Donor lymphocyte infusion after allogeneic haematopoietic cell transplantation for haematological malignancies: basic considerations and best practice recommendations from the EBMT.

Since the early description of three patients with relapsed leukaemia after allogeneic haematopoietic cell transplantation (HCT) who obtained complete remission after donor lymphocyte infusions (DLIs), the added value of this procedure to induce or maintain graft-versus-leukaemia immunity has been undisputed. For more than 30 years, DLIs have become common practice as prophylactic, pre-emptive, or therapeutic immunotherapy. However, as with many aspects of allogeneic HCT, centres have developed their own routines and practices, and many questions related to the optimal applications and toxicity, or to the immunobiology of DLI induced tumour-immunity, remain. As a part of the Practice Harmonization and Guidelines Committee and the Cellular Therapy and Immunobiology Working Party of the European Society for Blood and Marrow Transplantation effort, a panel of experts with clinical and translational knowledge in transplantation immunology and cellular therapy met during a 2-day workshop in September, 2023, in Lille, France, and developed a set of consensus-based recommendations for the application of unmanipulated DLI after allogeneic HCT for haematological malignancies. Given the absence of prospective data in the majority of publications, these recommendations are mostly based on retrospective studies and expert consensus.

Late Relapse after Allogeneic Stem Cell Transplantation in Patients Treated for Acute Myeloid Leukemia: Relapse Incidence, Characteristics, Role of Conditioning Regimen, and Outcome.

Late relapse, beyond 2 years following alloHSCT for AML, is rare. Among the 376 patients allografted for AML in our center between 1990 and 2016, 142 (38%) relapsed. The majority (68%) of relapses occurred during the first year following transplantation. Beyond 2 years after alloHSCT, relapse was observed in 26 patients, representing 6.9% of the whole transplanted cohort and 18.3% of the relapsing patients. Cytogenetics at relapse was available in 21 patients and remained for 15 of them concordant to that at diagnosis. The majority (85.7%) of the patients were in CR prior to transplant. Thirteen patients had grade 1-2 acute GvHD, while 13 other patients had grade 3-4 acute GvHD. None of these patients subsequently developed chronic GvHD. In multivariate analyses, a predictive factor of the absence of relapse 2 years after transplantation was the development of extensive chronic GVHD. Salvage therapy achieved new CR in 77% of these patients. We conclude that late relapse can affect a significant minority of patients allografted for AML, and the intensity of the conditioning regimen does not seem to have an impact on these relapses. Moreover, we were able to show that those patients can receive effective salvage therapy.

Successful treatment of congenital erythropoietic porphyria using matched unrelated hematopoietic stem cell transplantation in an adult: A case report.

Congenital erythropoietic porphyria (CEP), or Gunther disease, is a rare genetic disease responsible for severe dermatologic, hepatic and/or haematological damages related to the deficient activity of the uroporphyrinogen III synthase. Allogeneic stem cell transplantation (Allo-SCT) represents the only curative treatment and few allotransplanted cases have been reported in children but not in adults. Here we report for the first time the successful cure of a 46-year old man with CEP with a 5-year follow-up after Allo-SCT.

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.

Phase I study of zoledronic acid combined with escalated doses of interleukine-2 for early in vivo generation of Vγ9Vδ2 T-cells after haploidentical stem cell transplant with posttransplant cyclophosphamide.

The presence of donor Vγ9Vδ2 T-cells after haploidentical hematopoietic stem cell transplant (h-HSCT) has been associated with improved disease-free survival. These cells kill tumor cells in a non-MHC restricted manner, do not induce graft-versus-host disease (GVHD), and can be generated by stimulation with zoledronic acid (ZA) in combination with interleukin-2 (IL-2). This monocentric phase I, open-label, dose-escalating study (ClinicalTrials.gov: NCT03862833) aimed at evaluating the safety and possibility to generate Vγ9Vδ2 T-cells early after h-HSCT. It applied a standard 3 + 3 protocol to determine the maximum tolerated dose (MTD) of increasing low-doses of IL-2 (5 days [d] per week, 4 weeks) in combination with a single dose of ZA, starting both the first Monday after d + 15 posttransplant. Vγ9Vδ2 T-cell monitoring was performed by multiparameter flow cytometry on blood samples and compared with a control cohort of h-HSCT recipients. Twenty-six patients were included between April 2019 and September 2022, 16 of whom being ultimately treated and seven being controls who received h-HSCT only. At the three dose levels tested, 1, 0, and 1 dose-limiting toxicities were observed. MTD was not reached. A significantly higher number of Vγ9Vδ2 T-cells was observed during IL-2 treatment compared with controls. In conclusion, early in vivo generation of Vγ9Vδ2 T-cells is feasible after h-HSCT by using a combination of ZA and repeated IL-2 infusions. This study paves the way to a future phase 2 study, with the hope to document lesser posttransplant relapse with this particular adaptive immunotherapy.

