Exploring clinical and gene expression markers of benefit from FOLFOXIRI/bevacizumab in patients with BRAF-mutated metastatic colorectal cancer: Subgroup analyses of the TRIBE2 study

Background: Recent data from the TRIBE2 study have failed to suggest a higher magnitude of benefit from upfront FOLFOXIRI/bevacizumab in patients with BRAF-mutant metastatic colorectal cancer (mCRC) as previously reported in the TRIBE study. Patients and methods: Clinical characteristics and gene expression signatures of patients with BRAF-mutant mCRC enrolled in the TRIBE2 study were evaluated with the aim of understanding that patients may derive benefit from the intensification of the upfront chemotherapy. Results: Of 46 BRAF-mutant tumour samples analysed, 24 (52%) and 22 (48%) were classified as BM1 and BM2, respectively, and 27 (59%) and 19 (41%) were assigned to ligand-independent (LI) and ligand-dependent (LD) Wnt pathway subgroups, respectively. No prognostic impact was shown for both BM1/BM2 and LI/LD subtypes. No interaction was evident between BM1/BM2 or LI/LD signatures and the benefit provided by FOLFOXIRI/bevacizumab. Significant interaction effect was evident in terms of progression-free survival between treatment arm and primary tumour sidedness (P = 0.05) and Eastern Cooperative Oncology Group performance status (ECOG-PS; P < 0.001). Conclusions: Gene expression analysis failed to identify patients with BRAF-mutant mCRC candidate to upfront FOLFOXIRI/bevacizumab. ECOG-PS >0 and left-sidedness seem associated with no benefit from the intensified treatment. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The TRIBE2 study did not find specific gene expression signatures that could identify BRAF-mutant mCRC patients who may benefit more from upfront FOLFOXIRI/bevacizumab. However, it did show that patients with ECOG-PS >0 and left-sided tumors may not benefit from intensified treatment.