-
Annals of Hematology Jul 2021Secondary thrombocytosis is a frequent secondary finding in childhood infection and inflammation. Primary hereditary thrombocytosis may be caused by germline mutations... (Review)
Review
Secondary thrombocytosis is a frequent secondary finding in childhood infection and inflammation. Primary hereditary thrombocytosis may be caused by germline mutations within the genes encoding key regulators of thrombopoiesis, i.e., thrombopoietin (THPO) and its receptor c-MPL (MPL) or the receptor's effector kinase Januskinase2 (JAK2). Furthermore, somatic mutations in JAK2, MPL, and in the gene-encoding calreticulin (CALR) have been described to act as driver mutations within the so-called Philadelphia-negative myeloproliferative neoplasms (MPNs), namely essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF). Increasing knowledge on the molecular mechanisms and on the clinical complications of these diseases is reflected by the WHO diagnostic criteria and European LeukemiaNet (ELN) recommendations on the management of adult MPN. However, data on childhood thrombocytosis are rare, and no consensus guidelines for pediatric thrombocytosis exist. Current literature has highlighted differences in the epidemiology and molecular pathogenesis of childhood thrombocytosis as compared to adults. Furthermore, age-dependent complications and pharmacological specificities suggest that recommendations tailored to the pediatric population are necessary in clinical practice. Here we summarize literature on classification, diagnostics, and clinical management of childhood thrombocytosis.
Topics: Adolescent; Adult; Age of Onset; Algorithms; Anticoagulants; Calreticulin; Child; Disease Management; Female; Germ-Line Mutation; Humans; Hydroxyurea; Interferon-alpha; Janus Kinase 2; Male; Myelodysplastic-Myeloproliferative Diseases; Platelet Count; Quinazolines; Receptors, Thrombopoietin; Severity of Illness Index; Thrombocythemia, Essential; Thrombocytosis; Thrombophilia
PubMed: 33712866
DOI: 10.1007/s00277-021-04485-0 -
Frontiers in Oncology 2023Knowledge on the myeloproliferative neoplasms (MPNs) - polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF) - has accumulated since the... (Review)
Review
Knowledge on the myeloproliferative neoplasms (MPNs) - polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF) - has accumulated since the discovery of the JAK/STAT-activating mutations associated with MPNs: V617F, observed in PV, ET and PMF; and the and mutations, found in ET and PMF. The intriguing lack of disease specificity of these mutations, and of the chronic inflammation associated with MPNs, triggered a quest for finding what precisely determines that MPN patients develop a PV, ET or PMF phenoptype. The mechanisms of action of MPN-driving mutations, and concomitant mutations (, others), have been extensively studied, as well as the role played by these mutations in inflammation, and several pathogenic models have been proposed. In parallel, different types of drugs have been tested in MPNs (JAK inhibitors, interferons, hydroxyurea, anagrelide, azacytidine, combinations of those), some acting on both JAK2 and inflammation. Yet MPNs remain incurable diseases. This review aims to present current, detailed knowledge on the pathogenic mechanisms specifically associated with PV, ET or PMF that may pave the way for the development of novel, curative therapies.
PubMed: 37284191
DOI: 10.3389/fonc.2023.1196817 -
F1000Research 2014Essential thrombocythemia is a clonal myeloproliferative neoplasm characterized by an elevated platelet count, the potential for both microvascular and macrovascular...
Essential thrombocythemia is a clonal myeloproliferative neoplasm characterized by an elevated platelet count, the potential for both microvascular and macrovascular sequelae, and a risk for transformation to myelofibrosis or acute myeloid leukemia. A systematic and detailed initial analysis is essential for accurate diagnosis of essential thrombocythemia, as many etiologies are reactive and benign. Once a diagnosis has been made, risk stratification and symptom assessment are vital to guide the subsequent therapy. Treatment may be required in high-risk disease, such as in cases of advanced age or prior thrombotic events. Systemic therapy is aimed at reducing the thrombotic risk and includes daily low dose aspirin and in some patients, cytoreductive therapy. Currently, the first line cytoreductive therapy includes hydroxyurea or pegylated interferon, with a phase III clinical trial underway comparing these two important agents. Anagrelide and clinical trials are reserved for refractory or intolerant patients. Looking to the future, new therapies including Janus kinase 2 (JAK2) and telomerase inhibitors are promising and may become valuable to the treatment armamentarium for those afflicted with essential thrombocythemia.
