mCRC: Cetuximab Less Effective Immediately After Bevacizumab

Cetuximab is less effective immediately after bevacizumab in RAS wild type patients with metastatic colorectal cancer (mCRC) receiving FOLFOX (5-fluorouracil, leucovorin, oxaliplatin), a study presented at the 2016 Gastrointestinal Cancers Symposium in San Francisco, CA has shown.¹

Although FOFLOX and FOLFIRI (5-fluorouracil, leucovorin, irinotecan) are effective as first-line treatment, FOLFOX may be more effective in the second-line setting. Furthermore, it is unclear whether cetuximab, which has similar activity across all treatment lines unlike bevacizumab, may be a better option in the third-line setting.

Therefore, researchers sought to compare 2 different treatment sequences of cetuximab and FOLFOX in patients with mCRC who were refractory to frontline FOLFIRI plus bevacizumab.

For the phase 3 trial, investigators randomly assigned 110 patients to receive second-line irinotecan plus cetuximab followed by third-line FOLFOX-4 (Arm A) or the reverse sequence (Arm B).

Results showed median progression-free survival in Arm A was 9.9 months compared with 11.3 months in Arm B (HR, 0.85; 95% CI, 0.56 – 1.28; P = .427). Median overall survival was 12.3 months and 18.6 months, respectively (HR, 0.79; 95% CI, 0.52 – 1.22; P = .288).

Researchers found that the objective response rate in Arm A was 37% vs 57% in Arm B (P = .05).

In regard to safety, both treatments were well tolerated, with 2 serious adverse reactions in each arm.

“In RAS wild type patients progressing after a first line bevacizumab-based therapy, cetuximab should be given as first line or third line,” the authors concluded.

Reference

1. Cascinu S, Zaniboni A, Lonardi S, et al. Efficacy of cetuximab immediately after bevacizumab: a phase III multicenter trial comparing two different sequences of cetuximab and FOLFOX in K-Ras WT metastatic colorectal cancer patients refractory FOLFIRI/bevacizumab [abstract]. J Clin Oncol. 2016;34(suppl 4S; abstr 632).