Abstract
Many drugs vary in potency and/or toxicity according to the time of day when they are administered. In this study, we investigated whether antitumor efficacy of angiogenesis inhibitor, TNP-470 [O-(chloroacetyl-carbamoyl) fumagillol], could be improved by optimizing the dosing schedule. Tumor-bearing mice were housed under standardized light/dark cycle conditions (lights on at 7:00 AM, off at 7:00 PM) with food and water ad libitum. The antitumor effect of TNP-470 (30 mg/kg s.c.) was more potent in mice injected with the drug at the early light phase than it was when administered at the early dark phase. The diurnal change in the antitumor effect of TNP-470 was parallel to that in its antiangiogenic activity. The variation in the effects of TNP-470 was closely related to the diurnal variations in its inhibitory action on methionine aminopeptidase activity in tumor masses. There was a significant dosing time-dependent change in the concentration of TNP-470 in plasma. The higher concentration of TNP-470 in plasma was observed when its antitumor and antiangiogenic activities were increased. These results suggest that therapeutic efficacy of TNP-470 can be enhanced by choosing the most appropriate time of day to administer the drug.
Footnotes
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This study was supported by a grant-in-aid for Encouragement of Young Scientists from the Japan Society for the Promotion of Science (S.K., 13771448), a grant-in-aid from Japan Research Foundation for Clinical Pharmacology (S.K.), and a grant-in aid from Takeda Science Foundation (S.K.).
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DOI: 10.1124/jpet.102.043562
- Abbreviations:
- TNP-470
- O-(chloroacetyl-carbamoyl) fumagillol
- MetAP-2
- methionine aminopeptidase
- Met-MCA
- methionine 4-methyl coumary-7-amide
- AMC
- 7-amino-4-methylcoumarin
- NONMEM
- nonlinear mixed effect model
- AUC
- area under the plasma concentration-time curve
- AGM-1883
- fumagillol carbamate
- Received September 3, 2002.
- Accepted October 25, 2002.
- The American Society for Pharmacology and Experimental Therapeutics
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