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Introduction: The Philadelphia chromosome-negative myeloproliferative neoplasms are a group of slowly progressing haematological malignancies primarily characterised by an overproduction of myeloid blood cells. Patients are treated with various drugs, including the JAK1/2 inhibitor ruxolitinib. Mathematical modelling can help propose and test hypotheses of how the treatment works. Materials and methods: We present an extension of the Cancitis model, which describes the development of myeloproliferative neoplasms and their interactions with inflammation, that explicitly models progenitor cells and can account for treatment with ruxolitinib through effects on the malignant stem cell response to cytokine signalling and the death rate of malignant progenitor cells. The model has been fitted to individual patients' data for the JAK2 V617F variant allele frequency from the COMFORT-II and RESPONSE studies for patients who had substantial reductions (20 percentage points or 90% of the baseline value) in their JAK2 V617F variant allele frequency (n = 24 in total). Results: The model fits very well to the patient data with an average root mean square error of 0.0249 (2.49%) when allowing ruxolitinib treatment to affect both malignant stem and progenitor cells. This average root mean square error is much lower than if allowing ruxolitinib treatment to affect only malignant stem or only malignant progenitor cells (average root mean square errors of 0.138 (13.8%) and 0.0874 (8.74%), respectively). Discussion: Systematic simulation studies and fitting of the model to the patient data suggest that an initial reduction of the malignant cell burden followed by a monotonic increase can be recapitulated by the model assuming that ruxolitinib affects only the death rate of malignant progenitor cells. For patients exhibiting a long-term reduction of the malignant cells, the model predicts that ruxolitinib also affects stem cell parameters, such as the malignant stem cells' response to cytokine signalling. [ABSTRACT FROM AUTHOR]

Background: Essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (MF) are myeloproliferative neoplasms (MPN). Inflammation is involved in the initiation, progression, and symptomology of the diseases. The gut microbiota impacts the immune system, infection control, and steady‐state hematopoiesis. Methods: We analyzed the gut microbiota of 227 MPN patients and healthy controls (HCs) using next‐generation sequencing. We expanded our previous results in PV and ET patients with additional PV, pre‐MF, and MF patients which allowed us to compare MPN patients collectively, MPN sub‐diagnoses, and MPN mutations (separately and combined) vs. HCs (N = 42) and compare within MPN sub‐diagnoses and MPN mutation. Results: MPN patients had a higher observed richness (median, 245 [range, 49–659]) compared with HCs (191.5 [range, 111–300; p =.003]) and a lower relative abundance of taxa within the Firmicutes phylum; for example, Faecalibacterium (6% vs. 14%, p <.001). The microbiota of CALR‐positive patients (N = 30) resembled that of HCs more than that of patients with JAK2V617F (N = 177). In JAK2V617F‐positive patients, only minor differences in the gut microbiota were observed between MPN sub‐diagnoses, illustrating the importance of this mutation. Conclusion: The gut microbiota in MPN patients differs from HCs and is driven by JAK2V617F, whereas the gut microbiota in CALR patients resembles HCs more. [ABSTRACT FROM AUTHOR]

Initial diagnosis of overt myeloproliferative neoplasms (MPNs) represents the juncture during clonal evolution when symptoms or complications prompt an afflicted individual to seek medical attention. In 30-40% of the MPN subgroups essential thrombocythemia (ET) and myelofibrosis (MF), somatic mutations in the calreticulin gene (CALR) are drivers of the disease resulting in constitutive activation of the thrombopoietin receptor (MPL). In the current study, we describe a healthy CALR mutated individual during a 12 year follow-up from initial identification of CALR clonal hematopoiesis of indeterminate potential (CHIP) to the diagnosis of pre-MF. The pre-diagnostic exponential development dynamics of the malignant clone demonstrated close correlation with the platelet counts, neutrophil-to-lymphocyte (NLR) ratio, and inversely correlated to hemoglobin and erythrocyte counts. Backward extrapolation of the growth rate indicated the potential for discovery of the malignant clone many years prior to presentation of overt disease, opening a window of opportunity for early treatment intervention. We did not find any additional mutations associated with MPNs and the current case report provides novel information regarding the development of a driver mutation and the association with blood cell counts prior to clinical manifestation of symptoms suggesting that pre-diagnostic dynamics may supplement future diagnostic criteria for early diagnosis and intervention in MPN patients. [ABSTRACT FROM AUTHOR]

