rs822336 binding to C/EBPß and NFIC modulates induction of PD-L1 expression and predicts anti-PD-1/PD-L1 therapy in advanced NSCLC.

Efficient predictive biomarkers are needed for immune checkpoint inhibitor (ICI)-based immunotherapy in non-small cell lung cancer (NSCLC). Testing the predictive value of single nucleotide polymorphisms (SNPs) in programmed cell death 1 (PD-1) or its ligand 1 (PD-L1) has shown contrasting results. Here, we aim to validate the predictive value of PD-L1 SNPs in advanced NSCLC patients treated with ICIs as well as to define the molecular mechanisms underlying the role of the identified SNP candidate. rs822336 efficiently predicted response to anti-PD-1/PD-L1 immunotherapy in advanced non-oncogene addicted NSCLC patients as compared to rs2282055 and rs4143815. rs822336 mapped to the promoter/enhancer region of PD-L1, differentially affecting the induction of PD-L1 expression in human NSCLC cell lines as well as their susceptibility to HLA class I antigen matched PBMCs incubated with anti-PD-1 monoclonal antibody nivolumab. The induction of PD-L1 expression by rs822336 was mediated by a competitive allele-specificity binding of two identified transcription factors: C/EBPß and NFIC. As a result, silencing of C/EBPß and NFIC differentially regulated the induction of PD-L1 expression in human NSCLC cell lines carrying different rs822336 genotypes. Analysis by binding microarray further validated the competitive allele-specificity binding of C/EBPß and NFIC to PD-L1 promoter/enhancer region based on rs822336 genotype in human NSCLC cell lines. These findings have high clinical relevance since identify rs822336 and induction of PD-L1 expression as novel biomarkers for predicting anti-PD-1/PD-L1-based immunotherapy in advanced NSCLC patients.

Effective Neutralizing Antibody Response Against SARS-CoV-2 Virus and Its Omicron BA.1 Variant in Fully Vaccinated Hematological Patients.

SARS-CoV-2 and its variants cause CoronaVIrus Disease 19 (COVID-19), a pandemic disease. Hematological malignancies increase susceptibility to severe COVID-19 due to immunosuppression. Anti-SARS-CoV-2 neutralizing antibodies protect against severe COVID-19. This retrospective real-life study aimed to evaluate seropositivity and neutralizing antibody rates against SARS-CoV-2 and its Omicron BA.1 variant in hematological patients. A total of 106 patients with different hematologic malignancies, who have mostly received three or more vaccine doses (73%), were included in this study. Serum was collected between May and June 2022. The primary endpoint was anti-SARS-CoV-2 antibody response against ancestral (wild type; wt) and Omicron BA.1 virus, defined as a neutralizing antibody titer ≥ 1:10. Adequate neutralizing antibody response was observed in 75 (71%) and 87 (82%) of patients for wt and Omicron BA.1 variants, respectively.However, patients with B-cell lymphoproliferative disorders and/or those treated with anti-CD20 monoclonal antibodies in the prior 12 months showed a lower seropositivity rate compared to other patients against both Omicron BA.1 variant (73% vs 91%; P = 0.02) and wt virus (64% vs 78%; P = 0.16). Our real-life experience confirmed that full vaccination against SARS-CoV-2 induces adequate neutralizing antibody protection for both the wt virus and Omicron BA.1 variants, even in hematological frail patients. However, protective measures should be maintained in hematological patients, especially those with B-cell lymphoproliferative diseases treated with anti-CD20 monoclonal antibodies, because these subjects could have a reduced neutralizing antibody production.

Subclones with variants of uncertain clinical significance might contribute to ineffective hemopoiesis and leukemia predisposition.

