Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1140680 (ovarian cancer)
 28,141 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ecteinascidin-743 (ET-743), a tetrahydroisoquinoline alkaloid isolated from the Caribbean tunicate, Ecteinascidia turbinata, is under development by PharmaMar (the pharmaceutical subsidiary of Zeltia), the National Cancer Institute (NCI) and Ortho Biotech, as a potential treatment for several tumor types including breast cancer, lung cancer, ovarian cancer and melanoma. It appears to function by DNA minor groove alkylation, which induces topoisomerase I-mediated protein-linked DNA strand breakage [322446]. ET-743 is an analog of ET-729 [169825]. As of February 1999, it was in phase II trials [326363], [326268], [375811] and, in August 2001, PharmaMar expected phase II trials for breast, ovarian and non-small cell lung cancer to be completed by August 2002 [423408]. In June 2001, the EMEA awarded ET-743 Orphan Drug status for the treatment of soft tissue sarcoma [412446]. The orphan medicinal product designation is designed to expedite the registration of pharmaceuticals for life-threatening or debilitating conditions with low prevalence (< 5 per 10,000 in the EU), for which no satisfactory treatment exists. The designation offers the sponsor several incentives, such as centralized procedure review of the Marketing Authorization Application and, upon approval, ten-year marketing exclusivity throughout Europe for the therapeutic indication for which it was granted. PharmaMar is also collaborating with the European Organization for Research and Treatment of Cancer (EORTC); PharmaMar has obtained the worldwide rights to ET-743, amongst other ecteinascidins, from the University of Illinois [177268]. In August 2001, Dresdner Kleinwort Wasserstein predicted total sales, for all ET-743's indications, of $1 million in 2002, rising through $1106 million in 2007 to $2725 million in 2011 [423408].
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PMID:ET-743 (PharmaMar/NCI/Ortho Biotech). 1176 68

Ovarian cancer accounts for about 4% of all cancers in women in the United States, with over 23,000 cases diagnosed annually. Since patients often present with non-specific symptoms, diagnosis is generally made when disease has spread to the peritoneal cavity. Multi-modality therapy is established as the standard approach to treatment. Surgery remains a cornerstone of therapy for diagnosis, staging and treatment. Almost all patients receive some form of chemotherapy, either in the adjuvant setting or for locally advanced or advanced disease. The treatment of ovarian cancer has rapidly evolved in the past decade. Starting with the initial observation that alkylating agents were active in the treatment of this disease, new classes of agents have been rapidly incorporated in the therapeutic armamentarium. This has included the platinum compounds, taxanes and most recently, camptothecin derivatives, inhibitors of topoisomerase I. Much of the recent clinical research has revolved around how to incorporate these agents with surgery.
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PMID:New developments in the treatment of ovarian cancer. 1177 43

The camptothecins are a maturing class of anticancer agents. In this article, we review the pharmacology and antitumor activity of the camptothecin analogues that are approved for clinical use and those investigational agents undergoing clinical evaluation. Camptothecin is a naturally occurring cytotoxic alkaloid that has a unique intracellular target, topoisomerase I, a nuclear enzyme that reduces the torsional stress of supercoiled DNA during the replication, recombination, transcription, and repair of DNA. Topotecan and irinotecan are synthetic analogues designed to facilitate parenteral administration of the active lactone form of the compound by introducing functional groups to enhance solubility. They are now well-established components in the chemotherapeutic management of several neoplasms. Topotecan has modest activity in patients treated previously with ovarian and small cell lung cancer and is currently approved for use in the United States as second-line therapy in these diseases. Preliminary evidence of activity against hematological malignancies is also promising. Irinotecan is a prodrug that undergoes enzymatic conversion to the biologically active metabolite 7-ethyl-10-hydroxy-camptothecin. It is presently the treatment of choice when used in combination with fluoropyrimidines as first-line therapy for patients with advanced colorectal cancer or as a single agent after failure of 5-fluorouracil-based chemotherapy. Encouraging preliminary results suggest that irinotecan may have an increasing role in the treatment of other solid tumors, including small and non-small cell lung cancer, cervical cancer, ovarian cancer, gastric cancer, and malignant gliomas. Several additional camptothecin analogues are in various stages of clinical development, including 9-aminocamptothecin, 9-nitrocamptothecin, 7-(4-methylpiperazinomethylene)-10,11-ethylenedioxy-20(S)-camptothecin, exatecan mesylate, and karenitecin. Efforts to further optimize therapeutic effectiveness through drug delivery strategies that prolong tumor exposure to these S phase-specific agents, such as improving oral bioavailability through structure modification and innovative formulation approaches, alternative parenteral dosage forms, and administration schedules, are being actively pursued. Combining camptothecins with other anticancer drugs and treatment modalities, as well as gaining a better understanding of the factors contributing to tumor sensitivity and resistance, continues to be the object of considerable interest.
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PMID:Current perspectives on the clinical experience, pharmacology, and continued development of the camptothecins. 1189 91

