619Background: The benefits of matching targeted treatments to aberrations identified by molecular profiling (MP) is unclear. Outcomes in phase 1 settings have been traditionally reported across tumor histologies. We report outcomes based on a metastatic colorectal cancer (mCRC) population. Methods: Patients (pts) with mCRC receiving at least one dose of treatment on a phase 1 study were annotated for variants detected by MP. A precision oncology decision support (PODS) team determined variant function and actionability. A matched therapy (MT) was defined as allocation to a novel agent that targeted the aberration or predicted pathway deemed actionable by PODS. Progression-free survival (PFS) was estimated using the Kaplan-Meier method. A Cox proportional hazards model was used to estimate hazard ratios (HR). Results: A total of 370 patients enrolled onto 467 phase 1 trials were identified from January 2012 to April 2017. 106 enrolments were assigned to MT. Pts with microsatellite instability-high (MSI-H)...