BATF is a major driver of NK cell epigenetic reprogramming and dysfunction in AML.

Myelodysplastic syndrome and acute myeloid leukemia (AML) belong to a continuous disease spectrum of myeloid malignancies with poor prognosis in the relapsed/refractory setting necessitating novel therapies. Natural killer (NK) cells from patients with myeloid malignancies display global dysfunction with impaired killing capacity, altered metabolism, and an exhausted phenotype at the single-cell transcriptomic and proteomic levels. In this study, we identified that this dysfunction was mediated through a cross-talk between NK cells and myeloid blasts necessitating cell-cell contact. NK cell dysfunction could be prevented by targeting the αvß-integrin/TGF-ß/SMAD pathway but, once established, was persistent because of profound epigenetic reprogramming. We identified BATF as a core transcription factor and the main mediator of this NK cell dysfunction in AML. Mechanistically, we found that BATF was directly regulated and induced by SMAD2/3 and, in turn, bound to key genes related to NK cell exhaustion, such as HAVCR2, LAG3, TIGIT, and CTLA4. BATF deletion enhanced NK cell function against AML in vitro and in vivo. Collectively, our findings reveal a previously unidentified mechanism of NK immune evasion in AML manifested by epigenetic rewiring and inactivation of NK cells by myeloid blasts. This work highlights the importance of using healthy allogeneic NK cells as an adoptive cell therapy to treat patients with myeloid malignancies combined with strategies aimed at preventing the dysfunction by targeting the TGF-ß pathway or BATF.

Haploidentical versus HLA-matched sibling donor HCT with PTCy prophylaxis: HLA factors and donor age considerations.

HLA-matched sibling donors (MSDs) are preferred for hematopoietic cell transplantation (HCT). However, the use of alternative donors, especially haploidentical, is increasing, as is our understanding of the impact of HLA factors such as B-leader and DRB1-matching on its outcomes. Yet, data comparing these donor types, particularly considering these HLA factors, is lacking. Herein, we compared haploidentical-HCT (n=1052) to MSD-HCT (n=400), both with posttransplant cyclophosphamide (PTCy)-based graft-versus-host disease (GVHD) prophylaxis. The haploidentical group included older patients (median 49 vs. 46 years) with younger donors (39 vs. 45 years) compared to MSD recipients. Other characteristics were similar. In multivariate analysis, haploidentical group had similar overall survival (OS) [hazard ratio (HR), [95% confidence interval] 0.94, [0.78-1.14], p=.54], non-relapse mortality (HR 0.98 [0.72-1.32], p=.87) and relapse (HR 0.87, [0.70-1.08], p=.20) as the MSD group. Younger donors age was a significant predictor of improved OS. Next, we directly compared the outcomes of 'younger' haploidentical (donor age <35 years, n=347) versus an 'older' MSD (donor age >=50 years, n=143) in 'older' recipients (patient age >=50 years). Patients with 'younger' haploidentical B-leader matched donors had significantly superior OS (HR 0.65, [0.48-0.90], p=.009) compared to 'older' MSD group. Additionally, patients with 'younger' DRB1-mismatched haploidentical donors (HR 0.63 [0.46-0.87], p=.004) had significantly lower risk of relapse than 'older' MSDs. Our study suggests that haploidentical-HCT may offer comparable outcomes to MSD-PTCy HCT. Moreover, among 'older' patients, a 'younger' haploidentical B-leader matched donor might be preferable to an 'older' MSD. These findings need validation in larger datasets.

Interleukin-21 engineering enhances NK cell activity against glioblastoma via CEBPD.

Glioblastoma (GBM) is an aggressive brain cancer with limited therapeutic options. Natural killer (NK) cells are innate immune cells with strong anti-tumor activity and may offer a promising treatment strategy for GBM. We compared the anti-GBM activity of NK cells engineered to express interleukin (IL)-15 or IL-21. Using multiple in vivo models, IL-21 NK cells were superior to IL-15 NK cells both in terms of safety and long-term anti-tumor activity, with locoregionally administered IL-15 NK cells proving toxic and ineffective at tumor control. IL-21 NK cells displayed a unique chromatin accessibility signature, with CCAAT/enhancer-binding proteins (C/EBP), especially CEBPD, serving as key transcription factors regulating their enhanced function. Deletion of CEBPD resulted in loss of IL-21 NK cell potency while its overexpression increased NK cell long-term cytotoxicity and metabolic fitness. These results suggest that IL-21, through C/EBP transcription factors, drives epigenetic reprogramming of NK cells, enhancing their anti-tumor efficacy against GBM.

