S-1 combination therapy (SOX, IRIS) is expected to be promising and safe for mCRC. The SOBIC trial is a phase II trial designed to validate the effectiveness of first and second line oral combination chemotherapy (CT) in mCRC. This is the first report which evaluated the efficacy of S-1 combination CT for mCRC.
mCRC patients candidate were received first line SOX + Bev (7.5mg/kg of Bev, 130mg/m2 of oxaliplatin on day 1 and 80-120mg/day of S-1 for 2 weeks followed by a 1-week rest) followed by second line IRIS + Cmab (weekly Cmab 250 mg/m2 initial dose 400 mg/m2, 100 mg/m2 of irinotecan on day 1, 15 and 80-120mg/day of S-1 for 2 weeks followed by a 2-week rest) in KRAS wild patients, IRIS + Bev (5mg/kg of Bev on day 1, 15, 100 mg/m2 of irinotecan on day 1, 15 and 80-120mg/day of S-1 for 2 weeks followed by a 2-week rest) or IRIS (125 mg/m2 of irinotecan on day 1, 15 and 80-120mg/day of S-1 for 2 weeks followed by a 2-week rest) in KRAS mutant patients. The primary endpoint was second progression-free survival (PFS). The secondary endpoint included overall survival (OS), response rate (RR) in first and second line CT, R0 resection rate (R0-Rate) and safety. We estimated that a target sample size of 48 patients.
Among 52 patients were enrolled from May 2010 to March 2013 in HCCSG hospitals. 50 (male gender 60%, median age 65: 38 to 77) patients were included in the efficacy analysis. Second PFS was 24.2 months (95%CI: 17.7 to 35.2), OS was 35.2 months (95%CI: 27.8 to not reached). RR was 46.3% in first line CT, 20% in second line CT, respectively. In first line CT 10 (20%) patients underwent surgery, and R0 resection was achieved in all of the operable cases (R0-Rate was 20%). Surgery rate in second line CT was 12.5%. The main grade 3-4 adverse events were sensory neuropathy (18%), fatigue (10%), and anorexia (8%).
First line SOX+Bev, second line IRIS+Bev or IRIS+Cmab or IRIS was considered to be beneficial for mCRC patients.
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All authors have declared no conflicts of interest.