Three-year efficacy, safety, and survival findings from COMFORT-II, a phase 3 study comparing ruxolitinib with best available therapy for myelofibrosis

SOHO State of the Art Updates and Next Questions | Choosing and Properly Using a JAK Inhibitor in Myelofibrosis

Myelofibrosis (MF) is a chronic myeloid neoplasm characterized by myeloproliferation, bone marrow fibrosis, splenomegaly, and constitutional symptoms related to pro-inflammatory cytokine signaling. Biologically, MF is characterized by constitutive activation of JAK-STAT signaling; accordingly, JAK inhibitors have been rationally developed to treat MF. Following the initial approval of ruxolitinib in 2011, three additional agents have been approved: fedratinib, pacritinib, and momelotinib. As these therapies are noncurative, allogeneic stem cell transplantation remains a key treatment modality and patients with MF who are deemed candidates should be referred to a transplant center. This potentially curative but toxic approach is typically reserved for patients with higher-risk disease, and JAK inhibitors are recommended in the pretransplant setting. JAK inhibitors have proven effective at managing splenomegaly and constitutional symptoms and should be started early in the disease course in patients presenting with these clinical manifestations; asymptomatic patients may initially be followed with close surveillance. Drug-related myelosuppression has been a challenge with initial JAK inhibitors, particularly in patients presenting with a cytopenic phenotype. However, newer agents, namely pacritinib and momelotinib, have proven more effective in this setting and are approved for patients with significant thrombocytopenia and anemia, respectively. Resistance or disease progression is clinically challenging and may be defined by several possible events, such as increasing splenomegaly or progression to accelerated or blast phase disease. However, with multiple JAK inhibitors now approved, sequencing of these agents appears poised to improve outcomes. Additionally, novel JAK inhibitors and JAK inhibitor-based combinations are in clinical development.

Comparative efficacy and hematologic safety of different dosages of JAK inhibitors in the treatment of myelofibrosis: a network meta-analysis

Background

Myelofibrosis (MF) is a myeloproliferative neoplasm characterized by bone marrow fibrosis associated with substantial morbidity and mortality. The therapeutic landscape for MF has advanced with the development of Janus kinase inhibitors (JAKis) like ruxolitinib (RUX), fedratinib (FED), pacritinib (PAC), and momelotinib (MMB), aiming to alleviate symptoms and enhance patient comfort.

Methods

A network meta-analysis was conducted to assess the efficacy and safety of eleven JAKi treatment regimens across nine randomized controlled trials (RCTs) with a total of 2340 participants. Outcomes were evaluated in terms of spleen volume reduction (SVR), total symptom score reduction (TSSR), hematological safety profiles, and overall survival (OS).

Results

RUX and MMB were superior in achieving SVR and TSSR, with significant dose-response relationships observed. PAC and MMB were associated with a decreased risk of grade 3/4 anemia and thrombocytopenia compared to other JAKis. However, no substantial benefits in OS were observed with newer JAKis compared to RUX. The poorer OS outcomes with certain PAC dosages were likely influenced by baseline patient characteristics, particularly severe cytopenias.

Conclusion

The introduction of JAKis significantly changed the treatment of MF. This meta-analysis reaffirms the core role of RUX and positions MMB as a potentially powerful alternative for treating symptoms and reducing spleen size. Meanwhile, MMB and PAC have a positive effect on anemia in MF while FED is more tolerable for patients with thrombocytopenia. However, it should be noted that these results are influenced by baseline patient characteristics, particularly cytopenias, which affects both management and overall survival. Therefore, there is an urgent need for personalized dosing strategies to optimize the balance between efficacy and safety, with careful consideration of patient-specific factors.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023424179.

Ruxolitinib as a CaMKII inhibitor for treatment of cardiac arrhythmias: Applications and prospects

Recent studies have highlighted the critical role of calcium/calmodulin-dependent protein kinase II (CaMKII) overactivation in the pathogenesis of various cardiac arrhythmias. Ruxolitinib, a Janus kinase inhibitor widely used for the treatment of myelofibrosis and acute graft-vs-host disease, has expanded its research horizons to include its potential as a CaMKII inhibitor in the treatment of cardiac arrhythmias. This article reviews the basic pharmacologic properties of ruxolitinib and delves into the role of CaMKII in cardiac arrhythmias, including its structural fundamentals, activation mechanisms, and association with arrhythmic conditions. Furthermore, the current state of CaMKII inhibitor research is discussed, with a special focus on the advances and clinical potential of ruxolitinib in this field. Studies indicate that ruxolitinib effectively inhibits CaMKII activity and has therapeutic potential against cardiac arrhythmias in animal models and at the cellular level. In addition, we address the critical issues that need to be resolved before the clinical application of ruxolitinib in arrhythmia treatment, including dosage concerns, long-term inhibitory effects, potential impacts on the nervous system, and efficacy across different types of arrhythmias. Future research directions involve further exploration of the clinical application potential of ruxolitinib, particularly in diseases such as heart failure, hypertrophic cardiomyopathy, dilated cardiomyopathy, and ischemic arrhythmias. In summary, the efficacy, low toxicity, and safety profile of ruxolitinib as a CaMKII inhibitor in the treatment of cardiac arrhythmias suggest a promising future for its development as a therapeutic drug in this domain.

The Variation in the Traits Ameliorated by Inhibitors of JAK1/2, TGF-β, P-Selectin, and CXCR1/CXCR2 in the Gata1low Model Suggests That Myelofibrosis Should Be Treated by These Drugs in Combination

Studies conducted on animal models have identified several therapeutic targets for myelofibrosis, the most severe of the myeloproliferative neoplasms. Unfortunately, many of the drugs which were effective in pre-clinical settings had modest efficacy when tested in the clinic. This discrepancy suggests that treatment for this disease requires combination therapies. To rationalize possible combinations, the efficacy in the Gata1low model of drugs currently used for these patients (the JAK1/2 inhibitor Ruxolitinib) was compared with that of drugs targeting other abnormalities, such as p27kip1 (Aplidin), TGF-β (SB431542, inhibiting ALK5 downstream to transforming growth factor beta (TGF-β) signaling and TGF-β trap AVID200), P-selectin (RB40.34), and CXCL1 (Reparixin, inhibiting the CXCL1 receptors CXCR1/2). The comparison was carried out by expressing the endpoints, which had either already been published or had been retrospectively obtained for this study, as the fold change of the values in the corresponding vehicles. In this model, only Ruxolitinib was found to decrease spleen size, only Aplidin and SB431542/AVID200 increased platelet counts, and with the exception of AVID200, all the inhibitors reduced fibrosis and microvessel density. The greatest effects were exerted by Reparixin, which also reduced TGF-β content. None of the drugs reduced osteopetrosis. These results suggest that future therapies for myelofibrosis should consider combining JAK1/2 inhibitors with drugs targeting hematopoietic stem cells (p27Kip1) or the pro-inflammatory milieu (TGF-β or CXCL1).