Elucidating immune-related gene transcriptional programs via factorization of large-scale RNA-profiles.

Recent developments in immunotherapy, including immune checkpoint blockade (ICB) and adoptive cell therapy (ACT), have encountered challenges such as immune-related adverse events and resistance, especially in solid tumors. To advance the field, a deeper understanding of the molecular mechanisms behind treatment responses and resistance is essential. However, the lack of functionally characterized immune-related gene sets has limited data-driven immunological research. To address this gap, we adopted non-negative matrix factorization on 83 human bulk RNA sequencing (RNA-seq) datasets and constructed 28 immune-specific gene sets. After rigorous immunologist-led manual annotations and orthogonal validations across immunological contexts and functional omics data, we demonstrated that these gene sets can be applied to refine pan-cancer immune subtypes, improve ICB response prediction and functionally annotate spatial transcriptomic data. These functional gene sets, informing diverse immune states, will advance our understanding of immunology and cancer research.

Mitigating infection risks: The promise and challenge of bispecific antibodies in haematological malignancies.

Bispecific antibodies have shown significant clinical efficacy in patients with relapsed/refractory B-cell non-Hodgkin lymphomas and multiple myeloma, expanding treatment options for these patients. While these advancements are promising, it is important to be aware of associated side effects, such as cytokine release syndrome, neutropenia and infections. Gonugunta et al. provide valuable insights into the infection risks linked to the use of bispecific antibodies in haematological malignancies, drawing on both clinical trial data and real-world experiences. Commentary on: Gonugunta et al. Risk of infections with bispecific antibodies in B-cell non-Hodgkin lymphomas and multiple myeloma-The current state. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19633.

CD28 costimulation augments CAR signaling in NK cells via the LCK/CD3Z/ZAP70 signaling axis.

Multiple factors in the design of a chimeric antigen receptor (CAR) influence CAR T-cell activity, with costimulatory signals being a key component. Yet, the impact of costimulatory domains on the downstream signaling and subsequent functionality of CAR-engineered natural killer (NK) cells remains largely unexplored. Here, we evaluated the impact of various costimulatory domains on CAR-NK cell activity, using a CD70-targeting CAR. We found that CD28, a costimulatory molecule not inherently present in mature NK cells, significantly enhanced the antitumor efficacy and long-term cytotoxicity of CAR-NK cells both in vitro and in multiple xenograft models of hematologic and solid tumors. Mechanistically, we showed that CD28 linked to CD3Z creates a platform that recruits critical kinases, such as LCK and ZAP70, initiating a signaling cascade that enhances CAR-NK cell function. Our study provides insights into how CD28 costimulation enhances CAR-NK cell function and supports its incorporation in NK-based CARs for cancer immunotherapy.

Elucidating immune-related gene transcriptional programs via factorization of large-scale RNA-profiles.

Recent developments in immunotherapy, including immune checkpoint blockade (ICB) and adoptive cell therapy, have encountered challenges such as immune-related adverse events and resistance, especially in solid tumors. To advance the field, a deeper understanding of the molecular mechanisms behind treatment responses and resistance is essential. However, the lack of functionally characterized immune-related gene sets has limited data-driven immunological research. To address this gap, we adopted non-negative matrix factorization on 83 human bulk RNA-seq datasets and constructed 28 immune-specific gene sets. After rigorous immunologist-led manual annotations and orthogonal validations across immunological contexts and functional omics data, we demonstrated that these gene sets can be applied to refine pan-cancer immune subtypes, improve ICB response prediction and functionally annotate spatial transcriptomic data. These functional gene sets, informing diverse immune states, will advance our understanding of immunology and cancer research.

