Phase II study of S-1 plus leucovorin in patients with metastatic colorectal cancer

W. Koizumi, N. Boku, K. Yamaguchi, Y. Miyata, A. Sawaki, T. Kato, Y. Toh, I. Hyodo, T. Nishina, T. Furuhata, K. Miyashita, Y. Okada

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


Background: S-1, a novel oral fluoropyrimidine, is well tolerated in patients with metastatic colorectal cancer (mCRC). The response rate of S-1 for colorectal cancer is high, ranging from 35% to 40%. This study aimed to evaluate the safety and efficacy of S-1 combined with oral leucovorin (LV) to enhance antitumor activity in chemotherapy-naive patients with mCRC. Patients and methods: S-1 was given orally twice daily for two consecutive weeks at a daily dose of 80-120 mg, followed by a 2-week rest period, within a 4-week cycle. LV was given orally twice a day at a daily dose of 50 mg, simultaneously with S-1. Results: Of the 56 patients with previously untreated mCRC, 32 (57%) had partial responses. The median follow-up period was 27.2 months. The median time to progression was 6.7 months (95% confidence interval 5.4-7.9). The median survival time was 24.3 months. There was no treatment-related death or grade 4 toxicity. The most common grade 3 toxic effects were diarrhea (32%), anorexia (21%), stomatitis (20%), and neutropenia (14%). Conclusion: S-1 combined with LV therapy demonstrated promising efficacy and acceptable safety in chemotherapy-naive patients with mCRC without the concurrent use of irinotecan, oxaliplatin, or molecular-targeted drugs.

Original languageEnglish
Pages (from-to)766-771
Number of pages6
JournalAnnals of Oncology
Issue number4
Publication statusPublished - 14-10-2009

All Science Journal Classification (ASJC) codes

  • Hematology
  • Oncology


Dive into the research topics of 'Phase II study of S-1 plus leucovorin in patients with metastatic colorectal cancer'. Together they form a unique fingerprint.

Cite this