Background/aims: A phase I clinical trial has been planned to determine the recommended dose and to assess the safety and efficacy of combination chemotherapy of S-1 with cisplatin and irinotecan (SCI regimen) as a second-line treatment in 5-fluorouracil (5-FU) resistant colorectal cancer (CRC).
Methodology: Patients with unresectable recurrent or metastatic CRC were enrolled in this study for second-line treatment. On an outpatient basis, the patients received a treatment SCI regimen comprising S-1 oral administration for 28 days followed by withdrawal for 2 weeks, plus cisplatin and irinotecan were administered on days 1, 8, 15 and 22 by intravenous injection. These courses were repeated every 6 weeks. Starting doses were 70 mg/m2 S-1, 6 mg/m2 Cisplatin, and 60 mg/m2 Irinotecan.
Results: A total of 29 patients was enrolled. Dose-limiting toxicities were fatigue, nausea, and leucopenia. Twenty-three patients at recommended dose were evaluable for treatment response. The response rate was 21.7% (5 partial responses, 13 stable diseases, and 5 progressive diseases). The median progression-free survival rate was 4.3 months; the median survival time was 9.6 months.
Conclusions: The SCI regimen is feasible in an outpatient setting and should be considered as second-line chemotherapy for patients with 5-FU resistant CRC.