“Companion Diagnostics are medical tests that identify patients within a disease category who are most likely to positively respond to a particular drug, given that they have the exact molecular defect as other individuals with the disease and for whom the drug has been successful. The US FDA guidelines on Regulatory Review of Companion Diagnostics were released on August 6, 2014 and are viewed with both hope and apprehension by stakeholders around the world” according to an article via Thomson Reuters.