Real-world analysis of ruxolitinib in myelofibrosis: interim results focusing on patients who were naïve to JAK inhibitor therapy treated within the JAKoMo non-interventional, phase IV trial.

Ruxolitinib (RUX) is a Janus kinase 1/2 inhibitor (JAKi) approved in the EU for treating disease­related splenomegaly or symptoms in adults patients with myelofibrosis (MF). This is an interim analysis of JAKoMo, a prospective, non­interventional, phase IV study in MF. Between 2012-2019 (cutoff March 2021), 928 patients (JAKi-naïve and -pretreated) enrolled from 122 German centers. This analysis focuses on JAKi-naïve patients. RUX was administered according to the Summary of Product Characteristics. Compared to the COMFORT-I, -II, and JUMP trials, patients in JAKoMo were older (median 73 years), had poorer Eastern Cooperative Oncology Group (ECOG) performance statuses (16.5% had ECOG ≥ 2), and were more transfusion dependent (48.5%). JAKoMo represents the more challenging patients with MF encountered outside of interventional studies. However, patients with low-risk International Prognostic Scoring System (IPSS) scores or without palpable splenomegaly were also included. Following RUX treatment, 82.5% of patients experienced rapid (≤ 1 month), significant decreases in palpable spleen size, which remained durable for 24 months (60% patients). Symptom assessment scores improved significantly in Month 1 (median -5.2) up to Month 12 (-6.2). Common adverse events (AEs) were anemia (31.2%) and thrombocytopenia (28.6%). At cutoff, 54.3% of patients had terminated the study due to, death, AEs, or deterioration of health. No new safety signals were observed. Interim analysis of the JAKoMo study confirms RUX safety and efficacy in a representative cohort of real-world, elderly, JAKi-naïve patients with MF. Risk scores were used in less than half of the patients to initiate RUX treatment.Trial registration: NCT05044026; September 14, 2021.

GPRC5C drives branched-chain amino acid metabolism in leukemogenesis.

Leukemia stem cells (LSCs) share numerous features with healthy hematopoietic stem cells (HSCs). G-protein coupled receptor family C group 5 member C (GPRC5C) is a regulator of HSC dormancy. However, GPRC5C functionality in acute myeloid leukemia (AML) is yet to be determined. Within patient AML cohorts, high GPRC5C levels correlated with poorer survival. Ectopic Gprc5c expression increased AML aggression through the activation of NF-κB, which resulted in an altered metabolic state with increased levels of intracellular branched-chain amino acids (BCAAs). This onco-metabolic profile was reversed upon loss of Gprc5c, which also abrogated the leukemia-initiating potential. Targeting the BCAA transporter SLC7A5 with JPH203 inhibited oxidative phosphorylation and elicited strong antileukemia effects, specifically in mouse and patient AML samples while sparing healthy bone marrow cells. This antileukemia effect was strengthened in the presence of venetoclax and azacitidine. Our results indicate that the GPRC5C-NF-κB-SLC7A5-BCAAs axis is a therapeutic target that can compromise leukemia stem cell function in AML.

Kidney Dysfunction Is Associated with Thrombosis and Disease Severity in Myeloproliferative Neoplasms: Implications from the German Study Group for MPN Bioregistry.

Inflammation-induced thrombosis represents a severe complication in patients with myeloproliferative neoplasms (MPN) and in those with kidney dysfunction. Overlapping disease-specific attributes suggest common mechanisms involved in MPN pathogenesis, kidney dysfunction, and thrombosis. Data from 1420 patients with essential thrombocythemia (ET, 33.7%), polycythemia vera (PV, 38.5%), and myelofibrosis (MF, 27.9%) were extracted from the bioregistry of the German Study Group for MPN. The total cohort was subdivided according to the calculated estimated glomerular filtration rate (eGFR, (mL/min/1.73 m2)) into eGFR1 (≥90, 21%), eGFR2 (60-89, 56%), and eGFR3 (<60, 22%). A total of 29% of the patients had a history of thrombosis. A higher rate of thrombosis and longer MPN duration was observed in eGFR3 than in eGFR2 and eGFR1. Kidney dysfunction occurred earlier in ET than in PV or MF. Multiple logistic regression analysis identified arterial hypertension, MPN treatment, increased uric acid, and lactate dehydrogenase levels as risk factors for kidney dysfunction in MPN patients. Risk factors for thrombosis included arterial hypertension, non-excessive platelet counts, and antithrombotic therapy. The risk factors for kidney dysfunction and thrombosis varied between MPN subtypes. Physicians should be aware of the increased risk for kidney disease in MPN patients, which warrants closer monitoring and, possibly, early thromboprophylaxis.