[Secondary cancers following allogeneic hematopoietic stem cell transplantation: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]. / Cancers secondaires après allogreffe de cellules souches hématopoïétiques : recommandations de la Société francophone de greffe de moelle et de thérapie cellulaire (SFGM-TC).

The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) held the 13th edition of the Clinical Practices Harmonization Workshops. Our workgroup reviewed the current data on the incidence, screening methods and international guidelines for the prevention of secondary solid cancers following allogeneic hematopoietic stem cell transplantation. The purpose of this workshop was to provide recommendations for the screening and prevention of secondary malignancies to Francophone transplantation centers.

Assessment of monocytic-myeloid-derived suppressive cells (M-MDSC) before and after allogeneic hematopoietic stem cell transplantation in acute leukemia patients.

In this monocentric prospective study, the influence on long-term outcomes of peripheral blood levels of monocytic-myeloid-derived suppressive cells (M-MDSC) was investigated in 56 patients with acute leukemia (myeloid n = 47; lymphoid n = 9) before and after (Days+60/+90) allogeneic hematopoietic stem cell transplantation (Allo-HSCT). A risk of relapse was found to be associated with a level of pregraft M-MDSC above 1.4% by ROC curve analysis. In multivariate analysis, this threshold retained a strong statistical significance (HR: 5.94 [2.09-16.87], p = 0.001). Considering only the group of patients who were in complete remission prior to Allo-HSCT (n = 44), a significant prediction of relapse was found to be associated, in multivariate analysis, with a level of pregraft M-MDSC above 1.4% (HR: 55.01 [14.95-202.37], p < 0.001) together with pregraft-positive measurable -residual disease (MRD) (HR: 11.04 [1.89-64.67], p = 0.008). A poorer OS (HR: 6.05 [1.24-29.59], p = 0.026) and disease-free survival (HR: 6.52 [1.41-30.19], p = 0.016) were also associated with higher levels of pregraft M-MDSC. Remarkably, no relapse occurred in patients with pregraft-negative MRD and ≤1.4% of M-MDSC (vs. a 3-year relapse rate of 60% for others, p = 0.004). Patients developing grade 3-4 acute graft-versus-host-disease (GVHD, median occurrence: day+30 posttransplant) showed significantly higher levels of M-MDSC% at days +60 and +90, suggesting a possible amplification of these immunosuppressive cells as a reaction to GVHD. In conclusion, this prospective study demonstrates a negative impact of higher proportions of peripheral M-MDSC before Allo-HSCT in leukemic patients. This paves the way to potential therapeutic intervention to decrease M-MDSC levels before Allo-HSCT and thus perhaps the incidence of relapse in such patients.

Tocilizumab in combination with a standard induction chemotherapy in acute myeloid leukaemia patients (TOCILAM study): a single-centre, single-arm, phase 1 trial.

