First-hit SETBP1 mutations cause a myeloproliferative disorder with bone marrow fibrosis.

ABSTRACT: SETBP1 mutations are found in various clonal myeloid disorders. However, it is unclear whether they can initiate leukemia, because SETBP1 mutations typically appear as later events during oncogenesis. To answer this question, we generated a mouse model expressing mutated SETBP1 in hematopoietic tissue: this model showed profound alterations in the differentiation program of hematopoietic progenitors and developed a myeloid neoplasm with megakaryocytic dysplasia, splenomegaly, and bone marrow fibrosis, prompting us to investigate SETBP1 mutations in a cohort of 36 triple-negative primary myelofibrosis (TN-PMF) cases. We identified 2 distinct subgroups, one carrying SETBP1 mutations and the other completely devoid of somatic variants. Clinically, a striking difference in disease aggressiveness was noted, with patients with SETBP1 mutation showing a much worse clinical course. In contrast to myelodysplastic/myeloproliferative neoplasms, in which SETBP1 mutations are mostly found as a late clonal event, single-cell clonal hierarchy reconstruction in 3 patients with TN-PMF from our cohort revealed SETBP1 to be a very early event, suggesting that the phenotype of the different SETBP1+ disorders may be shaped by the opposite hierarchy of the same clonal SETBP1 variants.

Hematopoietic Stem Cell (HSC)-Independent Progenitors Are Susceptible to Mll-Af9-Induced Leukemic Transformation.

Infant acute myeloid leukemia (AML) is a heterogeneous disease, genetically distinct from its adult counterpart. Chromosomal translocations involving the KMT2A gene (MLL) are especially common in affected infants of less than 1 year of age, and are associated with a dismal prognosis. While these rearrangements are likely to arise in utero, the cell of origin has not been conclusively identified. This knowledge could lead to a better understanding of the biology of the disease and support the identification of new therapeutic vulnerabilities. Over the last few years, important progress in understanding the dynamics of fetal hematopoiesis has been made. Several reports have highlighted how hematopoietic stem cells (HSC) provide little contribution to fetal hematopoiesis, which is instead largely sustained by HSC-independent progenitors. Here, we used conditional Cre-Lox transgenic mouse models to engineer the Mll-Af9 translocation in defined subsets of embryonic hematopoietic progenitors. We show that embryonic hematopoiesis is generally permissive for Mll-Af9-induced leukemic transformation. Surprisingly, the selective introduction of Mll-Af9 in HSC-independent progenitors generated a transplantable myeloid leukemia, whereas it did not when introduced in embryonic HSC-derived cells. Ex vivo engineering of the Mll-Af9 rearrangement in HSC-independent progenitors using a CRISPR/Cas9-based approach resulted in the activation of an aberrant myeloid-biased self-renewal program. Overall, our results demonstrate that HSC-independent hematopoietic progenitors represent a permissive environment for Mll-Af9-induced leukemic transformation, and can likely act as cells of origin of infant AML.

A real-world economic analysis of biologic therapies for psoriatic arthritis in Italy: results of the CHRONOS observational longitudinal study.

