FOLFOXIRI-Bevacizumab or FOLFOX-Panitumumab in Patients with Left-Sided RAS/BRAF Wild-Type Metastatic Colorectal Cancer: A Propensity Score-Based Analysis

BACKGROUND: Doublets plus anti-epidermal growth factor receptors (EGFRs) are the preferred upfront option for patients with left-sided RAS/BRAF wild-type metastatic colorectal cancer (mCRC). Initial therapy with FOLFOXIRI-bevacizumab is superior to doublets plus bevacizumab independently from primary tumor sidedness and RAS/BRAF status. No randomized comparison between FOLFOXIRI-bevacizumab versus doublets plus anti-EGFRs is available in left-sided RAS/BRAF wild-type mCRC.

MATERIALS AND METHODS: We selected patients with left-sided RAS and BRAF wild-type mCRC treated with first-line FOLFOX-panitumumab or FOLFOXIRI-bevacizumab in five randomized trials: Valentino, TRIBE, TRIBE2, STEAM, and CHARTA. A propensity score-based analysis was performed to compare FOLFOXIRI-bevacizumab with FOLFOX-panitumumab.

RESULTS: A total of 185 patients received FOLFOX-panitumumab and 132 received FOLFOXIRI-bevacizumab. Median progression-free survival (PFS) and median overall survival (OS) were 13.3 and 33.1 months in the FOLFOXIRI-bevacizumab group compared with 11.4 and 30.3 months in the FOLFOX-panitumumab group (propensity score-adjusted hazard ratio (HR) for PFS, 0.82; 95% confidence interval (CI), 0.64-1.04; p = .11; propensity score-adjusted HR for OS, 0.80; 95% CI, 0.59-1.08; p = .14). No significant differences in overall response rate and disease control rate were observed. A statistically nonsignificant difference in favor of FOLFOXIRI-bevacizumab was observed for OS after secondary resection of metastases. Chemotherapy-related adverse events were more frequent in the FOLFOXIRI-bevacizumab group, with specific regard to grade 3 and 4 neutropenia (48% vs. 26%, adjusted p = .001).

CONCLUSION: Although randomized comparison is lacking, both FOLFOXIRI-bevacizumab and FOLFOX-panitumumab are valuable treatment options in left-sided RAS/BRAF wild-type mCRC.

IMPLICATIONS FOR PRACTICE: A propensity score-based analysis of five trials was performed to compare FOLFOX-panitumumab versus FOLFOXIRI-bevacizumab in left-sided RAS/BRAF wild-type metastatic colorectal cancer (mCRC). No significant differences were observed, but FOLFOXIRI-bevacizumab achieved numerically superior survival outcomes versus FOLFOX-panitumumab. Chemotherapy-related adverse events were more frequent in the FOLFOXIRI-bevacizumab group. These observations suggest that although doublet chemotherapy plus anti-EGFRs remains the preferred treatment in patients with left-sided RAS/BRAF wild-type mCRC, FOLFOXIRI-bevacizumab is a valuable option able to provide similar, if not better, outcomes at the price of a moderate increase in toxicity and may be adopted based on patients' preference and potential impact on quality of life.