[Appropriateness of Regorafenib Administration to Patients with Metastatic Colorectal Cancer]

Regorafenib(Reg), a multikinase inhibitor proven to be effective against metastatic colorectal cancer(mCRC), is recommended for salvage-line treatment. There are some reported cases of treatment failure due to adverse events, and some reports that indicate prolonged overall survival(OS)following a reduction of the initial dose. Nevertheless, reports concerning the appropriate dose are lacking. Therefore, we evaluated the method of administration of various doses of Reg to patients with mCRC at our institute. We administered Reg to 25 patients with mCRC from April 2014. The patients were divided into the following dose groups: 160, 120, or 80mg/day for the initial treatment dose, administered orally once per day for the first 3 weeks of each 4 week cycle or for the first 2 weeks of each 3-week cycle. The patients were retrospectively analyzed for OS in each group. The median OS of all cases was 9.40 months. The median OS was 9.26 and 9.40 months for the 28-day and 21-day cycle groups(p=0.64), respectively, and 13.7, 9.40, and 17.6 months(p=0.564)for the 160, 120, and 80 mg groups, respectively. Our findings indicate that a lower dose of Reg suppressed severe adverse events and prolonged survivalin patients with mCRC.