Topotecan stabilizes the topoisomerase I (Topo I) cleavable complex. We measured Topo I levels in white blood cells of patients with ovarian cancer treated with topotecan. Topotecan was given i.v. daily x 5 q 3 weeks in combination with paclitaxel (1 day before topotecan) and cisplatin (just prior topotecan). Our aim was to correlate Topo I levels to pharmacokinetics and toxicity. Topo I levels were determined using Western blotting and were expressed relative to the Topo I level present in 10 microg cell lysate of the human IGROV1 ovarian cancer cell line. We found no correlation between Topo I levels and (non-)hematological toxicity. Topo I levels after the fifth topotecan infusion were significantly negatively correlated with the AUC of topotecan (R = -0.64, p = 0.026), in contrast with Topo I levels prior to (R = -0.25, p = 0.4) and after (R = -0.30, p = 0.3) the first topotecan infusion. Topo I levels after the fifth topotecan infusion (48 +/- 27%, mean +/- SD) were higher than Topo I levels prior to and after the first topotecan infusion (3.0 +/- 4.7 and 2.7 +/- 3.6%, respectively) (p = 0.001). In conclusion, we detected a significant inverse correlation between Topo I level and topotecan AUC at day 5, and we found increasing Topo I levels during a daily x 5 schedule of treatment with topotecan.
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PMID:Topoisomerase I levels in white blood cells of patients with ovarian cancer treated with paclitaxel-cisplatin-topotecan in a phase I study. 1191 45

Ovarian cancer, the second most common gynecologic malignancy, accounts for approximately 14,000 deaths annually in the United States. Disease relapse after primary treatment, which consists mainly of surgery followed by platinum-based therapy, occurs in more than 60% of ovarian cancer patients overall, and in more than 80% of those diagnosed initially with advanced-stage disease. Responses to second-line chemotherapy agents range from 15% to 25%, and are usually partial responses of short duration. Irinotecan (CPT-11, Camptosar), a camptothecin derivative that inhibits topoisomerase I, is undergoing assessment for the treatment of ovarian cancer. Preclinical studies demonstrated antitumor activity in ovarian cancer. Early phase I or II trials showed response rates of 20% to 25% in patients with recurrent or refractory disease, with some responses noted in the relatively chemoresistant mucinous and clear cell tumors. Irinotecan has also been studied in combination regimens, most commonly irinotecan plus cisplatin. In a phase II trial of irinotecan plus cisplatin in platinum-sensitive or -resistant patients, response rates were 75% and 33%, respectively. Irinotecan seems to be relatively well tolerated; dose-limiting toxicities appear to be diarrhea, nausea and vomiting, and leukopenia/neutropenia.
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PMID:Irinotecan in epithelial ovarian cancer. 1210 3