Chronic neutrophilic leukemia and atypical chronic myeloid leukemia: 2024 update on diagnosis, genetics, risk stratification, and management

Chronic neutrophilic leukemia (CNL) is a rare BCR::ABL1-negative myeloproliferative neoplasm (MPN) defined by persistent mature neutrophilic leukocytosis and bone marrow granulocyte hyperplasia. Atypical chronic myeloid leukemia (aCML) (myelodysplastic "[MDS]/MPN with neutrophilia" per World Health Organization [WHO]) is a MDS/MPN overlap disorder featuring dysplastic neutrophilia and circulating myeloid precursors. Both manifest with frequent hepatosplenomegaly and less commonly, bleeding, with high rates of leukemic transformation and death. The 2022 revised WHO classification conserved CNL diagnostic criteria of leukocytosis ≥25 × 109/L, neutrophils ≥80% with <10% circulating precursors, absence of dysplasia, and presence of an activating CSF3R mutation. ICC criteria are harmonized with those of other myeloid entities, with a key distinction being lower leukocytosis threshold (≥13 × 109/L) for cases CSF3R-mutated. Criteria for aCML include leukocytosis ≥13 × 109/L, dysgranulopoiesis, circulating myeloid precursors ≥10%, and at least one cytopenia for MDS-thresholds (ICC). In both classifications ASXL1 and SETBP1 (ICC), or SETBP1 ± ETNK1 (WHO) mutations can be used to support the diagnosis. Both diseases show hypercellular bone marrow due to a granulocytic proliferation, aCML distinguished by dysplasia in granulocytes ± other lineages. Absence of monocytosis, rare/no basophilia, or eosinophilia, <20% blasts, and exclusion of other MPN, MDS/MPN, and tyrosine kinase fusions, are mandated. Cytogenetic abnormalities are identified in ~1/3 of CNL and ~15-40% of aCML patients. The molecular signature of CNL is a driver mutation in colony-stimulating factor 3 receptor-classically T618I, documented in >80% of cases. Atypical CML harbors a complex genomic backdrop with high rates of recurrent somatic mutations in ASXL1, SETBP1, TET2, SRSF2, EZH2, and less frequently in ETNK1. Leukemic transformation rates are ~10-25% and 30-40% for CNL and aCML, respectively. Overall survival is poor: 15-31 months in CNL and 12-20 months in aCML. The Mayo Clinic CNL risk model for survival stratifies patients according to platelets <160 × 109/L (2 points), leukocytes >60 × 109/L (1 point), and ASXL1 mutation (1 point); distinguishing low- (0-1 points) versus high-risk (2-4 points) categories. The Mayo Clinic aCML risk model attributes 1 point each for: age >67 years, hemoglobin <10 g/dL, and TET2 mutation, delineating low- (0-1 risk factor) and high-risk (≥2 risk factors) subgroups. Management is risk-driven and symptom-directed, with no current standard of care. Most commonly used agents include hydroxyurea, interferon, Janus kinase inhibitors, and hypomethylating agents, though none are disease-modifying. Hematopoietic stem cell transplant is the only potentially curative modality and should be considered in eligible patients. Recent genetic profiling has disclosed CBL, CEBPA, EZH2, NRAS, TET2, and U2AF1 to represent high-risk mutations in both entities. Actionable mutations (NRAS/KRAS, ETNK1) have also been identified, supporting novel agents targeting involved pathways. Preclinical and clinical studies evaluating new drugs (e.g., fedratinib, phase 2) and combinations are detailed.

Advances with janus kinase inhibitors for the treatment of myeloproliferative neoplasms: an update of the literature

INTRODUCTION

The hallmark discovery of hyperactivation of the janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway was a sentinel moment in the history of myeloproliferative neoplasms (MPNs). This finding paved the way for the development of JAK inhibitors, which now represent the foundation of myelofibrosis therapy. With four JAK inhibitors now approved for myelofibrosis, awareness of their clinical efficacy and safety data and recognition of their unique pharmacologic attributes are of critical importance. Additionally, ruxolitinib represents an integral part of the therapeutic arsenal for polycythemia vera.

AREAS COVERED

This review provides a broad overview of the published literature supporting JAK inhibitor therapy for MPNs. Primarily focusing on myelofibrosis, each of the four available JAK inhibitors is reviewed in detail, including pharmacology, efficacy, and safety data. Failure of JAK inhibitors and future directions in JAK inhibitor therapy are also discussed.

EXPERT OPINION

JAK inhibitors revolutionized the treatment of MPNs and have dramatically improved patient outcomes. However, data informing selection between currently available JAK inhibitors is limited. These agents are not curative and eventually fail most patients with myelofibrosis. Combining JAK inhibitors with novel targeted agents appears to be the most promising path to further improve outcomes.

Mathematical modelling of stem and progenitor cell dynamics during ruxolitinib treatment of patients with myeloproliferative neoplasms

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.

Mapping genotypes to chromatin accessibility profiles in single cells

In somatic tissue differentiation, chromatin accessibility changes govern priming and precursor commitment towards cellular fates1-3. Therefore, somatic mutations are likely to alter chromatin accessibility patterns, as they disrupt differentiation topologies leading to abnormal clonal outgrowth. However, defining the impact of somatic mutations on the epigenome in human samples is challenging due to admixed mutated and wild-type cells. Here, to chart how somatic mutations disrupt epigenetic landscapes in human clonal outgrowths, we developed genotyping of targeted loci with single-cell chromatin accessibility (GoT-ChA). This high-throughput platform links genotypes to chromatin accessibility at single-cell resolution across thousands of cells within a single assay. We applied GoT-ChA to CD34+ cells from patients with myeloproliferative neoplasms with JAK2V617F-mutated haematopoiesis. Differential accessibility analysis between wild-type and JAK2V617F-mutant progenitors revealed both cell-intrinsic and cell-state-specific shifts within mutant haematopoietic precursors, including cell-intrinsic pro-inflammatory signatures in haematopoietic stem cells, and a distinct profibrotic inflammatory chromatin landscape in megakaryocytic progenitors. Integration of mitochondrial genome profiling and cell-surface protein expression measurement allowed expansion of genotyping onto DOGMA-seq through imputation, enabling single-cell capture of genotypes, chromatin accessibility, RNA expression and cell-surface protein expression. Collectively, we show that the JAK2V617F mutation leads to epigenetic rewiring in a cell-intrinsic and cell type-specific manner, influencing inflammation states and differentiation trajectories. We envision that GoT-ChA will empower broad future investigations of the critical link between somatic mutations and epigenetic alterations across clonal populations in malignant and non-malignant contexts.

Ruxolitinib associated psoas muscle tuberculosis abscess in a primary myelofibrosis woman: A case report and literature review

RATIONALE

Primary myelofibrosis is a subtype of myeloproliferative neoplasm that leads to bone marrow fibrosis. Historically, the only curative option for primary myelofibrosis was allogeneic hematopoietic stem cell transplant. Ruxolitinib, a Janus kinase inhibitor, is now used for the treatment of primary myelofibrosis and polycythemia vera. It effectively improves symptoms related to splenomegaly and anemia. However, its association with the development of opportunistic infections has been observed in clinical studies and practical application.

PATIENT CONCERNS

A 64-year-old female with primary myelofibrosis and chronic hepatitis B infection who received ruxolitinib treatment. She was admitted for spiking fever and altered consciousness.

DIAGNOSIS

Tuberculosis meningitis was suspected but cerebrospinal fluid can't identify any pathogens. An abdominal computed tomography scan revealed a left psoas abscess and an enlarged spleen. A computed tomography-guided pus drainage procedure was performed, showing a strong positive acid-fast stain and a positive Mycobacterium tuberculosis polymerase chain reaction result.

INTERVENTIONS

antituberculosis medications were administered. The patient developed a psoas muscle abscess caused by tuberculosis and multiple dermatomes of herpes zoster during antituberculosis treatment.

OUTCOMES

The patient was ultimately discharged after 6 weeks of treatment without apparent neurological sequelae.

LESSONS

This case underscores the importance of clinicians evaluating latent infections and ensuring full vaccination prior to initiating ruxolitinib-related treatment for primary myelofibrosis.

Advances in pharmacotherapy for myelofibrosis: what is the current state of play?

INTRODUCTION

The introduction of the first JAK inhibitor (JAKi) ruxolitinib 10 years ago represented a pivotal advancement in myelofibrosis (MF) treatment, mostly in terms of spleen and symptoms response. Nowadays three more JAKi, fedratinib, pacritinib, and momelotinib, are available for both ruxolitinib-resistant and naïve patients. Moreover, many drugs are currently being investigated, both alone and in combination with JAKi.

AREAS COVERED

In this review we discuss the long-term data of ruxolitinib and more recent evidence coming from clinical trials of fedratinib, pacritinib, and momelotinib, used as first- or second-line MF therapy. More, focus is set on data from non-JAKi drugs, such as the quite extensively studied BET-inhibitors (pelabresib) and BCL-inhibitors (navitoclax), novel target therapies, and drugs aimed to improve anemia, still representing a major determinant of reduced survival in MF.

EXPERT OPINION

It's now evident that JAKi monotherapy, though clinically effective, is rarely able to change MF natural history; novel drugs are promising but long-term data are inevitably lacking. We feel that soon MF treatment will require clinicians to select the most appropriate JAKi inhibitor, based on patient characteristics, associating either front-line or in case of early suboptimal response, non-JAKi drugs with the aim to pursue disease modification.

