446P Bayesian monitoring of lapatinib (L) plus trastuzumab (T) treatment of HER2 positive metastatic colorectal cancer (mCRC): An observational cohort study

Abstract

HER2 positivity is found in 3-5% of mCRC. The phase II HERACLES-A trial showed that dual anti-HER2 therapy with T + L has 30% response rate (RR) in HER2+ RAS wt mCRC after failure of standard care (Sartore-Bianchi 2016). These data led to inclusion of T+ L among recommended treatments by NCCN and other guidelines, but still lack confirmation by large trials comparing treatments. The latter, especially for this uncommon subset of mCRC, would require efforts unbearable in the setting of independent clinical research.