During the 1980s, platinum-based regimens were yielding response rates typically less than 25%, median survival durations of about 25 weeks, and 1-year survival rates less than 25% in patients with advanced non-small-cell lung cancer (NSCLC). Currently, results from single institution phase II trials of agents introduced in the 1990s show a doubling of these numbers, and results from multiinstitutional trials are demonstrating response rates ranging from 30% to 40%, median survival durations of 40 weeks, and 1 year survivals of 40%. Single agent irinotecan shows significant activity against NSCLC in preclinical and early phase I/II clinical studies, with activity similar to that for other new agents. Therapeutic synergy is observed in preclinical tumor models when irinotecan and cisplatin are combined, and phase I/II trials of this combination have demonstrated response rates > or = 50%. Herein the author provides an overview of data from phase II trials of irinotecan and focuses on preliminary results of a large US multicenter phase II trial of weekly irinotecan plus monthly cisplatin in 52 patients with advanced NSCLC. A response rate of 28.9% (95% CI, 16.5%-41.2%) and a median survival of 9.9 months were observed in this trial. US studies to design a more optimal irinotecan/cisplatin regimen in the same patient population are ongoing, and early results are encouraging.