Opioid growth factor improves clinical benefit and survival in patients with advanced pancreatic cancer.

BACKGROUND: Advanced pancreatic cancer carries the poorest prognosis of all gastrointestinal malignancies. Once the tumor has spread beyond the margins of the pancreas, chemotherapy is the major treatment modality offered to patients; however, chemotherapy does not significantly improve survival. OBJECTIVE: Opioid growth factor (OGF; [Met(5)]-enkephalin) is a natural peptide that has been shown to inhibit growth of pancreatic cancer in cell culture and in nude mice.