Therapeutic index by combination of adriamycin and docetaxel depends on dosing time in mice

Mayumi Tabuchi, Hideto To, Hiromi Sakaguchi, Naho Goto, Ayako Takeuchi, Shun Higuchi, Shigehiro Ohdo

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Although the combination of adriamycin and docetaxel showed a better cure rate against metastatic breast cancer, severe myelosuppression and cardiotoxicity were dose-limiting factors. The purpose of this study was to establish a suitable dosing schedule, based on a chronopharmacologic approach, to relieve severe adverse effects. In experiment 1, adriamycin or docetaxel was injected i.p. at 2, 6, 10, 14, 18, or 22 hours after light onset (HALO) to estimate toxicities. In experiment 2, the dosing time dependency of toxicity and pharmacokinetics were assessed in the combination of adriamycin and docetaxel. In addition, G2-M phase in myelocyte cells was determined in nontreated mice. Adverse effects caused by adriamycin were shown to be the worst at 2 HALO and the best at 14 HALO. On the other hand, docetaxel-induced adverse effects were more severe at 14 HALO than at 2 HALO. In the combination study, the D(2)-A(14) group, in which docetaxel was administered at 2 HALO followed by adriamycin at 14 HALO, showed the most toxicity relief of all the treated groups. In the pharmacokinetic study, the dosing time dependency of toxicities was not related to the daily variation of pharmacokinetics of adriamycin and docetaxel. A significant 24-hour rhythm of G2-M phase distribution was found in myelocyte cells of nontreated mice. The daily variation of leukopenia caused by docetaxel corresponded to the 24-hour rhythm of G 2-M phase distribution. These findings reveal that the therapeutic index of the combined chemotherapy can be improved by administering adriamycin and docetaxel at the time when the most adverse effects are relieved in each drug.

Original languageEnglish
Pages (from-to)8448-8454
Number of pages7
JournalCancer Research
Issue number18
Publication statusPublished - Sept 15 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research


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