A total of 23 advanced gastric cancer patients older than 65 years received 500 mg/m(2) 5-fluorouracil i.v. on days 2-4, 120 mg/m(2) vepesid i.v. on days 2-4, 150 mg/m(2) 6S-leucovorin on days 2-4, and 5 MU/m(2) interferon alpha-2b on days 1-5, with cycles being repeated every 3 weeks. Toxicity was severe at an interferon (IFN) dose of 5 MU/m(2); only one patient tolerated this dose. In 18 patients an IFN dose of 3 MU/m(2) and in 3 other patients a dose of 4 MU/m(2) could be given without producing toxicity. At an IFN dose of 5 MU/m(2) the most common toxicities encountered were stomatitis (grade 4 in 1 patient and grade 3 in 12 patients), leukopenia (grade 4 in 1 patient and grade 3 in 5 patients), and thrombocytopenia (grade 3 in 3 patients). Two patients achieved a complete response and eight showed a partial response, resulting in an overall response rate of 45% [95% confidence interval (CI), 25%-64%]. The median survival was 7 months for all patients and 9 months for responding patients. In conclusion, without substantially increasing the toxicity, IFN can be added to the etoposide/leucovorin/5-fluorouracil combination, at a dose of 3 MU/m(2). To verify the possible enhancement by IFN of the activity of this combination, a randomized trial is under way.
