Comparison between three oxaliplatin-based regimens with bevacizumab in patients with metastatic colorectal cancer

A previous pivotal Phase III study (NO16966) demonstrated the benefit of the addition of bevacizumab (BV) to oxaliplatin-based regimens in metastatic colorectal cancer (MCRC). Our study evaluated the safety and efficacy of three oxaliplatin-based chemotherapy regimens (FOLFOX4 [intravenous twice-bolus and twice-infusional 5-fluorouracil/folinic acid plus oxaliplatin], mFOLFOX6 [intravenous once-bolus and once-infusional 5-fluorouracil/folinic acid plus oxaliplatin], and XELOX [capecitabine plus oxaliplatin]) plus BV in the first-line treatment of MCRC patients.

Patients with MCRC who started treatment between June 2007 and September 2010 were evaluated in this retrospective cohort study. We also evaluated early objective tumor response (EOTR) within 12 weeks, which was defined as a relative change of ≥30% in the sum of the longest diameters of target lesions when compared with baseline. The primary study endpoints were progression-free survival (PFS) and response rate.

A total of 185 patients received the following chemotherapy: FOLFOX4 + BV (FF4 arm, n=85), mFOLFOX6 + BV (FF6 arm, n=40), and XELOX + BV (XELOX arm, n=60). The overall response rates were 61.2%, 72.5%, and 75.0% (95% confidence interval: 50.6%-71.8%, 58.0%-87.0%, and 63.7%-86.3%). Median PFS was 18.0, 15.5, and 13.7 months, respectively (log-rank: P=0.254; data cut-off: May 2013). Patients with EOTR (n=117) had significantly better PFS than those without-EOTR (n=68) (17.5 versus 12.7 months, P=0.004).

This study suggests that these three BV plus oxaliplatin-based treatments might have comparable benefit in terms of tumor response and PFS. Moreover, EOTR may be a predictive factor for PFS in patients with MCRC.