Phase II study of S-1, docetaxel and cisplatin combination chemotherapy in patients with unresectable metastatic gastric cancer

Abstract

4537 Background: Our previous phase I trial demonstrated that combination of docetaxel, cisplatin and S-1 (DCS) chemotherapy was tolerable and showed a quite high RR (88.2%), with an appreciable downstaging rate in metastatic gastric cancer (Takayama et al, BJC 2007). In this study, we conducted a phase II study to assess the activity and toxicity of the DCS chemotherapy in patients with unresectable advanced gastric cancer. Methods: Eligibility criteria were pathologically proven unresectable gastric cancer, PS 0–1, normal organ functions, and no prior treatment. Patients received oral S-1 (40 mg/m2, b.i.d.) on days 1–14, intravenous cisplatin (60 mg/m2) and docetaxel (60 mg/m2) on day 8 every 3 weeks. Patients who achieved down staging underwent surgical resection. Results: Thirty-one patients from eight institutions were enrolled between March 2005 and April 2007. Clinical characteristics were as follows: median age 62 years (range 44–77), PS 0/1: 23/8, females/males: 7/24, well differentiated/undifferentiated adenocarcinoma: 10/21). The objective response rate was 87.1% with 1 complete response (3.2%) and 26 partial responses (83.9%) in 31 assessable patients. There were four stable diseases (12.9%) but no progressive disease. Of these 27 responders, six patients (22.2%) achieved downstaging, and 5 of these received subsequent curative gastrectomy. The median survival time (MST) and progression free survival (PFS) were 575 (95% C.I. 501.6–648.4) and 221 (95% C.I. 168.8–279.3) days, respectively. Grade 3–4 toxicities were: neutropenia in 51.6% (grade 4: 32%) of patients, anorexia in 29%, and nausea in 26.6%. Conclusions: The combination of docetaxel, cisplatin and S-1 (DCS) chemotherapy is highly active in unresectable advanced gastric cancer, and can be given safely with proper management of adverse events. DCS is one of the most powerful candidates to become standard regimen for unresectable metastatic gastric cancer. No significant financial relationships to disclose.