Phase II trial of rDNA alfa 2b interferon in patients with malignant carcinoid tumor.

Fourteen patients with malignant carcinoid tumors were treated with rDNA alfa 2b interferon by sc injection three times per week. Treatment was started at a dose of 2 milliunits/m2, with escalations to 3, 5, 7, and 10 milliunits/m2 at 2-week intervals depending on toxicity. No objective tumor regressions were seen, but five of 14 patients (36%) had 50% reduction in 24-hour 5-hydroxyindoleacetic acid excretion and six of nine (67%) with carcinoid syndrome had a good symptomatic response. Biochemical responses occurred during the first 8 weeks of treatment, and escalation of the dose of interferon did not increase the response rate. The rDNA alfa 2b interferon has activity in patients with the carcinoid syndrome and should be used at a low dose (2-3 milliunits/m2) until symptoms recur.