PCNU: phase II evaluation in advanced colorectal carcinoma.

PCNU, a N-(2-chloroethyl)-N-nitrosourea, was administered to 37 previously treated patients with metastatic adenocarcinoma of the colon and rectum. The drug dose was 100 mg/m2, intravenously, over one hour for good risk patients and 75 mg/m2 for poor risk patients. Poor risk patients were defined as patients over 65 years of age or having liver enzymes greater than twice normal. The infusion was repeated at 6 week intervals. Seventeen patients (median performance status 80%) received PCNU at the 100 mg/m2 dose; 20 patients (median performance status 70%) received PCNU at the 75 mg/m2 dose. Complete responses were not observed. One patient treated with 100 mg/m2 achieved a partial response. Toxicity was primarily hematological with life-threatening leukopenia and thrombocytopenia observed in six patients. PCNU administered in the described dose schedule demonstrated little therapeutic efficacy in this patient population.