Pharmacological Inhibition of Insulin Growth Factor-1 Receptor (IGF-1R) Alone or in Combination With Ruxolitinib Shows Therapeutic Efficacy in Preclinical Myeloproliferative Neoplasm Models.

Even after development of the JAK1/JAK2 inhibitor ruxolitinib, myeloproliferative neoplasm (MPN) patients require novel therapeutic options. While ruxolitinib can considerably improve quality of life and prolong survival, it does not modify the natural disease course in most patients. Moreover, resistance develops with prolonged use. Therefore, various combination treatments are currently being investigated. Published data provide a compelling rationale for the inhibition of insulin growth factor-1 receptor (IGF-1R) signaling in MPN. Here we report that genetic and pharmacological inhibition of IGF-1R selectively reduced Jak2V617F-driven cytokine-independent proliferation ex vivo. Two different structurally unrelated IGF-1R inhibitors ameliorated disease phenotype in a murine MPN model and significantly prolonged survival. Moreover, in mice, low-dose ruxolitinib synergized with IGF-1R inhibition to increase survival. Our data demonstrate preclinical efficacy of IGF-1R inhibition in a murine MPN model.

Prevalence and characteristics of myeloproliferative neoplasms with concomitant monoclonal gammopathy.

Of BCR-ABL negative myeloproliferative neoplasm (MPN) patients, 3-14 % display a concomitant monoclonal gammopathy (MGUS). Nonetheless, literature on co-occurring MPN and MGUS is scarce, the molecular underpinnings are unknown and it is unclear whether patients require a specific management. Here, we compared the clinical and genetic features of MPN patients with and without concomitant MGUS. Of 114 MPN patients prospectively studied by serum immunofixation (median age, 67 years; 36.0 % essential thrombocythemia [ET], 24.6 % polycythemia vera [PV], 11.4 % secondary myelofibrosis [sMF], 28.1 % primary myelofibrois [PMF]; 73.7 % JAK2 V617F positive), 10 (9 %) harbored an M-protein. No relevant clinical differences existed between MPN patients with or without M-protein. Seven additional MPN/MGUS patients were retrospectively identified in our MPN registry, yielding a total of 17 patients (7 ET, 3 PV, 3 sMF, 4 PMF). One patient developed multiple myeloma (MM) and one smoldering MM. Seven of 12 patients analyzed carried mutations (e.g. in ASXL1 or TET2) in addition to those in JAK2 or CALR, and 4 of 10 patients showed aberrant cytogenetics. M-protein was mainly IgG (12/17), followed by IgM (4/17). In the two patients that underwent allogeneic stem cell transplantation mutant JAK2 and M-protein were no longer detectable post-transplant. In conclusion, MGUS prevalence in our cohort was in the range of previous reports and at most slightly higher than expected in the general population. MGUS presence did not correlate with a specific MPN entity, clinical features or genetic alterations. Our observations suggest that there is no strong clinical or biological relationship between the occurrence of MGUS and MPN.

The transcription factor NFE2 enhances expression of the hematopoietic master regulators SCL/TAL1 and GATA2.

Activity of the transcription factor NFE2 is elevated in the majority of patients with myeloproliferative neoplasms (MPNs), either by overexpression of the wild-type alleles or by the presence of an activating mutation. In murine models, enhanced NFE2 activity causes an MPN phenotype with spontaneous transformation to acute leukemia. However, little is known about the downstream target genes activated by augmented NFE2 levels. Here, we describe that NFE2 regulates expression of the hematopoietic master regulators GATA2 and SCL/TAL1, which are in turn overexpressed in primary MPN cells, suggesting that concomitant aberrant activation of several transcription factors coordinately contributes to the cellular expansion characteristic of these disorders.