BACKGROUND: Splicing modifications, genomic instability, and hypomethylation are central mechanisms promoting myelodysplasia and acute myeloid leukemia (AML). In this real-life retrospective study, to elucidate pathophysiology of clonal hemopoiesis in hematological malignancies, we investigated clinical significance of mutations in leukemia-related genes of known pathogenetic significance and of variants of uncertain clinical significance (VUS) in a cohort of patients with MDS and AML. METHODS: A total of 59 consecutive subjects diagnosed with MDS, 48 with AML, and 17 with clonal cytopenia with unknown significance were screened for somatic mutations in AML-related genes by next-generation sequencing. RESULTS: We showed that TET2, SETBP1, ASXL1, EZH2, RUNX1, SRSF2, DNMT3A, and IDH1/2 were commonly mutated. MDS patients also showed a high genetic complexity, especially for SETBP1. Moreover, the presence of SETBP1 wild-type or two or more simultaneous VUS variants identified a subgroup of AML and MDS patients with better outcome, while the presence of single SETBP1 VUS variant was related to a worse prognosis, regardless TET2 mutational status. CONCLUSIONS: In conclusions, we linked both pathogenic and VUS variants in AML-related genes to clonal hematopoiesis; therefore, we proposed to consider those variants as prognostic markers in leukemia and myelodysplasia. However, further studies in larger prospective cohorts are required to validate our results.

c-Kit M541L variant is related to ineffective hemopoiesis predisposing to clonal evolution in 3D in vitro biomimetic co-culture model of bone marrow niche.

Hematopoietic stem cell (HSC) maintenance in vitro is challenging because stem cell survival relies on cell-to-cell contacts and paracrine signals from bone marrow (BM) microenvironment. Indeed, HSCs easily differentiate in conventional culture systems, and in vitro study of stem cell biology, leukemogenesis, and evolutionary trajectories is limited. 3D-culture systems can mimic tissue architecture and microenvironment thus preserving HSC phenotype. In this study, we developed a calcium alginate hydrogel-based 3D co-culture system of BM mononuclear cells (BMMCs) and BM-derived mesenchymal stem cells (BM-MSCs) to study hemopoiesis in health and disease, such as biological roles of c-Kit M541L somatic mutation of unknown significance. BMMCs and peripheral blood stem cells were obtained from an acute myeloid leukemia patient who experienced graft failure and his haploidentical donor, and from a healthy donor. Cells embedded in alginate scaffolds were cultured for up to 21 days, and flow cytometry immunophenotyping was performed at baseline and every seven days. Our results showed suitability of our 3D culture system in preserving HSC vitality and phenotype throughout the culture period, and also in maintaining composition and vitality of total BMMCs. Moreover, 3D in vitro culture results suggested that M541L c-Kit somatic mutation could be a loss-of-function alteration by reducing HSC maintenance ability thus quickly promoting differentiation, as documented by in vivo graft failure and in vitro absence of long-term culture stability. In conclusions, our 3D BM-like biomimetic culture system allowed long-term stemness maintenance, making it a valid and effective tool for in vitro study of physiological and pathological hemopoiesis.

Efficacy of Decitabine and Venetoclax as Salvage and Bridge Therapy to Haploidentical Hematopoietic Stem Cell Transplantation in a Multiresistant Acute Myeloid Leukemia Patient.

Treatment of relapsed/refractory or elderly unfit acute myeloid leukemia (AML) is still challenging, and hypomethylating agents in combination with venetoclax, an oral selective BCL2 inhibitor, might be successfully used as salvage therapy. However, clinical trials evaluating the efficacy and safety of this combination in the setting of multiresistant AML treatment also as a bridge to transplant are still ongoing. Here, we reported a 50-year-old male diagnosed with AML with normal cytogenetics and wild type for fms-like tyrosine kinase 3, nucleophosmin 1, and KIT, and treated with decitabine and venetoclax as the fifth line of therapy and after a relapse post-allogeneic transplant. The patient achieved a complete remission and successfully underwent a haploidentical transplant with an overall survival of 48.6 months.

Clinical efficacy of azacytidine and venetoclax and prognostic impact of Tim-3 and galectin-9 in acute myeloid leukemia and high-risk myelodysplastic syndromes: A single-center real-life experience.

