BACKGROUND: Myeloproliferative neoplasms (MPNs) are a group of chronic disorders of the bone marrow characterised by the overproduction of clonal myeloid stem cells. The most common driver mutation found in MPNs is a point mutation on exon 14 of the JAK2 gene, JAK2V617F. Various studies have suggested that measuring the variable allele frequency (VAF) of JAK2V617F may provide useful insight regarding diagnosis, treatment, risks and outcomes in MPN patients. In particular, JAK2V617F has been associated with increased risk of thrombotic events, a leading cause of mortality in MPNs.
OBJECTIVE: The aim of this study was to determine if JAK2V617F VAF was associated with clinical outcomes in patients with MPN.
METHODS: JAK2V617F VAF was determined by quantitative PCR (qPCR) in a cohort of 159 newly diagnosed MPN patients, and the association of JAK2V617F VAF and risk of thrombosis was examined in this cohort.
RESULTS: We observed a significantly higher JAK2V617F VAF in PV and PMF versus ET. A significant association was observed between JAK2V617F VAF and risk of thrombotic events. When patients were stratified by thrombotic events prior to and post diagnosis, an association with JAK2V617F VAF was only observed with post diagnosis thrombotic events. Of note, these associations were not observed when looking at each MPN subtype in isolation.
CONCLUSIONS: We have shown that a higher JAK2V617F VAF is associated with thrombotic events post MPN diagnosis. JAK2V617F VAF may therefore provide a valuable prognostic indicator for risk of thrombosis in MPNs.

UNASSIGNED: The treatment landscape of polycythemia vera (PV) has seen major advancements within the last decade including approval of ruxolitinib in the second line setting after hydroxyurea, ropegylated interferon-α2b, and advanced clinical development of a novel class of agents called hepcidin mimetics.
UNASSIGNED: We provide a comprehensive review of the evidence discussing the risk stratification, treatment indications, role and limitations of phlebotomy only approach and pivotal trials covering nuances related to the use of interferon-α (IFN-α), ruxolitinib, hepcidin mimetics, and upcoming investigational agents including HDAC and LSD1 inhibitors.
UNASSIGNED: The research paradigm in PV is slowly shifting from the sole focus on hematocrit control and moving toward disease modification. The discovery of hepcidin mimetics has come as a breakthrough in restoring iron homeostasis, achieving phlebotomy-independence and may lead to improved thrombosis-free survival with stricter hematocrit control. On the other hand, emerging data with IFN- α and ruxolitinib as well as combination of the two agents suggests the potential for achieving molecular remission in a subset of PV patients and long-term follow-up is awaited to validate the correlation of molecular responses with clinically relevant outcomes of progression-free and thrombosis-free survival.

