Updated Results of the SOFT Study

Conference Correspondent - ASCO 2014 - Colorectal and Head & Neck Cancer

S-1 (tegafur + CDHP + oxonic acid) is an oral DPD-inhibitory fluoropyrimidine combination that has activity in combination with oxaliplatin (SOX) in mCRC, and has been suggested as a replacement for mFOLFOX6. The SOFT study demonstrated that SOX + bevacizumab (Bev) was noninferior to mFOLFOX6 + Bev in terms of progression-free survival (PFS). A report at ASCO 2014 presented the 3-year overall survival (OS) data from the SOFT study (Nakamura M, et al. ASCO 2014. Abstract 3586). The SOFT study was an open-label, randomized phase 3 trial in which 512 chemotherapy-naïve patients with mCRC were randomized to receive either mFOLFOX6 + Bev or SOX + Bev. At the final 3-year analysis, the median OS was 29.7 months with mFOLFOX6 + Bev and 29.6 months with SOX + Bev (P = .0133). Median PFS was 11.7 months with mFOLFOX6 + Bev and 12.2 months with SOX + Bev (P = .0115). A subgroup analysis by age, gender, histology, history of surgery or adjuvant therapy, and presence and number of liver or lung metastases revealed no significant interactions between these factors and the assigned regimen. The adverse event profile of these 2 regimens was manageable with no new toxicity signals emerging. These results suggest that SOX + Bev could be used instead of mFOLFOX6 + Bev as first-line treatment of mCRC. The authors did not address the relative cost of mFOLFOX6 versus SOX.