Phase II study of CPT-11, a new camptothecin derivative, in metastatic colorectal cancer. CPT-11 Gastrointestinal Cancer Study Group.

Purpose: A phase II study was conducted to evaluate the antitumor effect and toxicity of CPT-11 in patients with metastatic colorectal cancer.

Patients And Methods: From December 1989 to March 1991, 67 patients with metastatic colorectal cancer were enrolled in this study. Sixty-three patients were assessable for toxicity and response. Their median age was 57 years (range, 24 to 72). Forty-six patients (73%) had a good performance status of 0 or 1. Fifty-one patients (81%) had received prior chemotherapy. The major sites of metastasis were liver (63%) and lung (44%). CPT-11 was administered as a 100 mg/m2 weekly intravenous infusion, or as 150 mg/m2 every 2 weeks. The dose was reduced based on the grade of leukopenia and diarrhea, if necessary.

Results: A partial response was obtained in 17 of 63 assessable patients (27%; 95% confidence interval, 16% to 38%). The response rate in patients with prior radiotherapy or chemotherapy was 25% (13 of 52). Liver metastases showed a 15% (six of 40) response and lung metastases showed a 39% (11 of 28) response. The median duration of partial response was 127 days (range, 49 to 353) and the median overall duration of response was 208 days (range, 99 to 381). The major toxicities (> or = grade 3) were leukopenia (16%), diarrhea (13%), nausea and vomiting (13%), and alopecia (11%). Adverse effects were generally well tolerated and reversible. Treatment could be continued on an outpatient basis for patients without severe toxicity. Hemorrhagic cystitis was not encountered in this study.

Conclusion: CPT-11 showed promising antitumor activity against metastatic colorectal cancer that was resistant to prior therapy. Further clinical trials of combination chemotherapy using CPT-11 are justified.