Abstract FLT3 internal tandem duplications (FLT3-ITD) are major genetic events in acute myeloid leukemia (AML). Although the clinical impact of FLT3-ITD “macroclones” (allelic ratio [AR] ≥0.05) is well established, the significance of low-level FLT3-ITD subclones (“microclones”) remains uncertain. We conducted a post hoc analysis of 1733 patients with newly diagnosed AML enrolled in the Backbone Intergroup 1 trial (ClinicalTrials.gov identifier: NCT02416388). Using next-generation sequencing (NGS), we detected FLT3-ITD microclones (AR between 0.0004 and 0.05) in 17.4% of patients without FLT3-ITD macroclones. Microclones and macroclones (low and high AR) were independently associated with increased relapse risk (cause-specific hazard ratio, 1.50 [95% confidence interval (CI), 1.18-1.91]; 1.98 [1.50-2.62]; and 2.33 [1.69-3.22], respectively) after adjustment for age, white blood cell count, other gene mutations, midostaurin treatment, and allogeneic hematopoietic stem cell transplantation. At 2 years, the cumulative incidence of relapse reached 42.5% (95% CI, 37.0-47.9) in patients with macroclones, 45.1% (38.3-51.6) in patients with microclones, and 29.4% (26.6-32.3) in patients without FLT3-ITD. In NPM1-mutated AML, both microclones and macroclones were associated with higher levels of measurable residual disease (MRD) and increased relapse risk, without independent impact on overall survival after adjustment for MRD. An analysis of paired samples further revealed that 41.8% of relapses in patients with FLT3-ITD microclones at diagnosis were associated with a macroclone at relapse. These findings challenge current risk stratification models and support the integration of NGS-based FLT3-ITD detection into the diagnostic and prognostic workflow for AML. Prospective trials addressing the management of patients with FLT3-ITD microclones are warranted, as is their consideration in future European LeukemiaNet guidelines.

ABSTRACT:The Group for Research in Adult Acute Lymphoblastic Leukemia (GRAALL)-2014 trial evaluated an intensive, age-adapted protocol for adults aged 18 to 59 years with Philadelphia chromosome negative acute lymphoblastic leukemia. The trial was motivated by findings from the previous GRAALL-2005 study, which reported excessive toxicity from pediatric-inspired therapy in older patients and no added benefit from allogeneic hematopoietic stem cell transplantation (allo-HSCT) among those with an early favorable response to treatment. Thus, the GRAALL-2014 protocol aimed to reduce treatment-related toxicity in patients aged ≥45 years and to limit allo-HSCT to patients with poor measurable residual disease (MRD) responses. A total of 743 patients were included, and outcomes were compared with those of GRAALL-2005 trial. The GRAALL-2014 study demonstrated reduced early mortality and higher complete remission rates in patients aged ≥45 years. MRD-guided transplantation decisions reduced allo-HSCT indications by ∼50%. Although older patients experienced a higher cumulative incidence of relapse, no significant difference in disease-free survival (DFS) was observed compared with historical cohorts across age subgroups. The overall 4-year DFS was 57.1% (95% confidence interval [CI], 53.4-61.1). Notably, 4-year overall survival improved significantly, from 65.5% (95% CI, 61.7-69.8) to 71.7% (95% CI, 67.7-76.0) in younger patients (P = .031) and from 49.6% (95% CI, 43.5-56.5) to 59.5% (95% CI, 53.5-66.3) in older patients (P = .011). These findings highlight the value of individualized treatment strategies that balance efficacy and safety. Future studies should investigate the integration of immunotherapy to further reduce treatment intensity and improve outcomes. This trial was registered at www.clinicaltrials.gov as #NCT02617004 and #NCT02619630.

CHRONOS is a multicenter, retrospective, cohort study involving acute graft-versus-host disease (aGvHD) adult patients with gastrointestinal (GI) symptoms, steroid- and ruxolitinib refractory, who initiated third-line therapy between 30 May 2019 and 30 September 2024. Primary endpoints were all-organ overall response rate (ORR) and GI-specific ORR (GI-ORR) around 28 days after treatment initiation. Secondary endpoints included duration of response, real-world progression-free survival (rwPFS) of underlying malignancy, and overall survival (OS). Fifty-nine patients from 16 sites in Europe were included. On Day 28, ORR was 36% (95% CI: 24-49%), GI-ORR was 37% (95% CI: 25-51%); 29% (95% CI: 11-49%) of responders lost response within 30 days, and 52% (95% CI: 29-72%) within 90 days. Median rwPFS and median OS were both 86 days (95% CI: 54-128 days). Median OS was higher in responders than in non-responders (186 versus 45 days). Over the 12-month follow-up period, 41 patients died, mainly due to aGvHD progression (n = 25), and infectious complications (n = 9). Within 3 months, Grade ≥ 2 infectious events occurred in 51% of patients; Grade 3-4 thrombocytopenia and neutropenia in 64% and 32%, respectively. These findings demonstrate limited effectiveness of third-line therapy in this cohort of steroid- and ruxolitinib-refractory aGvHD patients with GI symptoms.