Enhanced expression of the sphingosine-1-phosphate-receptor-3 causes acute myelogenous leukemia in mice.

Acute myeloid leukemia (AML) carries a 10-100 fold lower mutational burden than other neoplastic entities. Mechanistic explanations for why a low number of mutations suffice to induce leukemogenesis are therefore required. Here we demonstrate that transgenic overexpression of the wild type sphingosine-1-phosphate receptor 3 (S1P3) in murine hematopoietic stem cells is sufficient to induce a transplantable myeloid leukemia. In contrast, S1P3 expression in more mature compartments does not cause malignant transformation. Treatment with the sphingosine phosphate receptor modulator Fingolimod, which prevents receptor signaling, normalized peripheral blood cell counts and reduced spleen sizes in S1P3 expressing mice. Gene expression analyses in AML patients revealed elevated S1P3 expression specifically in two molecular subclasses. Our data suggest a previously unrecognized contribution of wild type S1P3 signaling to leukemogenesis that warrants the exploration of S1P3 antagonists in preclinical AML models.

Water pipe smoking as a cause of secondary erythrocytosis.

Water pipe (WP) smoking has become very popular in European countries. A 27-year-old male patient was referred to our clinic with erythrocytosis of unknown origin. His self-reported history included almost daily WP smoking since the age of 14 years. At presentation haemoglobin, haematocrit (Hct) and carboxy-haemoglobin (CO-Hb) levels were elevated to 19.7 g/dl, 54% and 15.4%, respectively. Erythrocytosis was completely reversible upon cessation of WP smoking. Upon follow-up, haemoglobin, Hct and CO-Hb levels undulated according to the intensity of WP usage. Our report shall raise awareness among physicians for WP smoking as a possible cause of secondary erythrocytosis, particularly among younger adults, and provide guidance for the clinical management.

[Structured Career Pathways in the University Medicine - From Promotion to Clinician Scientist Programs]. / Strukturierte Karrierewege in der Universitätsmedizin.

Scientifically active medical doctors are required for successful translation of novel basic findings into the clinic. However, there is an increasing tendency of young medical doctors to primarily follow a more clinically and not scientifically orientated career pathway. Therefore, the establishment of novel career education structures and career perspectives in university medicine are important to stop this development. Here, we will discuss the current situation and ongoing attempts to design novel structural programs that allow a better combination of clinical and scientific work by highlighting also current developments at the Faculty of Medicine at the University of Freiburg.

Gene mutations and clonal architecture in myelodysplastic syndromes and changes upon progression to acute myeloid leukaemia and under treatment.

Knowledge of the molecular and clonal characteristics in the myelodysplastic syndromes (MDS) and during progression to acute myeloid leukaemia (AML) is essential to understand the disease dynamics and optimize treatment. Sequencing serial bone marrow samples of eight patients, we observed that MDS featured a median of 3 mutations. Mutations in genes involved in RNA-splicing or epigenetic regulation were most frequent, and exclusively present in the major clone. Minor subclones were distinguishable in three patients. As the MDS progressed, a median of one mutation was gained, leading to clonal outgrowth. No AML developed genetically independent of a pre-existing clone. The gained mutation mostly affected genes encoding signalling proteins. Additional acquisition of genomic aberrations frequently occurred. Upon treatment, emergence of new clones could be observed. As confirmed by single-cell sequencing, multiple mutations in identical genes in different clones were present within individual patients. DNA-methylation profiling in patients without identification of novel mutations in AML revealed methylation changes in individual genes. In conclusion, our data complement previous observations on the mutational and clonal characteristics in MDS and at progression. Moreover, DNA-methylation changes may be associated with progression in single patients. Redundancy of mutated genes in different clones suggests fertile grounds promoting clonal selection or acquisition.

Epigenetic regulation of NFE2 overexpression in myeloproliferative neoplasms.

