Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic myeloid leukaemia (CML) is a clonal disease of stem cell origin that develops when a single pluripotent haemopoietic stem cell acquires the Philadelphia (Ph) chromosome. The unique fusion gene product translated, p210 (Bcr-Abl), is a constitutively active tyrosine kinase that is specific to, and has a central role in the pathogenesis of, CML, making it an atractive target for drug therapy. Imatinib mesylate (IM) is one such therapy that also targets Abl, c-kit and PDGF-R tyrosine kinases. Although IM induces a much higher rate of complete cytogenetic remission (CCR), with improved tolerability and better progression free survival compared to other licensed therapies, resistance is a significant clinical problem. The most common mechanism of IM resistance is mutation of the Bcr-Abl kinase catalytic domain. In addition, molecular persistence in patients in CCR is most likely attributable to persisting Ph(+) stem cells that are insensitive to IM by unknown mechanisms and this is a major focus of current research interest. Current results from pre-clinical in vitro work on novel agents and combination strategies as well as clinical trials including immunotherapy approaches are reviewed. Despite the widespread use of molecularly targeted therapies and the development of new therapeutic drugs and strategies, it is our belief that there is a requirement for further research into and development of stem cell-directed therapies to overcome molecular persistence. It is likely that a combination of molecularly targeted therapies or treatment modalities will finally eliminate the quiescent stem cell population, leading to a "molecular cure" of CML.
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PMID:Evolving molecular therapy for chronic myeloid leukaemia--are we on target? 1620 4

Imatinib mesylate (IM), a small molecule that is a selective inhibitor of the ABL, platelet derived growth factor receptor (PDGFR-R) and stem cell ligand receptor (c-kit) tyrosine kinases (TK). IM was also found to inhibit the TK activity of BCR/ABL fusion protein produced in chronic myelogenous leukemia, with marked clinical activity against the disease. Since both PDGF-R and c-kit both having a putative role in tumorigenesis, we investigated the efficacy and safety of the use of IM in patients with endocrine tumors unresponsive to conventional therapies that expressed c-kit and/or PDGF-R (within the framework of a comprehensive phase II multi-center study of IM in patients with solid tumors). IM was initiated at a dose of 400 mg/day, with possible dose escalation within 1 week to 600 mg/day and an option to raise the dose to 800 mg/day in the event of progression and in the absence of safety concerns for a period of up to 12 months. Between September 2002 and July 2003, 15 adult patients with disseminated endocrine tumors were recruited as follows: medullary thyroid carcinoma (MTC, n = 6); adrenocortical carcinoma (ACC, n = 4); malignant pheochromocytoma (pheo, n = 2); carcinoid (non-secreting, n = 2), neuroendocrine tumor (NET, n = 1). No objective responses were observed. MTC--disease progression in 4 patients, and treatment discontinuation in 2 patients due to adverse events; ACC--disease progression in 3 patients, and treatment discontinuation in 1 patient due to severe psychiatric adverse event; Pheo--disease progression in 2 patients; Carcinoid--stable disease in 1 patient (6.5 months), and disease progression in 1 patient; NET--disease progression in 1 patient. IM does not appear to be useful for treatment of malignant endocrine tumors, also causing significant toxicity in this patient population.
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PMID:The role of imatinib mesylate (Glivec) for treatment of patients with malignant endocrine tumors positive for c-kit or PDGF-R. 1672 80

Imatinib mesylate (IM), is a selective and competitive inhibitor of tyrosine kinases, including BCR-ABL, ABL, KIT, and the platelet-derived growth factor receptors (PDGF-R). It binds to the ATP-binding site of the target kinase and prevents the transfer of phosphate from ATP to the tyrosine residues of various substrates. At oral doses of 200-600 mg, the majority of patients with chronic myeloid leukaemia, Philadelphia chromosome-positive acute lymphoblastic leukemia expressing the BCR-ABL fusion protein and gastrointestinal stromal tumours (GIST) achieve a bio-molecular and clinical response, frequently complete, associated with limited toxicity. Several other human cancers, as small-cell lung carcinoma, melanoma, seminoma, some sarcomas, and adenoid cystic carcinomas may over-express KIT or PDGF-R, and clinical trials to evaluate the role of IM in the treatment of such cancers are currently ongoing. We determined c-KIT with Dako CD 117 antibody in 5 cases of advanced ocular melanoma (OM) and we found positive immuno-reactivity for CD 117 in three patients. We treated all patients with palliative-use IM at the oral dose of 400 mgr daily. We obtained in expressing positive immuno-reactivity for CD 117 patients: a reduction of malignant ascites in one, a partial remission in the neck nodes in another, and progression of liver metastases in the third. Evidences of progression has been reported in the other two patients expressing negative immuno-reactivity for CD 117. We conclude that the effect of IM should be assessed only in OM with positive immuno-histochemical c-kit (CD 117) expression. IM might be a potential therapeutic strategy for these patients.
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PMID:Tyrosine kinase inhibitor imatinib mesylate as anticancer agent for advanced ocular melanoma expressing immunoistochemical C-KIT (CD 117): preliminary results of a compassionate use clinical trial. 1676