FMS-like tyrosine kinase 3 (FLT3) mutations show variable detectability in relapse/refractory acute myeloid leukemia (AML) with unclear clonal evolution dynamics. This prospective noninterventional study examined clonal evolution and outcomes from AML diagnosis to relapse/refractory disease occurrences. Of 650 patients included, 172 were FLT3-positive (FLT3pos) and 472 were FLT3-negative (FLT3neg; 99.1

Limited data is available on outcomes of mixed phenotype acute leukemia (MPAL) following allogeneic stem cell transplantation (HCT), and the impact of haploidentical HCT with post-transplant cyclophosphamide in this setting is lacking. We retrospectively analyzed 195 adults with MPAL undergoing HCT in first complete remission from 2014 to 2023. The 2-year overall survival (OS) and leukemia free survival (LFS) were 70.7% and 56.4%. Relapse incidence (RI) was 29.8% and non-relapse mortality was 13.8% at 2 years. The cumulative incidence of grade II-IV and III-IV acute graft versus host disease (GvHD) was 28.8% and 9.3% at 100 days. The 2-year cumulative incidence of chronic GvHD was 36.6%. The 2-year GvHD-free-relapse free survival was 37.6% (95%CI 29.9-45.3%). In multivariate analysis, patients undergoing myeloablative conditioning had better OS (HR 0.5, 95%CI 0.27-0.93, p = 0.03) and LFS (HR 0.49, 95%CI 0.26-0.94, p = 0.03). The use of peripheral blood was associated with better LFS (HR 0.36, 95%CI 0.17-0.76, p = 0.008) and lower RI (HR 0.33, 95%CI 0.12-0.93, p = 0.04). In vivo T-cell depletion was associated with lower incidence of chronic GvHD (HR 0.32, 95%CI 0.17-0.63, p < 0.001). These findings highlight that conditioning intensity, graft source, and T-cell depletion strategies are critical factors in optimizing transplant outcomes for MPAL.

La réaction du greffon contre l’hôte aiguë (GVHDa) est une des causes principales de morbidité et de mortalité chez les patients allogreffés de cellules souches hématopoïétiques. Alors que le traitement consensuel de première ligne reste basé sur la corticothérapie systémique depuis de nombreuses années, le ruxolitinib a récemment eu l’autorisation de mise sur le marché et ce traitement est devenu la deuxième ligne de référence. Néanmoins, l’efficacité du ruxolitinib reste limitée à 40 % des patients cortico-résistants, justifiant la question cruciale du choix d’une troisième ligne. Parmi les modalités thérapeutiques décrites, cet atelier a permis de sélectionner la transplantation du microbiote fécal, l’injection de cellules stromales mésenchymateuses et la photophérèse extracorporelle comme celles qui semblent à ce jour les plus prometteuses ou ayant une balance bénéfice/risque conduisant à privilégier leur prescription. L’atelier a également souligné l’importance des travaux visant à produire des marqueurs ou des calculs de scores orientant vers une approche adaptée au risque, la plus précoce possible. À ce jour, à part la calprotectine, aucun marqueur ou score n’est utilisé en routine, mais tous font l’objet d’intenses recherches. Enfin, les mesures associées au traitement spécifique restent primordiales, et les nouveautés en matière d’apports alimentaires, de prophylaxies infectieuses et de régénération tissulaire sont abordées.

