A phase I study of S-1 plus weekly docetaxel in patients with metastatic gastric cancer

14005 Background: We conducted a study to define the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of S-1 plus weekly docetaxel in pts with metastatic gastric cancer (MGC), and to recommend a dose for phase II study Methods: Pts with MGC, age ≥ 18 yrs, ECOG PS 0–2, adequate organ function, and no or 1–2 prior chemotherapy were eligible. S-1 was given twice daily, p.o. on D1–14 and docetaxel i.v. on D1, 8, q 3 wks. Each cohort of 3 pts was treated with escalating doses of S-1/docetaxel at 60/25 (level I), 70/25 (level II), 70/30 (level III), 80/30 (level IV), 80/35 (level V), 90/35 (level VI), and 90/40 mg/m2 (level VII). The DLT pertaining to 1st cycle only was obtained. Results: Thirty pts with median age of 50 yrs (range: 27–71) with MGC received a median of 8 cycles (range: 1–12). A total of 222 cycles were administered. DLTs were; G3 elevated liver enzyme at level I (1/6 pts), gastric perforation at level V (1/6), G3 diarrhea and febrile neutropenia (FN) with G3 nausea/anorexia/fatigue at level VI (2/6), and FN and neutropenic infection (NI) with G3 stomatitis at level VII (2/3). After DLT occurred in 2 of 3 pts in level VII, 2 of additional 3 pts enrolled at level VI had DLT. Then, 1 pt developed DLT among additional 3 pts enrolled at level V. Therefore, MTD and recommended dose (RD) were level VI and V, respectively. There were 2 CRs, 17 PRs with response rate of 65.5% (95% CI 48.2–82.8%), 8 SDs and 2 PDs among 29 efficacy-evaluable pts. Conclusions: MTD for this regimen was S-1 90 mg/m2/d + docetaxel 35 mg/m2 and RD was S-1 80 mg/m2/d (D1–14) + docetaxel 35 mg/m2 (D1, 8). (Supported by National Cancer Center Grant; Docetaxel and S-1 were provided by Sanofi-Aventis Korea and Jeil Pharm. Co., respectively) [Table: see text] No significant financial relationships to disclose.