Ischemic stroke as an initial performance of polycythemia vera in young adults: A case report and literature review

INTRODUCTION

As the second leading cause of death and disability worldwide, stroke is mainly caused by atherosclerosis and cardiac embolism, particularly in older individuals. Nevertheless, in young and otherwise healthy individuals, the causes of stroke can be more diverse and may include conditions such as patent foramen ovale, vasculitis, coagulopathies, genetic factors, or other undetermined causes. Although these other causes of stroke account for a relatively small proportion compared to ischemic stroke, they are becoming increasingly common in clinical practice and deserve attention. Here, we present a rare female patient with polycythemia vera (PV) who was admitted to the hospital as a stroke patient without any previous medical history.

PATIENT CONCERNS

A 40-year-old young woman felt sudden dizziness and slow response. After 4 days of being admitted, she developed blurry vision on the right.

DIAGNOSES

Cranial magnetic resonance imaging revealed aberrant signals in the left temporal and parietal lobe, as well as multiple small focal signal abnormalities were observed in the left frontal lobe. Magnetic resonance angiography revealed partial stenosis of the left internal carotid artery. The patient's blood routine examination revealed a significant elevation in complete blood counts, particularly the increase in red blood cells, as well as prolonged clotting time. An abdominal ultrasound and abdomen computed tomography showed splenomegaly. The outcome of the genetic testing was positive for the Janus kinase JAK2 exon V617F mutation (JAK2/V617F). The patient was diagnosed with PV-related stroke.

INTERVENTIONS

The patient was treated with phlebotomy, cytoreductive therapy, and low-dose aspirin antiplatelet therapy and was regularly followed up in hematology and neurology clinics after discharge.

OUTCOMES

The patient's red blood cell, leukocyte, and thrombocyte counts had fully normalized, with her hemoglobin level measuring at 146 g/L and hematocrit value at 43%. Furthermore, there had been a significant improvement in neurological symptoms.

LESSONS

PV, a rare hematological disorder, can present with ischemic stroke as the initial performance, and the diagnosis mainly relies on routine blood tests, bone marrow biopsies, and genetic test. Therefore, clinicians should pay attention to PV, a low-prevalence disease, when encountering stroke in youth.

Serious infections in patients with VEXAS syndrome: data from the French VEXAS registry

INTRODUCTION

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome is an acquired autoinflammatory monogenic disease with a poor prognosis whose determinants are not well understood. We aimed to describe serious infectious complications and their potential risk factors.

METHODS

Retrospective multicentre study including patients with VEXAS syndrome from the French VEXAS Registry. Episodes of serious infections were described, and their risk factors were analysed using multivariable Cox proportional hazards models.

RESULTS

Seventy-four patients with 133 serious infections were included. The most common sites of infection were lung (59%), skin (10%) and urinary tract (9%). Microbiological confirmation was obtained in 76%: 52% bacterial, 30% viral, 15% fungal and 3% mycobacterial. Among the pulmonary infections, the main pathogens were SARS-CoV-2 (28%), Legionella pneumophila (21%) and Pneumocystis jirovecii (19%). Sixteen per cent of severe infections occurred without any immunosuppressive treatment and with a daily glucocorticoid dose ≤10 mg. In multivariate analysis, age >75 years (HR (95% CI) 1.81 (1.02 to 3.24)), p.Met41Val mutation (2.29 (1.10 to 5.10)) and arthralgia (2.14 (1.18 to 3.52)) were associated with the risk of serious infections. JAK inhibitors were most associated with serious infections (3.84 (1.89 to 7.81)) compared with biologics and azacitidine. After a median follow-up of 4.4 (2.5-7.7) years, 27 (36%) patients died, including 15 (56%) due to serious infections.

CONCLUSION

VEXAS syndrome is associated with a high incidence of serious infections, especially in older patients carrying the p.Met41Val mutation and treated with JAK inhibitors. The high frequency of atypical infections, especially in patients without treatment, may indicate an intrinsic immunodeficiency.

Momelotinib expands the therapeutic armamentarium for myelofibrosis: Impact on hierarchy of treatment choices

The primary objective of treatment in myelofibrosis (MF) is prolongation of life, which is currently accomplished only by allogeneic hematopoietic stem cell transplantation (AHSCT). Determination of optimal timing for AHSCT is facilitated by molecular risk stratification. Non-transplant treatment options in MF are palliative in scope and include Janus kinase 2 (JAK2) inhibitors (JAKi): momelotinib (FDA approved on September 15, 2023), ruxolitinib (November 16, 2011), fedratinib (August 16, 2019), and pacritinib (February 28, 2022); all four JAKi are effective in reducing spleen size and alleviating symptoms, considered a drug class effect and attributed to their canonical JAK-STAT inhibitory mechanism of action. In addition, momelotinib exhibits erythropoietic effect, attributed to alleviation of ineffective erythropoiesis through inhibition of activin A receptor type-I (ACVR1). In transplant-ineligible or deferred patients, the order of treatment preference is based on specific symptoms and individual assessment of risk tolerance. Because of drug-induced immunosuppression and other toxicities attributed to JAKi, we prefer non-JAKi drugs as initial treatment for MF-associated anemia that is not accompanied by treatment-requiring splenomegaly or constitutional symptoms. Otherwise, it is reasonable to consider momelotinib as the first-line JAKi treatment of choice, in order to target the triad of quality-of-life offenders in MF: anemia, splenomegaly, and constitutional symptoms/cachexia. For second-line therapy, we favor ruxolitinib, over fedratinib, based on toxicity profile. Pacritinib and fedratinib provide alternative options in the presence of severe thrombocytopenia or ruxolitinib-resistance/intolerance, respectively. Splenectomy remains a viable option for drug-resistant symptomatic splenomegaly and cytopenia.

A safety evaluation of ruxolitinib for the treatment of polycythemia vera

INTRODUCTION

Polycythemia Vera (PV) is a chronic myeloproliferative neoplasm hallmarked by deregulated proliferation of hematopoietic stem cells leading to prevalent expansion of red cell mass, increased rate of vascular events, splenomegaly, disease-associated symptoms, and risk of evolution to secondary myelofibrosis and blast phase. PV is pathogenetically associated with autonomously persistent activation of JAK2, which causes overproduction of blood cells and an inflammatory condition responsible for the clinical manifestations of the disease. Extensively supported by preclinical studies, targeting JAK2-dependent signaling represents a rational therapeutic approach to PV, finally leading to the approval of ruxolitinib, a JAK1/2 inhibitor.

AREAS COVERED (LITERATURE RESEARCH)

We analyzed reports of phase 2 and phase 3 trials with ruxolitinib in PV and relevant literature dealing with efficacy and safety aspects, including most recent real-world reports.

EXPERT OPINION

Ruxolitinib is the only JAK2 inhibitor approved for the treatment of PV with well-known efficacy for splenomegaly, symptoms, and potentially reduction of vascular events. The treatment regimen is notably manageable and safe, with the most prevalent side effects primarily encompassing myelosuppression, hyperlipidemia, non-melanoma skin cancer and infections, mainly reactivation of Herpes Zoster. These effects necessitate ongoing surveillance and proactive preventive measures.

Real-world outcomes with fedratinib therapy in patients who discontinued ruxolitinib for primary myelofibrosis

Aim: Fedratinib is an oral selective JAK2 inhibitor approved in the USA for the treatment of adult patients with intermediate-2 or high-risk primary or secondary myelofibrosis (MF). Methods: This observational study assessed adult US patients who received ruxolitinib for primary MF (Flatiron Health database: 1 January 2011-31 October 2020). Patients were stratified by post-ruxolitinib treatment (fedratinib vs non-fedratinib). Results: Characteristics were comparable between fedratinib (n=70) and non-fedratinib (n=159) groups (median age: 71.0 vs 70.0 years; females: 55.7 vs 50.3%; median follow-up: 7.0 vs 6.0 months). Median overall survival (not reached vs 17 months) and 12 month survival (71.6 vs 53.5%) were improved with fedratinib versus the non-fedratinib therapies. Conclusion: In MF patients who received frontline ruxolitinib, survival was improved with subsequent fedratinib versus non-fedratinib care.

