Phase 2 study of irinotecan and paclitaxel in patients with recurrent or refractory small cell lung cancer

BACKGROUND: Patients with extensive stage small cell lung cancer (SCLC) who develop disease progression with standard cisplatin-based therapy are reported to have a poor overall prognosis. Irinotecan and paclitaxel are active as single agents and exhibit preclinical synergy in SCLC cell lines. A phase 2 study was conducted to evaluate this combination in patients with recurrent or refractory SCLC. METHODS: Patients with SCLC who progressed with 1 prior chemotherapy regimen and had measurable disease present; an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 to 2; and adequate bone marrow, hepatic, and renal function were included in the study. Paclitaxel (at a dose of 75 mg/m²) and irinotecan (at a dose of 50 mg/m²) were administered intravenously on Days 1 and 8 of each 3-week treatment cycle. Therapy was continued until disease progression or unacceptable toxicity. The target response rate of interest was ≥30%. RESULTS: A total of 55 patients were enrolled, 51 of whom received at least 1 dose of therapy. The majority of the patients had an ECOG PS of 0 or 1 (96%). A median of 3 cycles of treatment was administered, and 15 patients received ≥6 cycles. Seventeen patients experienced toxicity of grade 3 or higher (neutropenia in 8 patients and fatigue in 5 patients). The overall response rate was 21%. The median survival was 25.4 weeks, and the 1-year survival rate was 22%. CONCLUSIONS: The regimen of irinotecan and paclitaxel was found to be tolerated well in patients with recurrent or refractory SCLC. Although modest anticancer activity was noted, the efficacy failed to meet the primary endpoint of interest.