Background: In acute myeloid leukaemia (AML), interleukin-6 (IL-6) promotes chemo-resistance and its levels correlate with poor prognosis. IL-6 blockade may represent a promising therapeutic strategy. We aimed to test, tocilizumab, an anti-IL-6 receptor (R) monoclonal antibody in combination with standard intensive AML induction chemotherapy. Methods: This investigator-initiated single-centre phase 1 trial was conducted at Nantes University Hospital in France. According to a continual reassessment method, three escalating doses were tested of intravenous (IV) tocilizumab (4, 6, and 8 mg/kg) administered at day (d) 8 of a standard AML induction chemotherapy (IV idarubicine 8 mg/m2 d1 to d5 + IV cytarabine 100 mg/m2 d1 to d7). All adults (aged ≥ 18 years) with an Eastern Cooperative Oncology Group performance status of 0-2 and with a newly diagnosed (excluding patients with a favourable risk according to ELN-2017 classification if <60 year-old) or a relapsed/refractory AML were eligible. The primary objective was to determine the maximum tolerated dose of tocilizumab to administrate with a standard intensive AML induction. Safety outcomes were continuously monitored for at each participant contact. This trial is registered with ClinicalTrials.gov, NCT04547062. Findings: Between Dec 29, 2020 and Dec 1, 2022, 12 patients were enrolled, of whom 75% had an ELN-2017 high-risk profile, and were treated with tocilizumab- two patients at 4 mg/kg, two at 6 mg/kg and eight at 8 mg/kg of tocilizumab. No dose-limiting toxicity related to tocilizumab was documented. There were nine serious adverse events, none of which were related to tocilizumab, and there was no treatment-related deaths. MTD was thus not reached. Two deaths occurred during induction. In the remaining ten evaluable patients, nine responded to treatment. Interpretation: The combination of tocilizumab with standard AML intensive induction appears to be safe and resulting responses are encouraging. A dose of 8 mg/kg of tocilizumab given at day 8 of induction could be used for further phase 2/3 studies. Funding: The Leucémie Espoir Atlantique Famille (LEAF)-"Tous avec Fabien" association.

Post-transplant cyclophosphamide as sole GHVD prophylaxis after matched reduced-intensity conditioning allotransplant.

BACKGROUND: Post-transplant cyclophosphamide (PTCY) alone as graft-versus-host disease (GVHD) prophylaxis may avoid/reduce short- and mid-term toxicities of drugs commonly used for GVHD prophylaxis, accelerate immune reconstitution after the graft to decrease infections and facilitate the early integration of adjunct maintenance therapies to prevent relapse. OBJECTIVE: A prospective phase 2 study was designed in order to assess the feasibility and safety of PTCY as a sole GVHD prophylaxis in adult patients receiving a Baltimore-based reduced-intensity conditioning (RIC) peripheral blood (PB) allogeneic hematopoietic stem cell transplantation (Allo-HSCT) with a matched donor. STUDY DESIGN: Patients were planned to be included stepwise up to 59 evaluable PTCY recipients, in order to be able to stop the protocol in case of excessive corticosteroid resistant grade 3-4 severe acute GVHD (aGVHD). Because a high incidence of grade 2-4 aGVHD was observed after analysis of the first 27 patients, the protocol was amended to test the addition of 1 day of anti-thymoglobulin to PTCY. In spite of this, the trial had to be stopped after 38 treated patients, because of an unacceptable rate of grade 3-4 aGVHD. Donors were matched related to 12 patients and unrelated to 26. RESULTS: With a median follow-up of 29.6 months, 2-year overall, disease-free and GVHD-free relapse-free (GRFS) survivals were respectively 65.4%, 62.1% and 46.9%. Cumulative incidences of grade 2-4 and 3-4 aGVHD at day 100 were 52.6% and 21.1%, respectively, while that of moderate/severe chronic(c) GVHD was 15.7% at 2 years. Addition of ATG to PTCY did influence neither aGVHD, cGVHD nor GRFS. CONCLUSION: Despite paradoxically good survivals, especially GRFS, this study failed to demonstrate that PTCY (± ATG) alone can be used for Baltimore-based RIC PB Allo-HSCT with matched donors. Other combinations should be tested to try and avoid long-term use of immunosuppressive drugs following Allo-HSCT in this setting.

Two Ways of Targeting a CD19 Positive Relapse of Acute Lymphoblastic Leukaemia after Anti-CD19 CAR-T Cells.

