Epigenetic control over cell-intrinsic immune response antagonizes self-renewal in acute myeloid leukemia.

Epigenetic modulation of the cell-intrinsic immune response holds promise as a therapeutic approach for leukemia. However, current strategies designed for transcriptional activation of endogenous transposons and subsequent interferon type-I (IFN-I) response, show limited clinical efficacy. Histone lysine methylation is an epigenetic signature in IFN-I response associated with suppression of IFN-I and IFN stimulated genes, suggesting histone demethylation as key mechanism of reactivation. In this study, we unveil the histone demethylase PHF8 as a direct initiator and regulator of cell-intrinsic immune response in acute myeloid leukemia (AML). Site-specific phosphorylation of PHF8 orchestrates epigenetic changes that upregulate cytosolic RNA sensors, particularly the TRIM25-RIG-I-IFIT5 axis, thereby triggering the cellular IFN-I response-differentiation-apoptosis network. This signaling cascade largely counteracts differentiation block and growth of human AML cells across various disease subtypes in vitro and in vivo. Through proteome analysis of over 200 primary AML bone marrow samples, we identify a distinct PHF8/IFN-I signature in half of the patient population, without significant associations with known clinically or genetically defined AML subgroups. This profile was absent in healthy CD34-positive hematopoietic progenitor cells, suggesting therapeutic applicability in a large fraction of AML patients. Pharmacological support of PHF8 phosphorylation significantly impairs growth of primary AML patient samples. These findings provide novel opportunities for harnessing the cell-intrinsic immune response in the development of immunotherapeutic strategies against AML.

Prevalence and clinical impact of CD56 and T-cell marker expression in acute myeloid leukaemia: A single-centre retrospective analysis.

Flow cytometry-based immunophenotyping is a mainstay of diagnostics in acute myeloid leukaemia (AML). Aberrant CD56 and T-cell antigen expression is observed in a fraction subset of AML cases, but the clinical relevance remains incompletely understood. Here, we retrospectively investigated the association of CD56 and T-cell marker expression with disease-specific characteristics and outcome of 324 AML patients who received intensive induction therapy at our centre between 2011 and 2019. We found that CD2 expression was associated with abnormal non-complex karyotype, NPM1 wild-type status and TP53 mutation. CD2 also correlated with a lower complete remission (CR) rate (47.8% vs. 71.6%, p = 0.03). CyTdT and CD2 were associated with inferior 3-year event-free-survival (EFS) (5.3% vs. 33.5%, p = 0.003 and 17.4% vs. 33.1%, p = 0.02, respectively). CyTdT expression was also correlated with inferior relapse-free survival (27.3% vs. 48.8%, p = 0.04). In multivariable analyses CD2 positivity was an independent adverse factor for EFS (HR 1.72, p = 0.03). These results indicate a biological relevance of aberrant T-cell marker expression in AML and provide a rationale to further characterise the molecular origin in T-lineage-associated AML.

Deep learning predicts therapy-relevant genetics in acute myeloid leukemia from Pappenheim-stained bone marrow smears.

ABSTRACT: The detection of genetic aberrations is crucial for early therapy decisions in acute myeloid leukemia (AML) and recommended for all patients. Because genetic testing is expensive and time consuming, a need remains for cost-effective, fast, and broadly accessible tests to predict these aberrations in this aggressive malignancy. Here, we developed a novel fully automated end-to-end deep learning pipeline to predict genetic aberrations directly from single-cell images from scans of conventionally stained bone marrow smears already on the day of diagnosis. We used this pipeline to compile a multiterabyte data set of >2 000 000 single-cell images from diagnostic samples of 408 patients with AML. These images were then used to train convolutional neural networks for the prediction of various therapy-relevant genetic alterations. Moreover, we created a temporal test cohort data set of >444 000 single-cell images from further 71 patients with AML. We show that the models from our pipeline can significantly predict these subgroups with high areas under the curve of the receiver operating characteristic. Potential genotype-phenotype links were visualized with 2 different strategies. Our pipeline holds the potential to be used as a fast and inexpensive automated tool to screen patients with AML for therapy-relevant genetic aberrations directly from routine, conventionally stained bone marrow smears already on the day of diagnosis. It also creates a foundation to develop similar approaches for other bone marrow disorders in the future.

Pretransplant spleen volume and outcome after hematopoietic stem cell transplantation (HSCT) in patients with acute myeloid leukemia (AML).

