Cancer chemotherapy and pharmacology
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Cancer Chemother. Pharmacol. · Jan 1996
Preclinical pharmacology and antitumour activity of the novel sequence-selective DNA minor-groove cross-linking agent DSB-120.
We examined the in vitro cytotoxicity, antitumour activity and preclinical pharmacokinetics of the novel sequence-selective, bifunctional alkylating agent DSB-120, a synthetic pyrrolo[1,4][2,1-c]benzodiazepine dimer. DSB-120 was shown to be a potent cytotoxic agent in vitro against a panel of human colon carcinomas [50% growth-inhibitory concentration (IC50) 42 +/- 7.9 nM, mean +/- SE, n = 7] and two rodent tumours (L1210 and ADJ/PC6). Antitumour activity was assessed in the bifunctional alkylating-agent-sensitive murine plasmacytoma ADJ/PC6 using a variety of administration protocols. ⋯ DSB-120 appeared to be unstable in vivo, with only 1% of an administered dose being recovered unchanged in 24-h urine samples. Plasma protein binding was extensive at 96.6%. In conclusion, the poor antitumour activity of DSB-120 may be a consequence of low tumour selectivity and drug uptake as a result of high protein binding and/or extensive drug metabolism in vivo.
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Cancer Chemother. Pharmacol. · Jan 1995
Comparative Study Clinical Trial Controlled Clinical TrialPretreatment H2 receptor antagonists that differ in P450 modulation activity: comparative effects on paclitaxel clearance rates and neutropenia.
Histamine-2 receptor antagonists (H2RAs) are principal components of the premedication regimen used to prevent major hypersensitivity reactions in patients receiving paclitaxel. Several different H2RAs, including cimetidine, ranitidine and famotidine, have been used in clinical trials of paclitaxel, as well as by clinicians in different geographic regions and hospitals primarily because of differences in the availability of the various H2RAs. However, H2RAs have highly variable cytochrome P450-modulating capabilities, and the P450 system appears to play a major role in paclitaxel metabolism and disposition. ⋯ Among patients who did not require G-CSF, mean percentage decreases in ANC were 87.7% and 84.2% after paclitaxel cycles preceded by cimetidine and famotidine, respectively. These measures of neutropenia did not differ significantly in paired analysis (p = 0.13). These results show that the H2RAs cimetidine and famotidine do not differentially affect the pharmacologic and toxicity profiles of paclitaxel when used in the premediation regimen to prevent major hypersensitivity reactions, and may be interchanged.
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Cancer Chemother. Pharmacol. · Jan 1995
Clinical Trial Controlled Clinical TrialA phase I trial of concomitant chemoradiotherapy with cisplatin dose intensification and granulocyte-colony stimulating factor support for advanced malignancies of the chest.
Concomitant chemoradiotherapy with cisplatin and combination chemotherapy in the neoadjuvant setting have both shown promising results. ⋯ (1) This intensive multimodality regimen can be given with aggressive supportive care incorporating GCSF. The recommended phase II doses for a 4-week cycle are cisplatin 50 mg/m2 week 1, and 100 mg/m2 week 2, IFN 2.5 MU, HU 500 mg every 12 h x 11 and 5-FU 800 mg/m2 per day with single fraction radiotherapy during weeks 1-3 and GCSF during weeks 1, 3, and 4. (2) GCSF can be safely administered and provides effective support of neutrophils when administered simultaneously with IFN, cisplatin, and chest radiotherapy. (3) There is synergistic renal toxicity when high doses of IFN and cisplatin are given together. (4) Hyperfractionated radiotherapy decreases the severity of esophagitis but increases thrombocytopenia. (5) Although highly toxic, response rates, time to progression and survival figures with this regimen are encouraging and support its investigation in the phase II setting.
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Cancer Chemother. Pharmacol. · Jan 1995
Comparative StudySynergistic and additive combinations of several antitumor drugs and other agents with the potent alkylating agent adozelesin.
Adozelesin is a highly potent alkylating agent that undergoes binding in the minor groove of double-stranded DNA (ds-DNA) at A-T-rich sequences followed by covalent bonding with N-3 of adenine in preferred sequences. On the basis of its high-potency, broad-spectrum in vivo antitumor activity and its unique mechanism of action, adozelesin has entered clinical trial. We report herein the cytotoxicity for Chinese hamster ovary (CHO) cells of several agents, including antitumor drugs, combined with adozelesin. ⋯ In experiments with hypomethylating agents, adozelesin combined synergistically with 5-azacytidine (5-aza-CR) and 5-aza-2'-deoxycytidine (5-aza-2'-CdR). Combinations of adozelesin with tetraplatin or 5-aza-2'-CdR were also tested against B16 melanoma cells in vitro and were found to be additive and synergistic, respectively. The synergistic cytotoxicity to CHO cells of adozelesin combinations with tetraplatin, 5-aza-CR, or pentoxifylline was not due to increased adozelesin uptake or increased alkylation of DNA by adozelesin.
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Cancer Chemother. Pharmacol. · Jan 1994
Comparative StudyBiodistribution of O6-benzylguanine and its effectiveness against human brain tumor xenografts when given in polyethylene glycol or cremophor-EL.
O6-Benzylguanine effectively inactivates the DNA-repair protein O6-alkylguanine-DNA alkyltransferase in tumor cells and has been shown to increase the cytotoxicity of chloroethylnitrosoureas. This study was undertaken to ascertain the optimal vehicle for further toxicological evaluation and eventual clinical trials of O6-benzylguanine. The solubility, metabolism, bioavailability and effectiveness of O6-benzylguanine as an adjuvant therapy with BCNU were compared using two vehicles, cremophor-EL and PEG 400. ⋯ In contrast, there was a 3-fold greater amount of O6-benzylguanine in the small intestine of mice at 1 h after i.p. injection of the drug in cremophor-EL as compared with PEG 400. The rate and extent of metabolism in the liver was the same, whether the parent drug was given in PEG 400 or in cremophor-EL. These studies demonstrate that O6-benzylguanine is a more effective enhancer of the antitumor activity of BCNU when it is given in PEG 400 than when it is delivered in cremophor-EL, which may be due to a more rapid distribution of the drug to the tumor.