Maria Luigia Randi

Patients with essential thrombocythemia (ET) are treated with once‐daily low‐dose aspirin to prevent thrombosis, but their accelerated platelet turnover shortens the antiplatelet effect. The short‐term Aspirin Regimens in EsSential Thrombocythemia trial showed that twice‐daily aspirin dosing restores persistent platelet thromboxane (TX) inhibition. However, the long‐term pharmacodynamic efficacy, safety and tolerability of twice‐daily aspirin remain untested. We performed a multicenter, randomized, open‐label, blinded‐endpoint, phase‐2 trial in which 242 patients with ET were randomized to 100 mg aspirin twice‐ or once‐daily and followed for 20 months. The primary endpoint was the persistence of low serum TXB₂, a surrogate biomarker of antithrombotic efficacy. Secondary endpoints were major and clinically relevant non‐major bleedings, serious vascular events, symptom burden assessed by validated questionnaires, and in vivo platelet activation. Serum TXB₂ was consistently lower in the twice‐daily versus once‐daily regimen on 10 study visits over 20 months: median 3.9 ng/mL versus 19.2 ng/mL, respectively; p < .001; 80% median reduction; 95% CI, 74%–85%. No major bleeding occurred. Clinically relevant non‐major bleedings were non‐significantly higher (6.6% vs. 1.7%), and major thromboses lower (0.8% vs. 2.5%) in the twice‐daily versus once‐daily group. Patients on the twice‐daily regimen had significantly lower frequencies of disease‐specific symptoms and severe hand and foot microvascular pain. Upper gastrointestinal pain was comparable in the two arms. In vivo platelet activation was significantly reduced by the twice‐daily regimen. In patients with ET, twice‐daily was persistently superior to once‐daily low‐dose aspirin in suppressing thromboxane biosynthesis and reducing symptom burden, with no detectable excess of bleeding and gastrointestinal discomfort.

Background: Erythrocytosis is a relatively common condition, however a large proportion of these patients (70%) remain without a clear etiologic explanation. Methods: We set up a targeted NGS panel for patients with erythrocytosis and 118 sporadic patients with idiopathic erythrocytosis were studied. Results: In 40 (34%) patients no variant was found while in 78 (66%) we identified at least one germinal variant; 55 patients (70.5%) had 1 altered gene, 18 (23%) had 2 alterations, and 5 (6.4%) had 3. An altered HFE gene was observed in 51 cases (57.1%), EGLN1 in 18 (22.6%) and EPAS1, EPOR, JAK2, and TFR2 variants in 7.7%, 10.3%, 11.5%, and 14.1% patients, respectively. In 23 patients (19.45%), more than 1 putative variant was found in multiple genes. Conclusions: Genetic variants in patients with erythrocytosis were detected in about 2/3 of our cohort. A NGS panel including more candidate genes should reduce the number of cases diagnosed as “idiopathic” erythrocytosis in whom a cause cannot yet be identified. It is known that HFE variants are common in idiopathic erythrocytosis. TFR2 alterations supports the existence of a relationship between genes involved in iron metabolism and impaired erythropoiesis. Some novel multiple variants were identified. Erythrocytosis appears to be often of multigenic nature.

The molecular basis of Down syndrome (DS) predisposition to leukemia is not fully understood but involves various factors such as chromosomal abnormalities, oncogenic mutations, epigenetic alterations, and changes in selection dynamics. Myeloid leukemia associated with DS (ML-DS) is preceded by a preleukemic phase called transient abnormal myelopoiesis driven by GATA1 gene mutations and progresses to ML-DS via additional mutations in cohesin genes, CTCF, RAS, or JAK/STAT pathway genes. DS-related ALL (ALL-DS) differs from non-DS ALL in terms of cytogenetic subgroups and genetic driver events, and the aberrant expression of CRLF2, JAK2 mutations, and RAS pathway-activating mutations are frequent in ALL-DS. Recent advancements in single-cell multi-omics technologies have provided unprecedented insights into the cellular and molecular heterogeneity of DS-associated hematologic neoplasms. Single-cell RNA sequencing and digital spatial profiling enable the identification of rare cell subpopulations, characterization of clonal evolution dynamics, and exploration of the tumor microenvironment’s role. These approaches may help identify new druggable targets and tailor therapeutic interventions based on distinct molecular profiles, ultimately improving patient outcomes with the potential to guide personalized medicine approaches and the development of targeted therapies.

