A phase II multi-institutional trial of low-dose N-(phosphonacetyl)-L-aspartate and high-dose 5-fluorouracil as a short-term infusion in the treatment of adenocarcinoma of the pancreas. A Southwest Oncology Group study. Adenocarcinoma of the pancreas is a highly lethal malignancy and chemotherapy has had little impact on the natural history of this disease. PALA, used to potentiate 5-fluorouracil (5-FU), has been shown to have synergy in vivo and in vitro. Twenty-seven patients were treated with an intravenous push dose of PALA (250 mg/m2) followed 24 hours later with a 24-hour infusion of 5-FU (2600 mg/m2). This regimen was repeated weekly. There was one partial response of 21 eligible patients with an estimated response rate of 5%. Toxicity was severe with one toxic death and four patients experiencing Grade 4 toxicity. 5-Fluorouracil and PALA, given in the schedule described, do not appear to be effective against adenocarcinoma of the pancreas. 