Twenty-two patients were enrolled in a clinical trial to determine the toxicity and efficacy of the novel immunomodulator Virulizin in patients with measurable, biopsy-proven pancreatic cancer. The dose was 0.11 ml/kg (minimum 7.5 ml) 3 times weekly for the first week, then twice weekly until disease progression. No toxicity was encountered. In the 17 evaluable patients there was no evidence of tumour regression. Six patients (35%) had disease stabilization for more than 3 months, and 2 are still alive with progressive disease, having had disease stabilization for 15 and 17 months. While the results do not suggest any cytotoxic activity at this dose and schedule, the possibility of an antiproliferative effect warrants further study of this agent.