Modified (m)-FOLFOXIRI plus cetuximab versus m-FOLFOXIRI plus bevacizumab as initial treatment of patients with unresectable RAS and BRAF wild-type metastatic colorectal cancer: Survival analysis of the phase II randomized DEEPER trial by JACCRO.

Abstract

120 Background: Triplet regimen, FOLFOXIRI, plus bevacizumab is considered as one of standard first-line treatments in metastatic colorectal cancer (mCRC). On the contrary, FOLFOXIRI plus anti-EGFR antibody has been shown to be a promising regimen with greater depth of response (DpR) in patients with RAS wild-type mCRC from the VOLFI and MACBETH trials (J Clin Oncol 2019, JAMA Oncol 2018). We therefore performed a randomized phase II study, DEEPER trial (JACCRO CC-13) [NCT02515734], to investigate the efficacy and safety of cetuximab (cet) vs. bevacizumab (bev) in combination with modified (m)-FOLFOXIRI in previously untreated mCRC patients with RAS wild-type tumors. We have reported a significantly better DpR of m-FOLFOXIRI plus cet compared to bev as the primary endpoint (Tsuji A, et al. ASCO 2021). Methods: This trial was a randomized phase II trial to evaluate modified (m)-FOLFOXIRI (irinotecan 150 mg/m2, oxaliplatin 85 mg/m2, 5-FU 2400 mg/m2) plus cet vs. bev as initial treatment in terms of DpR during the entire course as the primary endpoint in 360 patients with RAS wild-type mCRC. The aim of the trial was to show that median DpR of cet arm was more than 12.5% higher than bev arm, with a power of 85% at a significance level of 0.05, in per protocol set (PPS) consisted of patients evaluable for the DpR. Secondary endpoints included progression-free survival, overall survival, overall response rate, early tumor shrinkage rate, secondary resection rate, and toxicity. A total of 359 patients were enrolled between July 2015 and June 2019. For the PPS (median age 65y, 64% male, PS0/1: 91%/9%, left/right primary: 84%/16%), 159 and 162 patients were randomly assigned to the cet and bev arms, respectively. Clinical outcomes will be analyzed according to primary tumor sidedness which is included in the stratification factor. Additionally, we will collect data of BRAF status, and analyze the clinical outcomes in mCRC patients with RAS/ BRAF wild-type tumors and/or left-sided tumors. Pre-planned survival analysis will be performed to compare the two treatment arms at the time of 3 years after last patients’ enrollment using a log-rank test. All statistical tests are two-sided, and P values ≤ 0.05 are deemed significant. Statistical analyses will be performed using SAS version 9.4. Clinical trial information: NCT02515734 .