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

Imatinib mesylate is a drug that has been approved for treatment of chronic myeloid leukemia, Philadelphia-positive acute lymphoblastic leukemia, and advanced gastrointestinal stromal tumors. Several cases of hepatotoxicity, including fatal liver failure, have been reported with the long-term use of imatinib mesylate. Generally hepatotoxicity resolves after discontinuation of imatinib. Despite discontinuation of imatinib, hepatotoxicity can be progressive. Steroid may be useful in these patients and should be started early. We report a 53-year-old woman with advanced gastrointestinal stromal tumors who developed hepatotoxicity while receiving imatinib and subsequently acute liver failure. Ten weeks after commencing imatinib treatment, hepatotoxicity was determined. Imatinib was immediately ceased. Subsequently, a week later hepatic encephalopathy, jaundice, and coagulopathy occurred. Prednisolone was commenced. Liver biopsy was performed five weeks after the determining of hepatotoxicity. Biopsy showed sinusoidal congestion, necrosis of hepatocytes, inflammation, and hepatocyte drop out around the hepatic venule consistent with drug toxicity. Her liver function tests normalized with a nine-week prednisolone treatment. The patient was discharged. Her liver enzymes remained in normal range following visits. In cases of imatinib-induced acute hepatitis, the administration of prednisolone may be useful in the resolution of the acute episode and allow the reintroduction of a drug without risking recurrence of hepatitis.
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PMID:Imatinib mesylate-induced acute liver failure in a patient with gastrointestinal stromal tumors. 1966 40

Imatinib (Gleevec, Novartis), an inhibitor of BCR-ABL, platelet-derived growth factor, and KIT receptor tyrosine kinases, is widely used in the treatment of chronic myelogenous leukemia and gastrointestinal stromal tumors. We describe a case of activation of chronic hepatitis B infection associated with imatinib therapy.
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PMID:Reactivation of chronic hepatitis B infection related to imatinib mesylate therapy. 1966 26

Abstract Imatinib is widely used to treat chronic myeloid leukemia and gastrointestinal stromal tumors. The agent, administered orally, has approximately 98% oral bioavailability, achieves maximum plasma concentration approximately 2-4 hours after ingestion, and has a plasma half-life of approximately 18 hours. As maintaining an adequate plasma imatinib concentration is essential to achieving a favorable therapeutic response, it is important to determine whether gastrointestinal surgery, pathologic conditions, or anatomic changes negatively affect imatinib absorption, and thereby result in subtherapeutic plasma imatinib concentrations. We describe a 36-year-old, morbidly obese woman with chronic myeloid leukemia who received treatment with alpha-interferon and cytarabine over 5 years. Her chemotherapy was then switched to imatinib 400 mg/day because she failed to achieve a molecular response with the other two agents. A complete molecular response was achieved with imatinib. Four years later, she underwent a sleeve gastrectomy while receiving imatinib. Imatinib plasma pharmacokinetic values were assessed before and on four occasions during the year after the sleeve gastrectomy. The patient's trough plasma concentration before surgery (1558 ng/ml) was consistent with those found in the literature (>/= 1000 ng/ml), whereas her trough concentrations after surgery were 46-60% lower (629-836 ng/ml) than the preoperative value. Despite this, the patient remained in complete molecular remission for 1 year after surgery. Monitoring plasma imatinib concentrations is recommended in morbidly obese patients with chronic myeloid leukemia or gastrointestinal stromal tumors who undergo gastric procedures. Additional pharmacokinetic studies, however, are needed in these patients.
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PMID:Imatinib mesylate pharmacokinetics before and after sleeve gastrectomy in a morbidly obese patient with chronic myeloid leukemia. 1969 17