The novel camptothecin derivative BNP1350 (7-[2-trimethylsilyl)ethyl]-20(S)-camptothecin), also known as Karenitecin, has been developed for superior oral bioavailability and increased lactone stability. In our study, we describe the antiproliferative effects of BNP1350, SN-38 and topotecan in 4 human ovarian cancer cell lines. BNP1350 was found to be slightly more potent than SN-38 (p<0.01) and was considerably more potent than topotecan (p<0.01). We extended these studies to well-established human ovarian cancer xenografts in which we compared the growth inhibition induced by BNP1350 with that of topotecan given in equitoxic schedules. The growth inhibition in all 3 xenografts induced by BNP1350 was > or =75%, which was significantly better than that resulting from topotecan (p<0.05). We then selected BNP1350-resistant variants of the A2780 human ovarian cancer cell line, 2780K4 (resistance factor: 41) and 2780K32 (resistance factor: 90), to analyze possible resistance mechanisms. These variants exhibited cross-resistance against all camptothecins tested. In comparison with 2780K4 cells, 2780K32 cells were relatively more resistant against SN-38, topotecan, DX-8951f and BNP1350. In addition, 2780K32 cells were highly cross-resistant against mitoxantrone. In both 2780K4 and 2780K32, the amount of topoisomerase I was not changed but the catalytic activity was reduced. Furthermore, 2780K32 cells clearly overexpressed the breast cancer resistance protein (BCRP), as demonstrated for both the gene and the protein. In contrast to topotecan, BNP1350 proved not to be a good substrate for BCRP. Overall, we conclude that BNP1350 offers advantages over topotecan expressed by high efficacy in experimental human ovarian cancer and poor affinity for BCRP.
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PMID:Novel camptothecin derivative BNP1350 in experimental human ovarian cancer: determination of efficacy and possible mechanisms of resistance. 1211 82

Topotecan and irinotecan (CPT-11) are both anticancer agents active in the inhibition of topoisomerase I, an enzyme involved in DNA replication and RNA transcription. During the last decades, an immense amount of research into this class of anticancer agents has been conducted, the positive results of which led to the clinical use of topotecan and CPT-11 in ovarian cancer and colorectal cancer, respectively. Here, we review the currently most important pharmacologic aspects of these drugs, including their mechanisms of action, metabolism, activity- and toxicity-profiles and mechanisms of resistance, to provide a global insight into their pharmacology. We also discuss the effects of combinations with other anticancer agents, which have been tested for synergistic antitumor effects. Pharmacokinetic and pharmacodynamic biomodulation, to enhance the bioavailability of the active anticancer agent or to reduce drug related toxicities have currently reached clinical application. As pharmacogenetics enters the clinical stage, this will lead to more "fine-tuning" in anticancer treatment (for instance by individualized dosing). The clarification of the mechanisms of action and resistance of topotecan and CPT-11 should enable us to understand their pharmacological behavior even better and might lead to the development of more potent camptothecin-derivatives in the future.
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PMID:Pharmacology of topoisomerase I inhibitors irinotecan (CPT-11) and topotecan. 1218 13

Combinations of topoisomerase I (topo I) poisons and platinum derivatives have synergistic antitumoral effects. However, their clinical development is limited by supra-additive haematological toxicity. The aim of this study was to determine whether sustained doses of topotecan and oxaliplatin could be achieved using a synergistic sequence. 34 advanced cancer patients and 186 cycles were evaluable for toxicity over five dosing levels. Oxaliplatin at 85-110 mg/m(2) was given on day 1, followed by topotecan 0.5-1.25 mg/m(2)/day x 5 from day 1 to 5, every 3 weeks. Plasma pharmacokinetics (PK) of total and ultrafiltrable platinum, total and lactone forms of topotecan were determined in the first cycle. The dose-limiting toxicity (DT) was identified as grade 4 thrombocytopenia. The occurrence of grade 4 thrombocytopenia did not correlate with topotecan PK, but it did with the patient's characteristics. Severe thrombocytopenia was seen in 1/8 of patients without clinical or biological evidence of malnutrition, with a creatinine clearance higher than 1 ml/s, and no more than two previous chemotherapy regimens, while it was seen in 8/10 patients with one of these characteristics (P<0.004). In conclusion, the recommended doses of oxaliplatin 110 mg/m(2) and topotecan 1 mg/m(2)/day, every 3 weeks can be administered to patients with a favourable general status and pretreatment characteristics and a phase II study is worthwhile in ovarian cancer patients.
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PMID:Topotecan preceded by oxaliplatin using a 3 week schedule: a phase I study in advanced cancer patients. 1220 71

