517P - Folfoxiri Plus Bevacizumab (Bev) As First-Line Treatment of Ras Wild-Type (Wt) Metastatic Colorectal Cancer (Mcrc) Patients (Pts)

Abstract

ABSTRACT Aim: Phase III TRIBE trial demonstrated that FOLFOXIRI plus bev provides a significant advantage in PFS, response rate and OS as compared to FOLFIRI plus bev. No interaction between RAS mutational status and treatment effect was reported. The aim of the present analysis is to describe the clinical outcome of RAS wt pts treated with the triplet plus bev. Methods: Patients not bearing KRAS or NRAS codon 12, 13 and 61 mutations were defined as RAS wt. Best response according to RECIST, early response and deepness of response (DoR) were analysed. Patients achieving a >20% reduction in the sum of longest diameters of RECIST target lesions at week 8 compared to baseline were defined as early responders. A further analysis was performed in the RAS and BRAF wt subgroup. Results: Seventy-eight RAS wt patients received first-line FOLFOXIRI plus bev. BRAF mutation was detected in 14 (18%) RAS wt patients. Fifty-one (65%) out of 78 pts achieved RECIST response and 21 (27%) reported a disease stabilization for an overall disease control rate of 92%. Early response was reported in 44 (63%) out of 70 evaluable pts. The median DoR was 43.5% (range 100%/-38.2%). Twenty-three patients (29%) underwent a secondary resection with curative intent (R0/R1/R2) and a R0 resection was performed in 14 patients (18%). Median PFS and OS were 12.8 and 36.0 months, respectively. Out of 64 RAS and BRAF wt pts, RECIST response rate was 69% and median PFS and OS were 13.3 and 41.7 months, respectively. Conclusions: RAS wt pts treated with the triplet plus bev in the TRIBE trial achieved notable results in terms of RECIST response, PFS and OS. Though acknowledging limitations of cross-trial comparisons, these results compare favourably with those reported in phase III trials with first-line doublets plus an anti-EGFR monoclonal antibody, in particular for PFS. Disclosure: A. Falcone: Consultant, honoraria and research funding for Roche, Merck and Amgen. Consultant and honoraria fro Sanofi-Aventis, Bayer and Celgene.All other authors have declared no conflicts of interest.