Therapy of metastatic carcinoid tumor and the malignant carcinoid syndrome with recombinant leukocyte A interferon.

Twenty-seven patients with metastatic carcinoid tumor, 24 of whom had the malignant carcinoid syndrome, were treated with recombinant leukocyte A interferon at a planned dose of 24 x 10(6) U/m2. Twenty percent of patients with measurable tumor experienced an objective regression and 39% of those with the carcinoid syndrome experienced a reduction of more than 50% in urine 5-hydroxyindoleacetic acid (5HIAA) excretion. Flushing was partially or completely relieved in 65% of patients and diarrhea was relieved in 33%. Regrettably, these favorable treatment effects were transient in nature, with objective regressions persisting for a median of only 7 weeks and hormonal responses for a median of only 4 weeks. Any therapeutic gain experienced by these patients seemed to be outweighed by the frequency and severity of toxic reactions, which consisted primarily of chills and fever, fatigue, anorexia, weight loss, leukopenia, and abnormalities of liver function. Whereas other interferons, administration by alternative dosages and regimens, or incorporation of interferons into drug combinations may merit future study, we cannot recommend recombinant leukocyte A interferon, administered by the methods we employed, for routine therapy of the carcinoid tumor or syndrome.