Phase I study of N(1),N(11)-diethylnorspermine in patients with non-small cell lung cancer

Polyamines are essential for tumor growth; consequently, agents that interfere with their metabolisms have been developed as antineoplastic agents. Diethylnorspermine (DENSPM) is one such agent. A focused Phase I clinical trial in patients with advanced non-small cell lung cancer was undertaken. Twenty-nine patients were treated with DENSPM using a dosing schedule of once daily for 5 days. Doses ranged from 25 mg/m(2)/day to 231 mg/m(2)/day. The dose-limiting toxicity was determined to be gastrointestinal including asthenia, abdominal cramps, diarrhea, and nausea. The maximal tolerated dose was 185 mg/m(2)/day for 5 days. At drug dosages for which it was possible to estimate, serum half-life ranged from 0.5 to 3.7 h without apparent dose dependence. Maximal serum concentrations increased with dosage. However, the increase was greater than the proportional increase of the administered dose. There were no objective disease responses observed during the Phase I trial. The results of the Phase I clinical trial suggest that DENSPM can safely be administered to patients with minimal toxicity. Furthermore, the observed dose-limiting toxicity is unique to DENSPM, thus underscoring the potential for DENSPM to be a suitable agent for chemotherapy in combination with agents possessing different spectrums of toxicities.