Mortality in recipients of allogeneic haematopoietic cell transplantation in the era of cytomegalovirus primary prophylaxis: a single-centre retrospective experience.

OBJECTIVES: Allogeneic haematopoietic cell transplant (allo-HCT) recipients who are cytomegalovirus (CMV)-seronegative have better post-transplant outcomes than CMV-seropositive recipients. Letermovir (LTV) is approved for CMV primary prophylaxis in adults who are CMV-seropositive after allo-HCT, and its use is associated with improved long-term post-transplant outcomes. We analysed whether LTV has affected the relationship between CMV serostatus and post-transplant outcomes. METHODS: We conducted a retrospective single-centre cohort study of allo-HCT recipients, stratified according to donor (D) and recipient (R). CMV serostatus and the use of LTV: D-/R-, R+/LTV-, and R+/LTV+. Outcomes measured were all-cause and non-relapse mortality, clinically significant CMV infection, graft-versus-host disease, and relapse up to week 48 after allo-HCT. The D-/R- group served as the reference for comparisons in univariate, competing risk regression, and cumulative incidence functions. RESULTS: The analysis included 1071 consecutive allo-HCT recipients: 131 D-/R-, 557 R+/LTV-, and 383 R+/LTV+. All-cause mortality by day 100 was 6.1% for the D-/R- group, compared with 14.0% (p 0.024) and 7.8% (p 0.7) for the R+/LTV- and R+/LTV + groups, respectively. Non-relapse mortality by day 100 was 11.0%, 6.8% and 3.8% for R+/LTV-, R+/LTV+, and D-/R- groups, respectively, without significant difference. When including relapse as a competing event, the hazard ratio for non-relapse mortality was 1.83 (95% CI: 1.12-2.99, p 0.017) for R+/LTV- compared with D-/R- and 1.05 (95% CI 0.62-1.77, p 0.85) for R+/LTV + compared with D-/R-. DISCUSSION: CMV primary prophylaxis with LTV abrogated the mortality gap based on CMV serostatus, a protective effect that persisted after discontinuation of primary prophylaxis.

Results of a phase I trial with Haploidentical mbIL-21 ex vivo expanded NK cells for patients with multiply relapsed and refractory AML.

Natural killer (NK)-cells have potent anti-tumor effects, yet it remains unclear if they are effective for patients with relapsed acute myeloid leukemia (AML). In a phase I clinical trial, we treated 12 patients (median age 60 years) with refractory AML (median 5 lines of prior therapy, median bone marrow blast count of 47%) with fludarabine/cytarabine followed by 6 infusions of NK-cells expanded from haploidentical donors using K562 feeder cells expressing membrane-bound IL21 and 4-1BBL. Patients received 106-107/kg/dose. No toxicity or graft-versus-host disease (GVHD) was observed and MTD was not reached. Seven patients (58.3%) responded and achieved a complete remission (CR) with/without count recovery. Median time to best response was 48 days. Five responding patients proceeded to a haploidentical transplant from the same donor. After a median follow-up of 52 months, 1-year overall survival (OS) for the entire group was 41.7%, better for patients who responded with CR/CRi (57.14%), and for patients who responded and underwent transplantation (60%). Persistence and expansion of donor-derived NK-cells were identified in patients' blood, and serum IFNγ levels rose concurrently with NK cell infusions. A higher count-functional inhibitory KIR was associated with higher likelihood of achieving CR/CRi. In conclusion, we observed a significant response to ex vivo expanded NK-cell administration in refractory AML patients without adverse effects.

Eltrombopag improves platelet engraftment after haploidentical bone marrow transplantation: Results of a Phase II study.