Micheliolide exerts effects in myeloproliferative neoplasms through inhibiting STAT3/5 phosphorylation via covalent binding to STAT3/5 proteins

Ruxolitinib is a cornerstone of management for some subsets of myeloproliferative neoplasms (MPNs); however, a considerable number of patients respond suboptimally. Here, we evaluated the efficacy of micheliolide (MCL), a natural guaianolide sesquiterpene lactone, alone or in combination with ruxolitinib in samples from patients with MPNs, JAK2V617F-mutated MPN cell lines, and a Jak2V617F knock-in mouse model. MCL effectively suppressed colony formation of hematopoietic progenitors in samples from patients with MPNs and inhibited cell growth and survival of MPN cell lines in vitro. Co-treatment with MCL and ruxolitinib resulted in greater inhibitory effects compared with treatment with ruxolitinib alone. Moreover, dimethylaminomicheliolide (DMAMCL), an orally available derivative of MCL, significantly increased the efficacy of ruxolitinib in reducing splenomegaly and cytokine production in Jak2V617F knock-in mice without evident effects on normal hematopoiesis. Importantly, MCL could target the Jak2V617F clone and reduce mutant allele burden in vivo. Mechanistically, MCL can form a stable covalent bond with cysteine residues of STAT3/5 to suppress their phosphorylation, thus inhibiting JAK/STAT signaling. Overall, these findings suggest that MCL is a promising drug in combination with ruxolitinib in the setting of suboptimal response to ruxolitinib.

Next-Generation JAK2 Inhibitors for the Treatment of Myeloproliferative Neoplasms: Lessons from Structure-Based Drug Discovery Approaches

Selective inhibitors of Janus kinase (JAK) 2 have been in demand since the discovery of the JAK2 V617F mutation present in patients with myeloproliferative neoplasms (MPN); however, the structural basis of V617F oncogenicity has only recently been elucidated. New structural studies reveal a role for other JAK2 domains, beyond the kinase domain, that contribute to pathogenic signaling. Here we evaluate the structure-based approaches that led to recently-approved type I JAK2 inhibitors (fedratinib and pacritinib), as well as type II (BBT594 and CHZ868) and pseudokinase inhibitors under development (JNJ7706621). With full-length JAK homodimeric structures now available, superior selective and mutation-specific JAK2 inhibitors are foreseeable.

SIGNIFICANCE

The JAK inhibitors currently used for the treatment of MPNs are effective for symptom management but not for disease eradication, primarily because they are not strongly selective for the mutant clone. The rise of computational and structure-based drug discovery approaches together with the knowledge of full-length JAK dimer complexes provides a unique opportunity to develop better targeted therapies for a range of conditions driven by pathologic JAK2 signaling.

Janus kinase inhibitor ruxolitinib in combination with nilotinib and prednisone in patients with myelofibrosis (RuNiC study): A phase Ib, multicenter study

This phase Ib, non-randomized, open-label study evaluates the safety and tolerability of ruxolitinib in combination with nilotinib and prednisone in patients with naïve or ruxolitinib-resistant myelofibrosis (MF). A total of 15 patients with primary or secondary MF received the study treatment; 13 patients had received prior ruxolitinib treatment (86.7%). Eight patients completed seven cycles (53.3%) and six patients completed twelve cycles of treatment (40%). All the patients experienced at least one adverse event (AE) during the study (the most common AEs were hyperglycemia, asthenia, and thrombocytopenia), and 14 patients registered at least one treatment-related AE (the most common treatment-related AEs were hyperglycemia (22.2%; three grade 3 cases). Five treatment-related serious AEs (SAEs) were reported in two patients (13.3%). No deaths were registered throughout the study. No dose-limiting toxicity was observed. Four out of fifteen (27%) patients experienced a 100% spleen size reduction at Cycle 7, and two additional patients achieved a >50% spleen size reduction, representing an overall response rate of 40% at Cycle 7. In conclusion, the tolerability of this combination was acceptable, and hyperglycemia was the most frequent treatment-related AE. Ruxolitinib in combination with nilotinib and prednisone showed relevant clinical activity in patients with MF. This trial was registered with EudraCT Number 2016-005214-21.

MEK Inhibition Synergizes with TYK2 Inhibitors in NF1-Associated Malignant Peripheral Nerve Sheath Tumors

PURPOSE

Malignant peripheral nerve sheath tumors (MPNST) are aggressive sarcomas with limited treatment options and poor survival rates. About half of MPNST cases are associated with the neurofibromatosis type 1 (NF1) cancer predisposition syndrome. Overexpression of TYK2 occurs in the majority of MPNST, implicating TYK2 as a therapeutic target.

EXPERIMENTAL DESIGN

The effects of pharmacologic TYK2 inhibition on MPNST cell proliferation and survival were examined using IncuCyte live cell assays in vitro, and downstream actions were analyzed using RNA-sequencing (RNA-seq), qPCR arrays, and validation of protein changes with the WES automated Western system. Inhibition of TYK2 alone and in combination with MEK inhibition was evaluated in vivo using both murine and human MPNST cell lines, as well as MPNST PDX.

RESULTS

Pharmacologic inhibition of TYK2 dose-dependently decreased proliferation and induced apoptosis over time. RNA-seq pathway analysis on TYK2 inhibitor-treated MPNST demonstrated decreased expression of cell cycle, mitotic, and glycolysis pathways. TYK2 inhibition resulted in upregulation of the MEK/ERK pathway gene expression, by both RNA-seq and qPCR array, as well as increased pERK1/2 levels by the WES Western system. The compensatory response was tested with dual treatment with TYK2 and MEK inhibitors, which synergistically decreased proliferation and increased apoptosis in vitro. Finally, combination therapy was shown to inhibit growth of MPNST in multiple in vivo models.

CONCLUSIONS

These data provide the preclinical rationale for the development of a phase I clinical trial of deucravacitinib and mirdametinib in NF1-assosciated MPNST.

How I manage anemia related to myelofibrosis and its treatment regimens

Myelofibrosis (MF) is a myeloproliferative neoplasm characterized by mutations (most frequently in JAK2, CALR, or MPL), burdensome symptoms, splenomegaly, cytopenia, and shortened life expectancy. In addition to other clinical manifestations, patients with MF often develop anemia, which can either be directly related to MF pathogenesis or a result of MF treatment with Janus kinase (JAK) inhibitors, such as ruxolitinib and fedratinib. Although symptoms and clinical manifestations can be similar between the 2 anemia types, only MF-related anemia is prognostic of reduced survival. In this review, I detail treatment and patient management approaches for both types of anemia presentations and provide recommendations for the treatment of MF in the presence of anemia.

Targeting pleckstrin-2/Akt signaling reduces proliferation in myeloproliferative neoplasm models

Myeloproliferative neoplasms (MPNs) are characterized by the activated JAK2/STAT pathway. Pleckstrin-2 (Plek2) is a downstream target of the JAK2/STAT5 pathway and is overexpressed in patients with MPNs. We previously revealed that Plek2 plays critical roles in the pathogenesis of JAK2-mutated MPNs. The nonessential roles of Plek2 under physiologic conditions make it an ideal target for MPN therapy. Here, we identified first-in-class Plek2 inhibitors through an in silico high-throughput screening approach and cell-based assays, followed by the synthesis of analogs. Plek2-specific small-molecule inhibitors showed potent inhibitory effects on cell proliferation. Mechanistically, Plek2 interacts with and enhances the activity of Akt through the recruitment of downstream effector proteins. The Plek2-signaling complex also includes Hsp72, which protects Akt from degradation. These functions were blocked by Plek2 inhibitors via their direct binding to the Plek2 dishevelled, Egl-10 and pleckstrin (DEP) domain. The role of Plek2 in activating Akt signaling was further confirmed in vivo using a hematopoietic-specific Pten-knockout mouse model. We next tested Plek2 inhibitors alone or in combination with an Akt inhibitor in various MPN mouse models, which showed significant therapeutic efficacies similar to that seen with the genetic depletion of Plek2. The Plek2 inhibitor was also effective in reducing proliferation of CD34-positive cells from MPN patients. Our studies reveal a Plek2/Akt complex that drives cell proliferation and can be targeted by a class of antiproliferative compounds for MPN therapy.