With the advent of immunotherapy, the prognosis of older patients with Philadelphia-negative (Ph-neg) B-cell acute lymphoblastic leukemia (B-ALL) has significantly improved these recent years. Overall survival (OS) is now around 50% at 2 years, with the consequence that is it now possible to consider the outcome of relapsing patients (pts) after a first-line therapy. Here we studied the outcome of pts who relapsed after receiving a frontline immuno-chemotherapy with inotuzumab ozogamicin (InO), an anti-CD22 antibody conjugated to calicheamicin, as part of the EWALL-INO study (NCT03249870, JCO 2024). The RELAPSINO study aimed to retrospectively describe post-relapse outcome in pts included in the single arm phase 2 prospective multicenterEWALL-INO study. In this former study, InO was associated with low dose chemotherapy for 2 induction cycles. In case of complete response (CR), pts then received 6 consolidation cycles and an 18-month (m) POMP maintenance or an allogeneic stem cell transplantation (allo-SCT). At diagnosis, all pts were aged ≥ 55 years and had a newly diagnosed CD22+ Ph-neg B-ALL. A total of 131 pts were included between December, 2017, and March, 2022, and 49 relapses (incidence 38% at 2 years) were documented at last follow-up in May, 2023, including 45 in France, 2 in Finland and 2 in Czech Republic. The RELAPSINO study was approved by the Groupe Nantais d'Ethique dans le domaine de la Santé (GNEDS, reference 24-79-07-100, July 2024). For administrative reason, only French pts were included in this new study. Data regarding pts were updated until May, 2025, and analyses were performed in June, 2025. Since the last follow-up, 6 additional relapses have been documented among French pts. Among the 45 previous relapsed French pts, we excluded 3 pts who presented concomitant therapy-related myelodysplastic syndrome. In total, 48 French relapsed pts (male n=25, female n=23) were included in this updated analysis, of whom 60% had a high-risk cytogenetics at diagnosis. None had received an allo-SCT in CR1. At relapse, median age was 70 years (IQR, 67-74; range, 55-86) and median duration of CR1 was 15.2m (IQR 5.3-22.9). Site of relapse was bone marrow (BM) in 38 (79%) pts, extra-medullary in 4 pts (CNS n=2, testis n=1, vertebra bone n=1) and combined in 3 pts (BM + skin n=1, BM + ocular n=1, BM + CNS n=1) (missing n=3). Although none of the patients received the CD19-CD3 bi-specific T-cell engager blinatumomab before relapse, CD19 and CD22 expressions were negative at relapse in 5/41 (12%) and 9/40 (23%) of evaluable pts, respectively. A large majority of pts were re-treated (n=41, 85%) and 29/41 (71%) received blinatumomab as salvage regimen, either alone (n=14) or after low-dose (n=9) or intensive (n=6) chemotherapy. Twelve pts received chemotherapy only (low dose n=3, intensive n=9). No patient was re-treated with InO or received CAR-T cells as salvage regimen. Half of the pts (n=20/41, 49%) achieved CR2. One was consolidated with CAR-T cells and 4 with an allo-SCT. By multivariate analysis (MA), a CR1 duration > 12m (but not >15m or 18m) was the only significant factor associated with CR2 achievement (p=0.04). With a median follow-up from relapse of 30.3 months (95%CI, 25.0–NA), median event-free survival (EFS) and OS were 3.2m (95%CI 2.3-5.7) and 4.5m (95%CI 3.8-11.0), respectively. Two-year EFS and OS were respectively 15% and 19%. By MA, salvage regimen with intensive chemotherapy (p=0.01), CR1 duration >18m (but not >12m or 15m) (p=0.04), and CR2 (p<0.001) were significantly associated with better OS. Intensive chemotherapy (p=0.008) and CR1 duration >18m (but not >12m or >15m) (p=0.01) were also associated with significant better EFS. The 2-year cumulative incidence of relapse after CR2 was 53%. No predictive factor for second relapse was identified. Median LFS and OS after CR2 were 13m and 24m, respectively, with 2-year LFS and OS of 36% and 46%. In pts who did not achieve CR2, median OS was 3.8m only. Overall, 38 pts (79%) died, the main cause of death being relapse or progression (n=36, 95%). Two pts died in CR2 of unknown cause.Conclusion: Half of older Ph-neg B-ALL patients relapsing after a front-line Ino-based therapy can achieve a new remission and good survival. These encouraging results support the risk of re-treating patients, especially those with late relapse, even with intensive chemotherapy, which appears the best salvage regimen in this series.

IDH1 R132 mutations are found in about 5-10% of AML at diagnosis. Ivosidenib (IVO) is an oral, targeted, small-molecule inhibitor of the mIDH1 enzyme, approved for IDH1mut newly diagnosed AML aged ≥75 years or who are ineligible for intensive induction chemotherapy. In relapse/refractory settings (R/R), IVO monotherapy yielded promising complete remission or complete remission with partial hematologic recovery (CR/CRi) rate of 30.4% associated with a median overall survival (OS) of 8.8 months (Di Nardo, NEJM, 2018). However, there are very few data regarding IVO use outside clinical trials. In this study, we aimed to evaluate the efficacy and safety of IVO in R/R AML patients in real life settings. Method IVOOBS (NCT06377579) is a retrospective, non-interventional, multicentric