Cancer research
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We have investigated the tissue distribution, toxicity, and antitumor activity of anthracyclines encapsulated in hydrogenated phosphatidylinositol (HPI)-containing liposomes which show a characteristic long circulation time in plasma (J. Natl. Cancer Inst., 81: 1484-1488, 1989). ⋯ However, only the HPI-DOX formulation was significantly more active than free DOX in the treatment of the ascitic J6456 tumor at all dose levels tested. Therapeutic results with EPI encapsulated in HPI liposomes also showed an efficacy superior to that of free EPI. These studies provide evidence that anthracyclines delivered in long-circulating liposomes extravasate with relative selectivity in tumor areas, improving the overall therapeutic index.
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Clinical Trial
Phase I pharmacokinetic and pharmacodynamic study of a new anthrapyrazole, CI-937 (DUP937).
We performed a phase I trial of CI-937 (DUP937), an anthrapyrazole, with the following objectives: (a) to determine the maximally tolerated dose in humans; (b) to define the toxicity spectrum of this agent; (c) to describe the pharmacokinetics of the drug; (d) to test a pharmacokinetics based hypothesis of dose escalation; and (e) to relate drug pharmacokinetics to pharmacodynamics. CI-937 was administered as a single bolus injection every 3-4 weeks at doses ranging from 3.6 to 25.2 mg/m2. Thirty-two patients and 57 courses were evaluable for toxicity. ⋯ Only dose and baseline neutrophil count predicted a percentage change in WBCs in a multifactor analysis. Dose and prior chemotherapy predicted percentage change in neutrophil count in a multifactor analysis. We conclude that the dose-limiting toxicity of CI-937 is neutropenia and that the recommended phase II starting dose is 22 mg/m2.
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Female Syrian golden hamsters with N-nitrosobis(2-oxopropyl)amine-induced pancreatic cancers were treated for 2 months with new pseudononapeptide bombesin receptor antagonist [D-Tpi6,Leu13 psi (CH2NH)-Leu14]bombesin(6-14)(RC-3095), administered s.c. with implanted osmotic minipumps releasing 20 micrograms/day of the analogue. The results were compared to those obtained by treatment with somatostatin analogue RC-160 (35 micrograms/day and 150 micrograms/day) or [D-Trp6]luteinizing hormone-releasing hormone (25 micrograms/day), which inhibited the growth of pancreatic cancers in our previous studies. A new acetylated somatostatin analogue [formula: see text] (30 micrograms/day) also was used for comparison of therapeutic response. ⋯ The acetylated somatostatin analogue RC-160-II had a similar inhibitory effect on the tumors as the original analogue RC-160. Our results suggest that the increase in the dose of RC-160 improves the therapeutic response, and this finding should be taken into account in clinical use of this somatostatin analogue. In view of its strong inhibitory effect on experimental pancreatic tumors, the bombesin antagonist RC-3095 might be considered as a possible new agent for the therapy of human exocrine pancreatic cancer.
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Nude mice bearing xenografts of HT-29 human colon cancer cell line were treated for 4 weeks with a [D-Trp6] agonist of luteinizing hormone releasing hormone (LH-RH), somatostatin analogue (RC-160), and bombesin/gastrin releasing peptide antagonist (RC-3095). Some inhibitory effect of [D-Trp6] LH-RH microcapsules releasing 25 micrograms/day on tumor growth was observed that could be due to sex steroid deprivation, but the inhibition was not statistically significant. ⋯ Tumor volume, percentage change in tumor volume, and tumor weights were significantly decreased in both groups treated with RC-3095. This is the first report on inhibition of human colon cancer growth in vivo by bombesin antagonists.
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In the past decade, immunotherapies have been developed that are capable of causing prolonged cancer regressions in selected patients with advanced metastatic disease. In the past year, attempts at the gene therapy of cancer have begun. These experimental cancer treatments deserve vigorous exploration.