Prognostic Impact of Organomegaly in Mastocytosis: An Analysis of the European Competence Network on Mastocytosis

BACKGROUND

Organomegaly, including splenomegaly, hepatomegaly, and/or lymphadenopathy, are important diagnostic and prognostic features in patients with cutaneous mastocytosis (CM) or systemic mastocytosis (SM).

OBJECTIVES

To investigate the prevalence and prognostic impact of 1 or more organomegalies on clinical course and survival in patients with CM/SM.

METHODS

Therefore, 3155 patients with CM (n = 1002 [32%]) or SM (n = 2153 [68%]) enrolled within the registry of the European Competence Network on Mastocytosis were analyzed.

RESULTS

Overall survival (OS) was adversely affected by the number of organomegalies (OS: #0 vs #1 hazard ratio [HR], 4.9; 95% CI, 3.4-7.1, P < .001; #1 vs #2 HR, 2.1, 95% CI, 1.4-3.1, P < .001; #2 vs #3 HR, 1.7, 95% CI, 1.2-2.5, P = .004). Lymphadenopathy was frequently detected in patients with smoldering SM (SSM, 18 of 60 [30%]) or advanced SM (AdvSM, 137 of 344 [40%]). Its presence confered an inferior outcome in patients with AdvSM compared with patients with AdvSM without lymphadenopathy (median OS, 3.8 vs 2.6 years; HR, 1.6; 95% CI, 1.2-2.2; P = .003). OS was not different between patients having organomegaly with either ISM or SSM (median, 25.5 years vs not reached; P = .435). At time of disease progression, a new occurrence of any organomegaly was observed in 17 of 40 (43%) patients with ISM, 4 of 10 (40%) patients with SSM, and 33 of 86 (38%) patients with AdvSM, respectively.

CONCLUSIONS

Organomegalies including lymphadenopathy are often found in SSM and AdvSM. ISM with organomegaly has a similar course and prognosis compared with SSM. The number of organomegalies is adversely associated with OS. A new occurrence of organomegaly in all variants of SM may indicate disease progression.

Analysis of Predictive Factors for Early Response to Ruxolitinib in 320 Patients with Myelofibrosis From the Polish Adult Leukemia Group (PALG) Registry

INTRODUCTION

Ruxolitinib is widely used in myelofibrosis (MF). However, some patients do not optimally respond and require more efficacious treatment. Our analysis aimed to establish predictors of ruxolitinib response.

PATIENTS AND METHODS

We designed a multicenter, retrospective analysis of the efficacy of ruxolitinib treatment in patients with MF in 15 Polish hematology centers. As responses to ruxolitinib occur within the first 6 months, we used this point to evaluate the efficacy of treatment. Symptoms response was defined as ≥50% reduction of the MF constitutional symptoms assessed by Myeloproliferative Neoplasm Symptom Assessment Form Total Symptom Score (MPN-SAF TSS). Spleen response was defined as ≥50% reduction of the difference between the spleen's baseline length and the upper limit norm measured by ultrasonography.

RESULTS

320 MF patients were enrolled. At 6 months of therapy, the spleen response was detected in 140 (50%) patients, and symptoms response in 241 patients (76%). Multivariable analysis identified leukocytosis <25 G/L (OR 2.06, 95%CI: 1.12-3.88, P = .0200), and reticulin fibrosis MF 1 (OR 2.22, 95%CI: 1.11-4.46, P = .0249) contributed to better spleen response. The time interval between MF diagnosis and ruxolitinib administration shorter than 3 months, and platelets ≥150 G/L (OR 1.69, 95% CI 1.01-2.83, P = .0466) influenced symptoms response.

CONCLUSION

Establishing predictive factors for ruxolitinib response is particularly important given the potential for new therapies in MF. In patients with a low likelihood of responding to ruxolitinib, using other JAK inhibitors or adding a drug with a different mechanism of action to ruxolitinib may be of clinical benefit.

Interleukin 6/gp130 axis promotes neural invasion in pancreatic cancer

BACKGROUND

Nerve invasion (N-inv) is an important prognostic factor in pancreatic ductal adenocarcinoma (PDAC). Elucidation of circulating N-inv stimulators could provide deeper insights and novel perspectives for PDAC therapy. The interleukin (IL)-6/gp130 axis was evaluated in this study as a candidate N-inv stimulator.

METHODS

A human pancreatic cancer (PC) cell, Capan-1, was confirmed to have the stimulant activity of IL-6/gp130 axis through the evaluation of mRNA, cell surface protein and intracellular protein levels and chemotaxis and wound healing assay. The upregulation of IL-6/gp130 axis was evaluated using tumor-derived IL-6 level and intratumoral pSTAT3 expression in N-inv of murine sciatic nerves by intraneural injection of Capan-1 cell (N-inv model) and using resected pancreatic cancer tissue and clinical data from 46 PDAC patients.

RESULTS

mRNA and protein expressions of IL-6 and IL-6 receptor were found in whole cell lysate and condition medium from PC cell. Cell surface protein expression of gp130 were clearly detected on PC cell. IL-6 promoted migration and chemotaxis of PC cell. Serum IL-6 and tumoral IL-6 mRNA levels in N-inv model mice were significantly higher than those in subcutaneous tumor mice (p = 0.004 and p = 0.002, respectively). Silencing of IL-6 and gp130 on PC cell and administration of an anti-IL-6 receptor antibody, tocilizumab, suppressed N-inv, compared to each control (p = 0.070, p = 0.118 and p = 0.122, respectively). In PDAC patients, the high-N-inv group showed poor prognosis (p =0.059) and elevated serum levels of IL-6 and C-reactive protein, synthesis of which is promoted by IL-6, compared to those in the low-N-inv group (p = 0.006 and p = 0.075, respectively). Tumoral gp130 expression at N-inv was higher than that in the primary pancreatic tumor (p = 0.026).

CONCLUSION

Biological activity of IL-6/gp130 axis promoted N-inv in murine model and was upregulated in PDAC patients with severe N-inv. This study is the first evidence that the IL-6/gp130 axis offers a potential therapeutic target in PDAC with N-inv.

Real-World Outcomes of Ruxolitinib in Patients With Myelofibrosis Focusing on Red Blood Cell Transfusion: A Multicenter Study From the MPN Working Party of the Korean Society of Hematology

INTRODUCTION/BACKGROUND

Ruxolitinib is an established treatment for myelofibrosis (MF) that has demonstrated clinical benefit by reducing spleen size and debilitating MF-related symptoms. However, despite the efficacy of ruxolitinib, anemia remains a major adverse event that causes dose modification or discontinuation in real-world practice. Additionally, dependence on red blood cell (RBC) transfusion (TF) is common during treatment; therefore, we explored the outcome of ruxolitinib therapy with a primary focus on RBC TF.

PATIENTS/METHODS

We retrospectively reviewed the medical records of 123 MF patients treated with ruxolitinib between January 2012 and April 2020 at eight academic centers in Korea.

RESULTS

At ruxolitinib initiation, 38 patients (30.9%) underwent ≥ 2 units of RBC TF over 8 weeks. The most common reason for permanent discontinuation was intolerant anemia (10/63, 15.9%). The most common reasons for temporary interruption were nonhematologic toxicity (26/55, 21.1%), anemia (23/55, 18.7%) and thrombocytopenia (13/55, 10.6%). Among the 123 patients in the study, 57 (46.3%), 42 (34.1%), and 40 patients (32.5%) who were receiving or stopped ruxolitinib therapy had a status of RBC TF dependence, long-term RBC TF dependence, or severe RBC TF dependence, respectively. The presence of ≥ 2 units of RBC transfusion over 8 weeks at ruxolitinib initiation was an independent risk factor for persistent RBC TF dependence.

CONCLUSION

The requirement for RBC TF is commonly encountered during treatment of MF with ruxolitinib, particularly among those with pre-existing ≥ 2 units of RBC TF over 8 weeks. For those patients, overcoming the barrier of maintenance TF is demanding.