study including patients from 32 French centers with newly diagnosed or R/R IDH1mut AML treated with IVO through a compassionate use program. Here, we focused on R/R patients treated with IVO, either as monotherapy or in combination with other therapies between January 2017 and February 2024. The primary objective was OS. Secondary objectives were response rate (ELN2022 criteria), and toxicity. Overall response (ORR) was defined as patients reaching CR, CRi, or CRh at any time. Results Overall, 127 patients were included. Secondary AML were observed in 15.8% (post-MDS/MPN=16, t-AML=4). Median number of previous lines prior IVO onset were 1 [IQR:1-3]; 82 patients (67%) received intensive chemotherapy as first line,36 (29% ) were pre-exposed to VEN prior IVO initiation, while 20 (15.8%) patients received IVO as post hematopoietic stem cell transplantation (HSCT) salvage treatment. 93 patients received IVO monotherapy, 26 in combination with azacitidine (AZA) and 8 with venetoclax (VEN) +/- AZA (defined as AZA/IVO (+/-VEN) group) Most frequent co-mutations were NPM1 (32%), RUNX1 (23%), ASXL1 (21%) and BCOR (18%). Clinicians reported differentiation syndrome (DS) of any grade in of 12 patients (9.5%) (8 with IVO and 4 with IVO+AZA (+/-VEN)). QTc prolongation and febrile neutropenia was observed in 8 (7%) and 15 (12%) patients respectively. Regarding grade 3-4 hematological adverse events (AE), neutropenia, thrombocytopenia and anemia occurred in 4%, 14% and 18% respectively. There were 2 grade 5 AE related to IVO (1 pneumocystis carinii pneumonia and 1 DS) both in IVO monotherapy treated patients. ORR (CR/CRi/CRh) rates was 45.9% (35.8%/9.2%/0.9%), with 46.6% showing no response and 4.6% MLFS (6 patients died prior evaluation). Median time to best response was 2.8 months. Median time on IVO treatment was 6.2 months. ORRs were 39%, 48.6% (p=0.55) with a median time to achieve ORR of 3 months, and 2.8 months in IVO and IVO/AZA (+/-VEN) treated patients, respectively. 65% (68/102) and 75% (55/73) of patients were transfusion independent at 3 and 6 months after IVO initiation, respectively. Prior VEN exposition did not significantly influence ORR probability: (36.1% (13/36) in VEN pre-exposed vs 44.4% (40/90) in VEN naïve (p=0.39). Co-mutations at AML diagnosis did not influence ORR probability including MAPK/RTK mutations. In multivariate analysis for ORR, only higher platelets at IVO onset (HR=1.05, p=0.01) and HU use (HR=0.13, p=.002) were independently associated with ORR. In the 22 patients who received HU to manage initial leukocytosis, ORR rate was 13.6% compared to 53.5% for those without HU requirement (p<0.001). In responding patients, 22.8% (13/57) were bridged to HSCT after a median time of 4.2 months. Only 2 patients relapsed post-transplant. After a median follow-up of 13.9 months, median OS (mOS) of the entire cohort was 14 months. mOS with IVO monotherapy and AZA/IVO (+/-VEN) was 13.2 and 20.2 months, respectively (p=0.16). VEN exposure pre-IVO did not significantly influence OS compared to VEN-naïve patients (HR=0.90, p=0.69). In multivariate analysis, only higher platelets (HR=0.96, p=0.015) and HU use (HR=2.95, p<.001) were independently associated with OS. Conclusion In this real-life study, IVO compares favourably with previously reported prospective studies in R/R settings, with a manageable safety profile. HU use for proliferative disease at IVO onset is associated with a lower response rate and inferior outcome.

Accelerated-phase (AP) or blast-phase (BP) myeloproliferative neoplasms (MPNs) are associated with dismal prognosis, with non-curative therapies such as hypomethylating agents (HMAs) considered in patients not eligible for intensive therapy, while some studies advocate for combination therapy with either ruxolitinib (RUXO) or venetoclax (VEN). To assess the relationship between treatment modalities and outcome, herein, we report a multicentric cohort of 149 patients (median age, 75 years) with AP/BP MPN not eligible for intensive therapy and/or allogeneic hematopoietic cell transplantation who received azacitidine (AZA) alone (n = 60) or in combination (n = 89; VEN [n = 51], RUXO [n = 27], or both [n = 9], isocitrate dehydrogenase inhibitors [n = 2]) between January 2019 and October 2023. With a median follow-up of 15 months, the median overall survival of the full cohort was 8.04 months, with a 3-year overall survival (OS) of 13%. Among disease characteristics, OS was lower in patients with BP (6.24 vs. 18.00 months in patients with AP disease, P = 0.03), complex karyotype (6.00 vs. 13.08 months, P = 0.005), and TP53 mutations (8.04 vs. 11.04 months, P = 0.009). OS was nonsignificantly higher in patients receiving AZA combinations (10.08 vs. 6.96 months in patients receiving AZA monotherapy, P = 0.12). When analyzing AZA combinations separately, patients who were treated with AZA-RUXO had higher OS (18.00 vs. 9.00 vs. 10.08 months in patients receiving AZA-VEN and AZA-VEN-RUXO, P = 0.015). The improved survival with AZA-RUXO in the absence of complex karyotype and/or TP53 mutations warrants further prospective validation. New therapeutic options are urgently needed, especially in patients with complex karyotype and/or TP53 mutations.

