Post-transplant Relapse Research Articles

Clinical Safety of NK Cell in the Prevention of Leukemia Relapse Post-transplantation and in Treatment of the Elderly Leukemia Patients

To observe the safety of donor NK cell infusions in the settings of hematopoietic stem cell transplantation and after consolidation chemotherapy in elderly patients with acute myeloid leukemia (AML). Forty patients with AML were included, in which 21 patients aged over 60 years were at the stage of complete remission (CR) and 19 patients that received allogeneic hematopoietic stem cell transplantation (allo-HSCT). Mononucleated cells were isolated from peripheral blood from the donors (for allo-HSCT) or healthy immediate family members (elderly AML). The cells were seeded into the flasks pre-coated with NK cell specific activators, and expanded in media containing recombinant human IL-15 and IL-2 for 14 days. The cells were transfused intravenously after the identification of quality control. Trypan blue exclusion test was used for the determination of cell viability and counting. Flow cytometry analysis was performed to assess the surface antigenic profile. Seventy-eight infusions of the cell products were received by the elderly patients with AML after consolidation chemotherapy, 11 infusions were received by the patients during allo-HSCT and 32 infusions 3 moths after transplantation. The safety of cell therapy, body temperature, blood pressure and other indexes were observe during and 48 hours after cell transfusion. Meanwhile, the occurrence and severity of acute graft-versus-host disease (GVHD) were documented. Flow cytometry analysis showed that the proportion of NK cells (CD3-CD56+) in the mononucleated cells before culture was (14.10±4.22)% (n=121), and the proportion increased dramatically up to (87.29±8.75)% (n=121) after culture for 14 days, the number of NK cells increased to 753.47±140.13 times (n=121). The doses of the infused NK cells was (7.58±2.50)×107/kg per infusion. Moderate fever occurred in three cases after multiple infusions, and the temperature restored to normal on the same day after treatment. Fever was observed in one patient after every infusion of four times in total. The temperature reached to 38.5-39.0 ℃ and returned to normal within 1-2 hours after adequate antipyretic treatment, and then there was no discomfort. No GVHD was observed in the elderly AML patients, while 6 cases that received allo-HSCT developed moderate acute GVHD, among them grade I in 5 cases and grade II in 1 case. No other severe toxicities were observed. NK cell products with a high-purity could be obtained by ex vivo expansion with this protocol. The transfusion of these expanded cells is generally safe in the elderly patients with AML that have received chemotherapy or patients that received hematopoietic stem cell transplantation.

Multimodal multidisciplinary management of alcohol use disorder in liver transplant candidates and recipients.

Alcohol-related liver disease (ALD) is the most common indication for liver transplantation (LT) in the United States. The judicious allocation of organs and improvement in outcomes requires identification and monitoring of patients with ALD at high-risk for relapse post-transplantation. The controversial movement toward early LT for severe alcohol-related hepatitis (SAH) has also raised concern for alcohol relapse. While LT cures ALD, treatment of alcohol use disorder (AUD) must be included in the care plan to prevent a return to drinking and subsequent graft ALD. Patients with underlying AUD must be recognized, offered brief interventions and referred for multimodal multidisciplinary treatment that includes medications and psychotherapies along with sober support groups, family engagement, and a new dedication to healthy living in order to help sustain remission. Such comprehensive care will increase LT candidacy in patients with ALD while optimizing clinical outcomes of patients transplanted with AUD.

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.

Umbilical Cord Blood as a Source of Less Differentiated T Cells to Produce CD123 CAR-T Cells.

Simple SummaryWe used fresh or thawed Umbilical Cord Blood (UCB) to produce CAR-T cells directed against CD123, and we compared their functionality to Peripheral Blood (PB) CAR-T cells. T cells expressing CD123 CAR, derived from UCB, was exhibited through a high transduction rate, activation status, and cytotoxic potential in vitro as PB derived CAR-T cells. Moreover, we obtained T cells that had a less differentiated profile than the PB-derived T cells. UCB derived CAR-T can significantly control tumor progression in mice models. CAR-T obtained from thawed or fresh UCB gives the same results.Chimeric Antigen Receptor (CAR) therapy has led to great successes in patients with leukemia and lymphoma. Umbilical Cord Blood (UCB), stored in UCB banks, is an attractive source of T cells for CAR-T production. We used a third generation CD123 CAR-T (CD28/4-1BB), which was previously developed using an adult’s Peripheral Blood (PB), to test the ability of obtaining CD123 CAR-T from fresh or cryopreserved UCB. We obtained a cell product with a high and stable transduction efficacy, and a poorly differentiated phenotype of CAR-T cells, while retaining high cytotoxic functions in vitro and in vivo. Moreover, CAR-T produced from cryopreserved UCB are as functional as CAR-T produced from fresh UCB. Overall, these data pave the way for the clinical development of UCB-derived CAR-T. UCB CAR-T could be transferred in an autologous manner (after an UCB transplant) to reduce post-transplant relapses, or in an allogeneic setting, thanks to fewer HLA restrictions which ease the requirements for a match between the donor and recipient.