DX-8951f (exatecan mesylate), a new water-soluble derivative of camptothecin, is currently being evaluated in phase II clinical trials. Resistance may be acquired when treating cancer patients with DX-8951f. Therefore, we selected a subline of the human ovarian cancer cell line A2780 for resistance against DX-8951f to investigate possible mechanisms of resistance. This DX-8951f-resistant subline, designated 2780DX8 (resistance factor=9.3), displayed a typical cross-resistance pattern including compounds, such as topotecan (resistance factor =34), SN-38 (resistance factor =47), mitoxantrone (resistance factor =59) and doxorubicin (resistance factor =2.9), which have previously been associated with the expression of breast cancer resistance protein. 2780DX8 cells did not show changes in the topoisomerase I gene, in topoisomerase I protein levels or catalytic activity. Overexpression of breast cancer resistance protein could be detected, both at the mRNA and protein level, while staining for Pgp, MRP1, or LRP was negative. GF120918, an inhibitor of breast cancer resistance protein, was able to reverse the DX-8951f-induced resistance in 2780DX8 cells. In vivo experiments in well-established 2780DX8 human tumour xenografts demonstrated that the growth inhibition induced by CPT-11 was more affected by breast cancer resistance protein expression than that of DX-8951f. These data indicate for the first time that DX-8951f is able to induce breast cancer resistance protein as a mechanism of resistance. Breast cancer resistance protein, however, results in only minor reduction of antitumour activity of DX-8951f which is an advantage over topotecan and CPT-11/SN-38.
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PMID:Induction of breast cancer resistance protein by the camptothecin derivative DX-8951f is associated with minor reduction of antitumour activity. 1223 78

Ovarian cancer is the fifth leading cause of cancer death in women. Most patients with ovarian cancer respond to first-line chemotherapy, but many relapse within 18 to 22 months. The development of efficacious salvage therapies that increase overall survival while maintaining quality of life is a great challenge in the treatment of this disease. Topotecan, a novel topoisomerase I inhibitor, is currently indicated for the treatment of recurrent metastatic carcinoma of the ovary. In patients with relapsed ovarian cancer, the overall response rates on treatment with topotecan range from 19%-33% in platinum-sensitive patients, 14%-18% in platinum-resistant patients, and 5%-11% in platinum-refractory patients. The proportion of patients achieving stable disease ranges between 17% in refractory and 48% in sensitive patients. In phase III studies, topotecan was shown to be equivalent in efficacy to both paclitaxel and liposomal doxorubicin as second-line therapy in patients with relapsed ovarian cancer. Further, non-cross-resistance between topotecan and paclitaxel was demonstrated in a third-line, phase III crossover study, suggesting that topotecan may be effective in the first-line setting with paclitaxel and/or platinum. Hematologic toxicities include neutropenia, thrombocytopenia, and anemia; however, these toxicities are usually short lived, noncumulative, and manageable with dose modifications, including low-dose topotecan regimens. Nonhematologic toxicities are usually mild to moderate in severity. These data support the use of topotecan for second-line therapy and suggest that topotecan may also be effective in first-line therapy. Further studies with topotecan alone and in combination with other agents are needed to fully characterize the role and sequencing of topotecan in the salvage and first-line settings.
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PMID:Update on the role of topotecan in the treatment of recurrent ovarian cancer. 1232 28


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