Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The epipodophyllotoxins, etoposide and teniposide, have been used in leukemias and malignant lymphomas for the past 15 years. Although etoposide has acquired a place in many first-line protocols for lymphomas and, more recently, for leukemias, the role of teniposide has remained limited. Teniposide is a more potent inhibitor of topoisomerase II than etoposide, and has a less toxic effect on hematopoietic progenitor cells. Both drugs have been regarded as equitoxic and cross-resistant. The role of teniposide in front-line treatment of leukemias has only been established in childhood acute lymphoblastic leukemia (ALL). Some promising results have been obtained in small numbers of patients with refractory adult ALL and acute monoblastic leukemia. However, the remission rates and remission duration were not significantly different from those of other combination regimens. Data on teniposide in untreated acute nonlymphoblastic leukemia are very scarce. In non-Hodgkin's lymphoma, the antineoplastic activity of teniposide has been demonstrated in studies by the European Organization for Research and Treatment of Cancer and in two large studies conducted by the Australian and New Zealand Lymphoma Co-operative Chemotherapy Study Group. In these studies, teniposide had comparable but not significantly better activity than vincristine. The dose-dependent antineoplastic activity of teniposide has led to its use in several conditioning regimens in bone marrow transplantation for leukemias and lymphomas. The limited clinical data currently available on teniposide seem to warrant further clinical trials with this agent in leukemias and lymphomas.
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PMID:Teniposide in lymphomas and leukemias. 141 40

Allergic reactions of dramatic intensity were observed in 5 children treated with Teniposide (VM-26) for acute lymphoblastic leukaemia and histiocytosis X. In the further treatment this drug was replaced with epoxide, a cytostatic agent which is also a podophyllin derivative but in other chemical formulation. In none of these patients the allergic reaction returned.
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PMID:[Allergic reactions to teniposide (VM-26) in children with neoplasms]. 141 3

Teniposide, a semisynthetic epipodophyllotoxin, was found to be highly active against murine leukemias, and the combination of teniposide with cytosine arabinoside (ara-C) was curative in murine leukemia models. The antitumor activity in preclinical models prompted introduction of teniposide into the clinic in 1971. Although teniposide as a single agent rarely produced a complete remission in heavily pretreated leukemia patients, teniposide plus ara-C produced complete remissions in some patients with refractory and relapsed acute lymphoblastic leukemia (ALL). Innovative front-line and salvage regimens using teniposide have been developed that incorporate a multi-drug strategy with early intensification, rotation of drug combinations in maintenance, and regional therapy in an effort to improve the cure rate in leukemia. However, as the complexity of these regimens increases, the contribution of an individual component such as teniposide becomes less clear. Although some of these regimens for newly diagnosed and relapsed ALL are now thought to represent the best available therapy, teniposide remains an investigational agent. In this review, we outline and discuss the conflicts arising from the need to answer drug-specific issues, and, at the same time, facilitate the implementation of innovative, curative regimens.
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PMID:Teniposide in the treatment of leukemia: a case study of conflicting priorities in the development of drugs for fatal diseases. 327 27

Teniposide (VM-26) is an effective anticancer drug usually administered as a short infusion in doses of 150 to 165 mg/m2. The objectives of the trial reported here were to evaluate clinical responses and assess pharmacokinetic parameters as a determinant of outcome when VM-26 was administered as a 72-hour continuous infusion (CI) with doses escalated from 300 to 750 mg/m2 per course. Twenty-eight patients with recurrent leukemia, lymphoma, or neuroblastoma received 53 courses of CI VM-26 and 16 had measurable responses. There were two partial remissions and one stable disease among seven neuroblastoma patients and 13 of 21 leukemia/lymphoma patients had oncolytic responses (greater than or equal to 75% decrease in circulating blasts). Toxicity included moderate to severe mucositis and myelosuppression. Pharmacokinetic parameters determined during 35 courses administered to 23 patients were highly variable. Clearance (CI) ranged between 3.7 and 43.8 ml/min/m2, resulting in VM-26 plasma concentrations from 2.8 to 30.6 mg/L across all dose levels. The interpatient pharmacokinetic variability reflected in CI and VM-26 steady state concentrations (Css), obscured any dose-response relationship. However, when pharmacokinetic parameters for responding and nonresponding patients were compared, statistically significant relationships were observed. For responders, the mean Css was 15.2 mg/L and mean CI was 12.1 mL/min/m2; for nonresponders, mean Css was 6.2 mg/L (P less than .01) and mean CI was 21.3 mL/min/m2 (P less than .05). Thus, patients with higher CI and lower Css were less likely to respond. Clinical responses occurred in ten of ten patients with Css greater than 12 mg/L, and only five of 13 patients with Css less than 12 mg/L (P less than .01). In this study, interpatient pharmacokinetic variability yielded a four- to sixfold difference in intensity of systemic exposure (Css) within the same dose level, which was an important determinant of clinical response. These data indicate that achieving a VM-26 target concentration for individual patients could ensure an increased intensity of systemic exposure in patients with a high CI and improve the likelihood of effective therapy.
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PMID:Clinical pharmacodynamics of continuous infusion teniposide: systemic exposure as a determinant of response in a phase I trial. 359 7

The transcription factor MYB plays key roles in hematopoietic cells and has been implicated the development of leukemia. MYB has therefore emerged as an attractive target for drug development. Recent work has suggested that targeting MYB by small-molecule inhibitors is feasible and that inhibition of MYB has potential as a therapeutic approach against acute myeloid leukemia. To facilitate the identification of small-molecule MYB inhibitors we have re-designed and improved a previously established cell-based screening assay and have employed it to screen a natural product library for potential inhibitors. Our work shows that teniposide and etoposide, chemotherapeutic agents causing DNA-damage by inhibiting topoisomerase II, potently inhibit MYB activity and induce degradation of MYB in AML cell lines. MYB inhibition is suppressed by caffeine, suggesting that MYB is inhibited indirectly via DNA-damage signalling. Importantly, ectopic expression of an activated version of MYB in pro-myelocytic NB4 cells diminished the anti-proliferative effects of teniposide, suggesting that podophyllotoxins disrupt the proliferation of leukemia cells not simply by inducing general DNA-damage but that their anti-proliferative effects are boosted by inhibition of MYB. Teniposide and etoposide therefore act like double-edged swords that might be particularly effective to inhibit tumor cells with deregulated MYB.
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PMID:A novel cell-based screening assay for small-molecule MYB inhibitors identifies podophyllotoxins teniposide and etoposide as inhibitors of MYB activity. 3017 51