P574: CPX-351 COMBINED WITH HEMATOPOIETIC CELL TRANSPLANTATION WITH REGULATORY AND CONVENTIONAL T CELL IMMUNOTHERAPY FOR HIGH-RISK ACUTE MYELOID LEUKEMIA

Background: Patients with newly diagnosed acute myeloid leukemia with myelodysplasia-related changes (MRC-AML) or therapy-related AML (t-AML) have an extremely poor prognosis. CPX-351, a dual-drug liposomal encapsulation of cytarabine and daunorubicin, improved significantly rates of remission and overall survival (Lancet JE et al, JCO 2018). Allogeneic hematopoietic stem cell transplantation (HSCT) remains the only curative strategy for such patients, but incidence of post-transplant relapse is still unacceptably high. We developed a novel HSCT strategy that combines an age-adapted myeloablative irradiation-based conditioning regimen with regulatory and conventional T-cell adoptive immunotherapy (Treg/Tcon HSCT). HLA-haploidentical Treg/Tcon HSCT ensured low relapse rate (4%) and resulted in an unprecedented chronic graft versus host disease/relapse free survival (CRFS, 75%) in AML patients (Pierini et al., Blood Adv. 2021). Aims: We report preliminary outcomes of the combination therapy with CPX-351 and Treg/Tcon HSCT for MRC-AML and t-AML at our center. Methods: We included in the study all patients with MRC-AML or t-AML who were referred at our center from September 2019 to January 2022 and could be treated with CPX-351. Treg/Tcon HSCT consisted of a myeloablative conditioning regimen with total marrow/lymphoid irradiation, thiotepa, fludarabine and cyclophosphamide followed by an infusion of 2x106/Kg donor Tregs on day -4, 1x106/Kg Tcons on day -1 and a megadose (>6x106/Kg) of purified CD34+ hematopoietic progenitor cells on day 0. No pharmacological GvHD prophylaxis was given post-transplant (clinicaltrials.gov: #NCT03977103). Results: Seventeen patients with a median age of 57.5 years (46-72) were treated with CPX-351: 13 with newly diagnosed AML (11 MRC-AML and 2 t-AML) and 4 patients who relapsed after a previous HSCT and who acquired novel cytogenetic abnormalities (2 complex karyotypes, CK). 9/13 patients with newly diagnosed AML had karyotype abnormalities: 4 monosomy 7, 1 CK, 1 t(3;3), 1 isolated del(20q) and 2 (both t-AML) t(11;20) which resulted in NUP98-TOP1 fusion. Nine patients achieved complete remission (CR), 2 partial response (PR) and 2 had persistent disease. No patient experienced grade>3 extrahematologic toxicity. Ten/13 patients underwent a first HSCT (8 in CR, 2 in PR). Eight underwent Treg/Tcon HSCT (3 from HLA-matched, 5 from HLA-haploidentical donor), while 2 unmanipulated haploidentical HSCT followed by post-transplant cyclophosphamide (PT-Cy). All patients achieved full-donor engraftment. No patients experienced non-relapse mortality (NRM). Three/10 patients had a grade ≥ III acute GvHD; all of them are alive and off immunosuppressive therapy. At a median follow up of 16.2 months (range 9-29 months), 9/10 patients are alive and in CR with no chronic GvHD. No relapse occurred in the 8 patients who underwent Treg/Tcon HSCT, while one patient who underwent HSCT followed by PT-CY relapsed. The 4 patients who were treated after one previous HSCT received one single induction cycle with CPX-351, achieved CR and experienced no grade>3 extra-hematologic toxicity. All of them could undergo a second HSCT. NRM occurred in 1 patient (septic shock), while 3 patients are alive to date. Summary/Conclusion: CPX-351 allowed most of MRC-AML and t-AML patients to reach HSCT in CR despite high risk genetics and even when used in patients who relapsed after a 1st HSCT. Combination of CPX-351 with Treg-Tcon HSCT is safe and exert powerful antileukemic activity. Thus, it appears to be a promising strategy to ensure high rate of CRFS in very high-risk AML.

