A phase I trial of chlorambucil administered in short pulses in patients with advanced malignancies

We carried out a phase I trial with chlorambucil. Thirty patients with advanced cancer were entered in six dose levels: 36, 48, 60, 84, 108, and 144 mg/m². The drug was given in six divided oral doses every 6 hours and the regimen was repeated every 3 weeks. The median age was 62 years (31-84), median Kamofsky performance status (KPS) 60 (40-90). All patients but one had received prior radiation therapy, chemotherapy, or both. Central nervous system toxicity was dose limiting, occurring in 5 of 6 patients at 144 mg/m². It was characterized by transient seizures, hallucinations, lethargy, stupor, and coma. Metoclopramide was successful in controlling nausea and vomiting, which was severe if the antiemetic was not used. Leukopenia (3 patients) and thrombocytopenia (2 patients) were mild. One patient with colorectal carcinoma had a minor response, and two patients with non-small cell lung cancer had stable disease. A safe dose for phase II trials is 108 mg/m² in six 6-hourly oral doses.