Seminars in oncology
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Seminars in oncology · Feb 1996
ReviewPaclitaxel and doxorubicin, a highly active combination in the treatment of metastatic breast cancer.
The activity of single-agent paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has been documented in untreated and previously treated metastatic breast cancer, including both patients with anthracycline-resistant disease and those with extensive pretreatment. Such activity has prompted investigations of the optimal doses and schedules of paclitaxel/doxorubicin combinations. With one exception, paclitaxel has been administered as either a 24- or a 3-hour infusion, while the administration times for doxorubicin vary from bolus injection to 72-hour infusion. ⋯ Cardiotoxicity also occurred, as 15 patients had a significant decrease in left ventricular ejection fraction measured by isotope cardiography. Six of these developed congestive heart failure. This effect has been observed only in studies using short infusions of both drugs, and it is now being investigated whether lowering the peak doxorubicin concentration will preclude it.
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Phase I studies of CPT-11 (irinotecan) have been conducted in Europe, the United States, and Japan to determine the maximum tolerated dose (MTD) and the most appropriate intravenous administration schedule for further evaluation in phase II investigations. Diarrhea and/or neutropenia were the major dose-limiting toxicities in all the phase I studies. In Japanese and US investigations, the CPT-11 MTD was defined as 240 to 250 mg/m2 using a once every 3 weeks schedule and 100 and 150 mg/m2 using a weekly schedule. ⋯ European experience with a single infusion every 3 weeks showed diarrhea to be dose limiting at 350 mg/m2, but concomitant administration of high-dose loperamide allowed administration of CPT-11 at doses of up to 600 mg/m2. This latter schedule was better tolerated, achieved the highest dose intensity, and was considered to confer greater convenience in an outpatient setting when compared with the other European regimens. European phase II studies were therefore commenced using a CPT-11 schedule comprising a single intravenous infusion every 3 weeks at a dose of 350 mg/m2.
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Seminars in oncology · Feb 1996
ReviewCPT-11 in the treatment of colorectal cancer: clinical efficacy and safety profile.
CPT-11 (irinotecan) is a promising anticancer agent with a novel mechanism of action dependent on the inhibition of the DNA eukaryotic enzyme, topoisomerase I. The clinical utility of CPT-11 in advanced colorectal cancer has been documented in more than 400 patients recruited in phase II clinical trials in Europe, Japan, and United States. Among 178 eligible patients in a multicenter European study, the overall response rate to CPT-11 on a once-every-3-weeks regimen was 18%, and the median duration of response was 9.1 months. ⋯ CPT-11 appears to have activity similar to that of 5-FU in first-line treatment and, moreover, remains active after failure of 5-FU therapy. The specific gastrointestinal toxicity is manageable, and a better control of this type of toxicity is expected in the future. CPT-11 would therefore appear a welcome addition to the oncology armamentarium for this difficult-to-treat malignancy.
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Seminars in oncology · Feb 1996
ReviewRole of chemotherapy for advanced colorectal cancer: new opportunities.
Since the late 1950s, 5-fluorouracil (5-FU) has remained the most effective chemotherapeutic agent in the treatment of advanced colorectal cancer, although response rates to 5-FU monotherapy are typically no more than 15%. However, efforts at improving the response to this agent have involved its administration with biochemical-modulating agents and in protracted infusion schedules. The combination of 5-FU with folinic acid has evinced the most promising results, with an approximate twofold increase in response rate compared with monotherapy (23% versus 11%). ⋯ Prior disease progression on 5-FU does not affect the response to CPT-11, indicating no cross-resistance between the two agents. This suggests that CPT-11 is a promising new second-line agent for this difficult-to-treat disease. Additional studies will address the benefit of CPT-11 alone in second-line treatment and determine the role of CPT-11 in combination with thymidylate synthase inhibitors in first-line treatment.
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Seminars in oncology · Feb 1996
ReviewTransfer of drug resistance genes into hematopoietic progenitors to improve chemotherapy tolerance.
A number of drug resistance genes have been identified that may be useful in gene therapy approaches to ameliorate chemotherapy toxicity. Hematopoietic tissue is the most suitable target for drug resistance gene therapy because myelosuppression is the dose-limiting toxicity of the many chemotherapeutic agents. Recent studies have shown that murine and human hematopoietic progenitors can be transduced ex vivo using retroviral vectors to overexpress P-glycoprotein, dihydrofolate reductase, and O6-alkylguanine DNA alkyltransferase. ⋯ When compared with other somatic gene therapy approaches, drug resistance gene therapy has the aim of protecting normal cells and preventing toxicity. In addition many of these genes could be used to select for cells carrying the drug resistance gene as well as cotransduced therapeutic gene. Thus, gene transfer of drug resistance genes will have broad applications in the field of gene therapy as well as in protecting hematopoietic cells from chemotherapy toxicity.