PubMed: 25324966
DOI: 10.12688/f1000research.5361.1 -
Hematology. American Society of... Dec 2023Thrombotic complications are the primary contributor to morbidity and mortality in essential thrombocythemia (ET) and polycythemia vera (PV). Cytoreductive therapy is... (Review)
Review
Thrombotic complications are the primary contributor to morbidity and mortality in essential thrombocythemia (ET) and polycythemia vera (PV). Cytoreductive therapy is the main tool for primary or tertiary thrombosis prevention in these diseases. In general, high-thrombotic-risk patients and those with symptoms that may be ameliorated from cytoreductive therapy are candidates for this treatment, although the decision is highly individualized. Approved options for cytoreduction in ET and PV include hydroxyurea, long-acting interferons, anagrelide in ET, and ruxolitinib in PV. Selecting the ideal agent requires careful consideration of the toxicity profiles and individual treatment goals. In this review the existing literature on cytoreductive decisions in ET and PV is summarized, with an emphasis on risk-stratification, highlighting the need for personalized care in order to maximize the benefit of these therapies while minimizing toxicities.
Topics: Humans; Polycythemia Vera; Thrombocythemia, Essential; Cytoreduction Surgical Procedures; Hydroxyurea; Thrombosis
PubMed: 38066871
DOI: 10.1182/hematology.2023000451 -
Clinical Cancer Research : An Official... Mar 2019Gastrointestinal stromal tumor (GIST) is a common type of soft-tissue sarcoma. Imatinib, an inhibitor of KIT, platelet-derived growth factor receptor alpha (PDGFRA), and...
PURPOSE
Gastrointestinal stromal tumor (GIST) is a common type of soft-tissue sarcoma. Imatinib, an inhibitor of KIT, platelet-derived growth factor receptor alpha (PDGFRA), and a few other tyrosine kinases, is highly effective for GIST, but advanced GISTs frequently progress on imatinib and other approved tyrosine kinase inhibitors. We investigated phosphodiesterase 3 (PDE3) as a potential therapeutic target in GIST cell lines and xenograft models.
EXPERIMENTAL DESIGN
The GIST gene expression profile was interrogated in the MediSapiens IST Online transcriptome database comprising human tissue and cancer samples, and PDE3A and PDE3B expression was studied using IHC on tissue microarrays (TMA) consisting of 630 formalin-fixed human tissue samples. GIST cell lines were screened for sensitivity to 217 anticancer compounds, and the efficacy of PDE inhibitors on GIST was further studied in GIST cell lines and patient-derived mouse xenograft models.
RESULTS
GISTs expressed PDE3A and PDE3B frequently compared with other human normal or cancerous tissues both in the database and the TMAs. Anagrelide was identified as the most potent of the PDE3 modulators evaluated. It reduced cell viability, promoted cell death, and influenced cell signaling in GIST cell lines. Anagrelide inhibited tumor growth in GIST xenograft mouse models. Anagrelide was also effective in a GIST xenograft mouse model with exon 9 mutation that may pose a therapeutic challenge, as these GISTs require a high daily dose of imatinib.
CONCLUSIONS
PDE3A and PDE3B are frequently expressed in GIST. Anagrelide had anticancer efficacy in GIST xenograft models and warrants further testing in clinical trials.
Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Cyclic Nucleotide Phosphodiesterases, Type 3; Disease Models, Animal; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Gastrointestinal Stromal Tumors; High-Throughput Screening Assays; Humans; Mice; Platelet Aggregation Inhibitors; Quinazolines; Signal Transduction; Xenograft Model Antitumor Assays
PubMed: 30530703
DOI: 10.1158/1078-0432.CCR-18-0815 -
Expert Opinion on Emerging Drugs Jun 2019: Despite our recent progress in the understanding of essential thrombocythemia (ET) pathogenesis, the therapeutic management of this disease has remained largely... (Review)
Review
: Despite our recent progress in the understanding of essential thrombocythemia (ET) pathogenesis, the therapeutic management of this disease has remained largely unchanged in the past decades. Treatment has mostly focused on decreasing the risk of complications, especially prevention of thrombotic or hemorrhagic events. : Over recent years, the treatment options of ET have been expanding with some novel agents on the horizon. The classes of agents described in this review include targeted and immunomodulatory agents, such as JAK1/2 inhibitors, interferon-α, histone deacetylase inhibitors, telomerase inhibitors and human double minute 2 inhibitors. These compounds entered various stages of development, albeit the only portion of them is currently actively undergoing evaluation in clinical trials. In this review, we look at the current therapies and discuss novel agents available in the management of ET. : The drug development in ET possesses several challenges stemming from its relatively benign and prolonged disease course. Therapy focused on reducing the risk of thrombotic and hemorrhagic complications and symptom management needs to be chosen wisely as a vast majority of these patients have a near-normal life expectancy. To date, no therapy has shown effective and definitive alteration of the disease behavior. Although novel agents are in development and hopefully some of them will extend treatment armamentarium of ET, their exact role remains to be determined.
Topics: Humans; Hydroxyurea; Platelet Aggregation Inhibitors; Platelet Count; Quinazolines; Randomized Controlled Trials as Topic; Severity of Illness Index; Thrombocythemia, Essential
PubMed: 31050912
DOI: 10.1080/14728214.2019.1615437 -
The Lancet. Haematology Mar 2020Polycythaemia vera is a myeloproliferative neoplasm characterised by excessive proliferation of erythroid, myeloid, and megakaryocytic components in the bone marrow due... (Comparative Study)
Comparative Study Randomized Controlled Trial
BACKGROUND
Polycythaemia vera is a myeloproliferative neoplasm characterised by excessive proliferation of erythroid, myeloid, and megakaryocytic components in the bone marrow due to mutations in the Janus kinase 2 (JAK2) gene. Ruxolitinib, a JAK 1 and JAK 2 inhibitor, showed superiority over best available therapy in a phase 2 study in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea. We aimed to compare the long-term safety and efficacy of ruxolitinib with best available therapy in patients with polycythaemia vera who were resistant to or intolerant of hydroxyurea.
METHODS
We report the 5-year results for a randomised, open-label, phase 3 study (RESPONSE) that enrolled patients at 109 sites across North America, South America, Europe, and the Asia-Pacific region. Patients (18 years or older) with polycythaemia vera who were resistant to or intolerant of hydroxyurea were randomly assigned 1:1 to receive either ruxolitinib or best available therapy. Patients randomly assigned to the ruxolitinib group received the drug orally at a starting dose of 10 mg twice a day. Single-agent best available therapy comprised hydroxyurea, interferon or pegylated interferon, pipobroman, anagrelide, approved immunomodulators, or observation without pharmacological treatment. The primary endpoint, composite response (patients who achieved both haematocrit control without phlebotomy and 35% or more reduction from baseline in spleen volume) at 32 weeeks was previously reported. Patients receiving best available therapy could cross over to ruxolitinib after week 32. We assessed the durability of primary composite response, complete haematological remission, overall clinicohaematological response, overall survival, patient-reported outcomes, and safety after 5-years of follow-up. This study is registered with ClinicalTrials.gov, NCT01243944.