The transcription factor "nuclear factor erythroid 2" (NFE2) is overexpressed in the majority of patients with myeloproliferative neoplasms (MPNs). In murine models, elevated NFE2 levels cause an MPN phenotype with spontaneous leukemic transformation. However, both the molecular mechanisms leading to NFE2 overexpression and its downstream targets remain incompletely understood. Here, we show that the histone demethylase JMJD1C constitutes a novel NFE2 target gene. JMJD1C levels are significantly elevated in polycythemia vera (PV) and primary myelofibrosis patients; concomitantly, global H3K9me1 and H3K9me2 levels are significantly decreased. JMJD1C binding to the NFE2 promoter is increased in PV patients, decreasing both H3K9me2 levels and binding of the repressive heterochromatin protein-1α (HP1α). Hence, JMJD1C and NFE2 participate in a novel autoregulatory loop. Depleting JMJD1C expression significantly reduced cytokine-independent growth of an MPN cell line. Independently, NFE2 is regulated through the epigenetic JAK2 pathway by phosphorylation of H3Y41. This likewise inhibits HP1α binding. Treatment with decitabine lowered H3Y41ph and augmented H3K9me2 levels at the NFE2 locus in HEL cells, thereby increasing HP1α binding, which normalized NFE2 expression selectively in JAK2V617F-positive cell lines.

Oncogenic JAK2V617F causes PD-L1 expression, mediating immune escape in myeloproliferative neoplasms.

Recent evidence has revealed that oncogenic mutations may confer immune escape. A better understanding of how an oncogenic mutation affects immunosuppressive programmed death ligand 1 (PD-L1) expression may help in developing new therapeutic strategies. We show that oncogenic JAK2 (Janus kinase 2) activity caused STAT3 (signal transducer and activator of transcription 3) and STAT5 phosphorylation, which enhanced PD-L1 promoter activity and PD-L1 protein expression in JAK2V617F-mutant cells, whereas blockade of JAK2 reduced PD-L1 expression in myeloid JAK2V617F-mutant cells. PD-L1 expression was higher on primary cells isolated from patients with JAK2V617F-myeloproliferative neoplasms (MPNs) compared to healthy individuals and declined upon JAK2 inhibition. JAK2V617F mutational burden, pSTAT3, and PD-L1 expression were highest in primary MPN patient-derived monocytes, megakaryocytes, and platelets. PD-1 (programmed death receptor 1) inhibition prolonged survival in human MPN xenograft and primary murine MPN models. This effect was dependent on T cells. Mechanistically, PD-L1 surface expression in JAK2V617F-mutant cells affected metabolism and cell cycle progression of T cells. In summary, we report that in MPN, constitutive JAK2/STAT3/STAT5 activation, mainly in monocytes, megakaryocytes, and platelets, caused PD-L1-mediated immune escape by reducing T cell activation, metabolic activity, and cell cycle progression. The susceptibility of JAK2V617F-mutant MPN to PD-1 targeting paves the way for immunomodulatory approaches relying on PD-1 inhibition.

LSD1 Inhibition Prolongs Survival in Mouse Models of MPN by Selectively Targeting the Disease Clone.

Despite recent advances, the myeloproliferative neoplasms (MPNs) are attended by considerable morbidity and mortality. Janus kinase (Jak) inhibitors such as ruxolitinib manage symptoms but do not substantially change the natural history of the disease. In this report, we show the effects of IMG-7289, an irreversible inhibitor of the epigenetically active lysine-specific demethylase 1 (LSD1) in mouse models of MPN. Once-daily treatment with IMG-7289 normalized or improved blood cell counts, reduced spleen volumes, restored normal splenic architecture, and reduced bone marrow fibrosis. Most importantly, LSD1 inhibition lowered mutant allele burden and improved survival. IMG-7289 selectively inhibited proliferation and induced apoptosis of JAK2 V617F cells by concomitantly increasing expression and methylation of p53, and, independently, the pro-apoptotic factor PUMA and by decreasing the levels of its antiapoptotic antagonist BCLXL. These data provide a molecular understanding of the disease-modifying activity of the LSD1 inhibitor IMG-7289 that is currently undergoing clinical evaluation in patients with high-risk myelofibrosis. Moreover, low doses of IMG-7289 and ruxolitinib synergize in normalizing the MPN phenotype in mice, offering a rationale for investigating combination therapy.

Symptom burden profile in myelofibrosis patients with thrombocytopenia: Lessons and unmet needs.

