Weekly alternating therapy with irinotecan plus cisplatin and etoposide plus cisplatin in the treatment of patients with extensive small cell lung carcinoma

BACKGROUND: Irinotecan has significant activity in small-cell lung cancer (SCLC). The authors' previous phase 1 study of alternating weekly therapy with irinotecan/cisplatin (IP), etoposide/cisplatin (EP), and granulocyte-colony- stimulating factor (G-CSF) support was well tolerated and active in patients with SCLC. A phase 2 trial was conducted to estimate the efficacy of this regimen in previously untreated patients with extensive SCLC. METHODS: A total of 33 patients were treated between June 2002 and July 2007. Patients received 12 weeks of therapy with cisplatin (20 mg/m²) on Day 1 and irinotecan (100 mg/m²) on Day 1 and G-CSF on Days 2 to 5 (Weeks 1, 3, 5, 7, 9, and 11) followed by cisplatin (20 mg/m²) on Day 1 and etoposide (60 mg/m²) on Days 1 to 3 with G-CSF on Days 4 to 7 (Weeks 2, 4, 6, 8, 10, and 12). The primary endpoint was 1-year survival rate. RESULTS: Grade 4 neutropenia (toxicities were determined using the National Cancer Institute Common Toxicity Criteria [version 2.0]) was noted in 5 (1.5%) of 343 courses with neutropenic fever in only 5 (1%) of 343 courses. One patient died of neutropenic sepsis. Nonhematologic toxicities grade ≥2 were observed in 15 (4%) of 343 courses and were limited to fatigue, hyponatremia, and diarrhea. The overall objective response rate was 89% in 28 assessable patients (no complete responses and 25 partial responses). The median progression-free and overall survivals were 6.0 months and 10.9 months, respectively. The 1-year survival rate was 33%. CONCLUSIONS: Weekly therapy with IP alternating with EP and G-CSF support was well tolerated in patients with extensive SCLC, but did not demonstrate improved progression-free or overall survival when compared with historical controls at the study institution.