BACKGROUND: Psoriatic arthritis (PsA) is a chronic, immune-mediated, spondyloarthropathy characterised by musculoskeletal signs and symptoms with associated joint pain and tenderness. The average worldwide PsA prevalence is 133/100,000, while in the Italian population is 90-420/100,000. Traditionally, nonsteroidal anti-inflammatory drugs, glucocorticoid, and disease-modifying antirheumatic drugs have been used in the treatment of PsA. However, for those patients who are not adequately controlled with conventional therapies, the new biologics compounds represent a valid option. Biologic therapies have been shown to be more effective but also more expensive than conventional systemic treatments. Based on the CHRONOS study, the economic analyses presented in this paper aim to assess the annualised direct costs and the cost-per-responder of biologics in a real-world context assuming the Italian National Health System perspective. METHODS: The economic assessments were carried out on the overall cohort of patients, and on the tumour necrosis factor alpha inhibitors (TNFi) and the secukinumab subgroup, the most prescribed biologic therapies within the CHRONOS study. RESULTS: The annual economic impact of PsA in the overall group was €12,622, €11,725 in the secukinumab subgroup, and €12,791 in the TNFi subgroup. Biologics absorbed the main expenditure costs in the treatment of PsA accounting for about the 93% of total costs. At 6 months, secukinumab performed better in all the considered outcomes: cost-per-responder according to EULAR DAS28 and ACR50 response criteria were €12,661- €28,975, respectively, while they were €13,356 - €33,368 in the overall cohort and €13,138 - €35,166 in the TNFi subgroup. At 12 months secukinumab remained the subgroup with the lowest cost-per-responder ratio in EULAR DAS28 and ACR50 response criteria, while TNFi subgroup was the lowest one considered the ACR20. CONCLUSION: Despite some potential methodological limitations, our cost-per-response analysis provides physicians and payers additional insights which can complement the traditional risk-benefit profile assessment and drive treatment decisions.

Real-world evidence of biologic treatments in psoriatic arthritis in Italy: results of the CHRONOS (EffeCtiveness of biologic treatments for psoriatic artHRitis in Italy: an ObservatioNal lOngitudinal Study of real-life clinical practice) observational longitudinal study.

BACKGROUND: Biologics have demonstrated efficacy in PsA in randomized clinical trials. More evidence is needed on their effectiveness under real clinical practice conditions. The aim of the present work is to provide real-world evidence of the effectiveness of biologics for PsA in the daily clinical practice. METHODS: CHRONOS was a multicenter, non-interventional, cohort study conducted in 20 Italian hospital rheumatology clinics. RESULTS: 399 patients were eligible (56.9% females, mean (SD) age: 52.4 (11.6) years). The mean (SD) duration of PsA and psoriasis was 7.2 (6.9) and 15.3 (12.2) years, respectively. The mean (SD) duration of the biologic treatment under analysis was 18.6 (6.5) months. The most frequently prescribed biologic was secukinumab (40.4%), followed by adalimumab (17.8%) and etanercept (16.5%). The proportion of overall responders according to EULAR DAS28 criteria was 71.8% (95% CI: 66.7-76.8%) out of 308 patients at 6 months and 68.0% (95% CI: 62.7-73.3%) out of 297 patients at 1 year. Overall, ACR20/50/70 responses at 6 months were 41.2% (80/194), 29.4% (57/194), 17.1% (34/199) and at 1-year were 34.9% (66/189), 26.7% (51/191), 18.4% (36/196), respectively. Secondary outcome measures improved rapidly already at 6 months: mean (SD) PASI, available for 87 patients, decreased from 3.2 (5.1) to 0.6 (1.3), the proportion of patients with dactylitis from 23.6% (35/148) to 3.5% (5/142) and those with enthesitis from 33.3% (49/147) to 9.0% (12/133). CONCLUSIONS: The CHRONOS study provides real-world evidence of the effectiveness of biologics in PsA in the Italian rheumatological practice, confirming the efficacy reported in RCTs across various outcome measures.

The CHRONOS Real-World Evidence of Biologic Treatments in Psoriatic Arthritis in Italy: A Post Hoc Gender Analysis.

