Treatment of malignant endocrine pancreatic tumours with human leucocyte interferon

22 patients with advanced malignant endocrine pancreatic tumours were treated with human leucocyte interferon 3-6 X 10(6) IU per day. Objective responses (more than 50% reduction in tumour markers or tumour size) were seen in 7/7 with watery diarrhoea/hypokalaemia/achlorhydria syndrome, 3/4 with the Zollinger-Ellison syndrome, 6/9 with "non-functioning" tumours, and 1 with a mixed tumour mainly producing somatostatin. The median duration of response was 8.5 months, and all responders improved clinically. Adverse effects seemed more tolerable than those of cytotoxic treatment.