Clin Cancer Res
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Doxorubicin containing combination chemotherapy regimens are widely used for treatment of breast and other cancers. However, these regimens are associated with significant toxicities including myocardial dysfunction and alopecia. Analogues of doxorubicin are being developed to reduce these side effects. ⋯ Total clearance of drug was 4.2 liters.1 h/kg while the cumulative 24-h urinary excretion was less than 10% of the administered dose. The activity of the combination appears to be similar to doxorubicin-containing regimens, while the incidence of alopecia appears to be lower than the historical experience with doxorubicin. However, cardiotoxicity remains a significant problem.
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Clinical Trial
A phase I and pharmacokinetic study of a new camptothecin derivative, 9-aminocamptothecin.
Camptothecins are the only available antitumor agents which target the nuclear enzyme topoisomerase I. 9-Aminocamptothecin (9-AC) is a water-insoluble derivative of camptothecin which has demonstrated impressive antitumor activity in preclinical models. While two other water-soluble derivatives, CPT-11 and topotecan, have successfully completed Phase I and Phase II testing, biochemical and tissue culture studies suggest that camptothecin analogues differ in characteristics which may be important in determining antitumor activity. We performed a Phase I trial of 9-AC to determine the pharmacokinetics, dose-limiting toxicity, and maximum tolerated dose of this agent when administered as a 72-h continuous i.v. infusion. ⋯ Although significant interpatient variation in plasma 9-AC lactone levels was observed, pooled data were fit to a two-compartment model, with a terminal half-life of 36 h. Analyses of topoisomerase protein levels in peripheral blood cells indicated decreases in topoisomerase I accompanied by increases in topoisomerase II in two of three patients. 9-AC is an active antitumor agent and may be administered safely as a 72-h infusion in patients with cancer. Although Phase II trials with a 72-h infusion of 9-AC are warranted, alternate schedules should be evaluated given the dramatic preclinical activity seen with more prolonged administrations.
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Comparative Study
Expression of bcl-2 protein predicts efficacy of adjuvant treatments in operable node-positive breast cancer.
The proto-oncogene bcl-2 encodes a protein that inhibits apoptosis, a common mechanism of cell death caused by hormone and chemotherapy. We have analyzed bcl-2 protein expression by immuno-cytochemistry in primary node-positive breast cancers in two groups of patients (for a total of 180 cases). One group received adjuvant hormone therapy, the other chemotherapy (cyclophosphamide, methotrexate, and fluorouracil), and both groups were followed for a median time of 63 months. ⋯ Thus, in contrast to in vitro data on drug resistance, bcl-2 expression was associated with better outcomes in patients treated with hormone and chemotherapy. Overall, these results suggest that expression of bcl-2 protein and the number of metastatic lymph nodes are independent features predictive of clinical outcome in patients with node-positive breast cancer, irrespective of the type of adjuvant treatment. The determination of bcl-2 protein may prove to be a useful tool to distinguish patients for whom conventional forms of adjuvant therapy are beneficial from those with bcl-2 negative and ER-negative tumors for whom novel therapeutic strategies are needed.