STI571 (imatinib; Gleevec) was developed as the first molecularly targeted therapy. It was the result of an extensive search for molecules to block the aberrant activity of Abl kinase in the fusion protein Bcr-Abl. In addition, it can specifically inhibit the activity of c-Kit and PDGF receptors. This orally bioavailable drug has a low toxicity profile. It is approved to treat the patients with chronic myelogenous leukemia (CML) or gastrointestinal stromal tumor (GIST). It produces hematological, cytogenetic, and molecular remission with significant efficacy, particularly in patients with chronic-phase CML. However, there is well-documented proof of primary and secondary resistance to STI571 with progression of leukemia. More evidence indicates that this single drug may not be sufficient to completely eradicate BCR-ABL-positive stem cells. A variety of strategies has already been developed to improve the effectiveness of CML treatment, including targeting the expression or stability of the Bcr-Abl kinase itself, targeting signaling pathways activated by this kinase, as well as designing novel Abl inhibitors. In this review the molecular mechanisms of STI571 action, its effectivenes against CML, GIST, and melanoma, as well as new approaches to improve its efficacy, mainly by overcoming STI571 resistance, are discussed.
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PMID:[STI571: a summary of targeted therapy]. 1724 18

The phenylaminopyrimidine-derivate Imatinib mesylate has been developed for targeted inhibition of the Abelson kinase (c-ABL), which is constitutively activated when translocated to the genetic locus of the breakpoint cluster region (leading to the BCR/ABL fusion gene), thereby forming the causative pathogenetic event for the development of chronic myeloid leukemia (CML). Of note, due to its physico-chemical properties, kinase specificity of Imatinib is limited. Despite of its well documented clinical efficacy mediated by inhibition of constitutively activated tyrosine kinases such as BCR/ABL in CML, PDGF-RA in HES and mutated c-kit in GIST patients, other tyrosine kinases such as Flt-3, Lck and mitogen-activated kinases (MAPK) are affected as well. Accordingly, it has recently been shown that therapeutic doses of Imatinib also target a variety of immune cells, e.g. by modulating the differentiation of dendritic cells (DC) as well as by impeding proper T-cell and macrophage function. In contrast, combining Imatinib with Interleukin 2 (IL-2) potently activates NK-cells and led to the description of a new subclass of DC, so-called IK-DC. The latter mediate Imatinib/IL-2-induced regression of tumors in pre-clinical animal models via production of high amounts of IFN-gamma and the death receptor ligand TRAIL. Thus, Imatinib exerts potent immuno-modulatory effects in vitro and in vivo, which will be discussed together with their clinical relevance in detail throughout this review.
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PMID:The kinase inhibitor imatinib--an immunosuppressive drug? 1750 22

Imatinib mesilate, which efficiently inhibits BCR-ABL,and KIT as well as platelet-derived growth factor receptor (PDGF-R) kinases, is highly effective for clinical treatment of CML, Ph+ALL, and advanced GIST with good tolerability, respectively. Acquired resistance to the drug,however, becomes an clinically emerging problem with long-standing use. Meanwhile, sunitinib malate,which inhibits three VEGF-Rs and FLT 3 in addition to KIT as well as PDGF-R, was clinically evaluated in the phase II clinical trials for imatinib-resistant or intolerant GIST, and advanced renal cell carcinoma in Japan. Sunitinib is therapeutically effective for both on imatinib-resistant GIST and advanced renal cell carcinoma with modest tolerability, and is now under review for approval in Japan.
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PMID:[Imatinib . Sunitinib]. 1768 1