BACKGROUND: Therapeutic options for CD19+ relapses after anti-CD19 CAR-T cells are still debated; second infusion of anti-CD19 CAR-T cells, therapeutic antibodies, or targeted therapies can be discussed. Here, we explore the immunophenotyping and lysis sensitivity of CD19+ ALL relapse after anti-CD19 CAR-T cells and propose different therapeutic options for such a high-risk disease. METHODS: Cells from successive B-ALL relapses from one patient were collected. A broad immunophenotype analysis was performed. 51Cr cytotoxic assays, and long-term killing assays were conducted using T-cell effectors that are capable of cytotoxicity through three recognition pathways: antibody-dependent cell-mediated cytotoxicity (ADCC), anti-CD19 CAR-T, and TCR. RESULTS: Previously targeted antigen expression, even if maintained, decreased in relapses, and new targetable antigens appeared. Cytotoxic assays showed that ALL relapses remained sensitive to lysis mediated either by ADCC, CAR-T, or TCR, even if the lysis kinetics were different depending on the effector used. We also identified an immunosuppressive monocytic population in the last relapse sample that may have led to low persistence of CAR-T. CONCLUSION: CD19+ relapses of ALL remain sensitive to cell lysis mediated by T-cell effectors. In case of ALL relapses after immunotherapy, a large immunophenotype will make new therapies possible for controlling such high risk ALL.

[Haemorrhagic cystitis following hematopoietic stem cell transplantation: Prophylaxis, diagnosis, and treatment. Guidelines from the SFGM-TC]. / La cystite hémorragique après allogreffe de cellules souches hématopoïétiques : prophylaxie, diagnostic, et traitement. Recommandations de la SFGM-TC.

Hemorrhagic cystitis (HC) is a common complication after allogeneic hematopoietic cell transplantation (allo-HCT). Its manifestations range from microscopic hematuria without urinary symptoms to extensive and prolonged macroscopic hemorrhage requiring invasive interventions that can often prolong the duration of hospitalization and result in significant morbidity. The early onset of HC is related to allo-HCT conditioning regimen, whereas the late onset form is secondary to viral infection, most commonly due to BK virus. In the framework of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) practice harmonization workshops held in Lille in September 2021, the prophylaxis, the diagnostic approach and the treatments of HC following allografting were reviewed after analysis of published studies.

[Cardiac complications following allogeneic hematopoietic stem cell transplantation: Recommendations of the SFGM-TC]. / Complications cardiaques de la greffe de cellules souches hématopoïétiques : recommandations de la SFGM-TC.

Autologous and allogeneic hematopoietic stem cell transplantation (HSCT) can lead to early cardiac complications as well as late sequelae. A cardiac evaluation is essential in the pre-transplant assessment given the patient's comorbidities and previous chemotherapy treatments received. Various thresholds of cardiac function are recommended as eligibility criteria. The rise of haplo-identical transplantation with the use of post-transplant high-dose cyclophosphamide (PT-Cy) as a prophylaxis against graft-versus-host disease (GVHD) is accompanied by a resurgence of cardiological concerns. Arrhythmias are also a concern and the list of drugs implicated in this complication is growing. The rare occurrence of cardiac GVHD has been reported, although the entity is not well defined. Finally, although long-term follow-up recommendations exist, they are not accompanied by specific targets for cardiovascular risk factors, the presence of which is nevertheless increased after HSCT. In the framework of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) practice harmonization workshops held in Lille in September 2019, the prophylaxis, the diagnostic approach and the treatments of cardiac complication following HSCT were reviewed after analysis of published studies.

Assessment of COVID-19 Incidence and Severity Among Recipients of Allogenic Stem Cell Transplant After 1 or 2 mRNA Booster Doses During the Omicron Wave in France.

This cohort study assesses the incidence and severity of COVID-19 among vaccinated recipients of allogenic stem cell transplant in a single center after 1 or 2 messenger RNA booster doses during the Omicron wave in France.

Peripheral levels of monocytic myeloid-derived suppressive cells before and after first induction predict relapse and survivals in AML patients.

Myeloid Derived Suppressive Cells (MDSC) are capable to suppress innate and adaptive immune responses, thus favouring solid cancer progression. However, little is known about the role of MDSC in acute myeloid leukaemia (AML). In this monocentric prospective study, 73 adult AML patients, eligible for first-line intensive chemotherapy, were included with the aim to study the influence on long-term outcomes of peripheral blood (PB) levels of monocytic (M) MDSC (M-MDSC) assessed by flow cytometry. A percentage of peripheral M-MDSC higher than 0.55% of leukocytes at diagnosis and a decrease of M-MDSC% after induction came out both as independent negative prognostic factors for leukaemia-free and overall survival.

Strong SARS-CoV-2 T-Cell Responses after One or Two COVID-19 Vaccine Boosters in Allogeneic Hematopoietic Stem Cell Recipients.

