A phase II trial of 9-aminocaptothecin (9-AC) as a 120-h infusion in patients with non-small cell lung cancer

In a previous phase II trial of the synthetic topoisomerase I inhibitor, 9-aminocamptothecin (9-AC), given as a 72-h infusion, we identified modest single agent activity of 9% in patients with previously untreated advanced non-small cell lung cancer (NSCLC). Preclinical studies suggested that a more prolonged continuous infusion of the drug might lead to greater antitumor activity. A phase I study recommended a phase II dose of 25 μg/m²/hr for 120 h (3000 μg/m² over 5 days), administered for 2 consecutive weeks of a 3-week cycle. We utilized this schedule and enrolled 13 chemotherapy-naïve patients with Stage IIIB and IV NSCLC in this trial: median age 67 (range 57-74); 46% male; 92% stage IV; and median performance status 1. Twelve patients are available for response and toxicity evaluation after 2 cycles of therapy. One patient achieved a partial response. Four patients had stable disease while seven patients had progressive disease. Patients with stable or progressive disease after two cycles received no additional 9-AC, and were offered conventional chemotherapy. The median survival time was 10.2 months and the one-year survival rate 28% (95% confidence interval, 5-58%). Significant toxicities included myelosuppression, fatigue, and anorexia. One patient had grade 4 neutropenia following the first week of cycle 2, and did not receive additional therapy. There were no neutropenia-related infections. These data suggest that this prolonged schedule is unlikely to increase 9-AC's very modest activity in NSCLC above that seen with the simpler 72-h administration schedule. Further evaluation of 9-AC in NSCLC is not recommended.