A dose-escalation and pharmacokinetic study of gemcitabine and oxaliplatin in patients with advanced solid tumors

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.

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.

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.

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.