Myelofibrosis is a myeloproliferative neoplasm associated with progressive cytopenias and high symptom burden. MF patients with thrombocytopenia have poor prognosis but the presence of thrombocytopenia frequently precludes the use of JAK2 inhibitors. In this study, we assessed quality of life and symptom burden in 418 MF patients with (n=89) and without (n=329) thrombocytopenia using prospective data from the MPN-QOL study group database, including the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) and Total Symptom Score (MPN10). Thrombocytopenia, defined as platelet count <100×109/L (moderate 51-100×109/L; severe ≤50×109/L), was associated with anemia (76% vs. 45%, p<0.001), leukopenia (29% vs. 11%, p<0.001), and need for red blood cell transfusion (35% vs. 19%, p=0.002). Thrombocytopenic patients had more fatigue, early satiety, inactivity, dizziness, sad mood, cough, night sweats, itching, fever, and weight loss; total symptom scores were also higher (33 vs. 24, p<0.001). Patients with severe thrombocytopenia were more likely to have anemia (86% vs. 67%, p=0.04), leukopenia (40% vs. 20%, p=0.04), and transfusion requirements (51% vs. 20%, p=0.002) but few differences in symptoms when compared to patients with moderate thrombocytopenia. These results suggest that MF patients with thrombocytopenia experience greater symptomatic burden than MF patients without thrombocytopenia and may benefit from additional therapies.

The oligodendrocyte lineage transcription factor 2 (OLIG2) is epigenetically regulated in acute myeloid leukemia.

DNA methylation differences between normal tissue and cancerous tissue resulting in differential expression of genes are a hallmark of acute myeloid leukemia (AML) and can provide malignant cells with a growth advantage via silencing of specific genes, for example, transcription factors. Oligodendrocyte lineage transcription factor 2 (OLIG2) was reported to be differentially methylated and associated with prognosis in AML and, as reported for acute lymphoblastic leukemia and malignant glioma, may play a role in malignant transformation. We report that DNA methylation of OLIG2 is associated with decreased expression of mRNA in AML cell lines and patients. Moreover, in cell lines, decreased mRNA expression also translated into decreased OLIG2 protein expression. Treatment of non-expressing cell lines PL-21 and U-937 with the demethylating agent decitabine resulted in robust re-expression of OLIG2 on mRNA and protein levels. Furthermore, stable overexpression of OLIG2 in non-expressing cell lines Kasumi-1 and U-937, using a lentiviral vector system, led to moderate growth inhibition after 4 days and resulted in signs of differentiation in U-937 cells. Interestingly, although CD34 + cells from healthy donors and 10 of 12 AML patients exhibited no protein expression, OLIG2 was expressed in two patients, both bearing the translocation t(15;17), corresponding to OLIG2 expression in NB-4 cells, also harboring t(15;17). In conclusion, we provide first evidence that OLIG2 is epigenetically regulated via DNA methylation and expressed in a subset of AML patients. OLIG2 may exert antiproliferative activity in leukemia cell lines, and its potential leukemia-suppressing role in AML warrants further investigation.

Associations between gender, disease features and symptom burden in patients with myeloproliferative neoplasms: an analysis by the MPN QOL International Working Group.

The myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia and myelofibrosis, are distinguished by their debilitating symptom profiles, life-threatening complications and profound impact on quality of life. The role gender plays in the symptomatology of myeloproliferative neoplasms remains under-investigated. In this study we evaluated how gender relates to patients' characteristics, disease complications and overall symptom expression. A total of 2,006 patients (polycythemia vera=711, essential thrombocythemia=830, myelofibrosis=460, unknown=5) were prospectively evaluated, with patients completing the Myeloproliferative Neoplasm-Symptom Assessment Form and Brief Fatigue Inventory Patient Reported Outcome tools. Information on the individual patients' characteristics, disease complications and laboratory data was collected. Consistent with known literature, most female patients were more likely to have essential thrombocythemia (48.6% versus 33.0%; P<0.001) and most male patients were more likely to have polycythemia vera (41.8% versus 30.3%; P<0.001). The rate of thrombocytopenia was higher among males than females (13.9% versus 8.2%; P<0.001) and males also had greater red-blood cell transfusion requirements (7.3% versus 4.9%; P=0.02) with shorter mean disease duration (6.4 versus 7.2 years, P=0.03). Despite there being no statistical differences in risk scores, receipt of most therapies or prior complications (hemorrhage, thrombosis), females had more severe and more frequent symptoms for most individual symptoms, along with overall total symptom score (22.8 versus 20.3; P<0.001). Females had particularly high scores for abdominal-related symptoms (abdominal pain/discomfort) and microvascular symptoms (headache, fatigue, insomnia, concentration difficulties, dizziness; all P<0.01). Despite complaining of more severe symptom burden, females had similar quality of life scores to those of males. The results of this study suggest that gender contributes to the heterogeneity of myeloproliferative neoplasms by influencing phenotypic profiles and symptom expression.

