A combination phase I study of biweekly docetaxel and 5’-DFUR in patients with unresectable or recurrent gastric cancer

Abstract

14115 Background: Docetaxel (DOC) and 5’-DFUR (an intermetamolite of capecitabine) have single-agent activity in gastric cancer and have distinct mechanisms of action and no overlap of key toxicities. Synergistic interaction between DOC and 5’-DFUR is mediated by taxane-induced up-regulation of thymidine phosphorylase. The objectives of this study were to determine the maximum tolerated dose (MTD), the dose limiting toxicity (DLT) and the recommended dose (RD) of the combination therapy of biweekly DOC and 5’-DFUR. The DLT was set in low grade to treat the patients in the outpatient clinic. Methods: Eligibility criteria included patients with histologically proven unresectable or recurrent gastric cancer, no requirement of prior chemotherapy, a performance status of 0–2, adequate organ function and written informed consent. DOC was administered by 1-hour intravenous infusion (level 1, 2, 3, 4: 30, 35, 40, 45 mg/m2) biweekly for 4 weeks. 5’-DFUR was administered orally at a fixed dose of 600mg/body everyday. Toxicity and efficacy were evaluated during the 2 cycles for 8 weeks. Three or 6 patients were enrolled at each dose level. Administration of DOC was skipped in the event of grade 2 hematologic toxicity. DLT was defined as grade 3 hematologic toxicity, grade 2 non-hematologic toxicity. The MTD was defined as the dose level at which at least two of three patients or three of six patients presented with DLT. Results: Twelve patients with a median age of 58 years (range, 29 to 75) were enrolled in this study. Five patients have received prior chemotherapy. Eight patients were unresectable and 4 had recurrent tumors. At level 1 (n=3), 2 (n=3), 3 (n=3), no patients developed DLT. Two patients developed DLT at level 4 (n=3). All DLT was neutropenia. Only 1 developed grade 4 neutropenia at level 4. Non-hematological toxicity was uncommon. Level 4 was determined as the MTD. Of 8 evaluable patients, responses included 4 PR, 3 SD and 1 PD for an overall response rate of 50%. Conclusions: The MTD of DOC in this combination is 45 mg/m2 and the RD is 40 mg/m2. This regimen is well-tolerated with high response rate in outpatient setting. A phase II study is necessary to evaluate the response of this regimen. No significant financial relationships to disclose.