Allogeneic hematopoietic stem cell transplantation (HSCT) is an effective treatment modality for patients with acute myeloid leukemia (AML). Here, we investigated the predictive value of spleen volume on outcome parameters and engraftment kinetics after HSCT in a large cohort of AML patients. A total of 402 patients who received their first HSCT between January 2012 and March 2019 were included in this retrospective study. Spleen volume was correlated to clinical outcome and engraftment kinetics. Median follow-up was 33.7 months (95% confidence interval [CI], 28.9-37.4 months). Patients were subdivided based on median spleen volume of 238.0 cm3 (range 55.7-2693.5 cm3) into a small spleen volume (SSV) and a large spleen volume (LSV) group. LSV was associated with inferior overall survival (OS) after HSCT (55.7% vs. 66.6% at 2 years; P = 0.009) and higher cumulative incidence of NRM (28.8% vs. 20.2% at 2 years; P = 0.048). The adjusted hazard ratio for NRM in the LSV group was 1.55 (95% CI, 1.03-2.34). Time to neutrophil or platelet engraftment and the occurrence of acute or chronic graft-versus-host disease (GVHD) were not significantly different between both groups. Higher spleen volume at the time of HSCT was independently linked to adverse outcomes such as inferior OS and higher cumulative incidence of NRM in AML patients after HSCT. Engraftment kinetics and GVHD were not associated with spleen volume.

Clonally resolved single-cell multi-omics identifies routes of cellular differentiation in acute myeloid leukemia.

Inter-patient variability and the similarity of healthy and leukemic stem cells (LSCs) have impeded the characterization of LSCs in acute myeloid leukemia (AML) and their differentiation landscape. Here, we introduce CloneTracer, a novel method that adds clonal resolution to single-cell RNA-seq datasets. Applied to samples from 19 AML patients, CloneTracer revealed routes of leukemic differentiation. Although residual healthy and preleukemic cells dominated the dormant stem cell compartment, active LSCs resembled their healthy counterpart and retained erythroid capacity. By contrast, downstream myeloid progenitors constituted a highly aberrant, disease-defining compartment: their gene expression and differentiation state affected both the chemotherapy response and leukemia's ability to differentiate into transcriptomically normal monocytes. Finally, we demonstrated the potential of CloneTracer to identify surface markers misregulated specifically in leukemic cells. Taken together, CloneTracer reveals a differentiation landscape that mimics its healthy counterpart and may determine biology and therapy response in AML.

Amsacrine-based induction therapy in AML patients with cardiac comorbidities: a retrospective single-center analysis.

Intensive chemotherapy is the backbone of induction treatment in patients with acute myeloid leukemia (AML). However, AML patients with concomitant cardiac disease may not be eligible for anthracycline-based therapies. In a small cohort of patients, we have previously shown that anthracycline-free, amsacrine-based chemotherapy TAA (thioguanine, cytarabine, amsacrine) may be as effective as cytarabine/daunorubicin for induction therapy in these patients. In this systematic retrospective single-center analysis, we documented the outcome of 31 patients with significant cardiac comorbidities including coronary heart disease or cardiomyopathy receiving TAA as induction chemotherapy. Median (range) ejection fraction (EF) was 48% (30-67%) in this cohort. Patients with EF below 30% were considered unfit for intensive induction therapy. Event-free survival (EFS), overall survival (OS), and relapse-free survival (RFS) were 1.61, 5.46, and 13.6 months respectively. Poor outcome was primarily related to a high early mortality rate within the first 30 days of therapy, mainly caused by infectious complications. TAA cannot be recommended as a substitute of standard induction for AML patients with significant concomitant cardiac disease. In the era of novel agents, alternative strategies (e.g., hypomethylating agents plus venetoclax) should be considered when anthracycline-based regimens are not suitable.

A randomized phase 2 trial of nintedanib and low-dose cytarabine in elderly patients with acute myeloid leukemia ineligible for intensive chemotherapy.