UNASSIGNED: Ruxolitinib has been approved by the US FDA for the treatment of myeloproliferative neoplasms such as polycythemia vera and primary myelofibrosis. Ruxolitinib will remain a main stay in the treatment of MPN patients due to its effective therapeutic benefits. However, there have been instances of ruxolitinib resistance in MPN patients. As JAK2 is a direct target of ruxolitinib, we generated ruxolitinib-resistant clones to find out the mechanism of resistance.
UNASSIGNED: Cell-based screening strategy was used to detect the ruxolitinib-resistant mutations in JAK2. The Sanger sequencing method was used to detect the point mutations in JAK2. Mutations were re-introduced using the site-directed mutagenesis method and stably expressed in Ba/F3 cells. Drug sensitivities against the JAK2 inhibitors were measured using an MTS-based assay. JAK2 and STAT5 activation levels and total proteins were measured using immunoblotting. Computational docking studies were performed using the Glide module of Schrodinger Maestro software.
UNASSIGNED: In this study, we have recovered seven residues in the kinase domain of JAK2 that affect ruxolitinib sensitivity. All these mutations confer cross-resistance across the panel of JAK2 kinase inhibitors except JAK2-L983F. JAK2-L983F reduces the sensitivity towards ruxolitinib. However, it is sensitive towards fedratinib indicating that our screen identifies the drug-specific resistance profiles. All the ruxolitinib-resistant JAK2 variants displayed sensitivity towards type II JAK2 inhibitor CHZ-868. In this study, we also found that JAK1-L1010F (homologous JAK2-L983F) is highly resistant towards ruxolitinib suggesting the possibility of JAK1 escape mutations in JAK2-driven MPNs and JAK1 mutated ALL. Finally, our study also shows that HSP90 inhibitors are potent against ruxolitinib-resistant variants through the JAK2 degradation and provides the rationale for clinical evaluation of potent HSP90 inhibitors in genetic resistance driven by JAK2 inhibitors.
UNASSIGNED: Our study identifies JAK1 and JAK2 resistance variants against the type I JAK2 inhibitors ruxolitinib, fedratinib, and lestaurtinib. The sensitivity of these resistant variants towards the type II JAK2 inhibitor CHZ-868 indicates that this mode of type II JAK2 inhibition is a potential therapeutic approach against ruxolitinib refractory leukemia. This also proposes the development of potent and specific type II JAK2 inhibitors using ruxolitinib-resistance variants as a prototype.

The ETV6::ABL1 fusion defines a subgroup of myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions. We report a case of extramedullary involvement and leukemic transformation in myeloproliferative neoplasm (MPN), where ETV6::ABL1 was initially overlooked but later detected in the blast phase. ETV6::ABL1 burden was very low during the MPN phase but increased substantially during the blast phase. This correlation between ETV6::ABL1 burden and disease phenotype indicated that an immature leukemic clone is the sole carrier of ETV6::ABL1, suggesting that ETV6::ABL1 is not the primary driver of the MPN phase. Moreover, only the blast phase revealed somatic mutations in RUNX1 and STAG2, or complex karyotype, while the MPN phase revealed no molecular and cytogenetic abnormalities. Therefore, it remains uncertain whether the small clone of ETV6::ABL1 influenced the manifestation of MPN or if another underlying driver was responsible for the MPN phase, necessitating further research.

BACKGROUND: Myeloproliferative neoplasms (MPN) are hematologic malignancies characterized by cellular proliferation of one or more hematopoietic cell lines. Management has been focused on blood count control but addressing relief from symptoms and providing a better quality of life (QOL) are equally important in the care of these patients. The MPN Symptom Assessment Form-Total Symptom Score (MPN-SAF TSS) is used to determine symptoms at baseline and during treatment. Understanding the symptom burden is important in developing a holistic management plan for MPN. Hence, this study aimed to determine the symptom burden and QOL of Filipino patients with MPN.
METHODS: Using a validated Filipino version of the MPN-SAF-TSS questionnaire and the University of the Philippines-Department of Health QOL (UP-DOH QOL) questionnaire, a cross-sectional survey of consecutive patients with MPN from two public and two private tertiary hospitals was conducted. We purposively sampled adults, newly diagnosed or previously diagnosed with polycythemia vera (PV), essential thrombocythemia (ET), or myelofibrosis (MF). The mean scores were compared with the type of MPN using analysis of variance. Linear regression was done to determine the association of patients\' characteristics to the mean symptom burden and QOL scores, while logistic regression was used to determine the association of patient and disease characteristics with the level of symptom severity and QOL.
RESULTS: A total of 167 (63 PV, 66 ET, and 38 MF) patients were surveyed from four centers. The mean overall symptom burden score was 24.41 (standard deviation [SD] = 18.91) with MF having the highest score at 28.53, followed by PV at 23.75 and ET at 22.67. The majority (80.24%) had a high QOL with a mean global QoL score of 84.92 (SD = 16.75). Comparison of individual scores showed bone pain and weight loss were significantly higher in patients with MF compared to PV (p = 0.0002) and ET (p = 0.032); while pruritus was significantly higher in PV compared to ET and MF (p = 0.043). Logistic regression analysis showed female sex and being newly diagnosed (adjusted odds ratio [aOR] 11.22, 95% confidence interval [CI] 2.32-54.25) were associated with high symptom burden while having a controlled blood count (aOR 0.26, 95% CI 0.10-0.71) was associated with low symptom burden and high QOL.
CONCLUSIONS: The majority of the participants were symptomatic with moderate to severe symptom burden. While no statistically significant difference was seen among the three types of MPN in terms of overall mean symptom score, patients with MF were more likely to have a severe symptom burden while patients with ET had the least symptoms. Despite having symptoms, QOL was regarded as high. QoL was significantly higher among those with PV or ET than those with MF. Our study highlighted the utility of a validated symptom scoring system in determining the symptom burden and who would benefit from pharmacologic/non-pharmacologic symptom management. Results emphasized incorporating symptom scoring in clinical practice and going beyond blood counts in caring for our patients with MPN.

