Oncology
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Review
New advances in lung cancer chemotherapy: topotecan and the role of topoisomerase I inhibitors.
Objective tumor responses and survival rates with standard chemotherapy options for small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) have been disappointing. However, several promising new classes of agents have emerged in recent years, including the taxanes, mitotic spindle inhibitors, antimetabolites, and topoisomerase I and II inhibitors. The molecular target of several of these new agents is topoisomerase I, an enzyme that is essential for DNA replication and is up-regulated in tumor cells. ⋯ Preliminary trials also indicate that topotecan is well tolerated and has activity in the first-line treatment of NSCLC. In this article an overview of new agents in lung cancer chemotherapy is provided, with particular attention paid to the topoisomerase I inhibitors. A review of topotecan--the first topoisomerase I inhibitor to be approved for second-line therapy in SCLC--is presented as an illustration of the promise these new agents hold for the treatment of SCLC and NSCLC.
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Preclinical and phase I/II studies of Herceptin demonstrated a dose-related, non-linear pharmacokinetic profile. The results of a dose-finding study supported a regimen comprising an initial intravenous (i.v.) dose of 4 mg/kg with subsequent weekly doses of 2 mg/kg. However, pharmacokinetic and safety data suggested that increased dose and reduced frequency of Herceptin administration are feasible. ⋯ Subcutaneous (s.c.) administration of Herceptin would further simplify administration and studies are also underway to clinically evaluate s.c. administration of Herceptin in combination with paclitaxel. With the recent development of oral taxanes, it is predicted that combinations including an oral taxane, Xeloda and either 3-weekly or possibly s.c. Herceptin may become future therapies for breast cancer patients.
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To define the maximum tolerated dose (MTD) of irinotecan (CPT-11) given on days 1 and 8 with mitomycin C (MMC) given on day 1 in a monthly cycle, and to assess the toxicity and activity of this regimen in patients with previously treated colorectal carcinoma. ⋯ CPT-11 175 mg/m2 on days 1 and 8 associated with MMC 10 mg/m2 on day 1, every 4 weeks, is a safe and moderately active regimen in heavily pretreated patients with advanced colorectal carcinoma. The role of MMC in this combination is doubtful, and further attempts with other new agents should be made to improve the outcome in these patients.
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In HER2-positive breast cancer patients, the humanized anti-HER-2 monoclonal antibody trastuzumab (Herceptin) may improve overall survival. No reports exist regarding the application of trastuzumab in patients with cytotoxically induced cardiac failure and decreased left ventricular ejection fraction or about locally recurrent and advanced disease. In this case report, trastuzumab resulted in a complete and long-lasting response of recurrent and locally advanced breast cancer and was well tolerated in a severely cytotoxically pretreated patient with cardiac failure. We encourage other oncologists to offer trastuzumab also to severely cytotoxically pretreated patients with conditions after cardiac insufficiency or with locally advanced breast cancer.
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Somatostatin (SST) analogues are cornerstones in the symptomatic management of patients suffering from carcinoid tumors, and antiproliferative activity has also been reported for these agents. The most commonly applied SST analogues are octreotide (OCT) and lanreotide (LAN), which are both available in a slow release formulation. To the current knowledge, both OCT and LAN are thought to be equally effective for the management of various disorders. We report the case of a patient with a disseminated carcinoid, who progressed during dose-intensified treatment with slow-release LAN in combination with interferon-alpha, but developed a pronounced response after treatment was switched to the application of a depot formulation of OCT. ⋯ To our knowledge, this is the first case demonstrating both a symptomatic as well as objective response to OCT following progression during therapy with LAN in a patient with a carcinoid tumor. Our results suggest that refractoriness to treatment including a long-acting SST analogue does not automatically imply resistance to a related agent and should alert clinicians to the potential of non-cross-resistance between SST analogues in neuroendocrine malignancies.