We investigated the safety and efficacy of nintedanib added to low-dose cytarabine (LDAC) in a phase 1/2 study in patients 60 years or older with newly diagnosed or relapsed/refractory (r/r) AML ineligible for intensive chemotherapy. The results of the dose-finding phase 1 part have been previously published. Patients were randomized 1:1 to LDAC plus nintedanib or LDAC plus placebo stratified by AML status (newly diagnosed vs r/r). LDAC was applied subcutaneously at 20 mg twice daily on days 1 to 10. Nintedanib/placebo was orally administered twice daily on days 1 to 28 in 28-day cycles. The primary endpoint was overall survival (OS). Between 05/2017 and 09/2019, 31 patients were randomized and 30 were treated, before the study was terminated prematurely due to slow recruitment. Median (range) age of patients was 76 (60-84) years. Twenty-two patients (73%) had r/r AML. Median OS in patients treated with LDAC and nintedanib was 3.4 months, compared with 3.6 months in those treated in the placebo arm, with a HR adjusted for AML status of 1.19 (corresponding confirmatory adjusted 95% CI, 0.55-2.56; univariate log-rank P = 0.96). In the 22 patients with r/r AML, median OS was 3.0 months in the nintedanib and 3.6 months in the placebo arm (P = 0.36). One patient in the nintedanib and two patients in the placebo arm achieved a CR and entered maintenance treatment. Nintedanib showed no superior therapeutic activity over placebo when added to LDAC in elderly AML patients considered unfit for intensive chemotherapy. The trial was registered at clinicaltrials.gov NCT01488344.

Emerging antibody-based therapies for the treatment of acute myeloid leukemia.

The development of antibody-based therapeutics for patients with acute myeloid leukemia (AML) has long been hampered due to the shared expression of antigens on leukemic blasts and hematopoietic stem and progenitor cells (HSPC). Nevertheless, the first antibody-drug conjugate has been approved for the treatment of AML in the recent years. In addition, multiple antibody-based therapeutics including antibody-drug conjugates, bispecific antibodies and immunocytokines are currently being developed in clinical trials with some of them demonstrating encouraging results alone and/or in combination with current standard therapies. In this review we discuss current concepts of antibody-based therapies and results from emerging antibody-based therapeutics for the treatment of AML.

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

Natural 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.

Characteristics and Outcome of Elderly Patients (>55 Years) with Acute Lymphoblastic Leukemia.

Prognosis of elderly ALL patients remains dismal. Here, we retrospectively analyzed the course of 93 patients > 55 years with B-precursor (n = 88) or T-ALL (n = 5), who received age-adapted, pediatric-inspired chemotherapy regimens at our center between May 2003 and October 2020. The median age at diagnosis was 65.7 years, and surviving patients had a median follow-up of 3.7 years. CR after induction therapy was documented in 76.5%, while the rate of treatment-related death within 100 days was 6.4%. The OS of the entire cohort at 1 and 3 year(s) was 75.2% (95% CI: 66.4-84.0%) and 47.3% (95% CI: 36.8-57.7%), respectively, while the EFS at 1 and 3 years(s) was 59.0% (95% CI: 48.9-69.0%) and 32.9% (95% CI: 23.0-42.8%), respectively. At 3 years, the cumulative incidence (CI) of relapse was 48.3% (95% CI: 38.9-59.9%), and the CI rate of death in CR was 17.3% (95% CI: 10.9-27.5%). Older age and an ECOG > 2 represented risk factors for inferior OS, while BCR::ABL1 status, immunophenotype, and intensity of chemotherapy did not significantly affect OS. We conclude that intensive treatment is feasible in selected elderly ALL patients, but high rates of relapse and death in CR underline the need for novel therapeutic strategies.

Calcitonin receptor-like (CALCRL) is a marker of stemness and an independent predictor of outcome in pediatric AML.

We have recently identified the G protein-coupled neuropeptide receptor calcitonin receptor-like (CALCRL) as an independent prognostic biomarker and a therapeutic target in more than 1500 adult patients with acute myeloid leukemia (AML). Here, we confirmed CALCRL expression as a prognostic factor in a cohort of 284 pediatric patients with AML. High CALCRL expression was independently associated with event-free survival (hazard ratio [HR], 1.87; 95% confidence interval [CI], 1.36-2.57; P = .0001), overall survival (HR, 1.55; 95% CI, 1.06-2.27; P = .025), and cumulative incidence of relapse (HR, 2.10; 95% CI, 1.49-1.96; P < .0001) when adjusting for age, white blood cell count, and genetic risk. Despite its association with leukemia stem cell signatures, CALCRL expression remained associated with all end points when compared with the 17-gene leukemic stem cell score. The strong association of CALCRL expression with the risk of relapse also in the pediatric population supports its role as novel age-independent master regulator of relapse-initiating, drug-tolerant AML cells in humans.

CD70-specific CAR T cells have potent activity against acute myeloid leukemia without HSC toxicity.