Abstract LB563: Integrated multiomic profiling identifies the epigenetic regulator PRC2 as a therapeutic target to counteract leukemia immune escape and relapse

Abstract Background: Evasion from immune control represents one of the main drivers of acute myeloid leukemia (AML) relapse after allogeneic hematopoietic cell transplantation (allo-HCT). In particular, up to 40% of AML relapses display complete loss of surface expression of HLA class II molecules without any genetic lesion explaining this phenotype (Christopher et al, N Engl J Med, 2018; Toffalori et al, Nat Med, 2019). This led us to investigate the links between epigenetic changes, immune evasion and post-transplantation relapse. Methods: Starting from primary AML samples pairwise collected from five patients at diagnosis and relapse with non-genomic loss of HLA class II expression, we generated Patients-Derived Xenografts (PDXs) into NOD-SCID γ-chain null mice. Leukemic cells expanded in the mice and their original human counterparts were characterized for changes in gene expression (by RNA-Seq), DNA methylation profile (by RRBS), and chromatin accessibility (by ATAC-Seq). The results obtained by all these approaches and in the different patients were integrated by Multi-Omics Factor Analysis (MOFA) and Gene Set Enrichment Analysis (GSEA). Finally, we tested the immunological effects of epigenetic drugs on AML cells and on their recognition by T cells in ex-vivo short-term cultures and in PDXs. Results: We verified that PDXs faithfully recapitulate immune-related differences between AML diagnosis and post-transplantation relapse, including loss of expression of HLA class II molecules. Differences between diagnosis and post-transplantation relapse samples were mostly explained by changes in chromatin accessibility, and largely unrelated to the DNA methylation profile. In particular, in all five patients analyzed, we documented genomewide chromatin compaction at time of relapse, that was particularly evident for HLA class II genes and their master regulator CIITA, and not detected in relapses after sole chemotherapy. Integration of all the high-throughput technologies by MOFA, and of results from different patients by GSEA, pointed to the Polycomb Repressive Complex 2 (PRC2) as the main candidate mediator of HLA class II silencing.Pharmacological inhibition of PRC2 subunits rescued HLA class II expression in AML relapses ex vivo and in vivo, with consequent recovery of leukemia recognition by CD4+ T cells. Conclusions: Our results uncover a novel link between epigenetics and leukemia immune escape, which may rapidly translate into innovative strategies to cure or prevent AML post-transplantation relapse. Citation Format: Valentina Gambacorta, Stefano Beretta, Martina Ciccimarra, Laura Zito, Kety Giannetti, Angela Andrisani, Daniela Gnani, Lucia Zanotti, Giacomo Oliveira, Matteo G. Carrabba, Davide Cittaro, Ivan Merelli, Fabio Ciceri, Raffaella Di Micco, Luca Vago. Integrated multiomic profiling identifies the epigenetic regulator PRC2 as a therapeutic target to counteract leukemia immune escape and relapse [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB563.

Abstract 2335: DHODH inhibition modulates T cell metabolism reducing GVHD and prevents relapse following allogeneic HCT

