Phase I/II study of docetaxel and S-1 in patients with advanced gastric cancer

The aims of this phase I/II study of docetaxel and S-1 were to determine the dose-limiting toxicity (DLT), maximum-tolerated dose (MTD), and recommended dose (RD) in the phase I part and to explore the tumour response, survival and safety in the phase II part. Patients with histologically- or cytologically confirmed unresectable or recurrent gastric cancer were eligible. Treatment consisted of intravenous docetaxel on day 1 (starting dose 50 mg m(-2)) and oral S-1 at a fixed dose of 40 mg m(-2) twice daily on days 1-14, every 4 weeks up to six cycles. Nine patients took part in the phase I portion of the study. The MTD of docetaxel was determined to be 50 mg m(-2), with the DLTs of grade 3 infection associated with grade 3 neutropenia and grade 4 neutropenia during S-1 administration. The RD of docetaxel was 40 mg m(-2) in combination with S-1 40 mg m(-2) b.i.d. The efficacy and safety of this regimen was therefore assessed in 46 patients with at least one measurable lesion. The overall response rate and estimated median overall survival were 46% (95% CI, 31-61%) and 14.0 months (8.3-17.3 months), respectively. The most common grade 3/4 toxicity was neutropenia (67% of patients), which was predictable and manageable. This regimen showed promising activity with moderate toxicities in advanced gastric cancer.