Gastrointestinal stromal tumors (GIST) are characterized by activating mutations of KIT or platelet-derived growth factor receptor A (PDGFRA), and treatment with the tyrosine kinase inhibitor imatinib yields responses in the majority of patients. However, most patients develop secondary resistance, which is associated with a dismal prognosis. Histone deacetylase inhibitors (HDACI) have been shown to enhance imatinib activity in imatinib-resistant chronic myelogenous leukemia. Against this background, we explored whether HDACI might provide an alternative therapeutic strategy to KIT/PDGFRA kinase inhibitors in GIST. Inhibition of cell proliferation by HDACI was seen in KIT-positive but not in KIT-negative GIST cell lines, suggesting that HDACI activity is mainly conferred by targeting oncogenic KIT. KIT activity, expression, and activation of downstream pathways were strongly inhibited by several HDACI (SAHA, LBH589, VPA, trichostatin A, and NaButyrate). SAHA and LBH589 induced apoptosis in KIT-positive GIST, and strong synergism with imatinib was observed at low concentrations of SAHA and LBH589. Mechanistically, treatment with HDACI reduced KIT mRNA transcript levels and led to strong acetylation of HSP90, interfering with its activity as KIT chaperone. These results provide preclinical evidence for a disease-specific effect of HDACI in KIT-positive GIST, which could translate into therapeutic activity.
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PMID:Inhibitors of deacetylases suppress oncogenic KIT signaling, acetylate HSP90, and induce apoptosis in gastrointestinal stromal tumors. 1970 76

Imatinib mesylate is a rationally designed tyrosine kinase inhibitor that has revolutionized the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors. Although the efficacy and tolerability of imatinib are a vast improvement over conventional chemotherapies, the drug exhibits off-target effects. An unanticipated side effect of imatinib therapy is hypophosphatemia and hypocalcemia, which in part has been attributed to drug-mediated changes to renal and gastrointestinal handling of phosphate and calcium. However, emerging data suggest that imatinib also targets cells of the skeleton, stimulating the retention and sequestration of calcium and phosphate to bone, leading to decreased circulating levels of these minerals. The aim of this review is to highlight our current understanding of the mechanisms surrounding the effects of imatinib on the skeleton. In particular, it examines recent studies suggesting that imatinib has direct effects on bone-resorbing osteoclasts and bone-forming osteoblasts through inhibition of c-fms, c-kit, carbonic anhydrase II, and the platelet-derived growth factor receptor. The potential application of imatinib in the treatment of cancer-induced osteolysis will also be discussed.
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PMID:Dysregulation of bone remodeling by imatinib mesylate. 1989 95

Imatinib inhibits Bcr-Abl, c-KIT and PDGFR kinases. It is approved for the treatment of chronic myeloid leukemia (CML), gastrointestinal stromal tumors (GIST) and has further therapeutic potential. Male ICR mice were given imatinib PO (50 or 25 mg/kg, 5 doses every 2 h); euthanized 2 h after the last dose administration; plasma, liver, brain, spleen and kidney were collected and imatinib concentration measured by an optimized HPLC method for quantification in tissues. Methanol (1:1 v/v plasma) and pH 4, 40:30:30 (v/v/v) water-methanol-acetonitrile at 5 ml/g (brain) and 10 ml/g (spleen, kidney, liver) ratio was added to the samples, homogenized, sonicated, centrifuged (15,000 rpm, 5 min, 2 degrees C) and the supernatant injected into an Inertsil CN-3 column (4.6 mm x 150 mm, 5 microm) using 64:35:1 (v/v/v) water-methanol-triethylamine (pH 4.8), flow rate 1 ml/min, 25 degrees C. Imatinib eluted at 7.5 min (268 nm). Linearity: 0.1-50 microg/ml; precision, accuracy, inter- and intra-day variability was within 15%. Recovery was above 95% (plasma), 80% (brain) and 90% (kidney, liver, spleen). Imatinib tissue concentrations were 6-8 folds higher than plasma except brain, where the ratio decreased from 0.24 to 0.08 suggesting limited brain penetration, likely due to blood brain barrier efflux transporters. The extensive distribution supports the expansion of therapeutic applications.
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PMID:HPLC determination of imatinib in plasma and tissues after multiple oral dose administration to mice. 2006 64