Slow platelet recovery frequently occurs after haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with bone marrow graft and post-transplant cyclophosphamide (PCy)-based graft-versus-host disease (GVHD) prophylaxis. Improved platelet recovery may reduce the need for transfusions and improve outcomes. We investigated the safety and efficacy of eltrombopag, a thrombopoietin receptor agonist, at enhancing platelet recovery post-haplo-HSCT. The prospective study included patients ≥18 years of age who received haplo-HSCT with bone marrow graft and PCy. Patients received eltrombopag 300 mg/day starting on Day +5. The primary objective was to estimate platelet engraftment (>50 000/µL by Day 60). In a post hoc analysis, they were compared to a contemporary matched control group who did not receive eltrombopag. One hundred ten patients were included in the analysis (30 eltrombopag and 80 control). Seventy-three percent and 50% of patients in the eltrombopag group and control group, respectively, attained >50 000/µL platelet count by Day 60 (p = .043). No eltrombopag-related grade ≥4 adverse events were observed. Median time to platelet recovery (>20 000/µL) was 29 days with eltrombopag and 31 days for controls (p = .022), while its cumulative incidence was 90% (95% confidence interval [CI]: 78%-100%) with eltrombopag versus 67.5% (95% CI: 57%-78%) for controls (p = .014). Number of platelet transfusions received, overall survival, progression-free survival, GVHD rate, relapse rate, and non-relapse mortality were similar between groups. Overall, eltrombopag is safe and improves platelet recovery in patients undergoing haplo-HSCT with bone marrow graft and PCy.

Increased expression of CD70 in relapsed acute myeloid leukemia after hypomethylating agents.

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. While induction chemotherapy leads to remission in most patients, a significant number will experience relapse. Therefore, there is a need for novel therapies that can improve remission rates in patients with relapsed and refractory AML. CD70 is the natural ligand for CD27 (a member of the TNF superfamily) and appears to be a promising therapeutic target. Consequently, there is considerable interest in developing chimeric antigen receptor (CAR) T-cell therapy products that can specifically target CD70 in various neoplasms, including AML. In this study, we employed routine diagnostic techniques, such as immunohistochemistry and flow cytometry, to investigate the expression of CD70 in bone marrow samples from treatment-naïve and relapsed AML patients after hypomethylating agents (HMA). Also, we evaluated the impact of HMA on CD70 expression and examined CD70 expression in various leukemic cell subsets and normal hematopoietic progenitors.

Incidence and risk factors of early onset VOD/SOS differ in younger vs older adults after stem cell transplantation.

ABSTRACT: Veno-occlusive disease (VOD) is a rare but potentially life-threatening complication after allogeneic hematopoietic stem cell transplantation (allo-SCT). Although increasing awareness and modern transplant techniques have mitigated risk, the interaction of historic risk factors in the current era with posttransplant cyclophosphamide (PTCy) is unknown. We performed a retrospective single-center analysis of adult patients aged ≥18 years undergoing allo-SCT (N = 1561) using predominately PTCy as graft-versus-host disease (GVHD) prophylaxis (72%). We found a higher rate of VOD at 16.8% (20 of 119) in those aged ≤25 years compared with 3.8% (55 of 1442) in those aged >25 years, with unique predictors of VOD within each cohort. Multivariate classification and regression tree (CART) analysis confirmed age as the primary independent determinant of the rate of VOD. Among patients aged 18 to 25 years, disease risk index (DRI; 31% with high/very high DRI vs 12% low/intermediate DRI; P = .03) and prior lines of chemotherapy (24% with >1 vs 6% with ≤1; P = .03) were the strongest predictors of VOD. Incidence of VOD in patients aged >25 years of age consistently ranged between 3% and 5% across most risk factors evaluated, with only hepatic factors (baseline elevation of bilirubin, aspartate transferase, alanine aminotransferase) or gemtuzumab exposure associated with increased rates of VOD. There was no significant difference in rates of VOD in those receiving PTCy compared with those receiving alternate GVHD prophylaxis. Our data highlight the differences in incidence and predictors of VOD between younger (≤25) and older (>25) adults undergoing allo-SCT.

Safety, efficacy and determinants of response of allogeneic CD19-specific CAR-NK cells in CD19+ B cell tumors: a phase 1/2 trial.

