Choice of Frontline Tyrosine-Kinase Inhibitor and Early Events in Very Elderly Patients With Chronic Myeloid Leukemia in Chronic Phase: A "Campus CML" Study.

OBJECTIVES: The study aimed to evaluate the utilization of frontline TKI therapy in a large cohort of elderly CP-CML patients. METHODS: A retrospective analysis was conducted on 332 CP-CML patients aged 75 years or older among 1929 diagnosed from January 2012 to December 2019 followed at 36 participating Hematology Centers involved in the "Campus CML" project. RESULTS: Among the patients analyzed, 85.8% received imatinib (IM) while 14.2% received second-generation TKIs (2G-TKI), 59.5% dasatinib, and 40.5% nilotinib. Most patients initiated IM at standard dose (67.3%) while 32.7% at reduced dose. A similar trend was observed with 2G-TKIs. The cumulative incidence of permanent TKI discontinuation at 12 months was 28.4%, primarily due to primary resistance (10.1%) and extra-hematologic toxicity (9.5%), with no significant difference between IM and 2G-TKI groups. Following the introduction of generic IM in Italy in 2018, IM usage increased significantly compared with 2G-TKIs. CONCLUSIONS: IM was in our Centers the preferred frontline therapy for older CP-CML patients, with increasing utilization after the introduction of generic formulations. However, 2G-TKIs are still used in a substantial proportion of patients, suggesting individualized physician assessments regarding patient suitability and expectations. Further investigation is needed to assess efficacy and safety of reduced TKI doses in this patient population.

FLT3-targeted therapy restores GATA1 pathway function in NPM1/FLT3-ITD mutated acute myeloid leukaemia.

One-third of newly diagnosed adult acute myeloid leukaemia (AML) carry FLT3 mutations, which frequently occur together with nucleophosmin (NPM1) mutations and are associated with worse prognosis. FLT3 inhibitors are widely used in clinics with limitations due to drug resistance. AML cells carrying FLT3 mutations in both mouse models and patients present low expression of GATA1, a gene involved in haematopoietic changes preceding AML. Here, we show that FLT3 inhibition induces cellular responses and restores the GATA1 pathway and functions in NPM1/FLT3-ITD mutated AML, thus providing a new mechanism of action for this drug.

Mouse models of NPM1-mutated acute myeloid leukemia: biological and clinical implications.

Acute myeloid leukemia (AML) carrying nucleophosmin (NPM1) mutations displays distinct biological and clinical features that led to its inclusion as a provisional disease entity in the 2008 World Health Organization (WHO) classification of myeloid neoplasms. Studies of the molecular mechanisms underlying the pathogenesis of NPM1-mutated AML have benefited greatly from several mouse models of this leukemia developed over the past few years. Immunocompromised mice xenografted with NPM1-mutated AML served as the first valuable tool for defining the biology of the disease in vivo. Subsequently, genetically engineered mouse models of the NPM1 mutation, including transgenic and knock-in alleles, allowed the generation of mice with a constant genotype and a reproducible phenotype. These models have been critical for investigating the nature of the molecular effects of these mutations, defining the function of leukemic stem cells in NPM1-mutated AML, identifying chemoresistant preleukemic hemopoietic stem cells and unraveling the key molecular events that cooperate with NPM1 mutations to induce AML in vivo. Moreover, they can serve as a platform for the discovery and validation of new antileukemic drugs in vivo. Advances derived from the analysis of these mouse models promise to greatly accelerate the development of new molecularly targeted therapies for patients with NPM1-mutated AML.

The glucocorticoid-induced TNF receptor family-related protein (GITR) is critical to the development of acute pancreatitis in mice.