Background: Phenotypic features and outcome differences between sexes have been reported in psoriatic arthritis (PsA). However, little is known about sex differences in effectiveness of biologics in clinical practice. Methods: Post hoc gender analysis of the CHRONOS, a multicenter, noninterventional, retroprospective Italian real-world study assessing 6-month and 1-year effectiveness of biologics for PsA. Results: Eligible patients were 399, 43.1% men. Sociodemographic characteristics, type of arthritis, baseline Disease Activity Score 28 joints (DAS28), and duration of biologic treatment were rather homogeneous. More men were overweight/obese and naive to biologics. The most frequently used biologics were TNF-inhibitors and secukinumab in both sexes. DAS28 responders were 72.7% (women) and 70.5% (men) at 6 months, and 68.0% in both sexes at 1 year. American College of Rheumatology (ACR) response showed a trend for men versus women to achieve more frequently ACR50 (32.6% vs. 26.5% at 6 months; 34.9% vs. 20.0% at 1 year) and ACR70 (22.3% vs. 12.4% at 6 months and 25.0% vs. 13.0% at 1 year). Global satisfaction with treatment at enrollment and after 6 months was slightly higher among men [mean (standard deviation) Treatment Satisfaction Questionnaire for Medication-9 (TSQM-9) score: 68.6 (18.6) and 69.9 (18.2), respectively] than women [65.3 (18.2), 66.2 (18.5)]. Conclusions: Overall response to biologics for PsA was rather favorable. With similar baseline disease severity, men appear to have a somewhat earlier and better response with higher treatment satisfaction.

One Size Does Not Fit All: Heterogeneity in Developmental Hematopoiesis.

Our knowledge of the complexity of the developing hematopoietic system has dramatically expanded over the course of the last few decades. We now know that, while hematopoietic stem cells (HSCs) firmly reside at the top of the adult hematopoietic hierarchy, multiple HSC-independent progenitor populations play variegated and fundamental roles during fetal life, which reflect on adult physiology and can lead to disease if subject to perturbations. The importance of obtaining a high-resolution picture of the mechanisms by which the developing embryo establishes a functional hematopoietic system is demonstrated by many recent indications showing that ontogeny is a primary determinant of function of multiple critical cell types. This review will specifically focus on exploring the diversity of hematopoietic stem and progenitor cells unique to embryonic and fetal life. We will initially examine the evidence demonstrating heterogeneity within the hemogenic endothelium, precursor to all definitive hematopoietic cells. Next, we will summarize the dynamics and characteristics of the so-called "hematopoietic waves" taking place during vertebrate development. For each of these waves, we will define the cellular identities of their components, the extent and relevance of their respective contributions as well as potential drivers of heterogeneity.

Secukinumab Use in Patients with Moderate to Severe Psoriasis, Psoriatic Arthritis and Ankylosing Spondylitis in Real-World Setting in Europe: Baseline Data from SERENA Study.

INTRODUCTION: Secukinumab, a fully human monoclonal antibody that directly inhibits interleukin-17A, has demonstrated robust efficacy in the treatment of moderate to severe psoriasis (PsO), psoriatic arthritis (PsA) and ankylosing spondylitis (AS), with a rapid onset of action, sustained long-term clinical responses and a consistently favourable safety profile across phase 3 trials. Here, we report the clinical data at enrolment from SERENA, designed to investigate the real-world use of secukinumab across all three indications. METHODS: SERENA is an ongoing, longitudinal, observational study conducted at 438 sites across Europe in patients with moderate to severe plaque PsO, active PsA or active AS. Patients should have received at least 16 weeks of secukinumab treatment before enrolment in the study. RESULTS: Overall 2800 patients were included in the safety set; patients with PsA (N = 541) were older than patients with PsO (N = 1799) and patients with AS (N = 460); patients with PsO had a higher mean body weight than patients with PsA and patients with AS; and patients with PsO and patients with AS were predominantly male. Time since diagnosis was longer in patients with PsO compared with patients with PsA and patients with AS, and about 40% of patients were either current or former smokers. The proportion of obese patients (body mass index ≥ 30 kg/m2) was similar across indications. Patients were treated with secukinumab for a mean duration of 1 year prior to enrolment (range 0.89-1.04). The percentages of patients with prior biologics exposure were 31.5% PsO, 59.7% PsA and 55% AS. The percentages of patients prescribed secukinumab monotherapy were 75% (n = 1349) in PsO, 48.2% (n = 261) in PsA and 48.9% (n = 225) in AS groups. CONCLUSION: Baseline demographics of the study population are consistent with existing literature. This large observational study across all secukinumab indications will provide valuable information on the long-term effectiveness and safety of secukinumab in the real-world setting.