[Phase I study of CPT-11 and continuous 5-FU / l-leucovorin combination therapy(modified AIO regimen)in patients with metastatic colorectal cancer].

A combination of CPT-11, continuous 5-fluorouracil(5-FU)and leucovorin(LV), the Arbeitsgemeinschaft fur Internistische Onkologie(AIO)regimen, is widely used for the treatment of metastatic CRC. The efficacy and toxicity of this regimen, however, have not been determined in Japanese patients with metastatic CRC. Our objective was to evaluate the safety of the AIO regimen plus CPT-11 in Japanese colorectal carcinoma(CRC)patients. We investigated the maximum tolerated dose(MTD), dose-limiting toxicity(DLT), and recommended dose(RD)for CPT-11 and continuous 5-FU. CPT-11, 5-FU, and l-LV were administered on days 1, 8, and 15 of a 28-day cycle. The dose of CPT- 11 was escalated from 40 mg/m2 (level 1)to 80 mg/m2 (level 3). The 5-FU dose was then escalated from 1,000 mg/m2 (level 4)to 2,000 mg/m2 (level 5). If neither level met the criteria for the MTD, the recommended dose was defined as level 5, and the dose escalation was discontinued, because the maximum approved weekly dose of CPT-11 alone in Japan is 80 mg/m2 and the dose of 5-FU in the original AIO regimen was 2,000 mg/m2. A total of 18 patients were enrolled in this study. Hematological and non-hematological toxicity were infrequent and mild. There were no toxicities greater than grade 2 at each dose level. Level 5 did not meet the MTD criteria. Our results confirm that the modified AIO plus CPT-11 regimen is safe for Japanese patients. The recommended doses in the present study were CPT-11 80 mg/m2, 5-FU 2,000 mg/m2, and l-LV 250 mg/m2.