1. ¹Department of Respiratory Medicine, International Medical Center of Japan, 1-21-1 Toyama Shinjuku-ku, Tokyo 162-8655, Japan
2. ²Department of Respiratory Medicine, Saitama Cancer Center, Komuro, Ina 362-0806, Saitama, Japan

Correspondence: Dr Y Takeda, E-mail: ytakeda@imcj.hosp.go.jp

Received 11 August 2005; Revised 12 October 2005; Accepted 17 October 2005; Published online 15 November 2005.

Abstract

We conducted a phase I/II study in patients with advanced non-small-cell lung cancer (NSCLC) to increase the therapeutic index of the cisplatin–irinotecan combination by institution of an anti-late-diarrhoeal program (ADP). A total of 77 chemotherapy-naive patients with advanced NSCLC were enrolled. The cisplatin dose was fixed at 60 mg m^-2 (Day 1). Irinotecan was escalated in 5 mg m^-2 increments, starting from 60 mg m^-2 (Days 1 and 8). ADP consisted of oral sodium bicarbonate, magnesium oxide, basic water, and ursodeoxycholic acid, and was administered orally for 4 days with each dose of irinotecan. In the phase I portion, irinotecan pharmacokinetics was also examined. After the recommended dose of irinotecan with ADP was determined, a phase II study was conducted to evaluate the response. Maximum tolerated dose was reached at an irinotecan dose of 80 mg m^-2 (Grade 4 diarrhoea and neutropenia). Pharmacokinetic studies show that the maximum concentration and the area under the curve of both irinotecan and SN38 (active metabolite of irinotecan) tend to increase in the dose-dependent manner of irinotecan. The phase II portion of the study included 48 patients, who were treated with 75 mg m^-2 of irinotecan. Grade 3/4 toxicities included neutropenia in 65%, leucopenia in 33%, and late diarrhoea in 6% of the patients. During this treatment, PS did not change in 65% of patients. At the end of the chemotherapy, PS did not decline in 90% of patients. In the phase II portion, a response occurred in 63% (95% confidential interval (CI), 47–76%) of patients. Median time to progression was 19 weeks (95% CI, 15–22 weeks), and median survival was 52 weeks (95% CI, 39–64 weeks). This regimen of irinotecan and cisplatin with ADP resulted in promising efficacy with acceptable toxicity for patients with advanced NSCLC. This regimen is a candidate for the experimental arm towards future phase III studies.