In higher risk myelofibrosis patients, the only treatment able to improve survival and cure the disease is allogeneic hematopoietic stem cell (HSCT). However, not all potential candidates have a donor and it has been reported that transplantation from an HLA-mismatched donor gives disappointing results as compared to transplantation from an HLA matched donor. In this phase 2 trial (registered at clinicaltrial.com as NCT04728490), transplantation from an haplo-identical donor was proposed in patients without an HLA matched donor using fludarabine 30mg/m2/day (D) for 5 days – treosulfan 10g/m2/D for 3 days– thiotepa 5 mg/kg for one day– post-translant cyclophosphamide 50 mg/kg ion day +3 and day +5 (PTCY) -ciclosporine and mycophenolate mofetil plateform. The trial was sponsored by Hôpital Saint-Louis, APHP, Paris, France, with the financial support of MEDAC pharmaceutical and the scientific support and network of the French Society of Cellular Therapy (SFGM-TC). We conducted a single-arm phase 2 clinical trial to demonstrate that using an haplo-identical related donor will increase the relapse and rejection-free survival post-HSCT as compared to an historical cohort of patients received 9/10 HLA matched unrelated donor. Our hypothesis was that 1-year relapse and rejection-free survival could reach 55% instead of 30%. Using a 2-sided, one-sample log-rank test, with 90% statistical power and a 5% significance level, 28 patients had to be included. Secondary objectives were incidence of acute and chronic GVHD, hematological recovery, relapse, non-relapse mortality, severe infections and overall survival. Inclusion criteria were age 18-70 years, myelofibrosis, and at least two of the following characteristics: constitutional symptoms, hemoglobin level < 10g/dl, thrombocytopenia < 100G/L, peripheral blast > 1%, white blood cell (WBC) count > 25 G/L, poor cytogenetics (+8; -7/7q-;i(17q);-5;5q-;12p-;inv(3);11q23, and ECOG < 3. Follow-up was scheduled for 12 months and amended later to 24 months after transplantation. Results presented here are at one year endpoint. We included 29 patients in 15 French centres, one of whom did not receive the transplantation due to a fatal haemorrhage. Further analyses were based on the 28 transplanted patients; all patients are followed > 12 months, 3 patients are still followed-up on July 2025 to reach the 24th month. Median age at inclusion was 65 years (IQR: 58-67), 19 (68%) were men, 11 (39%) had general symptoms, 10 (36%) were transfusion dependant, 21 (75%) had hemoglobin level < 10 g/dl, 13 (46%) had platelet count < 100 G/L, 13 (46%) had peripheral blast >1%, 7 (25%) had WBC count >25 G/L, and 3/16 had a complex cytogenetic. 15 patients had grade 2 fibrosis, 12 grade 3 (and one unknown). Hematopoietic stem Cell Transplantation-Comorbidity Index was 0-1 in 20 (71%) patients and 2 or more in 8 (29%) patients. Among the 25 patients with NGS tested, 15(62%), 5 (21%) and one (4%) had JAK2V617F, CALR, and MPL mutation, respectively. Other genes frequently altered were ASXL1 (71%), TET2 (29%), EZH2 (25%) and RUNX1 (21%). Eighteen patients had primary myelofibrosis, 10 had secondary myelofibrosis. All the 28 patients received peripheral blood stem cells from their donor and cells were cryopreserved in 10 (36%) in the context of COVID-19 pandemia. One-year relapse and rejection-free survival was 64.3% (95%CI: 48.8-84.7), significantly above the historical rate of 35% in transplantation from a 9/10 unrelated donor. Cumulative incidence of grade 2-4 and grade 3-4 acute GVHD were 64.3% (95%CI: 43-79.4) and 25% (95%CI:10.8-42.2); 11 patients developed chronic GVHD, with 1-year cumulative incidence estimated at 39.3% (95%CI, 21.1-57.1). Cumulative incidence of neutrophils recovery on day 60 was 85.7% (95%CI: 63.9-94.8), and that of platelet recovery was 67.9% (46.4-82.2). One patient relapsed after HSCT, and 10 patients died due to viral pneumonia (SARS-COV-2, n=1 or influenza, n=1), multi-organ failure without documented infection (n=2), graft rejection/non engraftment (n=2), and acute GVHD (n=4). One-year overall survival was 67.9% (95%CI: 52.6 – 87.6). One-year non-relapse mortality (NRM) was 32.1% (95%CI: 15.8 – 49.7). In conclusion, the primary endpoint of one-year relapse and rejection -free survival was achieved. However, the NRM is the first cause of failure, mainly due to acute GVHD, MOF and infections justifying further investigations to reduce early toxicity.

