PARADIGM study: A multicenter, randomized, phase III study of mFOLFOX6 plus panitumumab or bevacizumab as first-line treatment in patients with RAS (KRAS/NRAS) wild-type metastatic colorectal cancer.

Abstract

85 Background: The optimal choice of monoclonal antibodies (mAbs) for first-line treatment in patients (pts) with RAS ( KRAS/NRAS) wild-type metastatic colorectal cancer (mCRC) remains controversial. The meta-analyses of subgroup analyses in phase III studies of pts with KRAS exon 2 wild-type mCRC suggested a longer overall survival (OS) with an anti-EGFR mAb over bevacizumab in pts with RAS wild-type mCRC or with left-sided primary tumors. However, there has been no prospective study comparing the two mAbs in these pt populations. This randomized phase III study was originally designed to demonstrate the superiority of panitumumab versus bevacizumab, both in combination with mFOLFOX6, for RAS wild-type mCRC, but we have revised the protocol to analyze efficacy in pts with a left-sided primary tumor as the primary (final) analysis. Methods: Eligible pts are aged 20-79 years with histologically/cytologically confirmed RAS wild-type chemotherapy-naive mCRC, and ECOG performance status 0-1. Between May 29, 2015 and Jun 8, 2017, 823 pts were randomized 1:1 to panitumumab plus mFOLFOX6 or bevacizumab plus mFOLFOX6 by the minimization method and the randomisation was stratified by institution, age (20-64 vs. 65-79 years), and liver metastases (present vs. absent). The primary analysis was revised to adopt a hierarchical testing procedure; we first compare OS between the two arms in left-sided primary tumor population, and only if there is statistically significant difference, then ITT population analysis will be performed. In this revised plan, the expected number of deaths is 420 in the left-sided population to provide 80% power to detect an OS hazard ratio of 0.74 at a one-sided significance level of 0.02101 determined on the alpha spending function approach after one interim analysis. A large-scale exploratory biomarker substudy to identify potential biomarker candidates using tumor tissue and circulating tumor DNA is also underway (Clinical trial no.: NCT02394834). The data cut off for the primary analysis is expected to be during 1Q 2021. Results: Results are expected in 2021. Conclusions: Results are expected in 2021. Clinical trial information: NCT0239475.