BACKGROUND AND PURPOSE: Pancreatitis represents a life-threatening inflammatory condition where leucocytes, cytokines and vascular endothelium contribute to the development of the inflammatory disease. The glucocorticoid-induced tumour necrosis factor (TNF) receptor family-related protein (GITR) is a costimulatory molecule for T lymphocytes, modulates innate and adaptive immune system and has been found to participate in a variety of immune responses and inflammatory processes. Our purpose was to verify whether inhibition of GITR triggering results in a better outcome in experimental pancreatitis. EXPERIMENTAL APPROACH: In male GITR knock-out (GITR(-/-)) and GITR(+/+) mice on Sv129 background, acute pancreatitis was induced after i.p. administration of cerulein. Other experimental groups of GITR(+/+) mice were also treated with different doses of Fc-GITR fusion protein (up to 6.25 µg·mouse⁻¹), given by implanted mini-osmotic pump. Clinical score and pro-inflammatory parameters were evaluated. KEY RESULTS: A less acute pancreatitis was found in GITR(-/-) mice than in GITR(+/+) mice, with marked differences in oedema, neutrophil infiltration, pancreatic dysfunction and injury. Co-treatment of GITR(+/+) mice with cerulein and Fc-GITR fusion protein (6.25 µg·mouse⁻¹) decreased the inflammatory response and tissue injury, compared with treatment with cerulein alone. Inhibition of GITR triggering was found to modulate activation of nuclear factor κB as well as the production of TNF-α, interleukin-1ß, inducible nitric oxide synthase, nitrotyrosine, poly-ADP-ribose, intercellular adhesion molecule-1 and P-selectin. CONCLUSIONS AND IMPLICATIONS: The GITR-GITR ligand system is crucial to the development of acute pancreatitis in mice. Our results also suggest that the Fc-GITR fusion protein could be useful in the treatment of acute pancreatitis.

The leukemia-associated cytoplasmic nucleophosmin mutant is an oncogene with paradoxical functions: Arf inactivation and induction of cellular senescence.

Mutations leading to aberrant cytoplasmic localization of Nucleophosmin 1 (NPM1) have been recently identified as the most frequent genetic alteration in acute myelogenous leukemia. However, the oncogenic potential of this nucleophosmin mutant (NPMc+) has never been established, which casts doubt on its role in leukemogenesis. By performing classical transformation assays, we find that NPMc+, but not wild-type NPM, cooperates specifically with adenovirus E1A to transform primary mouse embryonic fibroblasts in soft agar. We demonstrate that NPMc+ blocks the p19(Arf) (Arf) induction elicited by E1A. Surprisingly, however, we find that NPMc+ induces cellular senescence and that E1A is able to overcome this response. We propose a model whereby the NPMc+ pro-senescence activity needs to be evaded for oncogenic transformation, even though NPMc+ can concomitantly blunt the Arf/p53 pathway. These findings identify for the first time NPMc+ as an oncogene and shed new unexpected light on its mechanism of action.

Recurrent primary plasmacytoma of the eyelid with rapid regional metastasis.

In this case, originally reported as primary eyelid plasmacytoma, the tumor recurred on the same eyelid within 2 years of surgery. No plasma cell infiltration was observed at bone marrow biopsy. No serum or urinary monoclonal component was detected at immunofixation. Histology and immunohistochemistry confirmed plasma cell infiltration. Tumor cell clonality was determined by immunohistological staining; cells were positive for kappa light chain like the first eyelid tumor. Surgery was followed by radiotherapy. Twenty months later, biopsy of one enlarged right cervical lymph node showed massive diffuse infiltration of atypical plasma cells (CD20(-), CD79a(+), CD138(+), MUM1/IRF4(+)). Given the rapid diffusion to lymph nodes and the appearance of the monoclonal component, the lymph node was removed surgically. No adjuvant chemotherapy was given. Unexpectedly, the serum monoclonal component normalized. No plasma cell infiltration was observed at bone marrow biopsy. As this case might be a particularly slow-progressing extra-medullary plasmacytoma, this study recommends closely monitored follow-ups so that the aggressive form can be treated in time.

Mesenchymal cells: a vehicle for gene therapy.

T cell-depleted allogeneic stem cell transplantation is associated with delayed immunological reconstitution. Bone marrow stroma and interleukin 7 (IL-7) regulate homeostasis of T lymphocytes. We engineered human stromal cells with a retroviral vector containing the IL-7 gene and studied in vitro effects on T cells. Human stromal cells were successfully transduced and generated a layer that was morphologically and phenotypically normal. IL-7-engineered stromal cells conserve the biological properties of unmanipulated stromal cells. Through their production of IL-7, they enhance survival and homeostatic proliferation of naive T cells. Because of this cytokine production, they might be an ideal vehicle for gene therapy aimed at supporting lymphopoiesis in the T cell-deficient host.