Scheduled administration of low dose irinotecan before gemcitabine in the second line therapy of non-small cell lung cancer: a phase II study.

We had previously demonstrated that low dose irinotecan (CPT-11) leads to increased accumulation of cells in S-phase and shows a therapeutic synergy with S-phase specific chemotherapy such as gemcitabine and 5-fluorouracil. In this phase II study, our objectives were to evaluate the tolerability and activity of low dose CPT-11 followed 24 h later by gemcitabine as second line therapy in patients with metastatic non-small cell lung cancer (NSCLC). CPT-11 (60 mg/m) was administered 24 h before gemcitabine (1000 mg/m) on days 1, 2, 8, and 9 every 3 weeks. Twenty-nine patients were evaluable for response. The median follow-up was 7.4 months. Partial response (PR) was seen in two (6.9, 95% confidence interval (CI): 0.009-0.228). PR and stable disease were seen in 22 patients (75.9, 95% CI: 0.564-0.897). The median survival time was 13.8 months (95% CI: 8.1-19.3). The median time to progression was 4.6 months (95% CI: 2.6-6.2). Thirty-eight patients were evaluable for toxicity. Neutropenia (grade 3 or 4) was observed in 27 patients (71%). Eight patients did not receive cycle 2 of therapy owing to prolonged neutropenia. No treatment-related deaths occurred. Scheduled administration of low dose CPT-11, 24 h before gemcitabine in the second line therapy of NSCLC yielded comparable disease control rates (PR and stable disease) when compared with other studies using the two chemotherapy drugs in the traditional sequence. However, this approach was associated with higher grade 3/4 neutropenia and is not recommended for further study in metastatic NSCLC.