Abstract Introduction: The use of allogeneic hematopoietic cell transplantation to treat acute myeloid leukemia (AML) has risen in recent years. However, relapse remains the major cause of mortality post-transplant; while graft-versus-host disease (GVHD) - a T cell mediated immunological disorder is the major cause of non-relapse mortality. Dihydroorotate dehydrogenase (DHODH) supports T cell proliferation by playing a critical role in de novo pyrimidine synthesis and oxidative phosphorylation. We hypothesized that alloreactive T cells may rely on increased levels of pyrimidine pools and ATP to support rapid cell proliferation, making DHODH an interesting target to prevent GVHD. Additionally, DHODH inhibition is currently being pursued as a therapeutic option for AML. Therefore, we hypothesize that DHODH inhibition post-transplant will serve a dual purpose - i) target T cell metabolism to reduce GVHD and ii) prevent relapse due to direct anti-leukemic effects, thereby resulting in superior post-transplant outcomes. Methods: We tested the efficacy of a novel DHODH inhibitor (Cmpd 41), a lead clinical candidate, in preventing GVHD and retaining graft-versus-leukemia (GVL) effect. Human T cells isolated from PBMCs were activated with CD3/CD28 Dynabeads ± Cmpd 41. Cell proliferation (flow cytometry) and ATP production (Agilent Seahorse) was assessed. GVHD and GVL was assessedevaluated in a xenogeneic model where irradiated NSG mice received human PBMCS (~17x106 cells) and treated with vehicle or Cmpd 41 (10mg/kg, 2x/week) with addition of MOLM-13 cells (~1x104) for GVL. Splenocytes were harvested for analysis of cytokine production (intracellular flow cytometry). Results: DHODH inhibition with Cmpd 41 significantly reduced T cell proliferation and ATP production from both glycolysis and OXPHOS (fold change: Cmpd 41 vs. control- 0.56 and 0.68 respectively, p<0.01) compared to vehicle. DHODH inhibition significantly improved survival (mean survival: Cmpd 41 vs. vehicle: 56 days vs. 40 days, p<0.01) and reduced clinical scores (Cmpd 41 vs. vehicle: 1.8 vs. 4.2, p<0.05) compared to vehicle in the xenogeneic GVHD model. There was a significant reduction in IFN-γ and TNF-α cytokine producing T cells in the Cmpd 41 treated cohort compared to vehicle (Cmpd 41 vs. vehicle, IFN-γ: 8.33% vs. 31.28%, p<0.01; TNF-α: 1.37% vs. 27.25%, p<0.01). In a GVL model, mice that received both human PBMCs and Cmpd 41 showed decreased tumor growth and improved overall survival over mice given either treatment alone (p<0.01), showing that DHODH inhibition maintains GVL. Conclusion: DHODH inhibition is a novel approach to prevent and mitigate GVHD while retaining GVL effects. Combined with direct anti-leukemic effects, we propose that Cmpd 41 treatment in post-transplant relapse in the setting of past or active graft versus host disease will provide dual treatment of AML and GVHD thereby leading to improved patient outcomes. Citation Format: Kara M. Braunreiter, Lotus Neidemire-Colley, Natalie Sell, Yandi Gao, Sandip Vibhute, Chad Bennett, Ola A. Elgamal, Thomas Goodwin, Erin K. Hertlein, John C. Byrd, Parvathi Ranganathan. DHODH inhibition modulates T cell metabolism reducing GVHD and prevents relapse following allogeneic HCT [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2335.

Expansion, persistence, and efficacy of donor memory-like NK cells infused for posttransplant relapse.

BackgroundResponses to conventional donor lymphocyte infusion for postallogeneic hematopoietic cell transplantation (HCT) relapse are typically poor. Natural killer (NK) cell–based therapy is a promising modality to treat post-HCT relapse.MethodsWe initiated this ongoing phase I trial of adoptively transferred cytokine-induced memory-like (CIML) NK cells in patients with myeloid malignancies who relapsed after haploidentical HCT. All patients received a donor-derived NK cell dose of 5 to 10 million cells/kg after lymphodepleting chemotherapy, followed by systemic IL-2 for 7 doses. High-resolution profiling with mass cytometry and single-cell RNA sequencing characterized the expanding and persistent NK cell subpopulations in a longitudinal manner after infusion.ResultsIn the first 6 enrolled patients on the trial, infusion of CIML NK cells led to a rapid 10- to 50-fold in vivo expansion that was sustained over months. The infusion was well tolerated, with fever and pancytopenia as the most common adverse events. Expansion of NK cells was distinct from IL-2 effects on endogenous post-HCT NK cells, and not dependent on CMV viremia. Immunophenotypic and transcriptional profiling revealed a dynamic evolution of the activated CIML NK cell phenotype, superimposed on the natural variation in donor NK cell repertoires.ConclusionGiven their rapid expansion and long-term persistence in an immune-compatible environment, CIML NK cells serve as a promising platform for the treatment of posttransplant relapse of myeloid disease. Further characterization of their unique in vivo biology and interaction with both T cells and tumor targets will lead to improvements in cell-based immunotherapies.Trial RegistrationClinicalTrials.gov NCT04024761.FundingDunkin’ Donuts, NIH/National Cancer Institute, and the Leukemia and Lymphoma Society.

Pre-MEASURE: Multicenter evaluation of the prognostic significance of measurable residual disease testing prior to allogeneic transplantation for adult patients with AML in first remission.

