Final results of the Canadian phase I dose escalation trial of gemcitabine and cisplatin for advanced non-small cell lung cancer.

When given at doses of > or = 1,250 mg2 weekly x 3 with a 1-week break, single-agent gemcitabine induces responses in more than 20% of previously untreated patients with non-small cell lung cancer (NSCLC). This study was undertaken to determine the maximum tolerated doses for a 4-week cycle of gemcitabine and cisplatin given in combination weekly x 3 with a 1-week rest. Patients younger than 75 years were eligible if they had stage III/IV NSCLC, life expectancy > or = 12 weeks, hemoglobin > or = 10 g/dL, absolute granulocyte count > or = 2 x 10(9)/L, platelets > or = 100 x 10(9)/L, hepatic enzymes < or = 3 times the upper limit of normal, and serum creatinine < or = 130 mumol/L. The starting doses for gemcitabine and cisplatin were 1,000 mg/m2 and 25 mg/m2 per week x 3, respectively. At dose level 2 cisplatin was increased to 30 mg/m2/week x 3. Thereafter only the gemcitabine was increased, by 250 mg/m2/wk at each dose level, to a maximum of 2,250 mg/m2/wk at dose level 7. The median nadir granulocyte and platelet counts decreased with each dose level, but dose-limiting toxicity in two or more patients was not encountered in the first treatment cycle, even at dose level 7. Cumulative bone marrow toxicity was seen at all dose levels, and this resulted in frequent dose reductions or omissions. Dose delivery was well maintained over time only at dose level 1. Grade 3-4 nonhematologic toxicity was infrequent and rarely dose limiting. An assessment of all toxicities seen during the treatment cycles was undertaken using continual reassessment methodology. This model suggested that dose level 4 (cisplatin 30 mg/m2/wk and gemcitabine 1,500 mg/m2/wk) would be the maximum dose at which grade 4 toxicity would be expected in up to 33% of patients at any time over four treatment cycles. Of 47 patients evaluable for response, partial remission was seen in 14, with an overall response rate of 30% (confidence interval, 17% to 43%). The median duration of response was 16 weeks and the median survival time was 24 weeks (range, 3.5 to 64+ weeks). A phase II trial is planned in which dose level 4 will be evaluated in a larger cohort of patients with NSCLC.