OBJECTIVE: Myeloproliferative neoplasm (MPN) burdens the lives of those affected. MPN patients endure significant impacts on their physical, psychological, and social well-being. While pharmacological interventions offer some disease and symptom control, they often have unfavorable side effects. This review explores the potential of Integrative Oncology (IO) therapies in managing MPNs and their associated symptoms.
RESULTS: IO is dedicated to augmenting conventional treatments through integrating interventions targeting the mind, body, nutrition, supplements, and other supportive care therapies. Several small studies suggest the benefit of an IO approach in MPN patients. These benefits are postulated to be modulated through enhanced physical capacity, reduced disease-related inflammation, subconscious mind training, and gut microbiome modulation. By combining IO with evidence-based pharmacological treatments, the potential exists to enhance the quality of life and clinical outcomes for individuals with MPNs. Future research should prioritize well-powered studies, including diverse demographics and symptom profiles, with appropriate study duration, to draw definite conclusions regarding the observed effects.

UNASSIGNED: Myelofibrosis (MF) is a BCR-ABL-negative myeloproliferative neoplasm characterized by splenomegaly, constitutional symptoms, cytopenias, a potential for leukemic transformation, and increased mortality. Patients who are ineligible for stem cell transplant rely on pharmacologic therapies of noncurative intent, whose cornerstone consists of JAK inhibitors (JAKi). While current JAKi are efficacious in controlling symptoms and splenic volume, none meaningfully reduce clonal burden nor halt disease progression, and patients oftentimes develop JAKi intolerant, relapsed, or refractory MF. As such, there remains an urgent necessity for second-line options and novel therapies with disease-modifying properties.
UNASSIGNED: In this review, we delineate the mechanistic rationale, along with the latest safety and efficacy data, of investigational JAKi-based MF treatment strategies, with a focus on JAKi monotherapies and combinations of novel agents with approved JAKi. Our literature search consisted of extensive review of PubMed and clinicaltrials.gov.
UNASSIGNED: A myriad of promising MF-directed therapies are in late-phase studies. Following their approval, treatment selection should be tailored to patient-specific treatment goals and disease characteristics, with an emphasis on combination therapies of JAKi with novel agents of differing mechanistic targets that possess anti-clonal properties, in attempt to alter disease course and concurrently limit dose-dependent JAKi toxicities.