Treatment of acute myeloid leukemia (AML) and high-risk myelodysplastic syndromes (MDS) is difficult in older patients with comorbidities and high-risk disease factors. Venetoclax, the first-in-class Bcl-2 inhibitor, has proven efficacy and safety in combination with azacytidine for treatment of high-risk myeloid diseases. In this single-center real-life retrospective study, a total of 27 consecutive patients treated with azacytidine plus venetoclax were included, and clinical outcomes, hematological improvements, and biomarkers of responsiveness to therapy were compared to those observed in an historical cohort of 95 consecutive patients treated with azacytidine as single agent. Azacytidine plus venetoclax was effective and safe in older and frail AML and high-risk MDS patients, with median overall survival of 22.3 months, higher than that reported in phase III trial (14.7 months), and higher than that of historical cohort (5.94 months). Progression-free survival was higher in patients treated with the drug combination compared to those treated with azacytidine as single agent (p = 0.0065). Clinical benefits might increase when azacytidine and venetoclax are administered as upfront therapy (p = 0.0500). We showed that Tim-3 expression could be a promising therapeutic target in refractory/relapsed patients, and galectin-9 a biomarker of responsiveness to therapy. Moreover, patients treated with azacytidine and venetoclax displayed a higher overall survival regardless the presence of negative prognostic markers at diagnosis (e.g., increased WT1 copies and/or normalized blast count). These encouraging results in a real-world setting supported efficacy and safety of azacytidine plus venetoclax as upfront therapy in AML and high-risk MDS, with clinical outcomes comparable to those of clinical trials when an appropriate venetoclax management with bone marrow assessment at every first, second, fourth, and eighth cycle, and dose adjustments for toxicities are performed.

WT1 Expression Levels Combined with Flow Cytometry Blast Counts for Risk Stratification of Acute Myeloid Leukemia and Myelodysplastic Syndromes.

Wilm's tumor 1 (WT1), a zinc-finger transcription factor and an epigenetic modifier, is frequently overexpressed in several hematologic disorders and solid tumors, and it has been proposed as diagnostic and prognostic marker of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). However, the exact role of WT1 in leukemogenesis and disease progression remains unclear. In this real-world evidence retrospective study, we investigated prognostic role of WT1-mRNA expression levels in AML and MDS patients and correlations with complete blood counts, flow cytometry counts, and molecular features. A total of 71 patients (AML, n = 46; and MDS, n = 25) were included in this study, and WT1 levels were assessed at diagnosis, during treatment and follow-up. We showed that WT1 expression levels were inversely correlated with normal hemopoiesis in both AML and MDS, and positively associated with blast counts. Flow cytometry was more sensitive and specific in distinguishing normal myeloid cells from neoplastic counterpart even just using linear parameters and CD45 expression. Moreover, we showed that a simple integrated approach combining blast counts by flow cytometry, FLT3 mutational status, and WT1 expression levels might be a useful tool for a better prognostic definition in both AML and MDS patients.

Prophylactic letermovir decreases cytomegalovirus reactivation after stem cell transplantation: a single-center real-world evidence study.

Cytomegalovirus (CMV) reactivation is a major cause of morbidity and mortality after organ or hematopoietic stem cell transplantation (HSCT). Letermovir (LTV) is a novel antiviral agent approved for CMV prophylaxis after allogeneic transplantation. In this single-center real-world study, we evidenced the efficacy and safety of LTV for CMV prophylaxis in allogeneic HSCT recipients. A total of 133 consecutive patients who underwent autologous or allogeneic HSCT were included in the study, and a subgroup of 13 allogeneic HSCT recipients received CMV prophylaxis with LTV 240 mg/daily from day +7 to +100 (allo-LTV cohort). All patients in the allo-LTV cohort were at moderate or high risk of reactivation based on donor/recipient serology status, and 62% also received haploidentical HSCT and cyclophosphamide which further increased the CMV reactivation risk. CMV infection rate was also compared to that observed in allogeneic HSCT patients without CMV prophylaxis and autologous recipients who have the lowest reported CMV infection incidence and were used as a control cohort. In our experience, patients receiving LTV showed a significant decline in CMV reactivation incidence to similar rates described in autologous HSCT recipients (7.7% of allogeneic LTV-treated vs 68% of allogeneic recipients without prophylaxis vs 15% of autologous patients; p> 0.0001). The only patient in the allo-LTV cohort with CMV reactivation was a 25-year-old female with a diagnosis of very high-risk acute lymphoblastic leukemia who received a haploidentical HSCT after ex vivo T cell depletion. CMV reactivation occurred beyond LTV course, at +187 days from transplantation. In addition, we confirmed efficacy and safety of valganciclovir 450 mg/daily as pre-emptive therapy or for treatment of CMV disease in allogeneic and autologous HSCT recipients who experienced CMV reactivation even after LTV prophylaxis. However, further clinical trials in larger populations and longer follow-up are required to confirm our preliminary results.