The molecular basis of Down syndrome (DS) predisposition to leukemia is not fully understood but involves various factors such as chromosomal abnormalities, oncogenic mutations, epigenetic alterations, and changes in selection dynamics. Myeloid leukemia associated with DS (ML-DS) is preceded by a preleukemic phase called transient abnormal myelopoiesis driven by GATA1 gene mutations and progresses to ML-DS through additional mutations in cohesin genes, CTCF, RAS, or JAK/STAT pathway genes. DS-related ALL (ALL-DS) differs from non-DS ALL in terms of cytogenetic subgroups and genetic driver events and aberrant expression of CRLF2, JAK2 mutations, and RAS pathway activating mutations are frequent in ALL-DS. Recent advancements in single-cell multi-omics technologies have provided unprecedented insights into the cellular and molecular heterogeneity of DS-associated hematologic neoplasms. Single-cell RNA sequencing and digital spatial profiling enable the identification of rare cell subpopulations, characterization of clonal evolution dynamics, and exploration of the tumor microenvironment's role. These approaches may help identify new druggable targets and tailor therapeutic interventions based on distinct molecular profiles, ultimately improving patient outcomes with the potential to guide personalized medicine approaches and the development of targeted therapies.

This paper reviews the features of pediatric essential thrombocythemia (ET). ET is a rare disease in children, challenging pediatric and adult hematologists alike. The current WHO classification acknowledges classical Philadelphia-negative MPNs and defines diagnostic criteria, mainly encompassing adult cases. The presence of one of three driver mutations (JAK2V617F, CALR, and MPL mutations) represent the proof of clonality typical of ET. Pediatric ET cases are thus usually confronted by adult approaches. These can fit only some patients, because only 25–40% of cases present one of the driver mutations. The diagnosis of hereditary, familial thrombocytosis and the exclusion of reactive/secondary thrombocytosis must be part of the diagnostic process in children and can clarify most of the negative cases. Still, many children present a clinical, histological picture of ET, with a molecular triple wild-type status. Moreover, prognosis seems more benign, at least within the first few decades of follow-up. Thrombotic events are rare, and only minor hemorrhages are ordinarily observed. As per the management, the need to control symptoms must be balanced with the collateral effects of lifelong drug therapy. We conclude that these differences concert a compelling case for a very careful therapeutic approach and advocate for the importance of further cooperative studies.

Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by enhanced platelet production and thrombotic complications. The inhibition of platelet cyclooxygenase (COX) activity by the standard once-daily aspirin is mostly incomplete due to accelerated thrombopoiesis. The phase-2 Aspirin Regimens in EsSential thrombocythemia (ARES) trial has recently compared the efficacy of once- versus twice- or three-times daily low-dose aspirin in inhibiting platelet thromboxane (TX) A₂ production, as reflected by serum (s) TXB₂ measurements. The present sub-study characterized the determinants of the highly variable response to the standard aspirin 100 mg once-daily regimen in fully-compliant ET patients and the effects of the experimental dosing regimens on response variability. By multivariable analysis, the platelet count (directly) and cytoreductive treatment (inversely) were significantly associated with sTXB₂ values in 218 ET patients. However, the platelet count positively correlated with sTXB₂ in patients not being treated with cytoreductive drugs (rho=0.51, p2 quartile were older, more often on cytoreductive drugs, had lower platelet count and Janus-Associated Kinase2 (JAK2)-V617F allele frequency as compared to patients in the upper sTXB₂ quartiles. After two-weeks of a twice- or three-times daily aspirin regimen, the association between the platelet count and sTXB₂ became similar in cytoreduced and non-cytoreduced patients. In conclusion, the platelet count appears the strongest determinant of TXA₂ inhibition by once-daily low-dose aspirin in ET, with different patterns depending of cytoreductive treatment. More frequent aspirin dosing restores adequate platelet inhibition and reduces interindividual variability, independently of cytoreduction.