There is a pressing need for allogeneic chimeric antigen receptor (CAR)-immune cell therapies that are safe, effective and affordable. We conducted a phase 1/2 trial of cord blood-derived natural killer (NK) cells expressing anti-CD19 chimeric antigen receptor and interleukin-15 (CAR19/IL-15) in 37 patients with CD19+ B cell malignancies. The primary objectives were safety and efficacy, defined as day 30 overall response (OR). Secondary objectives included day 100 response, progression-free survival, overall survival and CAR19/IL-15 NK cell persistence. No notable toxicities such as cytokine release syndrome, neurotoxicity or graft-versus-host disease were observed. The day 30 and day 100 OR rates were 48.6% for both. The 1-year overall survival and progression-free survival were 68% and 32%, respectively. Patients who achieved OR had higher levels and longer persistence of CAR-NK cells. Receiving CAR-NK cells from a cord blood unit (CBU) with nucleated red blood cells ≤ 8 × 107 and a collection-to-cryopreservation time ≤ 24 h was the most significant predictor for superior outcome. NK cells from these optimal CBUs were highly functional and enriched in effector-related genes. In contrast, NK cells from suboptimal CBUs had upregulation of inflammation, hypoxia and cellular stress programs. Finally, using multiple mouse models, we confirmed the superior antitumor activity of CAR/IL-15 NK cells from optimal CBUs in vivo. These findings uncover new features of CAR-NK cell biology and underscore the importance of donor selection for allogeneic cell therapies. ClinicalTrials.gov identifier: NCT03056339 .

Effect of donor age in patients with acute myeloid leukemia undergoing haploidentical hematopoietic cell transplantation vary by conditioning intensity and recipient age.

We investigated the impact of donor age (younger [≤35 years] vs. older [>35 years]) after accounting for other non-HLA and HLA factors on outcomes of patients with acute myeloid leukemia undergoing HLA-haploidentical hematopoietic cell transplantation (n = 790). The effect differed by conditioning-partly related to the differences in the recipient age in myeloablative (MAC; median 46 years) versus reduced-intensity/non-myeloablative conditioning (RIC/NMA; median 61 years) groups. With MAC (n = 320), donor age had no impact on acute graft-versus-host disease (GVHD), but older donors were associated with a significantly higher risk of chronic GVHD (hazard ratio [HR]: 1.6, 95% confidence interval [CI]: 1.10-2.30, p = .02) independent of recipient age and other factors. Donor age had no impact on either relapse or non-relapse mortality (NRM). The impact of donor/recipient age on overall survival changed over time. Older donors were associated with significantly higher late overall mortality (>6 months) in younger recipients (≤ 50 years; HR: 2.2, 95% CI: 1.03-4.6, p = .04) but not older recipients. With RIC/NMA (n = 470), neither recipient's nor donor's age influenced the risk of GVHD. Donor age had no significant impact on the risk of relapse, but older donors were associated with a significantly higher risk of NRM (HR: 1.6, 95% CI: 1.02-2.6, p = .04) independent of recipient age. Older donor age was associated with significantly higher late overall mortality (>9 months) in older recipients (>50 years; HR: 1.66, 95% CI: 1.0-2.67; p = .049) but not in younger recipients. Donor selection based on donor age may require a tailored approach for a particular recipient.

Generation of Non-Alloreactive Antiviral Central Memory CD8 Human Veto T Cells for Cell Therapy.

