The emerging world role of irinotecan in lung cancer

Irinotecan (CPT-11, Camptosar), either alone or in combination with cisplatin (Platinol), has demonstrated activity in advanced non-small-cell lung cancer (NSCLC). In single-agent studies, response rates as high as 35% have been observed; in combination with cisplatin, response rates have ranged as high as 50%, with 1-year survival rates of 33% to 58%. A critical phase III randomized trial comparing irinotecan, either alone or in combination with cisplatin, to vindesine/cisplatin, demonstrated superior survival for stage IV patients receiving irinotecan. The first North American effort to replicate the schedule used in the phase III trial (cisplatin 80 mg/m2 and irinotecan 60 mg/m2 on days 1, 8, and 15 every month) yielded a response rate of 29%, median survival time of nearly 10 months, and 1-year survival rate of 37%. A subsequent multi-institutional trial conducted through Vanderbilt Cancer Center Affiliate Network and Fox Chase Cancer Center combined both agents on a weekly schedule in an attempt to exploit their putative synergy and to potentially decrease toxicity. This schedule, which employed irinotecan 65 mg/m2 and cisplatin 30 mg/m2 both weekly x 4, was better tolerated than the monthly cisplatin combination with a higher response rate (36%), median survival (11.6 months), and 1-year survival rate (46%). Multiple phase I and phase II studies have combined irinotecan with taxanes, either alone or in concert with carboplatin (Paraplatin), yielding similar response and survival rates. Finally, a critical phase III trial from Japan has demonstrated superior outcome for irinotecan and cisplatin vs standard etoposide/cisplatin in the treatment of extensive small-cell carcinoma of the lung. At least one North American trial will determine if these results are reproducible.