Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myelodysplastic syndrome (MDS) is a heterogeneous hematopoietic stem cell disorder characterized by bone marrow dysplasia and peripheral cytopenias. Eighty percent of patients found to have MDS are older than 60 years and therefore not eligible for the only potentially curative therapy, bone marrow transplantation. Currently, there is no standard for treating MDS; therapies range from supportive care with transfusions or hematopoietic growth factors and low-intensity cytarabine therapy, to intensive anti-acute myeloid leukemia-type chemotherapy. Some of these treatments induce a limited hematologic response, but none consistently extends survival. Many are highly toxic. More than half of patients with MDS die within 3 to 4 years of infections, bleeding complications, or progression to acute leukemia. Agents in development for MDS include all-trans retinoic acid (ATRA), decitabine, and thalidomide. Farnesyltransferase inhibitors modulate many of the cancer-signaling pathways implicated in MDS initiation or progression and may therefore be well suited for treatment of these biologically diverse hematologic malignancies. Phase I and II clinical studies in our center show that the oral FTI ZARNESTRA (formerly R115777, Ortho Biotech Oncology, Raritan, NJ) has promising anti-MDS activity, suggesting that further investigation of this agent and of this class in MDS is warranted.
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PMID:Myelodysplastic syndrome overview. 1221 89

Significant advances have been made in the development of targeted interventions for hematologic malignancies. Progress has been made in defining the molecular pathogenesis of human leukemias. Data indicate that nonrandom, somatically acquired translocations, inversions, and other abnormalities occur in many acute leukemias. In the treatment of acute promyelocytic leukemia (APL), targeted therapy with all-trans retinoic acid (ATRA) and anthracycline-based chemotherapy leads to dramatic improvements in disease-free survival. Imatinib mesylate, a signal transduction inhibitor that inhibits tyrosine kinase activity, the protein product of the ABL proto-oncogene, has remarkable activity in patients with chronic myeloid leukemia (CML) and Philadelphia chromosome-positive (Ph(+)) acute lymphoblastic leukemia (ALL). Farnesyltransferase inhibitors (FTIs), a promising class of agents that target multiple pathways including Ras proteins, are potential anticancer therapy for a wide range of malignancies, including leukemias and myelodysplastic syndromes (MDS). There also is evidence that recombinant human erythropoietin therapy (r-HuEPO) can benefit patients with chronic lymphocytic leukemia (CLL), multiple myeloma, and lymphomas. This supplement will discuss advances in our understanding of human leukemias, including the use of unconjugated monoclonal antibodies such as Campath-1H (Wellcome, Beckenham, UK, and Ilex Oncology, San Antonio, TX) and rituximab and immunoconjugates such as gemtuzumab ozogamicin and BL-22. Although these novel therapies are beginning to fulfill their promise, continued research efforts are needed to determine the optimal role of targeted therapy in acute and chronic leukemias.
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PMID:Advancing the treatment of hematologic malignancies through the development of targeted interventions. 1244 45

Farnesyltransferase inhibitors (FTIs) target multiple pathways including the Ras pathway implicated in the pathogenesis of some hematologic malignancies. R115777 and BMS-214662, selective FTIs in clinical development, exhibit preclinical activity against cell lines and tumor xenografts with or without ras mutations. Phase I dose-escalating trials at M.D. Anderson Cancer Center have explored the potential of these agents as monotherapy for leukemias and myelodysplastic syndrome (MDS). In 20 patients with MDS, two cycles of oral R115777 for 3 consecutive weeks followed by a 1-week rest produced an overall response rate of 30%, consistent with 29% reported in poor-prognosis acute leukemia or blast-phase chronic myelogenous leukemia (CML). Administration of BMS-214662 as a weekly intravenous infusion produced a decrease in bone marrow blasts of greater than 50% in 23% of patients with acute leukemia or MDS; 18% achieved normalization of blast counts to less than 5%. In both studies, most responding patients did not have ras mutations. The most common side effects at maximum tolerated doses of R115777 (400 mg twice daily) and BMS-214662 (118 mg/m(2) weekly) were myelosuppression and nausea, respectively. Further evaluation of FTIs for hematologic malignancies clearly is warranted. Future research should address whether molecular techniques can identify patients most likely to respond to an FTI, optimal administration schedules for these agents, and the value of incorporating an FTI into combination regimens for difficult-to-treat hematologic malignancies.
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PMID:Clinical development of farnesyltransferase inhibitors in leukemias and myelodysplastic syndrome. 1244 48

Farnesyltransferase inhibitors were initially developed as Ras inhibitors as they inhibit the prenylation necessary for Ras activation. It is clear now that their mechanism of action is more complex and probably involves other proteins unrelated to Ras. At least 3 drugs within this family have been investigated in acute myeloid leukemia, myelodysplastic syndromes, and other leukemias. These are tipifarnib (R115777, Zarnestra), lonafarnib (SCH66336, Sarasar), and BMS-214662. The first 2 are administered orally, whereas BMS-214662 is given intravenously. These drugs are at different stages of development, and design of treatment schedules and methodology of the available studies are very different. Although most of the information is still preliminary, these agents have demonstrated clear evidence of clinical activity in these diseases and very favorable toxicity profiles. Several studies are still ongoing to better define the efficacy of these agents in the treatment of leukemias, as well as to determine the best schedules, the role of combination with other agents, and the role of these agents in different settings, such as the management of minimal residual disease. It is very possible that these agents will soon find their way to the ranks of established agents for the management of myeloid malignancies
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PMID:Farnesyltransferase inhibitors in acute myeloid leukemia and myelodysplastic syndromes. 1455 73