Previous studies in mice demonstrated that CD8 T cells exhibit marked veto activity enhancing engraftment in several models for T cell-depleted bone marrow (TDBM) allografting. To reduce the risk of graft-versus-host disease (GVHD) associated with allogeneic CD8 veto T cells, these studies made use of naive CD8 T cells stimulated against third-party stimulators under cytokine deprivation and subsequent expansion in the presence of IL-15. More recently, it was shown that mouse CD8 veto T cells can be generated by stimulating CD8 memory T cells from ovalbumin immunized mice under cytokine deprivation, using ovalbumin as a third-party antigen. These cells also exhibited substantial enhancement of BM allografting without GVHD. In this study, we tested the hypothesis that stimulation and expansion of human CD8 memory T cells under IL-15 and IL-7 deprivation during the early phase of activation against recall viral antigens can lead to substantial loss of alloreactive T clones while retaining marked veto activity. Memory CD8 T cells were enriched by removal of CD45RA+, CD4+, and CD56+ cells from peripheral blood of cytomegalovirus (CMV)- and Epstein-Barr virus (EBV)-positive donors. In parallel, CD14+ monocytes were isolated; differentiated into mature dendritic cells (mDCs); pulsed with a library of CMV, EBV, adenovirus, and BK virus peptides; and irradiated. The CD8 T cell-enriched fraction was then cultured with the pulsed mDCs in the presence of IL-21 for 3 days, after which IL-15 and IL-7 were added. After 12 days of culture, the cells were tested by limiting dilution analysis for the frequency of alloreactive T cell clones and their veto activity. In preclinical runs using GMP reagents, we established that within 12 days of culture, a large number of highly homogenous CD8 T cells, predominantly expressing a central memory phenotype, could be harvested. These cells exhibited marked veto activity in vitro and >3-log depletion of alloreactivity. Based on these preclinical data, a phase 1-2 clinical trial was initiated to test the safety and efficacy of these antiviral CD8 central memory veto cells in the context of nonmyeloablative (NMA) T cell-depleted haploidentical hematopoietic stem cell transplantation (HSCT). In 2 validation runs and 11 clinical runs using GMP reagents, >1 × 1010 cells were generated from a single leukapheresis in 12 out of 13 experiments. At the end of 12 days of culture, there were 97 ± 2.5% CD3+CD8+ T cells, of which 84 ± 9.0% (range, 71.5% to 95.1%) exhibited the CD45RO+CD62L+ CM phenotype. Antiviral activity tested by intracellular expression of INF-γ and TNF-α and showed an average of 38.8 ± 19.6% positive cells on 6 hours of stimulation against the viral peptide mixture. Our results demonstrate a novel approach for depleting alloreactive T cell clones from preparations of antiviral CD8 veto cells. Based on these results, a phase 1-2 clinical trial is currently in progress to test the safety and efficacy of these veto cells in the context of NMA haploidentical T cell-depleted HSCT. Studies testing the hypothesis that these non-alloreactive CD8 T cells could potentially offer a platform for off-the-shelf veto chimeric antigen receptor T cell therapy in allogenic recipients, are warranted.

Ex Vivo Expanded Cord Blood Natural Killer Cells Combined with Rituximab and High-Dose Chemotherapy and Autologous Stem Cell Transplantation for B Cell Non-Hodgkin Lymphoma.

Relapse is the major cause of failure of high-dose chemotherapy (HDC) with autologous stem cell transplantation (ASCT) for B cell non-Hodgkin lymphomas (B-NHL). Improvement strategies include use in combination with effective immunotherapies. We hypothesized that the combination of rituximab/HDC/ASCT with expanded cord blood (CB)-derived natural killer (NK) cells is safe and active in B-NHL. Patients with B-NHL age 15 to 70 years and appropriate ASCT candidates were eligible for the study. The CB units were selected without considering HLA match with the recipient. The CB NK cells were expanded from day -19 to day -5. Treatment included rituximab on days -13 and -7, BEAM (carmustine/etoposide/cytarabine/melphalan) on days -13 to -7, lenalidomide on days -7 to -2, CB NK infusion (108/kg) on day -5, and ASCT (day 0). The primary endpoint was 30-day treatment-related mortality (TRM); secondary endpoints included relapse-free survival (RFS), overall survival (OS), and persistence of CB NK cells. We enrolled 20 patients. CB NK cells were expanded a median of 1552-fold with >98% purity and >96% viability. We saw no adverse events attributable to the CB NK cells and 0% 30-day TRM. At median follow-up of 47 months, the RFS and OS rates were 53% and 74%, respectively. CB NK cells were detectable in blood for 2 weeks, independent of HLA-mismatch status. CD16 expression in donor NK cells was correlated favorably with outcome, and homozygosity for the high-affinity CD16 variant (158 V/V) in CB, but not recipient, NK cells was correlated with better outcomes. Our data indicate that the combination of expanded and highly purified CB-derived NK cells with HDC/ASCT for B-NHL is safe. CD16 expression in donor NK cells, particularly if homozygous for the high-affinity CD16 variant, was correlated with better outcomes.