Tissue microarray technique is applicable to bone marrow biopsies of myeloproliferative neoplasms.

Tissue microarray (TMA) technique is an established high-throughput method to analyze multiple tissue specimens in parallel. However, in order to obtain reliable results from immunohistochemical analyses of TMA blocks, cell composition of TMA spots must correspond to whole tissue sections (WTS) particularly in tissues with a heterogeneous cell composition as it is the case in myeloproliferative neoplasms (MPN). The aim of this study was to validate TMA of bone marrow biopsies from MPN patients. TMAs of MPN bone marrow biopsies (ET: n = 26, PV: n = 26, and PMF: n = 29) were compiled in triplicates and MPN-specific histological parameters were assessed. Results of TMA spots were compared with WTS' results using the intra-class correlation coefficient (ICC). Immunohistochemical NFE2 and calreticulin stainings of the TMA with quantitative evaluation were performed. TMA construction was technically successful with a loss of 10 % of all spots. ICC calculation revealed high to moderate correlations of TMA with WTS, especially the parameters that are typically affected in MPN tissue, e.g. cellularity of hematopoiesis (ICC 0.62-0.89), number of megakaryocytes (ICC 0.50-0.71), micro-vessel density (ICC 0.56-0.91), or grade of myelofibrosis (ICC 0.56-0.89). Results of NFE2 and calreticulin immunohistochemistry of MPN TMAs are consistent with previously published data. Overall, our results show moderate to good correlation between histological data of WTS and TMA spots illustrating that the TMA technique is applicable to bone marrow biopsies of MPN patients. However, TMA construction in triplicates is necessary to reach sufficient correlation. MPN TMAs can be applied for serial immunohistochemical surveys of archived tissues to assess the mutation status or to further sub-classify MPN cases.

A novel role for nuclear factor-erythroid 2 in erythroid maturation by modulation of mitochondrial autophagy.

We have recently demonstrated that the transcription factor nuclear factor-erythroid 2, which is critical for erythroid maturation and globin gene expression, plays an important role in the pathophysiology of myeloproliferative neoplasms. Myeloproliferative neoplasm patients display elevated levels of nuclear factor-erythroid 2 and transgenic mice overexpressing the transcription factor develop myeloproliferative neoplasm, albeit, surprisingly without erythrocytosis. Nuclear factor-erythroid 2 transgenic mice show both a reticulocytosis and a concomitant increase in iron deposits in the spleen, suggesting both enhanced erythrocyte production and increased red blood cell destruction. We therefore hypothesized that elevated nuclear factor-erythroid 2 levels may lead to increased erythrocyte destruction by interfering with organelle clearance during erythroid maturation. We have previously shown that nuclear factor-erythroid 2 overexpression delays erythroid maturation of human hematopoietic stem cells. Here we report that increased nuclear factor-erythroid 2 levels also impede murine maturation by retarding mitochondrial depolarization and delaying mitochondrial elimination. In addition, ribosome autophagy is delayed in transgenics. We demonstrate that the autophagy genes NIX and ULK1 are direct novel nuclear factor-erythroid 2 target genes, as these loci are bound by nuclear factor-erythroid 2 in chromatin immunoprecipitation assays. Moreover, Nix and Ulk1 expression is increased in transgenic mice and in granulocytes from polycythemia vera patients. This is the first report implying a role for nuclear factor-erythroid 2 in erythroid maturation by affecting autophagy.