Bevacizumab versus aflibercept with FOLFIRI after FOLFOX and bevacizumab in RAS mutant metastatic colon cancer a Turkish oncology group study

We aimed to compare FOLFIRI and bevacizumab with FOLFIRI and aflibercept in terms of overall survival (OS), progression-free survival (PFS) and safety in patients with RAS-mutant metastatic colon cancer who progressed after first-line FOLFOX or XELOX and bevacizumab treatment. This retrospective study included 243 patients from 15 different centres in Turkey. The endpoints of the study were OS, PFS and safety and side effect outcomes. The median age of the patients included in the study was 60 (21-85) years. Of the patients enrolled in the study, 114 patients (46.9%) received aflibercept and 129 patients (53.1%) received bevacizumab. Median OS was 11.2 (95% CI: 9.1-13.2) months in patients receiving FOLFIRI + aflibercept and 14.1 (95% CI: 11.2-17.1) months in patients receiving FOLFIRI + bevacizumab. The median PFS was 5.7 (95% CI: 4.9-6.5) months in the aflibercept arm and 7.7 (95% CI: 7.1-8.3) months in the bevacizumab arm. Grade 3-4 side effects were observed in 58 (50.9%) patients in the aflibercept arm and 33 (25.6%) patients in the bevacizumab arm. As a result of our study, in patients with metastatic RAS-mutant colon cancer who progressed after first-line oxaliplatin-based doublet chemotherapy and bevacizumab, better OS and PFS results were obtained in patients receiving bevacizumab with FOLFIRI compared to patients receiving aflibercept with FOLFIRI. In addition, the side effect profile was more tolerable in the bevacizumab arm.