Treatment of malignant endocrine pancreatic tumors with human leukocyte interferon.

Twelve patients with malignant endocrine pancreatic tumors refractory to cytotoxic treatment were treated with human leukocyte interferon im at daily doses of 3 X 10(6)-6 X 10(6) IU. Ten of 12 patients showed an objective response with a mean duration of 15.2 months, median, 11 months (range, 2-36+). All ten patients had a decrease in tumor markers and an objective reduction in tumor size was also noted in four. Improvement of clinical manifestations was seen in all cases with an objective response. Adverse effects, including influenza-like syndrome, reduction of blood cells, and chemical signs of liver dysfunction occurred, but were reversible or could be circumvented by dose reduction. One patient developed hypothyreosis on an autoimmune basis; another patient developed liver steatosis. Although the number of patients is small, the results are promising. Interferon therapy seems to be as potent as cytotoxic treatment but with far less side effects. This study indicates that further trials with interferon in patients with less advanced stages of malignant endocrine pancreatic tumor should be performed.