Myeloproliferative Neoplasms, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology

The classic Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) consist of myelofibrosis, polycythemia vera, and essential thrombocythemia and are a heterogeneous group of clonal blood disorders characterized by an overproduction of blood cells. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for MPN were developed as a result of meetings convened by a multidisciplinary panel with expertise in MPN, with the goal of providing recommendations for the management of MPN in adults. The Guidelines include recommendations for the diagnostic workup, risk stratification, treatment, and supportive care strategies for the management of myelofibrosis, polycythemia vera, and essential thrombocythemia. Assessment of symptoms at baseline and monitoring of symptom status during the course of treatment is recommended for all patients. This article focuses on the recommendations as outlined in the NCCN Guidelines for the diagnosis of MPN and the risk stratification, management, and supportive care relevant to MF.

Impact of molecular profiling on the management of patients with myelofibrosis

Myelofibrosis (MF) is a chronic myeloproliferative neoplasm (MPN) characterized by a highly heterogeneous clinical course, which can be complicated by severe constitutional symptoms, massive splenomegaly, progressive bone marrow failure, cardiovascular events, and development of acute leukemia. Constitutive signaling through the JAK-STAT pathway plays a fundamental role in its pathogenesis, generally due to activating mutations of JAK2, CALR and MPL genes (i.e., the MPN driver mutations), present in most MF patients. Next Generation Sequencing (NGS) panel testing has shown that additional somatic mutations can already be detected at the time of diagnosis in more than half of patients, and that they accumulate along the disease course. These mutations, mostly affecting epigenetic modifiers or spliceosome components, may cooperate with MPN drivers to favor clonal dominance or influence the clinical phenotype, and some, such as high molecular risk mutations, correlate with a more aggressive clinical course with poor treatment response. The current main role of molecular profiling in clinical practice is prognostication, principally for selecting high-risk patients who may be candidates for transplantation, the only curative treatment for MF to date. To this end, contemporary prognostic models incorporating molecular data are useful tools to discriminate different risk categories. Aside from certain clinical situations, decisions regarding medical treatment are not based on patient molecular profiling, yet this approach may become more relevant in novel treatment strategies, such as the use of vaccines against the mutant forms of JAK2 or CALR, or drugs directed against actionable molecular targets.

The role of JAK inhibitors in hematopoietic cell transplantation

The Janus Kinase (JAK)/Signal Transducers and Activators of Transcription (STAT) pathway is essential for both the regulation of hematopoiesis and the control of inflammation. Disruption of this pathway can lead to inflammatory and malignant disease processes. JAK inhibitors, designed to control the downstream effects of pro-inflammatory and pro-angiogenic cytokines, have been successfully used in pre-clinical models and clinical studies of patients with autoimmune diseases, hematologic malignancies, and the hematopoietic cell transplantation (HCT) complication graft versus host disease (GVHD). In the last decade, JAK inhibitors Ruxolitinib, Fedratinib, and most recently Pacritinib have been United States Federal Drug Administration (FDA) approved for the treatment of myelofibrosis (MF). Ruxolitinib was also recently approved for the treatment of steroid refractory acute as well as chronic GVHD; JAK inhibitors are currently under evaluation in the pre-HCT setting in MF and for the prevention of GVHD. This review will focus on the role of JAK inhibitors in the treatment of hematologic malignancies, the potential function of pre-HCT JAK inhibitors in patients with MF, and the role of JAK inhibitors in the prevention and treatment of acute and chronic GVHD.

Is there a real risk of bacterial infection in patients receiving targeted and biological therapies?

Over the past decades, the advent of targeted and biological therapies has revolutionized the management of cancer and autoimmune, hematological and inflammatory conditions. Although a large amount of information is now available on the risk of opportunistic infections associated with some of these agents, the evidence regarding the susceptibility to bacterial infections is more limited. Biological agents have been shown to entail a variable risk of bacterial infections in pivotal randomized clinical trials and post-marketing studies. Recommendations on risk minimization strategies and therapeutic interventions are therefore scarce and often based on expert opinion, with only a few clear statements for some particular agents (i.e. meningococcal vaccination for patients receiving eculizumab). In the present review the available information regarding the incidence of and risk factors for bacterial infection associated with the use of different groups of biological agents is summarized according to their mechanisms of action, and recommendations based on this evidence are provided. Additional information coming from clinical research and real-world studies is required to address unmet questions in this emerging field.

Fatal Disseminated Tuberculosis and Concurrent Disseminated Cryptococcosis in a Ruxolitinib-treated Patient with Primary Myelofibrosis: A Case Report and Literature Review

Ruxolitinib, a Janus kinase inhibitor, improves symptoms in patients with myelofibrosis. However, its association with the development of opportunistic infections has been a concern. We herein report a 71-year-old man with primary myelofibrosis who developed disseminated tuberculosis and concurrent disseminated cryptococcosis during ruxolitinib treatment. We also reviewed the literature on disseminated tuberculosis and/or cryptococcosis associated with ruxolitinib treatment. This is the first case of disseminated tuberculosis and concurrent disseminated cryptococcosis during treatment with ruxolitinib. We therefore suggest considering not only disseminated tuberculosis but also cryptococcosis in the differential diagnosis of patients with abnormal pulmonary shadows during ruxolitinib treatment.

Targeting human CALR-mutated MPN progenitors with a neoepitope-directed monoclonal antibody

Calreticulin (CALR) is recurrently mutated in myelofibrosis via a frameshift that removes an endoplasmic reticulum retention signal, creating a neoepitope potentially targetable by immunotherapeutic approaches. We developed a specific rat monoclonal IgG2α antibody, 4D7, directed against the common sequence encoded by both insertion and deletion mutations. 4D7 selectively bound to cells co‐expressing mutant CALR and thrombopoietin receptor (TpoR) and blocked JAK‐STAT signalling, TPO‐independent proliferation and megakaryocyte differentiation of mutant CALR myelofibrosis progenitors by disrupting the binding of CALR dimers to TpoR. Importantly, 4D7 inhibited proliferation of patient samples with both insertion and deletion CALR mutations but not JAK2 V617F and prolonged survival in xenografted bone marrow models of mutant CALR‐dependent myeloproliferation. Together, our data demonstrate a novel therapeutic approach to target a problematic disease driven by a recurrent somatic mutation that would normally be considered undruggable.

Chronic neutrophilic leukemia: 2022 update on diagnosis, genomic landscape, prognosis, and management

DISEASE OVERVIEW

Chronic neutrophilic leukemia (CNL) is a rare, often aggressive myeloproliferative neoplasm (MPN) defined by persistent mature neutrophilic leukocytosis, bone marrow granulocyte hyperplasia, and frequent hepatosplenomegaly. The 2013 seminal discovery of oncogenic driver mutations in colony-stimulating factor 3 receptor (CSF3R) in the majority of patients with CNL not only established its molecular pathogenesis but provided a diagnostic biomarker and rationale for pharmacological targeting.

DIAGNOSIS

In 2016, the World Health Organization (WHO) recognized activating CSF3R mutations as a central diagnostic feature of CNL. Other criteria include leukocytosis of ≥25 × 10⁹ /L comprising >80% neutrophils with <10% circulating precursors and rare blasts, and absence of dysplasia or monocytosis, while not fulfilling criteria for other MPN.

MANAGEMENT

There is currently no standard of care for management of CNL, due in large part to the rarity of disease and dearth of formal clinical trials. Most commonly used therapeutic agents include conventional oral chemotherapy (e.g., hydroxyurea), interferon, and Janus kinase (JAK) inhibitors, while hematopoietic stem cell transplant remains the only potentially curative modality.

DISEASE UPDATES

Increasingly comprehensive genetic profiling in CNL, including new data on clonal evolution, has disclosed a complex genomic landscape with additional mutations and combinations thereof driving disease progression and drug resistance. Although accurate prognostic stratification and therapeutic decision-making remain challenging in CNL, emerging data on molecular biomarkers and the addition of newer agents, such as JAK inhibitors, to the therapeutic arsenal, are paving the way toward greater standardization and improvement of patient care.

