Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023467 (acute myeloid leukemia)
 35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The topoisomerase (topo) II-directed agents etoposide, daunorubicin (DNR), and amsacrine (m-AMSA) are widely used in the treatment of acute myelogenous leukemia (AML). In the present study, multiple aspects of topo II-mediated drug action were examined in marrows from adult AML patients. Colony-forming assays revealed that the dose of etoposide, DNR, or m-AMSA required to diminish leukemic colony formation by 90% (LD90) varied over a greater than 20-fold range between different pretreatment marrows. Measurement of nuclear DNR accumulation in the absence and presence of quinidine revealed evidence of P-glycoprotein (Pgp) function in 8 of 82 samples at diagnosis and 5 of 36 samples at first relapse, but the largest quinidine-induced increment in DNR accumulation (< 2-fold) was too small to explain the variations in drug sensitivity. Restriction enzyme-based assays and sequencing of partial topo II alpha and topo II beta cDNAs from the most highly resistant specimens failed to demonstrate topo II gene mutations that could account for resistance. Western blotting of marrow samples containing greater than 80% blasts revealed that the content of the two topo II isoenzymes varied over a greater than 20-fold range, but did not correlate with drug sensitivity in vitro or in vivo. In addition, levels of topo II alpha and topo II beta in 46 of 47 clinical samples were lower than in human AML cell lines. Immunoperoxidase staining showed that these low topo II levels were accompanied by marked cell-to-cell heterogeneity, with topo II alpha being abundant in some blasts and diminished or absent from others. There was a trend toward increasing percentages of topo II alpha-positive cells in pretreatment marrows that contained more S-phase cells. Consistent with this observation, treatment of patients with granulocyte-macrophage colony-stimulating factor for 3 days before chemotherapy resulted in increases in topo II alpha-positive cells concomitant with increases in the number of cells traversing the cell cycle. These observations have implications for the regulation of topo II in AML, for the use of topo II-directed chemotherapy, and for future attempts to relate drug sensitivity to topo II levels in clinical material.
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PMID:Topoisomerase II levels and drug sensitivity in adult acute myelogenous leukemia. 790 87

The efficacy and toxicity of a regimen consisting of amsacrine (m-AMSA), cytarabine, and thioguanine for remission-induction therapy in poor prognosis categories of acute myeloid leukaemia (AML) were determined in a single arm study of 46 patients. The study group consisted of 17 patients with disease refractory to daunorubicin plus cytarabine-based induction regimens, 22 patients with disease which had relapsed during daunorubicin plus cytarabine maintenance therapy, or following completion of this maintenance programme after receiving > or = 500 mg daunorubicin/m2, and 7 previously untreated patients where cardiac disease contraindicated anthracycline therapy. Complete remission (CR) was attained in 46%, and probability of survival was comparable to published results for first-line treatment with daunorubicin plus cytarabine regimens. There was no statistically significant difference in CR rate or probability of survival between these three categories of poor prognosis AML, and cardiotoxic complications were uncommon despite extensive anthracycline exposure in the majority. In the 43% of patients who were 60-76 years of age, there was no statistically significant difference in CR rate or probability of survival relative to patients < 60 years. This observation fails to support the view that less myelotoxic regimens with lesser efficacy should be the basic approach to treatment of AML in patients > or = 60 years of age.
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PMID:An effective age-unrestricted m-AMSA-based second-line regimen for poor prognosis acute myeloid leukaemia. 811 87

118 patients with acute leukemias, including initial, relapsed and refractory cases, were treated with domestic Amsacrine (m-AMSA), singly or combined with other drugs. The total CR rate was 39.5% in ALL and 38.8% in ANLL, the response rate was 47.5% for both types of acute leukemias. The CR rate of relapsed and refractory ALL and ANLL treated with combination chemotherapy including domestic m-AMSA was 30.8% and 46.2% respectively. Domestic m-AMSA was similar to the foreign product and many other antitumor drugs in side effects and toxicity. The pharmacokinetics parameters of the drugs, C12h/C6h,K21 and Cmax were correlated with the therapeutic effectiveness.
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PMID:[Phase II clinical trial of domestic amsacrine in patients with acute leukemias. Cooperative Group for Treating Acute Leukemias with Domestic m-AMSA]. 840 29