In the western countries about half of the hospitalized patients are anemic. Generally, these patients are old, often with multiple diseases and anemia worsens the prognosis finally increasing the risk of death. We describe here a monocentric, observational study that evaluates 249 consecutive adult patients (160 women and 89 men) with anemia admitted in the internal medicine department over 5 months period. They represent 71.5% of all patients admitted in the study period. Demographic, historic and clinical data, laboratory tests, duration of hospitalization, re-admission at 30 days and death were recorded. Patients were stratified by age (75-84= old, >85 years= oldest-old), anemia severity, and etiology of anemia. In 37 old and 25 oldest-old patients anemia was mild, in 43 old and 46 oldest-old moderate and in 20 old and 7 oldest-old severe in agreement with WHO criteria. Moderate anemia was significantly more common in oldest-old (p=0.01) The causes of anemia were iron deficiency in 19 patients, other deficiencies in 5, chronic diseases in 68, hematologic neoplasms in 11, multifactorial in 43 and undetermined in 32. Oldest-old have higher frequency of multifactorial anemia (p=0.04) while hematologic neoplasms were more common in old patients (p=0.03). Most patients with undetermined anemia had mild/moderate forms.An anti-anemic treatment, mainly blood transfusion, was adopted in 100% of oldest-old patients and in 60% of old (p= 0.04). Anemia (and/or its treatment) was reported in the discharge letter in 19 old and in 22 oldest old patients. From a general point of view, physicians seem to disregard anemia, in the context of more important pathologic conditions. In oldest-old patients, multifactorial anemia seems to be consider only “one more cause of disability”. When a border line anemia occurs, even if it can represent a relevant adverse condition in frailty, is poorly considered.

Essential thrombocythemia (ET) is characterized by abnormal megakaryopoiesis and enhanced thrombotic risk. Once-daily (od), low-dose aspirin is the recommended antithrombotic regimen, but accelerated platelet generation may reduce the duration of platelet cyclooxygenase (COX)-1 inhibition. We performed a multicenter, double-blind trial to investigate the efficacy of three aspirin regimens in optimizing platelet COX-1 inhibition while preserving COX-2-dependent vascular thromboresistance. Two-hundred-forty-five patients on chronic od low-dose aspirin were randomized (1:1:1) to receive 100 mg aspirin od, twice-daily, bid), or three-times daily (tid) for 2 weeks. Serum thromboxane B₂ (sTXB₂), a validated biomarker of platelet COX-1 activity, and urinary prostacyclin metabolite (PGIM) excretion were measured at randomization and after 2 weeks, as primary surrogate endpoints of efficacy and safety, respectively. Urinary TX metabolite (TXM) excretion, gastrointestinal tolerance, and ET-related symptoms were also investigated. Evaluable patients assigned to the bid and tid regimens showed substantially reduced inter-individual variability and lower median values of sTXB₂: 19.3[9.7-40], 4 [2.1-6.7], and 2.5[1.4-5.65] ng/ml in the od (n=85), bid (n=79) and tid (n=79) arms, respectively. Urinary PGIM was comparable in the three arms. Urinary TXM was significantly reduced by 35% in both experimental arms. Patients in the tid arm reported a higher abdominal discomfort score. In conclusion, the currently recommended aspirin regimen of 75-100 od for cardiovascular prophylaxis appears largely inadequate in reducing platelet activation in the vast majority of ET patients. The antiplatelet response to low-dose aspirin can be markedly improved by shortening the dosing interval to 12 hours, with no improvement by further reducing it. (EudraCT 2016-002885-30)