A prognostic model to predict survival after 6 months of ruxolitinib in patients with myelofibrosis

Ruxolitinib (RUX) is extensively used in myelofibrosis (MF). Despite its early efficacy, most patients lose response over time and, after discontinuation, have a worse overall survival (OS). Currently, response criteria able to predict OS in RUX-treated patients are lacking, leading to uncertainty regarding the switch to second-line treatments. In this study, we investigated predictors of survival collected after 6 months of RUX in 209 MF patients participating in the real-world ambispective observational RUXOREL-MF study (NCT03959371). Multivariable analysis identified the following risk factors: (1) RUX dose <20 mg twice daily at baseline, months 3 and 6 (hazard ratio [HR], 1.79; 95% confidence interval [CI], 1.07-3.00; P = .03), (2) palpable spleen length reduction from baseline ≤30% at months 3 and 6 (HR, 2.26; 95% CI, 1.40-3.65; P = .0009), (3) red blood cell (RBC) transfusion need at months 3 and/or 6 (HR, 1.66; 95% CI, 0.95-2.88; P = .07), and (4) RBC transfusion need at all time points (ie, baseline and months 3 and 6; HR, 2.32; 95% CI, 1.19-4.54; P = .02). Hence, we developed a prognostic model, named Response to Ruxolitinib After 6 Months (RR6), dissecting 3 risk categories: low (median OS, not reached), intermediate (median OS, 61 months; 95% CI, 43-80), and high (median OS, 33 months; 95% CI, 21-50). The RR6 model was validated and confirmed in an external cohort comprised of 40 MF patients. In conclusion, the RR6 prognostic model allows for the early identification of RUX-treated MF patients with impaired survival who might benefit from a prompt treatment shift.

Myelofibrosis: Genetic Characteristics and the Emerging Therapeutic Landscape

Primary myelofibrosis (PMF) is one of three myeloproliferative neoplasms (MPN) that are morphologically and molecularly inter-related, the other two being polycythemia vera (PV) and essential thrombocythemia (ET). MPNs are characterized by JAK-STAT-activating JAK2, CALR, or MPL mutations that give rise to stem cell-derived clonal myeloproliferation, which is prone to leukemic and, in case of PV and ET, fibrotic transformation. Abnormal megakaryocyte proliferation is accompanied by bone marrow fibrosis and characterizes PMF, while the clinical phenotype is pathogenetically linked to ineffective hematopoiesis and aberrant cytokine expression. Among MPN-associated driver mutations, type 1-like CALR mutation has been associated with favorable prognosis in PMF, while ASXL1, SRSF2, U2AF1-Q157, EZH2, CBL, and K/NRAS mutations have been shown to be prognostically detrimental. Such information has enabled development of exclusively genetic (GIPSS) and clinically integrated (MIPSSv2) prognostic models that facilitate individualized treatment decisions. Allogeneic stem cell transplantation remains the only treatment modality in MF with the potential to prolong survival, whereas drug therapy, including JAK2 inhibitors, is directed mostly at the inflammatory component of the disease and is therefore palliative in nature. Similarly, disease-modifying activity remains elusive for currently available investigational drugs, while their additional value in symptom management awaits controlled confirmation. There is a need for genetic characterization of clinical observations followed by in vitro and in vivo preclinical studies that will hopefully identify therapies that target the malignant clone in MF to improve patient outcomes.

Effects of Ruxolitinib and Calcitriol Combination Treatment on Various Molecular Subtypes of Breast Cancer

The anticancer effects of ruxolitinib and calcitriol against breast cancer were reported previously. However, the effect of ruxolitinib and calcitriol combination treatment on various molecular subtypes of breast cancer remains unexplored. In this study, we used MCF-7, SKBR3, and MDA-MB-468 cells to investigate the effect of ruxolitinib and calcitriol combination treatment on cell proliferation, apoptosis, cell cycle, and cell signaling markers, in vitro and in vivo. Our results revealed the synergistic anticancer effect of ruxolitinib and calcitriol combination treatment in SKBR3 and MDA-MB-468 cells, but not in MCF-7 cells in vitro, via cell proliferation inhibition, apoptosis induction, cell cycle arrest, and the alteration of cell signaling protein expression, including cell cycle-related (cyclin D1, CDK1, CDK4, p21, and p27), apoptosis-related (c-caspase and c-PARP), and cell proliferation-related (c-Myc, p-p53, and p-JAK2) proteins. Furthermore, in the MDA-MB-468 xenograft mouse model, we demonstrated the synergistic antitumor effect of ruxolitinib and calcitriol combination treatment, including the alteration of c-PARP, cyclin D1, and c-Myc expression, without significant drug toxicity. The combination exhibited a synergistic effect in HER2-enriched and triple-negative breast cancer subtypes. In conclusion, our results suggest different effects of the combination treatment of ruxolitinib and calcitriol depending on the molecular subtype of breast cancer.

Deferasirox in the management of iron overload in patients with myelofibrosis treated with ruxolitinib: The multicentre retrospective RUX-IOL study

Deferasirox (DFX) is used for the management of iron overload (IOL) in many haematological malignancies including myelofibrosis (MF). The 'RUX-IOL' study retrospectively collected 69 MF patients treated with ruxolitinib (RUX) and DFX for IOL to assess: safety, efficacy in term of iron chelation response (ICR) and erythroid response (ER), and impact on overall survival of the combination therapy. The RUX-DFX therapy was administered for a median time of 12.4 months (interquartile range 3.1-71.2). During treatment, 36 (52.2%) and 34 (49.3%) patients required RUX and DFX dose reductions, while eight (11.6%) and nine (13.1%) patients discontinued due to RUX- or DFX-related adverse events; no unexpected toxicity was reported. ICR and ER were achieved by 33 (47.8%) and 32 patients (46.4%) respectively. Thirteen (18.9%) patients became transfusion-independent. Median time to ICR and ER was 6.2 and 2 months respectively. Patients achieving an ER were more likely to obtain an ICR also (p = 0.04). In multivariable analysis, the absence of leukocytosis at baseline (p = 0.02) and achievement of an ICR at any time (p = 0.02) predicted improved survival. In many MF patients, the RUX-DFX combination provided ICR and ER responses that correlated with improved outcome in the absence of unexpected toxicities. This strategy deserves further clinical investigation.

Ruxolitinib versus dexamethasone in hospitalized adults with COVID-19: multicenter matched cohort study

BACKGROUND

Several anti-cytokine therapies were tested in the randomized trials in hospitalized patients with severe acute respiratory syndrome coronavirus 2 infection (COVID-19). Previously, dexamethasone demonstrated a reduction of case-fatality rate in hospitalized patients with respiratory failure. In this matched control study we compared dexamethasone to a Janus kinase inhibitor, ruxolitinib.

METHODS

The matched cohort study included 146 hospitalized patients with COVID-19 and oxygen support requirement. The control group was selected 1:1 from 1355 dexamethasone-treated patients and was matched by main clinical and laboratory parameters predicting survival. Recruitment period was April 7, 2020 through September 9, 2020.

RESULTS

Ruxolitinib treatment in the general cohort of patients was associated with case-fatality rate similar to dexamethasone treatment: 9.6% (95% CI [4.6-14.6%]) vs 13.0% (95% CI [7.5-18.5%]) respectively (p = 0.35, OR = 0.71, 95% CI [0.31-1.57]). Median time to discharge without oxygen support requirement was also not different between these groups: 13 vs. 11 days (p = 0.13). Subgroup analysis without adjustment for multiple comparisons demonstrated a reduced case-fatality rate in ruxolitnib-treated patients with a high fever (≥ 38.5 °C) (OR 0.33, 95% CI [0.11-1.00]). Except higher incidence of grade 1 thrombocytopenia (37% vs 23%, p = 0.042), ruxolitinib therapy was associated with a better safety profile due to a reduced rate of severe cardiovascular adverse events (6.8% vs 15%, p = 0.025). For 32 patients from ruxolitinib group (21.9%) with ongoing progression of respiratory failure after 72 h of treatment, additional anti-cytokine therapy was prescribed (8-16 mg dexamethasone).