The prognosis of patients with acute myeloid leukemia (AML) remains dismal, highlighting the need for novel innovative treatment strategies. The application of chimeric antigen receptor (CAR) T-cell therapy to patients with AML has been limited, in particular by the lack of a tumor-specific target antigen. CD70 is a promising antigen to target AML, as it is expressed on most leukemic blasts, whereas little or no expression is detectable in normal bone marrow samples. To target CD70 on AML cells, we generated a panel of CD70-CAR T cells that contained a common single-chain variable fragment (scFv) for antigen detection, but differed in size and flexibility of the extracellular spacer and in the transmembrane and the costimulatory domains. These CD70scFv CAR T cells were compared with a CAR construct that contained human CD27, the ligand of CD70 fused to the CD3ζ chain (CD27z). The structural composition of the CAR strongly influenced expression levels, viability, expansion, and cytotoxic capacities of CD70scFv-based CAR T cells, but CD27z-CAR T cells demonstrated superior proliferation and antitumor activity in vitro and in vivo, compared with all CD70scFv-CAR T cells. Although CD70-CAR T cells recognized activated virus-specific T cells (VSTs) that expressed CD70, they did not prevent colony formation by normal hematopoietic stem cells. Thus, CD70-targeted immunotherapy is a promising new treatment strategy for patients with CD70-positive AML that does not affect normal hematopoiesis but will require monitoring of virus-specific T-cell responses.

Dose escalation and expansion phase I studies with the tumour-targeting antibody-tumour necrosis factor fusion protein L19TNF plus doxorubicin in patients with advanced tumours, including sarcomas.

BACKGROUND: L19TNF is a recombinant fusion protein composed of a human antibody fragment and human tumour necrosis factor. L19TNF targets the EDB domain of oncofetal fibronectin highly expressed in tumour vasculature and induces tumour remission in mouse tumours. We summarise two phase I trials testing a combination of L19TNF with doxorubicin in patients with solid tumours, particularly soft tissue sarcomas (STS). PATIENTS AND METHODS: The first study, an open-label, dose-escalation and expansion phase I study of L19TNF plus doxorubicin, enrolled 27 patients. Three cohorts (10.4-17 µg/kg L19TNF) of patients received L19TNF intravenously at days 1, 3, and 5 and doxorubicin (75 mg/m2, then 60 mg/m2) on day 1 every 3 weeks. The expansion cohort enrolled patients with STS. The second study tried to re-escalate the doxorubicin dose to 75 mg/m2 with 13 µg/kg L19TNF. Among primary objectives was the establishment of a recommended dose (RD). RESULTS: The combination was safely applicable. Dose-limiting toxicity occurred either at 17 µg/kg L19TNF or at 75 mg/m2 doxorubicin. RD is 13 µg/kg L19TNF plus 60 mg/m2 doxorubicin. In 15 STS patients of the extension cohort evaluable for efficacy, antitumour activity was observed with complete remission in 1, partial remission in 1 and minor tumour shrinkage in 7 patients. The median overall survival for this heavily pretreated cohort was 14.9 months. CONCLUSION: L19TNF can be safely applied in combination with doxorubicin and induces encouraging tumour remissions in patients with soft tissue sarcomas.

Adrenomedullin-CALCRL axis controls relapse-initiating drug tolerant acute myeloid leukemia cells.

Drug tolerant/resistant leukemic stem cell (LSC) subpopulations may explain frequent relapses in acute myeloid leukemia (AML), suggesting that these relapse-initiating cells (RICs) persistent after chemotherapy represent bona fide targets to prevent drug resistance and relapse. We uncover that calcitonin receptor-like receptor (CALCRL) is expressed in RICs, and that the overexpression of CALCRL and/or of its ligand adrenomedullin (ADM), and not CGRP, correlates to adverse outcome in AML. CALCRL knockdown impairs leukemic growth, decreases LSC frequency, and sensitizes to cytarabine in patient-derived xenograft models. Mechanistically, the ADM-CALCRL axis drives cell cycle, DNA repair, and mitochondrial OxPHOS function of AML blasts dependent on E2F1 and BCL2. Finally, CALCRL depletion reduces LSC frequency of RICs post-chemotherapy in vivo. In summary, our data highlight a critical role of ADM-CALCRL in post-chemotherapy persistence of these cells, and disclose a promising therapeutic target to prevent relapse in AML.

Low-density lipoprotein receptor (LDLR) is an independent adverse prognostic factor in acute myeloid leukaemia.