Serious cardiac arrhythmias and QT interval prolongation have been reported following Amsacrine chemotherapy. The underlying mechanism is unknown. In this study, electrolyte and electrocardiographic parameters were prospectively studied in patients with acute myeloid leukemia (AML) treated with an Amsacrine containing combination chemotherapy regime. Data were collected immediately before and at 20 (+20) and 90 (+90) min after commencement of Amsacrine administration. Sixteen episodes were studied in six consecutive patients over a continuous 9 month period. One patient developed asymptomatic ventricular tachycardia during administration. Results from +20 and +90 min were compared with baseline by Wilcoxon matched pairs test. There was no significant change in potassium, albumin, or ionized calcium concentration at +20 or +90 min. The magnesium concentration at +20 min was significantly reduced (mean -0.04 mmol/liter; P < 0.05) but not so at +90 min. Sodium concentration at +20 min was significantly reduced (mean - 1.9 mmol/liter; P < 0.01). Electrocardiographic analysis showed no significant alteration in PR interval or QRS duration. Heart rate fell significantly from baseline, mean change -10 and -8 min-1 at +20 and +90 min, respectively (P < 0.01 for both). Corrected QT interval (QTc) was significantly prolonged at +20 min (+0.05) and +90 min (+0.05) (P = 0.0001 and P < 0.0001, respectively). This study confirms the high incidence of QTc prolongation with Amsacrine administration and suggests that transient hypomagnesemia may contribute to the risk of cardiac arrhythmia in this setting.
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PMID:Induction of hypomagnesemia during Amsacrine treatment. 843 99

A new flow cytometric method is described to detect DNA strand breaks associated with apoptosis, by labeling the 3'-OH termini in the breaks with biotinylated dUTP in a reaction employing exogenous terminal deoxynucleotidyl transferase. The method has been applied in studies on leukemic HL-60 and MOLT-4 cell lines to reveal whether it is specific to apoptotic cells, and whether it can be used in the clinic to detect DNA breakage in leukemic cells during chemotherapy. There was labeling of mononuclear cells in peripheral blood of all 11 patients studied during chemotherapy for acute lymphoblastic, acute myelogenous, or chronic myelogenous leukemia (ALL, AML, or CML) in blastic crisis, indicating induced DNA damage; the number of labeled cells increased from 1-8% before treatment up to 80% during the course of treatment. The DNA topoisomerase inhibitors mitoxantrone, VP-16 (etoposide), and m-AMSA (amsacrine) were more effective in inducing DNA breaks than was hydroxyurea or cytosine arabinoside (AraC). Cells with DNA breaks were identified in peripheral blood for up to 5 days following administration of Mitoxantrone and VP-16. In the case of DNA aneuploid leukemias, the DNA breaks were predominant in the aneuploid cell subpopulations, whereas presumably non-neoplastic diploid cells were unlabeled. In one case of ALL there were two distinct subpopulations of aneuploid cells: one responded to the treatment (by DNA breakage) and the other was non-responding. Thus, cells undergoing apoptosis can be detected by this method of labeling DNA strand breaks and the technique is applicable for analysis of response of leukemic cells to chemotherapy. With this method it may be possible to identify tumor cell sensitivity or resistance to particular drugs early in the course of treatment.
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PMID:Induction of DNA strand breaks associated with apoptosis during treatment of leukemias. 848 18

Between 1984 and 1990, 972 patients aged 1-79 years with acute myeloid leukaemia (AML), from 85 British hospitals, were entered into the MRC's 9th AML trial. Patients were randomized between DAT 1 + 5 (daunorubicin for 1 d, with cytarabine and 6-thioguanine for 5 d) and DAT 3 + 10 (same dose drugs for 3 and 10 d respectively) as induction therapy. The 63% who achieved complete remission (CR) were randomized to receive two courses of DAT 2 + 7 alternating with two courses of either MAZE (m-AMSA, 5-azacytidine, etoposide) or COAP (cyclophosphamide, vincristine, cytarabine, prednisone). Finally, those still in CR were randomized to receive either 1 year of maintenance treatment with eight courses of cytarabine and thioguanine followed by four courses of COAP, or no further cytotoxic therapy. Resistance to induction therapy was less common with the DAT 3 + 10 regimen than with DAT 1 + 5 (13% v 23%; P = 0.0001) and hence, despite a 5% increase in the risk of induction death, the CR rate was higher (66% v 61%; P = 0.15). Moreover, CR was achieved more rapidly with DAT 3 + 10 (median 34 v 46 d; P < 0.0001) and thus patients required less time in hospital (mean 20 v 29 d) and less blood product support. 5-year relapse-free survival (28% v 23%; P = 0.05) and survival (23% v 18%; P < 0.05) were also better with DAT 3 + 10. Post-remission intensification of therapy with MAZE resulted in fewer relapses (66% v 74% at 5 years; P = 0.03) but patients allocated MAZE required considerably more supportive care and 14 (4.5%) died following 312 MAZE courses, whereas no deaths occurred following COAP. 5-year survival was not significantly higher with MAZE (37% v 31%). Finally, although 1 year of outpatient maintenance treatment appeared to delay, but not prevent, recurrence it did not improve 5-year survival which was non-significantly worse for those allocated maintenance treatment (41% v 44%). We conclude that the more intensive induction regimen, DAT 3 + 10, is not only more effective than DAT 1 + 5, even for older patients, but is also less expensive; intensive post-remission therapy with MAZE achieves better leukaemic control but at the cost of substantial toxicity; whereas low-level maintenance therapy confers no apparent advantage in survival as well as being inconvenient and costly.
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PMID:Dose intensification in acute myeloid leukaemia: greater effectiveness at lower cost. Principal report of the Medical Research Council's AML9 study. MRC Leukaemia in Adults Working Party. 875 14

