3519 Background: Several studies of oxaliplatin plus S-1 combination therapy (SOX) conducted in Asia have shown promising efficacy and safety for metastatic colorectal cancer (mCRC), suggesting the potential to replace mFOLFOX6. We performed a randomized phase III trial to determine whether SOX plus bevacizmab (SOX+Bev) is non-inferior to mFOLFOX6 plus bevacizmab (mFOLFOX6+Bev) in terms of progression-free survival (PFS). Methods: The SOFT study was a randomized, open-label, phase III trial. Chemotherapy-naïve patients (pts) with mCRC, an ECOG PS of 0-1, and adequate organ functions were randomized to receive either mFOLFOX6+Bev (5 mg/kg of bevacizumab, followed by 200 mg/m2 of l-leucovorin given simultaneously with 85 mg/m2 of oxaliplatin, followed by a 400 mg/m2 bolus of 5-FU on day 1 and then 2,400 mg/m2 of 5-FU over 46 h, every 2 weeks) or SOX+Bev (7.5 mg/kg of bevacizumab, 130 mg/m2 of oxaliplatin on day 1, and 40−60 mg of S-1 twice daily for 2 weeks, followed by a 1-week rest). The primary endpoint was PFS. A sample size of 225 pts per group was estimated to be necessary based on a median PFS of 10.0 months in each group and an 80% power to demonstrate non-inferiority of SOX+Bev with a 2.5-month margin (hazard ratio, HR = 1.33) and a 2-sided alpha of 0.05. Results: A total of 512 pts were enrolled from February 2009 to March 2011. Data were analyzed after confirming >388 events as planned. Demographic factors were well balanced. Pts received a median of 12 cycles (1 cycle = 2 weeks) of mFOLFOX6+Bev and 8 cycles (1 cycle = 3 weeks) of SOX+Bev (range: 1−16). Median PFS was 11.5 months (95% CI: 10.7−13.2) with mFOLFOX6+Bev and 11.7 months (95% CI: 10.7−12.9) with SOX+Bev. The adjusted HR for PFS was 1.043 (95% CI: 0.860−1.266), and the p value for non-inferiority was 0.0139. Response rate was 62.7% with mFOLFOX6+Bev and 61.5% with SOX+Bev. Grade 3/4 toxicities (%) with mFOLFOX6+Bev/SOX+Bev were leukopenia 8.4/2.4, neutropenia 33.7/8.8, anorexia 1.2/5.2, and diarrhea 2.8/9.2. Conclusions: SOX+Bev is non-inferior to mFOLFOX6+Bev with respect to PFS as 1st-line treatment for mCRC and thus can replace mFOLFOX6+Bev. Clinical trial information: JapicCTI-090699.
FOLFOX4 versus sequential dose-dense FOLFOX7 followed by FOLFIRI in patients with resectable metastatic colorectal cancer (MIROX): a pragmatic approach to chemotherapy timing with perioperative or postoperative chemotherapy from an open-label, randomized phase III trial