The low-density lipoprotein receptor (LDLR) is a membrane receptor that mediates the endocytosis of low-density lipoprotein (LDL). Uptake of LDL has been proposed to contribute to chemotherapy resistance of acute myeloid leukaemia (AML) cell lines in vitro. In the present study, we analysed LDLR expression and survival using bone marrow biopsies from 187 intensively treated patients with AML. Here, increasing LDLR expression was associated with decreasing overall (58·4%, 44·2%, and 24·4%; P = 0·0018), as well as event-free survival (41·7%, 18·1%, and 14·3%; P = 0·0077), and an increasing cumulative incidence of relapse (33·9%, 55·1%, and 71·4%; P = 0·0011). Associations of LDLR expression with survival were confirmed in 557 intensively treated patients from two international validation cohorts. In the analytic and validation cohorts, LDLR expression remained associated with outcome in multivariable regression analyses including the European LeukemiaNet genetic risk classification. Thus, LDLR predicts outcome of patients with AML beyond existing risk factors. Furthermore, we found low expression levels of LDLR in most healthy tissues, suggesting it as a promising target for antibody-based pharmacodelivery approaches in AML.

Magnesium levels and outcome after allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia.

Low intake of magnesium has been associated with the occurrence of lymphomas and decreased magnesium levels suppress the cytotoxic function of T cells and natural killer cells in patients with "X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia" (XMEN) syndrome. These cell types are also important mediators of immune-mediated effects after allogeneic hematopoietic stem cell transplantation. Here, we show that high posttransplant magnesium levels independently associate with a lower incidence of relapse, a higher risk of acute graft-versus-host disease, and a higher non-relapse mortality in 368 patients with acute myeloid leukemia from our center. Magnesium serum levels might impact on donor-cell-mediated immune responses in acute myeloid leukemia.

ACCELERATE: A Patient-Powered Natural History Study Design Enabling Clinical and Therapeutic Discoveries in a Rare Disorder.

Geographically dispersed patients, inconsistent treatment tracking, and limited infrastructure slow research for many orphan diseases. We assess the feasibility of a patient-powered study design to overcome these challenges for Castleman disease, a rare hematologic disorder. Here, we report initial results from the ACCELERATE natural history registry. ACCELERATE includes a traditional physician-reported arm and a patient-powered arm, which enables patients to directly contribute medical data and biospecimens. This study design enables successful enrollment, with the 5-year minimum enrollment goal being met in 2 years. A median of 683 clinical, laboratory, and imaging data elements are captured per patient in the patient-powered arm compared with 37 in the physician-reported arm. These data reveal subgrouping characteristics, identify off-label treatments, support treatment guidelines, and are used in 17 clinical and translational studies. This feasibility study demonstrates that the direct-to-patient design is effective for collecting natural history data and biospecimens, tracking therapies, and providing critical research infrastructure.

First-In-Class CD13-Targeted Tissue Factor tTF-NGR in Patients with Recurrent or Refractory Malignant Tumors: Results of a Phase I Dose-Escalation Study.

BACKGROUND: Aminopeptidase N (CD13) is present on tumor vasculature cells and some tumor cells. Truncated tissue factor (tTF) with a C-terminal NGR-peptide (tTF-NGR) binds to CD13 and causes tumor vascular thrombosis with infarction. METHODS: We treated 17 patients with advanced cancer beyond standard therapies in a phase I study with tTF-NGR (1-h infusion, central venous access, 5 consecutive days, and rest periods of 2 weeks). The study allowed intraindividual dose escalations between cycles and established Maximum Tolerated Dose (MTD) and Dose-Limiting Toxicity (DLT) by verification cohorts. RESULTS: MTD was 3 mg/m2 tTF-NGR/day × 5, q day 22. DLT was an isolated and reversible elevation of high sensitivity (hs) Troponin T hs without clinical sequelae. Three thromboembolic events (grade 2), tTF-NGR-related besides other relevant risk factors, were reversible upon anticoagulation. Imaging by contrast-enhanced ultrasound (CEUS) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) showed major tumor-specific reduction of blood flow in all measurable lesions as proof of principle for the mode of action of tTF-NGR. There were no responses as defined by Response Evaluation Criteria in Solid Tumors (RECIST), although some lesions showed intratumoral hemorrhage and necrosis after tTF-NGR application. Pharmacokinetic analysis showed a t1/2(terminal) of 8 to 9 h without accumulation in daily administrations. CONCLUSION: tTF-NGR is safely applicable with this regimen. Imaging showed selective reduction of tumor blood flow and intratumoral hemorrhage and necrosis.