Background: Gemcitabine and oxaliplatin have broad antineoplastic activity and favorable toxicity. We conducted a phase I study to determine the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of the combination in patients with advanced solid tumors.
Patients and methods: Sixty-eight patients with advanced stage solid tumors were enrolled. Treatment was first-line for 35% of patients, second-line for 27%, and third-line for 38%. Gemcitabine was administered at escalating doses of 1000-2000 mg/m(2) as a 30-min intravenous (i.v.) infusion on days 1 and 8 and oxaliplatin at 60-130 mg/m(2) as a 4-h i.v. infusion on day 8 every 21 days without growth factor support.
Results: The MTD was defined at gemcitabine 1800 mg/m(2) on days 1 and 8 and oxaliplatin 130 mg/m(2) on day 8. Twelve dose levels were evaluated and DLTs occurring during the first cycle consisted of grade 4 neutropenia, grade 3 asthenia or mucositis and grade 1-3 neutropenia or thrombocytopenia resulting in treatment delays. A total of 266 cycles were administered with only one episode of febrile neutropenia and no toxic deaths. Seven (3%) and 26 (10%) cycles were complicated by grade 4 and 3 neutropenia, respectively, three (1%) and 13 (5%) by grade 4 and 3 thrombocytopenia, and eight (3%) by grade 3 anemia. The most common non-hematological toxicity was grade 2/3 asthenia observed in 23% of cycles. Responses were observed in patients with a variety of epithelial neoplasms. The pharmacokinetic study revealed no significant interaction between the two drugs.
Conclusions: The combination of gemcitabine and oxaliplatin has excellent tolerability and promising activity in patients with advanced solid tumors. As the MTD exceeds the recommended single-agent dose for gemcitabine, and a dose-response effect has not been established, we recommend using both drugs at full doses, e.g. gemcitabine 1200-1400 mg/m(2) on days 1 and 8 and oxaliplatin 130 mg/m(2) on day 8 for further phase II studies.