The myeloproliferative neoplasms are associated with chronic kidney disease but whether clonal haematopoiesis of indeterminate potential (CHIP) is associated with impaired kidney function is unknown. In the Danish General Suburban Population Study (N = 19 958) from 2010 to 2013, 645 individuals were positive for JAK2V617F (N = 613) or CALR (N = 32) mutations. Mutation‐positive individuals without haematological malignancy were defined as having CHIP (N = 629). We used multiple and inverse probability weighted (IPW)‐adjusted linear regression analysis to estimate adjusted mean (95% confidence interval) differences in estimated glomerular filtration rate (eGFR; ml/min/1.73 m2) by mutation status, variant allele frequency (VAF%), blood cell counts, and neutrophil‐to‐lymphocyte ratio (NLR). We performed 11‐year longitudinal follow‐up of eGFR in all individuals. Compared to CHIP‐negative individuals, the mean differences in eGFR were −5.6 (−10.3, −0.8, p =.02) for CALR, −11.9 (−21.4, −2.4, p = 0.01) for CALR type 2, and −10.1 (−18.1, −2.2, p =.01) for CALR with VAF ≥ 1%. The IPW‐adjusted linear regression analyses showed similar results. NLR was negatively associated with eGFR. Individuals with CALR type 2 had a worse 11‐year longitudinal follow‐up on eGFR compared to CHIP‐negative individuals (p =.004). In conclusion, individuals with CALR mutations, especially CALR type 2, had impaired kidney function compared to CHIP‐negative individuals as measured by a lower eGFR at baseline and during 11‐year follow‐up. [ABSTRACT FROM AUTHOR]

We report the two-year end-of-study results from the phase 2 COMBI II clinical trial (#EudraCT2018-004150-13) investigating the combination treatment of ruxolitinib and low-dose pegylated interferon-α2a in patients with newly diagnosed polycythemia vera. The primary outcome was safety and key secondary endpoints were efficacy, based on hematological parameters, quality of life measurements, and JAK2V617F variant allele frequency (VAF). We used the 2013 ELN and IWG-MRT remission criteria. The remission criteria included remissions in symptoms, splenomegaly, peripheral blood counts, and bone marrow. We included 25 patients with PV with a median age of 70 years; 5 of those had prior thromboembolic events and three had CT-verified splenomegaly. Two patients stopped both study drugs, one of these due to progression to post-PV myelofibrosis; only that patient had a grade 3 infection. No events of herpes zoster infections were observed. No patients discontinued treatment due to psychiatric symptoms. The peripheral blood cell count remission rate was 92% at 24 months. Using the 2013 ELN and IWG-MRT remission criteria, 14 (56%) achieved remission at 24 months; 3 (12%) achieved complete remission, and 11 (44%) achieved partial remission. The following items from the Myeloproliferative Neoplasm Symptom Total Symptom Score were significantly reduced: abdominal discomfort, night sweats, itching, and bone pain. The median JAK2V617F VAF decreased from 47% (95%CI, 35-59%) to 7% (95%CI, 3-15%), and 60% of patients achieved molecular remission. In conclusion, combination treatment improved cell counts; bone marrow cellularity, and fibrosis; and decreased JAK2V617F VAF; with acceptable toxicity in patients with polycythemia vera. EudraCT2018-004150-13., (Copyright © 2024 American Society of Hematology.)

Essential thrombocythemia (ET) is part of the Philadelphia chromosome-negative myeloproliferative neoplasms. It is characterized by an increased risk of thromboembolic events and also to a certain degree hypermetabolic symptoms. The gut microbiota is an important initiator of hematopoiesis and regulation of the immune system, but in patients with ET, where inflammation is a hallmark of the disease, it is vastly unexplored. In this study, we compared the gut microbiota via amplicon-based 16S rRNA gene sequencing of the V3-V4 region in 54 patients with ET according to mutation status Janus-kinase 2 ( JAK2V617F )-positive vs JAK2V617F -negative patients with ET, and in 42 healthy controls (HCs). Gut microbiota richness was higher in patients with ET (median-observed richness, 283.5; range, 75-535) compared with HCs (median-observed richness, 191.5; range, 111-300; P < 0.001). Patients with ET had a different overall bacterial composition (beta diversity) than HCs (analysis of similarities [ANOSIM]; R = 0.063, P = 0.004). Patients with ET had a significantly lower relative abundance of taxa within the Firmicutes phylum compared with HCs (51% vs 59%, P = 0.03), and within that phylum, patients with ET also had a lower relative abundance of the genus Faecalibacterium (8% vs 15%, P < 0.001), an important immunoregulative bacterium. The microbiota signatures were more pronounced in patients harboring the JAK2V617F mutation, and highly similar to patients with polycythemia vera as previously described. These findings suggest that patients with ET may have an altered immune regulation; however, whether this dysregulation is induced in part by, or is itself inducing, an altered gut microbiota remains to be investigated. IMPORTANCE Essential thrombocythemia (ET) is a cancer characterized by thrombocyte overproduction. Inflammation has been shown to be vital in both the initiation and progression of other myeloproliferative neoplasms, and it is well known that the gut microbiota is important in the regulation of our immune system. However, the gut microbiota of patients with ET remains uninvestigated. In this study, we characterized the gut microbiota of patients with ET compared with healthy controls and thereby provide new insights into the field. We show that the gut microbiota of patients with ET differs significantly from that of healthy controls and the patients with ET have a lower relative abundance of important immunoregulative bacteria. Furthermore, we demonstrate that patients with JAK2V617F -positive ET have pronounced gut microbiota signatures compared with JAK2V617F -negative patients. Thereby confirming the importance of the underlying mutation, the immune response as well as the composition of the microbiota.