Rheumatoid arthritis (RA) is a chronic inflammatory disease that is associated with joint destruction. Imatinib mesylate (imatinib) is an inhibitor that specifically targets a set of protein tyrosine kinase, such as abl, c-kit, and platelet-derived growth factor receptor (PDGFR) and it is widely used to treat chronic myeloid leukemia (CML). The purpose of the present study is to determine whether imatinib can provide benefit in the arthritis induced by anti-collagen type II antibody (CAIA) in mice, a model that provides an opportunity to study the effector inflammatory phase of arthritis without involving the priming phase of the immune responses. Mice treated with intraperitoneal administration of imatinib (1 or 10 mg/kg) prior to the development of CAIA displayed significant reductions in the severity of CAIA as assessed by arthritis score, histology, and synovial PDGF and vascular endothelial growth factor expression. In addition, treatment of the mice that had developed CAIA with intraperitoneal administration of imatinib (1 or 10 mg/kg) inhibited the progression of arthritis as assessed by those parameters. These results suggest that imatinib prevents and treats CAIA. Imatinib may thus have both a preventive and therapeutic potential for the joint inflammation at the effector stage of RA.
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PMID:Imatinib mesylate both prevents and treats the arthritis induced by type II collagen antibody in mice. 1769 64

Imatinib inhibits tyrosine kinases important in osteoclast (c-Fms) and osteoblast (platelet-derived growth factor receptor [PDGF-R], c-Abl) function, suggesting that long-term therapy may alter bone homeostasis. To investigate this question, we measured the trabecular bone volume (TBV) in iliac crest bone biopsies taken from chronic myeloid leukemia (CML) patients at diagnosis and again after 2 to 4 years of imatinib therapy. Half the patients (8 of 17) showed a substantive increase in TBV (> 2-fold), after imatinib therapy, with the TBV in the posttreatment biopsy typically surpassing the normal upper limit for the patient's age group. Imatinib-treated patients exhibited reduced serum calcium and phosphate levels with hypophosphatemia evident in 53% (9 of 17) of patients. In vitro, imatinib suppressed osteoblast proliferation and stimulated osteogenic gene expression and mineralized-matrix production by inhibiting PDGF receptor function. In PDGF-stimulated cultures, imatinib dose-dependently inhibited activation of Akt and Crk-L. Using pharmacologic inhibitors, inhibition of PI3-kinase/Akt activation promoted mineral formation, suggesting a possible molecular mechanism for the imatinib-mediated increase in TBV in vivo. Further investigation is required to determine whether the increase in TBV associated with imatinib therapy may represent a novel therapeutic avenue for the treatment of diseases that are characterized by generalized bone loss.
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PMID:Long-term imatinib therapy promotes bone formation in CML patients. 1804 96

Imatinib mesylate (imatinib) is highly effective in the treatment of chronic myeloid leukemia (CML) but is less effective in eliminating CML stem cells. We investigated whether SKI-606, a potent Bcr-Abl and Src kinase inhibitor without anti-PDGF or c-Kit activity, could effectively target primitive CML progenitors. CML and normal progenitors were cultured with SKI-606 or imatinib. SKI-606 effectively inhibited Bcr-Abl kinase activity in CML CD34(+) cells and inhibited Src phosphorylation more potently than imatinib. However, SKI-606 and imatinib resulted in similar suppression of CML primitive and committed progenitor proliferation and growth in CFC and LTC-IC assays. Exposure to either agent alone or in combination resulted in only modest increase in apoptosis. Evaluation of downstream signaling pathways indicated that Akt and STAT5 activity was not changed, but a delayed increase in MAPK activity was seen at high concentrations of SKI-606. SKI-606 inhibited normal progenitor proliferation to a lesser extent than imatinib. SKI-606 effectively inhibits Bcr-Abl and Src kinase activity and inhibits CML progenitor growth with relatively little effect on normal progenitors. However, SKI-606 does not demonstrate increased ability to eliminate primitive CML progenitors by apoptosis compared with imatinib, emphasizing the need for additional strategies besides Bcr-Abl kinase inhibition for curative therapy of CML.
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PMID:Effective and selective inhibition of chronic myeloid leukemia primitive hematopoietic progenitors by the dual Src/Abl kinase inhibitor SKI-606. 1805 43

Imatinib mesylate is a selective inhibitor of the bcr/abl, c-kit and PDGF receptor tyrosine kinases. Its ocular toxicity is little known with mild periorbital oedema being the most commonly reported side effect. We here describe our experience on ocular complications in imatinib treated Ph+ CML patients, which consisted of a wide spectrum of adverse effects ranging from periobital oedema to serious adverse events such as glaucoma.
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PMID:Ocular side effects in chronic myeloid leukemia patients treated with imatinib. 1806 64


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