Drug plasma monitoring has emerged as an important tool to obtain optimal levels of a particular drug among individual patients. Plasma monitoring of imatinib levels would appear to be practical in cases where there is lack of response, heightened toxicity, or evidence of poor adherence to therapy. However, the potential role of monitoring plasma drug concentrations in guiding treatment decisions and optimizing patient therapy has yet to be established. Currently, there are no clinical recommendations regarding how to incorporate imatinib drug plasma monitoring in patients with either chronic myeloid leukemia or gastrointestinal stromal tumors, indications for which imatinib is approved. Here, the latest research and evidence regarding imatinib drug plasma monitoring is discussed. Three cases are presented to illustrate the most common examples where monitoring imatinib plasma concentrations may help to guide treatment decisions. These cases include a suboptimal response to imatinib treatment, lack of patient adherence to imatinib, and imatinib-related toxicity. By understanding the potential role of monitoring plasma imatinib concentrations in patients with chronic myeloid leukemia or gastrointestinal stromal tumors, physicians can identify patients who may benefit from drug plasma monitoring and consider incorporating the data in order to improve patient outcomes.
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PMID:Drug plasma monitoring in CML and GIST: A case-based discussion. 2009 79

Many clinically validated kinases, such as BCR-ABL, c-Kit, PDGFR, and EGFR, become resistant to adenosine triphosphate-competitive inhibitors through mutation of the so-called gatekeeper amino acid from a threonine to a large hydrophobic amino acid, such as an isoleucine or methionine. We have developed a new class of adenosine triphosphate competitive inhibitors, exemplified by HG-7-85-01, which is capable of inhibiting T315I- BCR-ABL (clinically observed in chronic myeloid leukemia), T670I-c-Kit (clinically observed in gastrointestinal stromal tumors), and T674I/M-PDGFRalpha (clinically observed in hypereosinophilic syndrome). HG-7-85-01 is unique among all currently reported kinase inhibitors in having the ability to accommodate either a gatekeeper threonine, present in the wild-type forms of these kinases, or a large hydrophobic amino acid without becoming a promiscuous kinase inhibitor. The distinctive ability of HG-7-85-01 to simultaneously inhibit both wild-type and mutant forms of several kinases of clinical relevance is an important step in the development of the next generation of tyrosine kinase inhibitors.
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PMID:Discovery of a small-molecule type II inhibitor of wild-type and gatekeeper mutants of BCR-ABL, PDGFRalpha, Kit, and Src kinases: novel type II inhibitor of gatekeeper mutants. 2029 8

Over the last ten years, several new and therapeutically relevant cancer drugs targeting tyrosine kinases signaling pathways have been developed. Tyrosine kinase inhibitors (TKIs) are a pharmaceutical class of small molecules, orally available, well-tolerated, worldwide approved drugs for the treatment of several neoplasms, including lung, breast, kidney and pancreatic cancer as well as gastro-intestinal stromal tumors and chronic myeloid leukemia. This comprehensive review focuses on the most relevant members of the first and the second generation TKIs designed to interact with receptor and nonreceptor TKs. Attention is mainly focused on molecular mechanisms in in vitro and in vivo models related to the clinical activity of the drugs and to the development of resistance to treatment, still the major challenge in cancer research and care.
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PMID:Tyrosine kinase inhibitors. 2038 77

c-Kit is a receptor tyrosine kinase (RTK) with a pivotal role in melanogenesis, gametogenesis, and hematopoiesis. Aberrantly activated RTK and related downstream signaling partners were identified as key elements in the molecular pathogenesis of several malignancies. This finding culminated in a two-class model integrating constitutive activating and maturation arrest-inducing mutations as key elements for the pathogenesis of acute myelogenous leukemia (AML). c-Kit is expressed by myeloblasts in about 60% to 80% of patients, and the most frequently observed activating RTK mutations in AML (next to FLT3) are mutations or internal tandem duplications in c-Kit, with an overall incidence of 17%. The identification of small-molecule tyrosine kinase inhibitors capable of blocking key kinase switches introduced a paradigm change in the treatment of diseases like gastrointestinal stromal tumors and chronic myelogenous leukemia. Despite encouraging preclinical data, it appears that a complex clonal disease like AML will probably benefit from a synergistic approach of targeted drugs used (at least for now) in combination with conventional chemotherapy.
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PMID:Clinical implications of c-Kit mutations in acute myelogenous leukemia. 2042 18


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