Background There are very scarce data regarding the outcome of elderly patients with acute lymphoblastic leukemia (ALL) who received allogeneic hematopoietic stem cell transplantation (alloHSCT) as consolidation therapy in 1rst or higher complete remission (CR). Most studies evaluating the benefit of alloHSCT in ALL include both young and elderly populations. Thus, the optimal conditioning regimen still need to be determined in a frail population represented by patients over 60 years old. In addition, total body irradiation (TBI) dose is of first importance, as prior reports demonstrated its potential higher anti-leukemic effect. We here present the outcome of ALL patients older than 59 years from the Société Francophone de Greffe de Moelle et Thérapie Cellulaire (SFGM-TC) registry. Method This is a retrospective study. The primary outcome was overall survival (OS). Secondary outcomes were progression free survival (PFS), non-relapse mortality (NRM), relapse incidence (RI), acute Graft-versus-host disease (aGvHD) grade II-IV, chronic GvHD, neutrophil engraftment and GvHD-free relapse-free survival (GRFS). Competing risks analyses were performed to analyze NRM with competing event relapse, and aGvHD grade II-IV, chronic GvHD and neutrophil engraftment with competing events relapse and death. Univariable analyses were performed using the log-rang test for OS and PFS, while Gray's test was used for cumulative incidence (CI). Multivariable analyses were performed using the Cox proportional hazards regression model including age, ALL subtype, time from diagnosis to alloHSCT, disease status at alloHSCT, donor to patient CMV status, donor to patient sex, ATG use, myeloablative conditioning (MAC), TBI use. Results A total of 316 patients ≥ 60 years old transplanted for ALL from 2012 to 2022 in 36 participating centers were included in this study. Patient's characteristics are described in Table 1. With a median follow up of 34.5 months (IQR 29.5-38.8), 3-year OS was 46% (95% CI 40-53%) (Figure 1A) with only the disease status at transplant impacting negatively OS, 53% (95% CI 46-60%) in CR1, 32% (95% CI 21-49%) in CR2, 29% (95% CI 13-63%) in advanced disease, p=0.002 and the ALL subtype, 59% (95% CI 51-68%) in Ph+ ALL, 40% (95% CI 29-54%) in Ph- ALL, 34% (95% CI 20-55%) in T-ALL, 20% (95% CI 9-42%) in other/NA, p<0.001. 3-year PFS was 41% (95% CI 35-48%) (Figure 1B) with the disease status at transplant impacting negatively, 49% (95% CI 42-57%) in CR1, 26% (95% CI 16-42%) in CR2, 22% (95% CI 9-58%) in advanced disease, p<0.001, the ALL subtype, 51% (95% CI 42-61%) in Ph+ ALL, 41% (95% CI 31-54%) in Ph- ALL, 21% (95% CI 10-41%) in T-ALL, 21% (95% CI11-43%) in other/NA, p<0.001, year of HSCT worse < 2018, p=0.007, CMV -/- worse, p=0.033, absence of TBI worse, p=0.018. 3-year NRM was 23% (95% CI 18-28%) (Figure 1C) and none of the factors impacted it. 3-year RI was 36% (95% CI 31-42%) (Figure 1D) with the disease status at transplant impacting negatively, 29% (95% CI 23-36%) in CR1, 50% (95% CI 35-63%) in CR2, 56% (95% CI 26-77%) in advanced disease, p=0.0042, the ALL subtype, 26% (95% CI 19-34%) in Ph+ ALL, 43% (95% CI 31-54%) in Ph- ALL, 57% (95% CI 38-73%) in T-ALL, 42% (95% CI 25-59%) in other/NA, p=0.0064, year of HSCT worse < 2018, p=0.0216, CMV -/- worse, p<0.001, absence of TBI worse, p=0.0069, MRD worse, p=0.0111. 3-year GRFS was 30% (95% CI 25-37%) with the disease status at transplant impacting negatively, 35% (95% CI 28-43%) in CR1, 22% (95% CI 13-37%) in CR2, 23% (95% CI 9-59%) in advanced disease, p=0.029, the ALL subtype, 37% (95% CI 30-47%) in Ph+ ALL, 33% (95% CI 23-46%) in Ph- ALL, 15% (95% CI 7-32%) in T-ALL, 17% (95% CI 8-38%) in other/NA, p=0.0029, year of HSCT worse < 2018, p<0.001. CI of aGVHD grade II-IV was 33% (95% CI 28-38%), grade III-IV 11% (95% CI 8-15%), cGVHD 35% (95% CI30-41%), extensive cGVHD 21% (95% CI 16-26%).Multivariable analyses confirmed a worse OS and PFS for advanced disease, with a HR of 1.79 (95% CI 1.22-2.64), p=0.00322 and ALL subtype with a HR for other than Ph+ ALL of 1.99 (95%CI 1.42-2.79). Conclusion: This study suggests that alloHSCT is a reasonable option for elderly ALL patients without any impact of age but advanced disease and ALL subtype other than Ph+ ALL negatively influenced the outcome.

