Japanese Journal of Clinical Oncology Advance Access published online on October 31, 2009
Japanese Journal of Clinical Oncology, doi:10.1093/jjco/hyp124
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Two Dosages of Oral Fluoropyrimidine S-1 of 35 and 40 mg/m2 bid: Comparison of the Pharmacokinetic Profiles in Korean Patients with Advanced Gastric Cancer
1 Cancer Metastasis Research Center, Yonsei University College of Medicine
2 Department of Medical Oncology, Yonsei Cancer Center, Yonsei University College of Medicine
3 Department of Internal Medicine, Yonsei University College of Medicine
4 Department of Surgery, Yonsei University College of Medicine, Seoul, Korea
For reprints and all correspondence: Hyun Cheol Chung, Department of Medical Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, 250 Seongsanno (134, Shinchon-Dong), Seodaemun-Gu, Seoul 120-752, Korea. E-mail: unchung8{at}yuhs.ac
Received May 14, 2009; accepted August 23, 2009
Objective: In this study, we compared the pharmacokinetic profiles of 5-fluorouracil (5-FU), tegafur, 5-chloro-2,4-dihydroxypyridine (CDHP) and potassium oxonate (Oxo) after administration of S-1 at 35 or 40 mg/m2 bid for 28 consecutive days, in Cycles 1 and 3, in patients with advanced gastric cancer.
Methods: Three patients were enrolled for each dosage. S-1 dosage was assigned based on body surface area (BSA), which is different from the Japanese dosing system. The median daily dose per BSA was 76 mg/m2, ranging from 70 to 88 mg/m2.
Results: Plasma levels of 5-FU, tegafur, CDHP and Oxo at 4 h post-dose reached steady-state on day 8. The estimated steady-state level was dependent on S-1 dosage. There were no intercyclic differences of pre-dose and 4 h post-dose levels between Cycles 1 and 3, implying no cumulative effect of S-1 was shown probably due to 2-week drug-resting period. Pharmacokinetic profiles on day 28 were similar to previous Japanese report. Cmax and AUC0–48 h values of each S-1 component increased depending on S-1 dosage. Pharmacokinetic parameters were not correlated with tumor response or toxicity.
Conclusions: We suggest that these pharmacokinetic profiles of Asian population could provide a basis for schedule optimization and for additional studies on interaction with other antitumor drugs.
Key Words: S-1 gastric cancer pharmacokinetics Asian population