7006 Background: Measurable residual disease (MRD) prior to allogeneic hematopoietic cell transplantation (alloHCT) is associated with increased relapse and death in patients with acute myeloid leukemia (AML) in cytomorphological complete remission (CR). We recently demonstrated AML MRD detected in pre-alloHCT blood by DNA-sequencing was associated with increased relapse and decreased overall survival in patients randomized to reduced intensity conditioning (RIC) versus myeloablative conditioning (MAC). The clinical utility of such ultra-deep next-generation sequencing (NGS-MRD) had not yet been reported in a large multi-center cohort. Methods: Patients aged 18 or older who underwent first alloHCT between 2013-2017 for AML in first CR (CR1), reported to be FLT3, NPM1, IDH1, IDH2 and/or Kit mutated at diagnosis, with a pre-conditioning remission blood sample available in the CIBMTR biobank were eligible for this study. Ultra-deep anchored multiplex PCR-based NGS-MRD for the above mutations was performed on 500ng gDNA with error-corrected variant calling as previously described. The pre-specified statistical analysis plan was registered on OSF. Results: Of 457 patients with a sample available, 448 had sufficient clinical annotation and DNA for analysis. 147 of these 448 patients (33%) experienced relapse at a median of 5.6 months post-alloHCT. NGS-MRD was positive in 129 pre-alloHCT patient samples (29%), averaging 1.35 mutation(s)/patient (range: 1-4). 173 mutations were detected with a median VAF of 0.18% (range: 0.0054-62%), most frequently FLT3-ITD (n = 43 patients), NPM1 (n = 48), and IDH2 (n = 46). Testing positive by NGS-MRD prior to alloHCT was associated with a 3yr RFS of 36% (95% CI: 28-45%) compared with 56% (51-62%) in those testing negative (p < 0.001). Detection of NPM1 and/or FLT3-ITD mutations prior to alloHCT was associated with a 3yr relapse probability of 55% (43-67%) and RFS of 26% (16-37%). NGS-MRD impact was modified by conditioning intensity: positive patients receiving RIC/NMA had the highest relapse of 57% at 3yr, testing negative followed by RIC/NMA had the same relapse rate at 3yr (35%) as those who tested positive but received MAC (p < 0.001). At three years, those positive for FLT3-ITD and/or NPM1 mutations prior to RIC/NMA alloHCT had a relapse probability of 67% (50-83%) with a RFS of 19% (8-33%). HR for relapse if NGS-MRD positive pre-alloHCT in CR1 was 2.3 (p < 0.001, 95% CI 1.6-3.1) when adjusting for conditioning intensity and age group. Conclusions: In this largest cohort of NGS-MRD testing prior to alloHCT for AML reported to date, we confirm the ability to identify patients in CR1 but at high-risk of subsequent relapse. This evidence provides the foundation for future precision medicine approaches to reduce post-transplant AML relapse.

P-165 The feasibility of tumor recurrence detection in liver post-transplantation for patients with hepatocellular carcinoma via personalized, tumor-informed ctDNA testing

Hepatocellular carcinoma (HCC) is an aggressive malignancy for which liver transplantation can be curative. Unfortunately, ∼8-20% of HCC patients will go on to relapse post-transplantation. Personalized and tumor-informed circulating tumor DNA (ctDNA) testing (SignateraTM, bespoke mPCR NGS assay) has been validated to accurately predict relapse across solid tumors, ahead of radiological imaging. Here, we demonstrate the feasibility of ctDNA testing for monitoring relapse in HCC patients who underwent liver transplantation with curative intent. A total of 10 HCC patients, stage I-IV, who underwent curative liver transplantation with longitudinal ctDNA monitoring were included in the analysis. Alpha-fetoprotein (AFP) levels and images were measured during surveillance in a subset of patients. In this cohort of 10 patients, 2 (20%) tested ctDNA positive during surveillance, both of whom relapsed. Of these, one tested ctDNA positive two months prior to imaging. Of the 8 patients who did not test ctDNA positive during surveillance, all remained disease-free by imaging. Two patients had elevated AFP, neither of whom relapsed. Of the 2 patients who relapsed, AFP levels were available for one patient and fell within the normal range. Our study illustrated the feasibility of performing longitudinal ctDNA assessment in patients with HCC (post-transplantation) during surveillance. ctDNA status but not AFP was associated with recurrence and was able to inform disease status ahead of imaging. To facilitate clinical decision-making, specifically with adjuvant therapy and immunosuppression management, additional studies with larger patient cohorts will be needed to validate the clinical utility of ctDNA testing in HCC.

Feasibility of disease recurrence monitoring in liver post-transplantation for patients with hepatocellular carcinoma via personalized and tumor-informed ctDNA test.