A full exploration of immune responses is deserved after anti-SARS-CoV-2 vaccination and boosters, especially in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although several reports indicate successful humoral responses in such patients, the literature is scarce on cellular specific immunity. Here, both B- (antibodies) and T-cell responses were explored after one (V3 n = 40) or two (V4 n = 12) BNT162b2 mRNA vaccine boosters in 52 allo-HSCT recipients at a median of 755 days post-transplant (<1 year n = 9). Results were compared with those of 12 controls who had received only one booster (BNT162b2 n = 6; mRNA-1273 n = 6). All controls developed protective antibody levels (>250 BAU/mL) and anti-spike T-cell responses. Similarly, 81% of the patients developed protective antibody levels, without difference between V3 and V4 (82.5% vs. 75%, p = 0.63), and 85% displayed T-cell responses. The median frequency of anti-spike T cells did not differ either between controls or the whole cohort of patients, although it was significantly lower for V3 (but not V4) patients. COVID-19 infections were solely observed in individuals having received only one booster. These results indicate that four vaccine injections help to achieve a satisfactory level of both humoral and cellular immune protection in allo-HSCT patients.

Dramatic Recovery after Etoposide Phosphate Infusion for Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome following Treatment with Tisagenlecleucel in a Young Patient with Relapsed Acute Lymphoblastic Leukemia: A Case Report.

The occurrence of a secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS) after CAR T-cell infusion is very rare and mostly fatal. Treatment recommendations for such a complication are not yet established. Here, we report the dramatic recovery of HLH/MAS following tisagenlecleucel infusion in a young patient with relapsed acute lymphoblastic leukemia using etoposide phosphate (EP). We propose that monitoring for the occurrence of HLH/MAS should be part of surveillance after CAR T-cell infusion and that EP treatment appears to be useful to control this severe and rare complication.

Impact on outcomes of mixed chimerism of bone marrow CD34+ sorted cells after matched or haploidentical allogeneic stem cell transplantation for myeloid malignancies.

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT), proposed to patients with high-risk myeloid malignancies, may ultimately fail because of disease relapse. Bone marrow (BM) CD34+ cells in Allo-HSCT recipients can be either re-emerging recipient malignant cells or donor cells attesting of hematopoietic reconstitution. In this context, investigating donor/recipient chimerism in the population of BM CD34+ sorted cells (BM-CD34+SC) was performed in 261 Allo-HSCT recipients (matched n = 145, haploidentical n = 65, matched unrelated n = 51) with myeloid malignancies. BM-CD34+SC chimerism was compared to that of whole peripheral blood (PB) cells as well as other Allo-HSCT-related parameters, and impact on relapse and survival was assessed. Thresholds of 98% donor cells for PB and 90% for BM-CD34+SC were found to allow relapse prediction. This was completed by the application of machine learning tools to explore the predictive value of these parameters in multidimensional models with repeated iterations. BM-CD34+SC mixed chimerism stood out with all these methods as the most robust predictor of relapse with a significant impact on disease-free and overall survivals even after haploidentical Allo-HSCT and/or PTCY administration. This marker therefore appears to be of great interest for the decision of preemptive treatment to avoid post-transplant relapse.

Effectiveness of a third dose of BNT162b2 anti-SARS-CoV-2 mRNA vaccine over a 6-month follow-up period in allogenic hematopoietic stem cells recipients.

This study reports the effectiveness of three injections of BNT162b2 anti-SARS-CoV-2 mRNA vaccine in 141 Allo-HSCT recipients with a median follow-up of 6 months post-third shot. We demonstrate a long-term high protection of Allo-HSCT recipients since only 2 infections and one death related to COVID-19 occurred.

Anti-SARS-CoV-2 vaccines in recipient and/or donor before allotransplant.

The impact of pre-transplant anti-severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccine in 20 recipients of allogeneic hematopoietic stem cell transplantation (Allo-HSCT) and/or their donors is reported here, showing that the persistence of anti-SARS-CoV-2 antibodies can be detected in almost all patients, whatever the type of vaccine used, and up to 9 months post transplant. Also, an anti-SARS-CoV-2 spike glycoprotein CD3+ T-cell response could be detected in six (35%) of 17 evaluable patients. This study provides a rationale to consider anti-SARS-CoV-2 vaccination of both recipients and donors before Allo-HSCT.