By Steven M. Anderson, Ph.D., Chief Scientific Officer, Covance
One of the most promising advancements in oncology in recent years is the alignment of new immuno-oncology therapeutic approaches with the tools of precision medicine. Using cell-, tissue- or genomic-based biomarkers, the interaction between an individual’s immune system and tumor can be better understood, ultimately enabling a more personalized approach to therapy. Genomic- based biomarkers are powerful tools used to assess tumor mutational burden, production of novel or neo- antigens and hallmarks of genomic instability, which may be useful as measures of response or resistance to immune therapies.
The increased focus on the use of biomarker assays in clinical trials has supported the development of companion diagnostics (CDx) – assays required to identify patients who are suitable for a particular therapy – and complementary diagnostics – assays providing additional information about the benefit versus risks of a particular therapy. Accurate and robust detection of tumor characteristics to stratify patients is already informing clinical decisions. For example, patients with microsatellite instability in colorectal cancer (CRC) and other solid tumors show a better response to immune checkpoint-based therapy when compared to patients with genomically stable tumors. High levels of PD-1/PD-L1 expression also correlate with increased responses to checkpoint inhibitors in a number of cancers.