e16123 Background: Hepatocellular carcinoma (HCC) is an aggressive malignancy for which liver transplantation can be curative. Unfortunately, ̃8-20% of HCC patients will go on to relapse post-transplantation. Personalized and tumor-informed circulating tumor DNA (ctDNA) testing (Signatera, bespoke mPCR NGS assay) has been validated to accurately predict relapse across solid tumors, ahead of radiological imaging. Here, we demonstrate the feasibility of ctDNA testing for monitoring relapse in HCC patients who underwent liver transplantation with curative intent. Methods: A total of 10 HCC patients, stage I-IV, who underwent curative liver transplantation with longitudinal ctDNA monitoring were included in the analysis. Alpha-fetoprotein (AFP) levels and images were measured during surveillance in a subset of patients. Results: In this cohort of 10 patients, 2 (20%) tested ctDNA positive during surveillance, both of whom relapsed. Of these, one tested ctDNA positive two months prior to imaging. Of the 8 patients who did not test ctDNA positive during surveillance, all remained disease-free by imaging. Two patients had elevated AFP, neither of whom relapsed. Of the 2 patients who relapsed, AFP levels were available for one patient and fell within the normal range. Conclusions: Our study illustrated the feasibility of performing longitudinal ctDNA assessment in patients with HCC (post-transplantation) during surveillance. ctDNA status but not AFP was associated with recurrence and was able to inform disease status ahead of imaging. To facilitate clinical decision-making, specifically with adjuvant therapy and immunosuppression management, additional studies with larger patient cohorts will be needed to validate the clinical utility of ctDNA testing in HCC.

Using stroma-anchoring cytokines to augment ADCC: a phase 1 trial of F16IL2 and BI 836858 for posttransplant AML relapse

AbstractNatural killer (NK) cells are key effectors in cancer immunosurveillance and posttransplant immunity, but deficiency of environmental signals and insufficient tumor recognition may limit their activity. We hypothesized that the antibody-mediated anchoring of interleukin-2 (IL-2) to a spliced isoform of the extracellular matrix (ECM) glycoprotein tenascin-C would potentiate NK-cell–mediated antibody-dependent cellular cytotoxicity against leukemic blasts. In this novel-novel combination, dose-escalation, phase 1 trial, we enrolled patients with posttransplant acute myeloid leukemia (AML) relapse to evaluate the safety, pharmacokinetics, pharmacodynamics, and preliminary activity of the antibody-cytokine fusion F16IL2 (10 × 106 to 20 × 106 IU IV; days 1, 8, 15, and 22 of each 28-day cycle) in combination with the anti-CD33 antibody BI 836858 (10-40 mg IV, 2 days after each F16IL2 infusion). Among the 15 patients (median [range] age, 50 [20-68] years) treated across 4 dose levels (DLs), 6 (40%) had received 2 or 3 prior transplantations. The most frequent adverse events were pyrexia, chills, and infusion-related reactions, which were manageable, transient and of grade ≤2. One dose-limiting toxicity occurred at each of DLs 3 (pulmonary edema) and 4 (graft-versus-host disease). Three objective responses were observed among 7 patients treated at the 2 higher DLs, whereas no responses occurred at the 2 starting DLs. Combination therapy stimulated the expansion and activation of NK cells, including those expressing the FcγRIIIA/CD16 receptor. ECM-targeted IL-2 combined with anti-CD33 immunotherapy represents an innovative approach associated with acceptable safety and encouraging biologic and clinical activity in posttransplant AML relapse. This trial was registered at EudraCT as 2015-004763-37.

Post-Transplantation Day +100 Minimal Residual Disease Detection Rather Than Mixed Chimerism Predicts Relapses after Allogeneic Stem Cell Transplantation for Intermediate-Risk Acute Myelogenous Leukemia Patients Undergoing Transplantation in Complete Remission

Chimerism and minimal residual disease (MRD) are suggested to be prognostic for post-transplantation relapse in patients with acute myelogenous leukemia (AML). Nevertheless, the predictive value of both approaches in homogeneous populations remains underinvestigated. Here we suggest that MRD may have greater predictive value for relapse than mixed chimerism (MC) in intermediate-risk AML patients. Seventy-nine patients with intermediate-risk AML (40 males; median age, 57 years [range, 19 to 77 years]) were included. MRD detection on day +100 was performed in bone marrow via multiparameter flow cytometry (MFC) and quantitative real-time PCR (qPCR) for patients with an NPM1 mutation. Chimerism analysis was performed in peripheral blood. MC was defined as the persistence of <99.9% of donor alleles. The area under the receiver operating characteristic curve was highest for qPCR-MRD (.93), followed by MFC-MRD (.80) and MC (.65). The highest rate of relapse at 3 years was observed in day +100 qPCR-MRD-positive patients (100%), followed by MFC-MRD-positive patients (55%; P < .001). No patients with MC and without detectable MRD experienced relapse. The median 3-year overall survival (OS) and leukemia-free survival (LFS) for patients with MC without detectable MRD were both 86% (range, 61% to 96%), significantly higher than the values in day +100 MFC-MRD-positive patients (OS, 61% [range, 36% to 84%]; LFS: 30% [range, 11% to 59%]) and with day +100 qPCR-MRD-positive patients (OS: 17% [range, 3% to 56%], P = .001; LFS: 0%, P < .001). In patients with intermediate-risk AML, the qPCR-MRD on day +100 was highly predictive for relapse and long-term survival after allogeneic stem cell transplantation, followed closely by MFC-MRD. In contrast, chimerism status had limited predictive potential. Thus, molecular and flow cytometry MRD monitoring rather than MC in the first several months post-transplantation can identify patients at increased risk of relapse who may benefit from early post-transplantation preemptive intervention.