Acute graft-versus-host disease (GVHDa) is one of the leading causes of morbidity and mortality after allogeneic hematopoietic stem cell transplant (HSCT) patients. While the first-line consensus treatment has been based on systemic corticosteroid therapy for many years, ruxolitinib has recently been approved and has become the standard second-line treatment. Nevertheless, the effectiveness of ruxolitinib remains limited to 40 % of cortico-resistant patients, raising the crucial question of selecting a third-line treatment. Among the therapeutic modalities described, this workshop selected fecal microbiota transplantation (FMT), mesenchymal stromal cells (MSC) injection, and extracorporeal photopheresis (ECP) as the most promising or with a benefit/risk balance that favors their prescription at this stage. The workshop also highlighted the importance of research aimed at identifying markers or score calculations that guide toward a risk-adapted approach as early as possible. To date, aside from calprotectin, no marker or score is routinely used, but all are the subject of intense research. Finally, measures associated with specific treatment remain crucial, and new developments in dietary contributions, infection prophylaxis, and tissue regeneration are also addressed.

Introduction: FLT3 internal tandem duplications (ITD) are found in approximately 25% AML and defined by an allelic ratio (AR)≥0.05, hereinafter referred to as macroclones (Mclones). We previously described the prevalence of FLT3-ITD microclones (µclones), defined by an AR<0.05, in a cohort of patients with FLT3-ITD Mclones (Joudinaud, Blood Adv 2025). Here we aimed at assessing the prevalence and prognostic value of FLT3-ITD µclones in the French multicenter BIG-1 trial. Methods: The BIG-1 trial (NCT02416388) included patients (pts) aged 18-60 years with newly diagnosed AML treated by intensive chemotherapy (CBF-AML and APL excluded). This post-hoc analysis required DNA fragment analysis (FA) to detect FLT3-ITD Mclones (AR≥0.05). Samples with negative or AR<0.05 FA were used for NGS on a NovaSeq 6000. Regions of interest were sequenced with an average depth of 3000x then analyzed with FiLT3r algorithm for quantification of FLT3-ITD (Boudry, BMC Bioinformatics 2022) allowing an AR threshold detection at 4x10e-4. Patients with an AR 0.0004-0.05 were referred to µclones, other patients were considered without FLT3-ITD. Midostaurin (MIDO) has been introduced in 07/2018 according to its label. Results: 1,733 pts with available DNA were included in this analysis from 01/2015 to 02/2022, 353 (20.4%) had FLT3-ITD Mclones (±µclones, MACRO group) including 175 (49.6%) pts with high AR (≥0.5), 240 (13.8%) had FLT3-ITD µclones only (MICRO group) and 1,140 (65.8%) were FLT3-ITD negative. Overall, median age was 50y and 848 pts were female without differences between the three groups. As expected, according to ELN-2022, risk groups were favorable for 0.6%/40.9%/35.2%, intermediate for 82.4%/28.3%/15.8% and adverse for 17.0%/30.8%/49.0% of pts in MACRO, MICRO and negative groups, respectively. Among the 668 pts with NPM1 mutation, 237 (35.5%), 130 (19.4%) and 301 (45.1%) pts were in MACRO, MICRO and negative groups, respectively, with significant differences for each pairwise comparison. MIDO was administered to 134 patients (38%) in the MACRO group, 18 (7.5%) in the MICRO group, and 18 (1.6%) in the negative group, the latter two based on FLT3-TKD mutations. In multivariate analyses, compared to absence of FLT3-ITD, µclones were significantly and independently associated with an increased risk of relapse (sHR 1.46 [1.15-1.85]; P=0.002), as well as presence of FLT3-ITD Mclones (sHR 2.09 [1.65-2.66]; P<0.001), as a whole, or divided in two groups with low AR<0.5 (sHR 1.93 [1.46-2.56]; P<0.001) and high AR≥0.5 (sHR 2.36 [1.73-3.22]; P<0.001), adjusted for confounding factors including allo-SCT in CR1 as time-dependent variable. The other independent predictive factors in multivariate analyses for CIR were: age, cytogenetic risk, NPM1, CEBPA bZIP and TP53 mutations, MIDO and allo-SCT. 5y-CIR estimations were 47.5%, 47.9% and 37.5%, 2y-CIR estimations were 42.5%, 45.1% and 29.4% in MACRO, MICRO and negative groups, respectively. Presence of FLT3-ITD µclones was also significantly and independently associated with an increased risk of death or relapse (aHR: 1.39 [1.13-1.71]; P=0.002), as were Mclones with low and high AR. 5y-RFS were 41.9%, 40.6% and 47.7% in MACRO, MICRO or negative groups, respectively. Given the impact of FLT3-ITD mutations in the ELN 2022 risk definition of patients with NPM1 gene mutation, we conducted an analysis in this subgroup. In multivariate analyses, FLT3-ITD µclones were significantly and independently associated with increased CIR (sHR 1.66 [1.24-2.24]; P=0.001), shorter RFS (aHR 1.71 [1.29-2.27]; P<0.001) and shorter OS (aHR 1.48 [1.02-2.14]; P=0.04) compared to negative group. After two courses of chemotherapy, NPM1 BM MRD was ≥1% in 24.1%, 15.7%, 16.3% and 6.7% of pts in MACRO group with high and low AR, MICRO group and negative group respectively. Conclusion: In younger AML pts, FLT3-ITD microclones increase the risk of relapse and shorten RFS. In the NPM1 mutated subgroup, such FLT3-ITD microclones also shorten OS. Our results advocate for a change of practice from fragment analysis to high-sensitivity molecular techniques for FLT3-ITD detection, consider the mutation in the ELN classification regardless of the diagnostic threshold of 0.05 and investigate FLT3 inhibitors in this population.

