BACKGROUND: The methotrexate analogue 10-ethyl-10-deazaaminopterin (10-EdAM, or edatrexate) has shown antitumor activity in preclinical testing and clinical studies of patients with breast, lung and head and neck carcinomas. A phase II study was conducted in patients with advanced pancreatic adenocarcinoma. PATIENTS AND METHODS: Forty patients were enrolled on the clinical trial. Edatrexate was administered intravenously at a dose of 80 mg/m2 weekly for 5 weeks. The treatment course was repeated every 6 weeks. RESULTS: Two partial responses were observed. Both of these patients had partial responses which lasted 2 and 3.5 months. The median survival for all patients was 3.5 months. Serious (grade 3 or 4) toxic effects were primarily mucosal, hematologic, and dermatologic. Two patients experienced severe pulmonary toxic reactions. CONCLUSION: At the dose and schedule used, edatrexate was poorly tolerated and did not demonstrate significant antitumor activity.