FINDINGS
We enrolled patients between Oct 27, 2010, and Feb 13, 2013, and the study concluded on Feb 9, 2018. Of 342 individuals screened for eligibility, 222 patients were randomly assigned to receive ruxolitinib (n=110, 50%) or best available therapy (n=112, 50%). The median time since polycythaemia vera diagnosis was 8·2 years (IQR 3·9-12·3) in the ruxolitinib group and 9·3 years (4·9-13·8) in the best available therapy group. 98 (88%) of 112 patients initially randomly assigned to best available therapy crossed over to receive ruxolitinib and no patient remained on best available therapy after 80 weeks of study. Among 25 primary responders in the ruxolitinib group, six had progressed at the time of final analysis. At 5 years, the probability of maintaining primary composite response was 74% (95% CI 51-88). The probability of maintaining complete haematological remission was 55% (95% CI 32-73) and the probability of maintaining overall clinicohaematological responses was 67% (54-77). In the intention-to-treat analysis not accounting for crossover, the probability of survival at 5 years was 91·9% (84·4-95·9) with ruxolitinib therapy and 91·0% (82·8-95·4) with best available therapy. Anaemia was the most common adverse event in patients receiving ruxolitinib (rates per 100 patient-years of exposure were 8·9 for ruxolitinib and 8·8 for the crossover population), though most anaemia events were mild to moderate in severity (grade 1 or 2 anaemia rates per 100 patient-years of exposure were 8·0 for ruxolitinib and 8·2 for the crossover population). Non-haematological adverse events were generally lower with long-term ruxolitinib treatment than with best available therapy. Thromboembolic events were lower in the ruxolitinib group than the best available therapy group. There were two on-treatment deaths in the ruxolitinib group. One of these deaths was due to gastric adenocarcinoma, which was assessed by the investigator as related to ruxolitinib treatment.
INTERPRETATION
We showed that ruxolitinib is a safe and effective long-term treatment option for patients with polycythaemia vera who are resistant to or intolerant of hydroxyurea. Taken together, ruxolitinib treatment offers the first widely approved therapeutic alternative for this post-hydroxyurea patient population.
FUNDING
Novartis Pharmaceuticals Corporation.
Topics: Antineoplastic Combined Chemotherapy Protocols; Antiviral Agents; Drug Therapy, Combination; Fibrinolytic Agents; Follow-Up Studies; Humans; Hydroxyurea; Interferon alpha-2; Interferon-alpha; Nitriles; Pipobroman; Polycythemia Vera; Polyethylene Glycols; Prognosis; Pyrazoles; Pyrimidines; Quinazolines; Recombinant Proteins; Survival Rate; Time Factors
PubMed: 31982039
DOI: 10.1016/S2352-3026(19)30207-8 -
Nature Communications Oct 2021Molecular glues are a class of small molecular drugs that mediate protein-protein interactions, that induce either the degradation or stabilization of target protein. A...
Molecular glues are a class of small molecular drugs that mediate protein-protein interactions, that induce either the degradation or stabilization of target protein. A structurally diverse group of chemicals, including 17-β-estradiol (E2), anagrelide, nauclefine, and DNMDP, induces apoptosis by forming complexes with phosphodiesterase 3A (PDE3A) and Schlafen 12 protein (SLFN12). They do so by binding to the PDE3A enzymatic pocket that allows the compound-bound PDE3A to recruit and stabilize SLFN12, which in turn blocks protein translation, leading to apoptosis. In this work, we report the high-resolution cryo-electron microscopy structure of PDE3A-SLFN12 complexes isolated from cultured HeLa cells pre-treated with either anagrelide, or nauclefine, or DNMDP. The PDE3A-SLFN12 complexes exhibit a butterfly-like shape, forming a heterotetramer with these small molecules, which are packed in a shallow pocket in the catalytic domain of PDE3A. The resulting small molecule-modified interface binds to the short helix (E552-I558) of SLFN12 through hydrophobic interactions, thus "gluing" the two proteins together. Based on the complex structure, we designed and synthesized analogs of anagrelide, a known drug used for the treatment of thrombocytosis, to enhance their interactions with SLFN12, and achieved superior efficacy in inducing apoptosis in cultured cells as well as in tumor xenografts.
Topics: Animals; Antineoplastic Agents; Apoptosis; Binding Sites; Cryoelectron Microscopy; Cyclic Nucleotide Phosphodiesterases, Type 3; Drug Design; HeLa Cells; Humans; Hydrophobic and Hydrophilic Interactions; Indoles; Intracellular Signaling Peptides and Proteins; Mice; Multiprotein Complexes; Naphthyridines; Pyridazines; Quinazolines; Tumor Burden; Xenograft Model Antitumor Assays
PubMed: 34707099
DOI: 10.1038/s41467-021-26546-8