CONCLUSIONS

Ruxolitinib may be an alternative initial anti-cytokine therapy with comparable effectiveness in patients with potential risks of steroid administration. Patients with a high fever (≥ 38.5 °C) at admission may potentially benefit from ruxolitinib administration. Trial registration The Ruxolitinib Managed Access Program (MAP) for Patients Diagnosed With Severe/Very Severe COVID-19 Illness NCT04337359, CINC424A2001M, registered April, 7, 2020. First participant was recruited after registration date.

Risk of mortality and second malignancies in primary myelofibrosis before and after ruxolitinib approval

BACKGROUND

Primary myelofibrosis (PMF) is associated with morbidity and mortality. Ruxolitinib gained US FDA approval for treatment of intermediate/high-risk PMF in November 2011. We evaluated differences in survival and second primary malignancy (SPM) incidence among US PMF patients in the years before and after ruxolitinib approval.

METHODS

We conducted a retrospective study utilizing the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER)-18 database for PMF patients. We divided patients into five-year cohorts pre- (2007-2011) and post-ruxolitinib (2012-2016) approval and compared relative survival rates (RSRs) to the standard population and standardized incidence rates (SIRs) of SPMs between cohorts.

RESULTS

We included 2020 patients diagnosed with PMF from 2007-2016 in this study. There was no difference in the four-year RSRs between cohorts (54 % vs. 57 %, p = 0.776). More patients developed SPMs in the post-ruxolitinib cohort (8% vs. 6%, p = 0.041). The majority of SPMs were hematologic with higher incidence of AML transformation in the post-ruxolitinib cohort (SIR 125.29 vs. 70.55).

CONCLUSIONS

PMF prognosis remains poor in the years following ruxolitinib's approval. SPM incidence including AML transformation is higher in the years after approval. Further studies are needed to determine the true impact of ruxolitnib on population outcomes.

Clinical Efficacy of Ruxolitinib in Patients with Myelofibrosis: A Nationwide Population-Based Study in Korea

Previous studies have reported the survival benefit after ruxolitinib treatment in patients with myelofibrosis (MF). However, population-based data of its efficacy are limited. We analyzed the effects of ruxolitinib in MF patients with data from the Korean National Health Insurance Database. In total, 1199 patients diagnosed with MF from January 2011 to December 2017 were identified, of which 731 were included in this study. Patients who received ruxolitinib (n = 224) were matched with those who did not receive the drug (n = 507) using the 1:1 greedy algorithm. Propensity scores were formulated using five variables: age, sex, previous history of arterial/venous thrombosis, and red blood cell (RBC) or platelet (PLT) transfusion dependence at the time of diagnosis. Cox regression analysis for overall survival (OS) revealed that ruxolitinib treatment (hazard ratio (HR), 0.67; p = 0.017) was significantly related to superior survival. In the multivariable analysis for OS, older age (HR, 1.07; p < 0.001), male sex (HR, 1.94; p = 0.021), and RBC (HR, 3.72; p < 0.001) or PLT (HR, 9.58; p = 0.001) transfusion dependence were significantly associated with poor survival, although type of MF did not significantly affect survival. Considering evidence supporting these results remains weak, further studies on the efficacy of ruxolitinib in other populations are needed.

From Biology to Clinical Practice: Iron Chelation Therapy With Deferasirox

Iron chelation therapy (ICT) has become a mainstay in heavily transfused hematological patients, with the aim to reduce iron overload (IOL) and prevent organ damage. This therapeutic approach is already widely used in thalassemic patients and in low-risk Myelodysplastic Syndrome (MDS) patients. More recently, ICT has been proposed for high-risk MDS, especially when an allogeneic bone marrow transplantation has been planned. Furthermore, other hematological and hereditary disorders, characterized by considerable transfusion support to manage anemia, could benefit from this therapy. Meanwhile, data accumulated on how iron toxicity could exacerbate anemia and other clinical comorbidities due to oxidative stress radical oxygen species (ROS) mediated by free iron species. Taking all into consideration, together with the availability of approved oral iron chelators, we envision a larger use of ICT in the near future. The aim of this review is to better identify those non-thalassemic patients who can benefit from ICT and give practical tips for management of this therapeutic strategy.

Classical Philadelphia-negative myeloproliferative neoplasms (MPNs): A continuum of different disease entities

Classical Philadelphia-negative myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell-derived disorders characterized by uncontrolled proliferation of differentiated myeloid cells and close pathobiologic and clinical features. According to the 2016 World Health Organization (WHO) classification, MPNs include polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The 2016 revision aimed in particular at strengthening the distinction between masked PV and JAK2-mutated ET, and between prefibrotic/early (pre-PMF) and overt PMF. Clinical manifestations in MPNs include constitutional symptoms, microvascular disorders, thrombosis and bleeding, splenomegaly secondary to extramedullary hematopoiesis, cytopenia-related symptoms, and progression to overt MF and acute leukemia. A dysregulation of the JAK/STAT pathway is the unifying mechanistic hallmark of MPNs, and is guided by somatic mutations in driver genes including JAK2, CALR and MPL. Additional mutations in myeloid neoplasm-associated genes have been also identified, with established prognostic relevance, particularly in PMF. Prognostication of MPN patients relies on disease-specific clinical models. The increasing knowledge of MPN biology led to the development of integrated clinical and molecular prognostic scores that allow a more refined stratification. Recently, the therapeutic landscape of MPNs has been revolutionized by the introduction of potent, selective JAK inhibitors (ruxolitinib, fedratinib), that proved effective in controlling disease-related symptoms and splenomegaly, yet leaving unmet critical needs, owing the lack of disease-modifying activity. In this review, we will deal with molecular, clinical, and therapeutic aspects of the three classical MPNs aiming at highlighting either shared characteristics, that overall define a continuum within a single disease family, and uniqueness, at the same time.

Effects of ruxolitinib on infection in patients with myeloproliferative neoplasm: a meta-analysis

OBJECTIVE

Infections in ruxolitinib-treated myeloproliferative neoplasm (MPN) patients were reported frequently. This work aimed to systematically estimate the risk of infection associated with ruxolitinib in MPN patients.

METHODS

The PUBMED, CNKI, EMBASE, Cochrane and CBM databases were searched to identify all related studies. Odds ratio (OR) and 95% confidence interval (CI) were used to express the difference between groups. I² was calculated to evaluate heterogeneity. Revman software was used to conduct the analysis.

RESULTS

Eleven randomized control trials were included in this analysis. The risk of overall infections was not different at the early stage of ruxolitinib use (OR, 95%CI: 1.23, [0.91, 1.67]). In the extension phase, overall infection was significantly lower in patients receiving ruxolitinib (OR, 95%CI: 0.53, [0.36, 0.79]). Herpes zoster infection was at higher risk both at early stage and in the extension phase (OR, 95%CI: 7.39, [1.33, 41.07]), (OR, 95%CI: 5.23, [1.46, 18.79]), respectively.

CONCLUSION

Our study suggested that ruxolitinib increased the risk of herpes zoster infection. However, current studies were not enough to estimate the effects of ruxolitinib on the risk of overall infection in patients with myeloproliferative neoplasm.

The Role of Neutrophilic Granulocytes in Philadelphia Chromosome Negative Myeloproliferative Neoplasms

Philadelphia chromosome negative myeloproliferative neoplasms (MPN) are composed of polycythemia vera (PV), essential thrombocytosis (ET), and primary myelofibrosis (PMF). The clinical picture is determined by constitutional symptoms and complications, including arterial and venous thromboembolic or hemorrhagic events. MPNs are characterized by mutations in JAK2, MPL, or CALR, with additional mutations leading to an expansion of myeloid cell lineages and, in PMF, to marrow fibrosis and cytopenias. Chronic inflammation impacting the initiation and expansion of disease in a major way has been described. Neutrophilic granulocytes play a major role in the pathogenesis of thromboembolic events via the secretion of inflammatory markers, as well as via interaction with thrombocytes and the endothelium. In this review, we discuss the molecular biology underlying myeloproliferative neoplasms and point out the central role of leukocytosis and, specifically, neutrophilic granulocytes in this group of disorders.