A pilot study was conducted using a combination of cisplatin (70 mg/m2 i.v., day 1), etoposide (60 mg/m2 i.v., days 1 through 5), continuous-infusion 5-fluorouracil (800 mg/m2 i.v., days 1 through 5), and allopurinol (600 mg p.o., days 1 through 7). Treatment was repeated every 3-4 weeks. Ten patients with metastatic non-small cell lung cancer were treated. Significant toxicities were observed, including electrocardiographic changes simulating acute myocardial infarction in three patients. There was no objective response, therefore the study was closed early according to its design.