The outcome of patients with Hodgkin lymphoma and early relapse after autologous stem cell transplant has improved in recent years.

Hodgkin lymphoma (HL) patients who relapse after autologous-stem-cell- transplantation (auto-SCT) have traditionally had a poor prognosis. We analyzed 1781 adult HL patients who relapsed between 2006 and 2017 after a first auto-SCT. The 4-year overall survival (OS) after relapse continuously increased from 32% for patients relapsing in 2006-2008, to 63% for patients relapsing in 2015-2017 (p = 0.001). The improvement over time was predominantly noted in patients who had an early relapse (within 12 months) after auto-SCT (p = 0.01). On multivariate analysis, patients who relapsed in more recent years and those with a longer interval from transplant to relapse had a better OS, whereas increasing age, poor performance status, bulky disease, extranodal disease and presence of B symptoms at relapse were associated with a worse OS. Brentuximab vedotin (BV), checkpoint inhibitors (CPI) and second transplant (SCT2; 86% allogeneic) were used in 233, 91 and 330 patients respectively. The 4-year OS from BV, CPI, and SCT2 use was 55%, 48% and 55% respectively. In conclusion, the outcome after post-transplant relapse has improved significantly in recent years, particularly in the case of early relapse. These large-scale real-world data can serve as benchmark for future studies in this setting.

Liver transplantation for severe alcoholic hepatitis: A multicenter Italian study

There is increasing evidence that early liver transplantation (eLT), performed within standardized protocols can improve survival in severe alcoholic hepatitis (sAH). The aim of the study was to assess outcomes after eLT for sAH in four Italian LT centers and to compare them with non-responders to medical therapy excluded from eLT. Patients admitted for sAH (2013-2019), according to NIAAA criteria, were included. Patients not responding to medical therapy were placed on the waiting list for eLT after a strict selection. Histological features of explanted livers were evaluated. Posttransplant survival and alcohol relapse were evaluated. Ninety-three patients with severe AH were evaluated (65.6% male, median [IQR] age: 47 [42-56] years). Forty-five of 93 patients received corticosteroids, 52 of 93 were non-responders and among these, 20 patients were waitlisted. Sixteen patients underwent LT. Overall, 6-, 12-, and 24-month survival rates were 100% significantly higher compared with non-responders to medical therapy who were denied LT (45%, 45%, and 36%; p<.001). 2/16 patients resumed alcohol intake, one at 164days and one at 184days. Early LT significantly improves survival in sAH non-responding to medical therapy, when a strict selection process is applied. Further studies are needed to properly assess alcohol relapse rates.

TNFR2 blockade of regulatory T cells unleashes an antitumor immune response after hematopoietic stem-cell transplantation

BackgroundTargeting immune checkpoints that inhibit antitumor immune responses has emerged as a powerful new approach to treat cancer. We recently showed that blocking the tumor necrosis factor receptor-type 2 (TNFR2)...

Single-agent 5-azacytidine as post-transplant maintenance in high-risk myeloid malignancies undergoing allogeneic hematopoietic cell transplantation.

Relapse is a major cause of treatment failure after allogeneic hematopoietic cell transplantation (allo-HCT) in myeloid malignancies. Additional strategies have been devised to further maximize the immunologic effect of allo-HCT, notably through maintenance therapy with hypomethylating agents such as 5-azacytidine (AZA). We conducted a single-center retrospective study to investigate the efficacy of AZA after allo-HCT for high-risk myeloid malignancies. All patients transplanted between Jan 2014 and Sept 2019 for high-risk acute myeloid leukemia (n = 123), myelodysplastic syndrome (n = 51), or chronic myelomonocytic leukemia (n = 11) were included. Patients who died, relapsed, or developed grade ≥ 2 acute graft-versus-host disease before day + 60 were excluded, as well as those who were eligible for anti-FMS-like tyrosine kinase 3 maintenance. Of the 185 included patients, 65 received AZA while 120 did not. Median age at transplant was 59years; 51.9% of patients were males. The median follow-up was 24months for both groups. Regarding main patient characteristics and transplantation modalities, the two groups were comparable. In multivariate analyses, there were no significant differences between the two groups in terms of 2-year cumulative incidence of relapse (HR = 1.19; 95% confidence interval (CI) 0.67-2.12; p = 0.55), overall survival (HR = 0.62; 95%CI 0.35-1.12; p = 0.12) and event-free survival (HR = 0.97; 95%CI 0.60-1.58; p = 0.91) rates. In conclusion,single-agent AZA does not appear to be an optimal drug for preventing post-transplant relapse in patients with high-risk myeloid malignancies. This study highlights the need for prospective studies of alternative therapies or combination approaches in the post-transplant setting.