Farnesyltransferase inhibitors (FTIs) are small-molecule inhibitors that selectively inhibit farnesylation of a number of intracellular substrate proteins such as Ras. Preclinical work has revealed their ability to effectively inhibit tumor growth in vitro and in vivo in animal models across a wide range of malignant phenotypes. Myeloid malignancies are appropriate disease targets, in that they express relevant biologic targets, such as Ras, Mitogen-Activated Protein Kinase (MAPK), AKT, and others that may depend upon farnesyl protein transferase (FTase) activity to promote proliferation and survival. Phase I trials in acute leukemias and myelodysplasia have demonstrated biologic and clinical activities as determined by target enzyme inhibition, low toxicity, and both complete and partial responses. As a result, phase II trials have been initiated in a variety of hematologic malignancies and disease settings, in order to further validate clinical activity and to identify downstream signal transduction targets that may be modified by these agents. It is anticipated that these studies will serve to define the optimal roles of FTIs in patients with hematologic malignancies and provide insight into effective methods by which to combine FTIs with other agents.
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PMID:Farnesyltransferase inhibitors (FTIs) in myeloid malignancies. 1512 88

Farnesyltransferase inhibitors (FTIs) are small-molecule inhibitors that selectivly inhibit farnesylation of a number of intracellular substrate proteins such as Ras. Preclinical work has revealed their ability to effectively inhibit tumor growth in vitro and in vivo in animal models across a wide range of malignant phenotypes. Acute myeloid leukemias (AMLs) are appropriate disease targets in that they express relevant biologic targets such as Ras, MEK, AKT, and others that may depend upon farnesyl protein transferase activity to promote cell proliferation and survival. Indeed, different intracellular proteins are substrates for prenylation. Interruption of prenylation may prevent substrates from undergoing maturation which may result in the inhibition of cellular events that depend on the function of those substrates. Phase I trials in AML and myelodysplasia have demonstrated biologic and clinical activities as determined by target enzyme inhibition, low toxicity, and both complete and partial responses. As a result, phase II trials have been initiated in order to further validate clinical activity and to identify downstream signal transduction targets that may be modified by these agents. It is anticipated that these studies will serve to define the optimal roles of FTIs in patients with these hematologic malignancies and provide insight into effective methods by which to combine FTIs with other agents.
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PMID:[Farnesyltransferase inhibitors: preliminary results in acute myeloid leukemia]. 1582 Sep 17

Farnesyltransferase inhibitors (FTIs) inhibit certain cellular signal transduction pathways, and are being evaluated for activity in hematologic malignancies. Tipifarnib and lonafarnib are orally available FTIs that are active against a variety of targets and inhibit several pathways involved in the pathogenesis of hematologic malignancies. FTIs have demonstrated activity in a variety of hematologic diseases, including acute myeloid leukemia, myelodysplastic syndrome, chronic myeloid leukemia, and multiple myeloma. This article reviews the clinical experience with tipifarnib and lonafarnib in the treatment of hematologic malignancies.
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PMID:Farnesyltransferase inihibitors in hematologic malignancies. 1729 17

Farnesyltransferase inhibitors (FTIs) represent a new class of signal transduction inhibitors that block the processing of cellular polypeptides that have cysteine terminal residues and, by so doing, interdict multiple pathways involved in proliferation and survival of diverse malignant cell types. Tipifarnib is an orally bioavailable, nonpeptidomimetic methylquinolone FTI that has exhibited clinical activity in patients with myeloid malignancies including elderly adults with acute myelogenous leukemia (AML) who are not candidates for traditional cytotoxic chemotherapy, patients with high-risk myelodysplasia, myeloproliferative disorders, and imatinib-resistant chronic myelogenous leukemia. Because of its relatively low toxicity profile, tipifarnib provides an important alternative to traditional cytotoxic approaches for elderly patients who are not likely to tolerate or even benefit from aggressive chemotherapy. In this review, we will focus on the clinical development of tipifarnib for treatment of newly diagnosed AML, both as induction therapy for elderly adults with poor-risk AML and as maintenance therapy following achievement of first complete remission following induction and consolidation therapies for poor-risk AML. As with all other malignancies, the optimal approach is likely to lie in rational combinations of tipifarnib with cytotoxic, biologic and/or immunomodulatory agents with non-cross-resistant mechanisms of action. Gene expression profiling has identified networks of differentially expressed genes and gene combinations capable of predicting response to single agent tipifarnib. The clinical and correlative laboratory trials in progress and under development will provide the critical foundations for defining the optimal roles of tipifarnib and in patients with AMl and other hematologic malignancies.
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PMID:Tipifarnib in the treatment of newly diagnosed acute myelogenous leukemia. 1970 79