In the world of personalized diagnostics, history does not necessarily predict the future. Following the much anticipated FDA approval of the first immuno-oncology drug Keytruda® (Merck) for NSCLC patients in October 2015 as a Companion Diagnostic (CDx) for PD-L1 testing , all eyes then went to Bristol Myers Squibb with competitor OPDIVO® as the CheckMate 057 trial data emerged for non- squamous NSCLC patient use. Much to the surprise of the oncology community, only two weeks following the Keytruda CDx approval, OPDIVO was approved as a "complementary diagnostic," a classification unfamiliar in diagnostics not requiring PD-L1 testing for clinical use in nsNSCLC. Really ? What are the implications of a complementary diagnostic test vs a CDx?Since the development of the first companion diagnostic in 1998, HercepTestTM (Dako North America, an Agilent Company) to select breast cancer patients eligible for Herceptin, the field of personalized diagnostics has evolved significantly. Today with advances in molecular diagnostics, FISH and PCR technologies are commonplace in Companion Diagnostics for HER2 FISH and kRAS/ BRAF respectively. Immunohistochemistry continues to be the mainstay for HER2, EGFR and the new PD-L1 companion diagnostic tests. In the future, we can expect Genome signature assays with techniques such as next generation sequencing (NGS) to become relevant in the personalized diagnostics space.
