Phase II trial of PCNU in breast carcinoma.

The Eastern Cooperative Oncology Group undertook a limited institution phase II study of PCNU in advanced, metastatic breast cancer. The study was limited to patients treated with 1 to 2 prior chemotherapy regimens. Accrual goals were 30 patients but the study was terminated after 10 patients had no response, with a rapid time to progression of 4 weeks, despite considerable hematologic toxicity. Based on this experience and negative results in two prior studies in more heavily pretreated patients, we conclude PCNU is inactive in breast cancer.