophage activation syndrome were lower in the vitamin C/D group, whereas there was no difference in response rate, relapse incidence, and overall survival (OS). However, the multivariate analysis for OS showed a significant interaction between vitamin C/D and NPM1 mutation, meaning that vitamin C/D supplementation was significantly and independently associated with better OS in patients with NPM1 mutations (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.30-0.90; P = .019) compared with patients with wild-type NPM1 (HR, 1.01; 95% CI, 0.68-1.51; P = .95). In conclusion, vitamin C/D supplementation is safe and could influence the outcomes of patients with AML undergoing intensive chemotherapy.

Allogeneic transplantation in advanced cutaneous T-cell lymphomas (CUTALLO): a propensity score matched controlled prospective study.

BACKGROUND: Advanced-stage cutaneous T-cell lymphomas (CTCLs) are rare, usually refractory, and fatal diseases. Case series have suggested that allogeneic haematopoietic stem cell transplantation (HSCT) might improve the prognosis of advanced-stage CTCLs. The objective of this study was to investigate the effect of allogeneic HSCT compared with non-HSCT therapy on the outcome of individuals with advanced-stage CTCLs. METHODS: In this prospective, multicentre, matched controlled trial, conducted at 30 hospitals, participants with advanced CTCLs were allocated treatment: if they had an available compatible related donor they were assigned to allogeneic HSCT, or if not they were allocated to non-allogeneic HSCT therapy. Key inclusion criteria were participants aged 18-70 years, with advanced stage mycosis fungoides or Sézary syndrome, and at least one poor prognostic criteria. Participants were excluded if they were not in complete or partial remission of the disease. Propensity score 1:1 matching with replacement (ie, that each participant treated with HSCT was matched to the participant with the closest propensity score treated with non-HSCT therapy, even if they had already been matched) was used to handle confounding factors, with the balance of covariate distribution between HSCT and non-HSCT groups assessed using standardised mean differences. The primary endpoint was progression-free survival in the matched intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02520908), and is currently active but not recruiting. FINDINGS: From June 1, 2016, to March 3, 2022, total of 99 participants were enrolled at 17 centres in France. Participants with a sibling or matched unrelated donor were assigned to allogeneic HSCT (HSCT group, n=55 [56%]) and participants without a donor were assigned to non-allogeneic HSCT treatment (non-HSCT group, n=44 [44%]). The median follow-up among survivors was 12·6 months (IQR 11·0-35·2). In the HSCT group, 51 participants (93%) were 1:1 matched to participants from the non-HSCT group. In the intention-to-treat analysis, median progression-free survival was significantly longer in the HSCT group (9·0 months [95% CI 6·6-30·5]) than in the non-HSCT group (3·0 months [2·0-6·3]), with a hazard ratio of 0·38 (95% CI 0·21-0·69; p<0·0001). In the per-protocol population, 40 participants (78%) in the HSCT group had 101 serious events and 29 participants (67%) in the non-HSCT group had 70 serious adverse events. The most common serious adverse event other than graft-versus-host disease in both groups was infections, occurring in 30 participants (59%) in the HSCT group and in 19 participants (44%) in the non-HSCT group. INTERPRETATION: Allogeneic HSCT was associated with significantly longer progression-free survival in participants with advanced-stage CTCLs. These results indicate that allogeneic HSCT treatment should be made available to individuals with high-risk, advanced-stage mycosis fungoides or Sézary syndrome who achieve pre-transplant disease remission. FUNDING: French Ministry of Health, National Cancer Institute, Programme Hospitalier de Recherche Clinique en Cancérologie.

Diagnosis and severity criteria for sinusoidal obstruction syndrome/veno-occlusive disease in adult patients: a refined classification from the European society for blood and marrow transplantation (EBMT).

Sinusoidal obstruction syndrome, also known as veno-occlusive disease (SOS/VOD), is a potentially life-threatening complication that can develop after hematopoietic cell transplantation (HCT). A new definition for diagnosis, and a severity grading system for SOS/VOD in adult patients, was reported a few years ago on behalf of the European Society for Blood and Marrow Transplantation (EBMT). The aim of this work is to update knowledge regarding diagnosis and severity assessment of SOS/VOD in adult patients, and also its pathophysiology and treatment. In particular, we now propose to refine the previous classification and distinguish probable, clinical and proven SOS/VOD at diagnosis. We also provide an accurate definition of multiorgan dysfunction (MOD) for SOS/VOD severity grading based on Sequential Organ Failure Assessment (SOFA) score.

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.

Late relapse after hematopoietic stem cell transplantation for acute leukemia: a retrospective study by SFGM-TC.

Late relapse (LR) after allogeneic hematopoietic stem cell transplantation (AHSCT) for acute leukemia is a rare event (nearly 4.5%) and raises the questions of prognosis and outcome after salvage therapy. We performed a retrospective multicentric study between January 1, 2010, and December 31, 2016, using data from the French national retrospective register ProMISe provided by the SFGM-TC (French Society for Bone Marrow Transplantation and Cellular Therapy). We included patients presenting with LR, defined as a relapse occurring at least 2 years after AHSCT. We used the Cox model to identify prognosis factors associated with LR. During the study period, a total of 7582 AHSCTs were performed in 29 centers, and 33.8% of patients relapsed. Among them, 319 (12.4%) were considered to have LR, representing an incidence of 4.2% for the entire cohort. The full dataset was available for 290 patients, including 250 (86.2%) with acute myeloid leukemia and 40 (13.8%) with acute lymphoid leukemia. The median interval from AHSCT to LR was 38.2 months (interquartile range [IQR], 29.2 to 49.7 months), and 27.2% of the patients had extramedullary involvement at LR (17.2% exclusively and 10% associated with medullary involvement). One-third of the patients had persistent full donor chimerism at LR. Median overall survival (OS) after LR was 19.9 months (IQR, 5.6 to 46.4 months). The most common salvage therapy was induction regimen (55.5%), with complete remission (CR) obtained in 50.7% of cases. Ninety-four patients (38.5%) underwent a second AHSCT, with a median OS of 20.4 months (IQR, 7.1 to 49.1 months). Nonrelapse mortality after second AHSCT was 18.2%. The Cox model identified the following factors as associated with delay of LR: disease status not in first CR at first HSCT (odds ratio [OR], 1.31; 95% confidence interval [CI], 1.04 to 1.64; P = .02) and the use of post-transplantation cyclophosphamide (OR, 2.23; 95% CI, 1.21 to 4.14; P = .01). Chronic GVHD appeared to be a protective factor (OR, .64; 95% CI, .42 to .96; P = .04). The prognosis of LR is better than in early relapse, with a median OS after LR of 19.9 months. Salvage therapy associated with a second AHSCT improves outcome and is feasible, without creating excess toxicity.