Phase II study of sequential treatment with S-1 and cisplatin for metastatic gastric cancer

This single-arm, phase II clinical study evaluated the efficacy and safety of sequential treatment with S-1 followed by cisplatin in patients with advanced or recurrent gastric cancer.

Fifty patients with histologically confirmed advanced or recurrent gastric cancer and an Eastern Cooperative Oncology Group performance status of 0–2 who had measurable and/or assessable lesions and gave written informed consent were enrolled. S-1 (40 mg/m², bid) was administered on days 1–21, and cisplatin (70 mg/m²) was given as an intravenous infusion on day 22 of a 35-day cycle. Treatment was continued until disease progression or intolerable adverse events. Cisplatin was administered for 6 cycles. Adverse events were assessed according to Common Terminology Criteria of Adverse Events version 3.0, and efficacy was evaluated according to the Response Evaluation Criteria in Solid Tumors version 1.0 for patients with measurable lesions and by the criteria of the Japanese Research Society for Gastric Cancer for all patients.

Efficacy could be evaluated in 49 of the 50 enrolled patients. The median age was 62 years. Lesions were measurable in 38 patients and assessable in 11. The response rate was 44.7% in patients with measurable lesions and 40.8% overall. The progression-free survival and overall survival were, respectively, 233 days (7.8 months) and 574 days (19.0 months) in patients with measurable lesions and 192 days (6.4 months) and 402 days (13.4 months) overall. Serious adverse events (grade 3 or higher) included neutropenia (24.5%), anemia (20.4%), and anorexia (20.4%) and were safely managed.

The safety and effectiveness of sequential treatment with S-1 followed by cisplatin every 35 days is equivalent to that reported for conventional chemotherapeutic regimens in patients with advanced or recurrent gastric cancer.