This report summarizes indications and results of autologous bone marrow transplantation (ABMT) performed in childhood acute myeloid leukemia (AML) in Italy since 1984. A total of 158 patients have been reported from 12 teams to the AIEOP-BMT Registry: 110 have been autografted in first complete remission (CR) and 48 in second remission. Several conditioning regimens have been utilized, mainly consisting of BAVC (an original polichemotherapy schedule, BCNU, mAMSA, VP-16 and Ara-C) (63 cases) and of total body irradiation (TBI) plus Melphalan (33 cases): other 28 patients received different TBI-including regimens, and 34 received various chemotherapy regimens (Busulfan plus cyclophosphamide +/- VP-16, Busulfan plus Melphalan, Melphalan alone). Projected event-free survival (EFS) for patients autografted in first CR is 41.4% (S.E. 5.5%) at 7 years, with a total of 53 patients in continuous CR. EFS is better in patients receiving a TBI-including regimen: 78.8% versus 27.2% (p = 0.0001). In particular, results obtained in a subgroup of 21 cases receiving TBI + melphalan and purged marrow are particularly encouraging, with a EFS > 85% projected a 7 years. The overall EFS in second CR is 41.5% at 7 years, and no difference have been observed after a TBI-including regimen or after a chemotherapy regimen, being EFS 43.1% and 39.3% for these 2 groups respectively. A total of 11 transplant-related deaths occurred, with 5 patients (4.5%) dead in first CR and 6 (12%) dead in second CR within 100 days from transplant. From these data, ABMT is confirmed to represent an effective treatment for AML after first relapse, while the encouraging results obtained in first CR with TBI-including regimens should be confirmed with a longer follow up and a larger number of patients.
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PMID:Autologous bone marrow transplantation in children with acute myeloblastic leukemia: report from the Italian National Pediatric Registry (AIEOP-BMT). 893 1

1 The topoisomerase II inhibitor amsacrine is used in the treatment of acute myelogenous leukemia. Although most anticancer drugs are believed not to cause acquired long QT syndrome (LQTS), concerns have been raised by reports of QT interval prolongation, ventricular fibrillation and death associated with amsacrine treatment. Since blockade of cardiac human ether-a-go-go-related gene (HERG) potassium currents is an important cause of acquired LQTS, we investigated the acute effects of amsacrine on cloned HERG channels to determine the electrophysiological basis for its proarrhythmic potential. 2 HERG channels were heterologously expressed in human HEK 293 cells and Xenopus laevis oocytes, and the respective potassium currents were recorded using patch-clamp and two-microelectrode voltage-clamp electrophysiology. 3 Amsacrine blocked HERG currents in HEK 293 cells and Xenopus oocytes in a concentration-dependent manner, with IC50 values of 209.4 nm and 2.0 microm, respectively. 4 HERG channels were primarily blocked in the open and inactivated states, and no additional voltage dependence was observed. Amsacrine caused a negative shift in the voltage dependence of both activation (-7.6 mV) and inactivation (-7.6 mV). HERG current block by amsacrine was not frequency dependent. 5 The S6 domain mutations Y652A and F656A attenuated (Y652A) or abolished (F656A, Y652A/F656A) HERG current blockade, indicating that amsacrine binding requires a common drug receptor within the pore-S6 region. 6 In conclusion, these data demonstrate that the anticancer drug amsacrine is an antagonist of cloned HERG potassium channels, providing a molecular mechanism for the previously reported QTc interval prolongation during clinical administration of amsacrine.
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PMID:Inhibition of cardiac HERG currents by the DNA topoisomerase II inhibitor amsacrine: mode of action. 1514 58

Many elderly patients with newly diagnosed acute myeloid leukemia (AML) present with cardiac comorbidity precluding the use of anthracycline containing chemotherapy regimens. Amsacrine, a topoisomerase II inhibitor, has been proposed as possible alternative to anthracyclines. Here, we report about the combination of amsacrine (210 mg/m(2)), in replacement for daunorubicin (DNR), with standard dose cytarabine and thioguanine (TAA) to elderly patients (>or=60 years of age) with impaired cardiac function. The outcome of 16 patients with a median age of 66 years treated between 1997 and 2003 was compared with standard treatment regimens of the AMLCG study group in a matched-pair analysis. There were no statistically significant differences in response rate, relapse free survival or overall survival between TAA treated patients or standard therapy. In conclusion, replacing anthracyclines with amsacrine for induction therapy of AML patients with significant cardiac comorbidities represents a treatment option without compromising the potential curability of the disease.
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PMID:Amsacrine containing induction therapy in elderly AML patients: comparison to standard induction regimens in a matched-pair analysis. 1767 30


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