Bone marrow fibrosis in myeloproliferative neoplasm (MPN), myelodysplastic syndromes (MDS), MPN/MDS overlap syndromes and acute myeloid leukemia (AML) is associated with poor prognosis and early treatment failure. Myelofibrosis (MF) is accompanied by reprogramming of multipotent bone marrow mesenchymal stromal cells (MSC) into osteoid and fiber-producing stromal cells. We demonstrate NRP2 and osteolineage marker NCAM1 (neural cell adhesion molecule 1) expression within the endosteal niche in normal bone marrow and aberrantly in MPN, MDS MPN/MDS overlap syndromes and AML (n = 99), as assessed by immunohistochemistry. Increased and diffuse expression in mesenchymal stromal cells and osteoblasts correlates with high MF grade in MPN (p < 0.05 for NRP2 and NCAM1). Single cell RNA sequencing (scRNAseq) re-analysis demonstrated NRP2 expression in endothelial cells and partial co-expression of NRP2 and NCAM1 in normal MSC and osteoblasts. Potential ligands included transforming growth factor β1 (TGFB1) from osteoblasts and megakaryocytes. Murine ThPO and JAK2V617F myelofibrosis models showed co-expression of Nrp2 and Ncam1 in osteolineage cells, while fibrosis-promoting MSC only express Nrp2. In vitro experiments with MC3T3-E1 pre-osteoblasts and analysis of Nrp2-/- mouse femurs suggest that Nrp2 is functionally involved in osteogenesis. In summary, NRP2 represents a potential novel druggable target in patients with myelofibrosis.

Typical BCR::ABL1-negative myeloproliferative neoplasms (MPN) are mainly referred to as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofbrosis (PMF). Granulocytes in MPN patients are involved in their inflammation and form an important part of the pathophysiology of MPN patients. It has been shown that the immunophenotype of granulocytes in MPN patients is altered. We used flow cytometry to explore the immunophenotype of MPN patients and correlate it with clinical parameters. The results showed that PMF patients and PV patients had higher CD15+CD11b+ granulocytes than ET patients and normal controls. When grouped by gene mutation, changes in the granulocyte immunophenotype of MPN patients were independent of the JAK2V617F and CALR mutations. There was no significant heterogeneity in immunophenotype between ET patients and Pre-PMF, and between Overt-PMF and Pre-PMF patients. Granulocytes from some MPN patients showed an abnormal CD13/CD16 phenotype with a significant increase in mature granulocytes on molecular and cytomorphological grounds, and this abnormal pattern occurred significantly more frequently in PMF patients than in ET patients. CD15-CD11b- was negatively correlated with WBC and Hb and positively correlated with DIPSS score, whereas high CD10+ granulocytes were significantly and negatively associated with prognostic system IPSS and DIPSS scores in PMF patients. In conclusion, this study demonstrates the landscape of bone marrow granulocyte immunophenotypes in MPN patients. MPN patients, especially those with PMF, have a significant granulocyte developmental overmaturation phenotype. CD10+ granulocytes may be involved in the prognosis of PMF patients.

Although polycythemia vera (PV) is a chronic and incurable disease, effective management can allow most patients to maintain functional lives with near-normal life expectancy. However, there remain several inter-related factors that contribute to many ongoing challenges associated with the management of PV, which this review aims to explore. First, as a disease hallmarked by constitutive activation of the JAK/STAT pathway, PV is often accompanied by inflammatory symptoms that negatively impact quality of life. Next, patients often require recurrent therapeutic phlebotomies to maintain their hematocrit below the 45% threshold that has been associated with a decreased risk of thrombotic events. The need to closely monitor hematocrit and perform conditional therapeutic phlebotomies ties patients to the healthcare system, thereby limiting their autonomy. Furthermore, many patients describe therapeutic phlebotomies as burdensome and the procedure is often poorly tolerated, further contributing to quality-of-life decline. Phlebotomy needs can be reduced by utilizing cytoreductive therapy; however, standard first-line cytoreductive options (i.e., hydroxyurea and interferon) have not been shown to significantly improve symptom burden. Collectively, current PV management, while reducing thrombotic risk, often has a negative impact on patient quality of life. As researchers continue to advance towards the goal of developing a disease-modifying therapy for patients with PV, pursuit of nearer-term opportunities to shift the current treatment paradigm towards improving symptoms without compromising quality of life is also warranted, for example, by reducing or eliminating the frequent use of phlebotomy.