Introduction: Midostaurin (MIDO) was approved by the FDA in 04/2017 for the treatment of FLT3 mutated AML patients in combination with intensive chemotherapy (ICT) with daunorubicin (DAUNO) administered at 60 mg/m² for 3 days based on the findings of the RATIFY trial (Stone, NEJM 2017). Moreover, the UK NCRI AML17 trial (Burnett, Blood 2016) demonstrated that higher DAUNO exposure at 90 mg/m² (without MIDO) provided a particular benefit for patients with FLT3 mutated AML. The aim of this post-hoc study was to assess the impact of MIDO in combination with higher-dose anthracyclines (DAUNO or idarubicin) in the BIG-1 trial (Hunault, NEJM Ev 2025). Methods: Between 01/2015 and 07/2021, the BIG-1 trial (NCT02416388) included patients (pts) aged 18-60 years with newly diagnosed AML treated with ICT (CBF-AML and APL excluded). DNA fragment analysis (FA) detected FLT3-ITD (AR≥0.05 for positivity) and FLT3-TKD mutations were detected depending on each center's usual procedures. The protocol planned single and first induction cycle containing anthracycline. Pts may receive either DAUNO (90 mg/m², d1-3) or idarubicin (9 mg/m², d1-5), combined with cytarabine 200 mg/m² (d1-7). After its approval, MIDO has been introduced in 07/2018 during the course of the trial and provided by Novartis. This offered the opportunity to assess the role of MIDO in this context using an internal control group. Of note, MIDO was omitted during the post-induction cycles in the few pts who entered nested randomized studies evaluating dexamethasone (N=46) or vosaroxin (N=13) in combination with HDAC or IDAC, respectively. Results: Overall, 382 (84.7%) pts had FLT3-ITD, 83 (18.4%) had a TKD mutation and 14 had both, leading to the inclusion of 451 pts in this analysis. 282 (62.5%) pts received ICT without MIDO (ICT group: internal control) and 169 (37.4%) received ICT with MIDO (ICT+MIDO group). Median age was 50.1y and 263 pts were female. ELN-2022 genetic risk was favorable, intermediate and adverse in 49 (10.9%), 319 (70.7%) and 77 (17.1%) pts. 302 (67%) pts carried also a NPM1 mutation without significant differences between the two groups. Following induction, the rate of CR/CRi was 77.3% vs 88.7% in ICT vs ICT+MIDO groups (p=0.002), respectively. Early death rate at d30 was 4.3% vs 1.2% (p=0.006). After adjustment on confounding factors including allo-HSCT in CR1 as a time-dependent variable in multivariate analysis, MIDO was significantly and independently associated with a decreased risk of relapse (sHR 0.63 [0.46-0.85]; P=0.003). At 2 and 5 years, cumulative incidence of relapse (CIR) was 43.6% vs 35% and 48.1% vs 40.9%, in the ICT and ICT+MIDO group respectively. The two other independent predictive factors for relapse were ELN-2022 genetic risk and allo-SCT in CR1 as protective factor. Anthracycline, gender, age and WBC did not significantly influence CIR. MIDO was also significantly and independently associated with a decreased risk of death or relapse (aHR 0.74 [0.55-0.98]; P=0.036), as well as ELN-2022 genetic risk and allo-SCT in CR1. At 2 and 5 years, RFS was 49.7% vs 55.4% and 42.5% vs 46.4%, in the ICT and ICT+MIDO group respectively. Again, anthracycline, gender, age and WBC did not significantly influence RFS. MIDO was significantly and independently associated with a decreased risk of death, relapse or failure (aHR: 0.65 [0.50-0.84]; P=0.001), as well as WBC, ELN-2022 genetic risk and allo-SCT in CR1. At 2 and 5 years, EFS was 43.3% vs 54.2% and 37.6% vs 44%, in ICT and ICT+MIDO groups respectively. Anthracycline, gender and age did not significantly influence EFS. Finally, MIDO was significantly and independently associated with a decreased risk of death (aHR: 0.70 [0.50-0.96]; P=0.02), as well as WBC, age and ELN-2022 genetic risk but neither allo-HSCT in CR1, nor sex, nor the type of anthracycline was associated with OS. At 2 and 5 years, OS was 62.8% vs 73.2% and 52.8% vs 62%, in ICT and ICT+MIDO group respectively. Conclusion: Subject to the limitations of this non-randomized study, adding MIDO to high-dose anthracycline-based chemotherapy improves CIR, RFS, EFS and OS independently of other factors, resulting in notable 5-year cure rates.