[Current Status and Issues of Companion Diagnostics for Non-Small Cell Lung Cancer]

There have been many driver gene abnormalities identified in NSCLC, and the development and clinical adoption of targeting drugs for such are progressing. This has, as a result, complicated the situation surrounding companion diagnostics (CDx). Lung cancer treatment guidelines recommend the use of Multiplex testing that allow for CDx for many driver gene abnormalities to be used prior to 1L treatment for advanced lung cancer. The problem is that insurance rules stipulate that only one of Multiplex test is deemed reimbursable per junction in time, particular CDx are linked to particular targeted drugs instead of particular driver gene abnormalities, and none of the currently available Multiplex tests contain the CDx for all genetic mutations for which drugs have been approved. This results in a fair number of cases in which regulatory issues ensue. It is also very difficult to obtain enough of a tissue sample to get accurate results in Multiplex testing for advanced NSCLC. CDx are not full-proof, as results must be interpreted with a consideration of the potential for a false-negative due to the nature of tests. This paper, therefore, will focus on the issues with CDx from the viewpoint of medical oncologists in the clinical setting.