Molecular subtypes and outcomes in regorafenib-treated patients with metastatic colorectal cancer (mCRC) enrolled in the CORRECT trial.

3558 Background: In the CORRECT Ph3 trial (NCT01103323), regorafenib improved overall survival (OS) and progression-free survival (PFS) vs placebo in patients with mCRC who progressed on standard therapies (Grothey 2013). Initial biomarker analyses suggested that regorafenib provides a clinical benefit in various mutational subgroups (Jeffers 2013). Here we present additional exploratory analyses to evaluate clinical benefit in CRC subgroups defined by gene expression. Methods: Gene expression analysis (Affymetrix ST1.0 array) was conducted on archival tumor tissue from 281 of the 760 patients (37%) enrolled in CORRECT. Next-generation sequencing (NGS) was done on 239 specimens (FoundationONE). Gene expression data were subjected to hierarchical molecular tumor classification (Marisa 2013). Cox proportional hazards models were used to identify potential prognostic or predictive biomarkers. Results: The distribution of the 6 different CRC subtypes characterized by gene expression clusters originally define...