Prognostic role of serum cytokines and soluble HLA-G levels in children with leukemia who undergo allogeneic stem cell transplantation

This is the first study to have investigated the prognostic role of cytokines and soluble human leukocyte antigen-G (sHLA-G) levels in pediatric leukemia patients who have undergone allogeneic stem cell transplantation (allo-SCT). Forty-one patients with acute leukemia (n = 28, acute lymphoblastic leukemia (ALL) and n = 13, acute myeloblastic leukemia) were recruited. Patients were examined at diagnosis (n = 26), in the pre-transplantation period (PreTx) (n = 26), on the day of transplantation (Tx0) (n = 41), and on post-transplantation Days 14 (PostTx14) (n = 41) and 28 (PostTx28) (n = 41). Serum levels of pro-inflammatory cytokines (interleukin [IL]-1, IL-2, IL-6, Tumor necrosis factor [TNF]-α), anti-inflammatory cytokines (IL-4, IL-10), and sHLA-G were measured by Enzyme-Linked ImmunoSorbent Assay. Median levels of all cytokines tested and sHLA-G were significantly higher at diagnosis and at the post-transplant time points than at PreTx (all p < 0.05). At the time of diagnosis (specifically ALL) and at PostTx14, elevated IL-4, IL-10, and/or sHLA-G were associated with higher post-transplant relapse rates (all p < 0.05). Elevated IL-2 and TNF-α at Tx0 were associated with lower survival rates (both p < 0.05). Levels of serum cytokines and sHLA-G may be useful predictors of survival and relapse in pediatric leukemia patients who undergo allo-SCT.

Improved NK Cell Recovery Following Use of PTCy or Treg Expanded Donors in Experimental MHC-Matched Allogeneic HSCT

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is complicated by graft- versus-host disease (GVHD), which causes immune dysfunction and further delays immune reconstitution through its effects on primary and secondary lymphoid organs. Treatments to prevent GVHD and improve immune recovery following allo-HSCT are needed. Post-transplantation cyclophosphamide (PTCy) is a well-established and clinically widely used method for GVHD prophylaxis after HLA-matched as well as haploidentical allo-HSCT, as well as a promising strategy in the setting of mismatched unrelated donor allo-HSCT. Recently, regulatory T cells (Tregs), a critical subset for immune homeostasis and tolerance induction, have been evaluated for use as GVHD prophylaxis in experimental models and clinical trials. Natural killer (NK) cells are one of the first lymphoid populations to reconstitute following allo-HSCT and are important mediators of protective immunity against pathogens, and are also critical for limiting post-transplantation relapse of hematologic cancers. Several reports have noted that a delay in NK cell recovery may occur following experimental mouse allo-HSCT as well as after clinical allo-HSCT. Here we examined how 2 treatment strategies, PTCy and donor expanded Tregs (TrED), in experimental MHC-matched allo-HSCT affect NK recovery. Our experiments show that both strategies improved NK cell numbers, with PTCy slightly better than TrED, early after allo-HSCT (1 month) compared with untreated allo-HSCT recipients. Importantly, NK cell IFN-γ production and cytotoxic function, as reflected by CD107 expression as well as in vivo killing of NK-sensitive tumor cells, were improved using either PTCy or TrED versus control allo-HSCT recipients. In conclusion, both prophylactic treatments were found to be beneficial for NK recovery and NK cell function following MHC-matched minor antigen-mismatched experimental allo-HSCT. Improved NK recovery could help provide early immunity toward tumors and pathogens in these transplant recipients.

25 - Donor-Derived Adoptive T-Cell Therapy Targeting Multiple Tumor Associated Antigens to Prevent Post-Transplant Relapse in Patients with ALL

25 - Donor-Derived Adoptive T-Cell Therapy Targeting Multiple Tumor Associated Antigens to Prevent Post-Transplant Relapse in Patients with ALL