[A phase I study of TS-1 and weekly cisplatin in patients with advanced gastric cancer]

This is a phase I study to determine the maximum tolerated dose (MTD) and toxicity of a combination of TS-1 and weekly cisplatin (CDDP) in advanced gastric cancer patients. TS-1 was administered orally twice daily after meals, at a standard dose of 80 mg/m2. One course consisted of 21 days' consecutive administration followed by 14 days' rest. Cisplatin (CDDP) was injected intravenously on days 8, 15 and 22 using the following dose levels: dose level 1 20 mg/m2, dose level 2 25 mg/m2, and dose level 3 30 mg/m2. Twelve patients were entered in this trial. One of the 6 patients at dose level 3 had neutropenia NCI-CTC grade 3, while another patient at dose level 3 suffered from DLT (liver function grade 3. The maximal tolerable dose (MTD) was not reached using dose level 3. Partial responses were seen in 5 (62.5%) of 8 patients with evaluable lesions. At level 2 (25 mg/m2), the response rate was 100%. We recommended dose level 2 for phase II trials from the standpoint of toxicity and response rate.