A late phase II study of CPT-11 was conducted to evaluate the antitumor effect and toxicity of CPT-11 in patients with advanced pancreatic cancer as a cooperative study of 19 institutions. From February 1990 to June 1992, 61 patients with advanced pancreatic cancer were enrolled in this study. Fifty-seven patients were evaluable for toxicity and 35 for response. CPT-11 was administered as a 100 mg/m2 weekly intravenous infusion (regimen A) or as a 150 mg/m2 every two weeks (regimen B). The response rate was 11.4% (4/35). The primary tumor showed a 10.3% (3/29) response and the liver metastases showed a 10.5% (2/19) response. The major toxicities were myelosuppression and gastrointestinal symptoms. The incidences (> or = Grade 2) of leukopenia, anemia, anorexia, nausea/vomiting, alopecia and diarrhea were 61.4% (35/57), 56.1% (32/57), 70.2% (40/57), 56.1% (32/57), 40.4% (23/57) and 36.8% (21/57), respectively. The incidence of diarrhea was higher with regimen A than with regimen B, but the antitumor activity was no different between the two regimens. These results suggested that CPT-11 has some antitumor activity against advanced pancreatic cancer.