Brian Henick, MD, discusses the different ways to identify biomarkers of immunotherapy response in patients with lung cancer and how refining these approaches may improve individualized treatment approaches in the future.
Brian Henick, MD, associate director, Experimental Therapeutics, director, Translational Research in Aerodigestive Cancers in Medical Oncology, Columbia University Herbert Irving Comprehensive Cancer Center, discusses the different ways to identify biomarkers of immunotherapy response in patients with lung cancer and how refining these approaches may improve individualized treatment approaches in the future.
Currently, the methods for localizing PD-L1 in tumors vary depending on the tumor type, Henick says. For instance, in lung cancer, the tumor proportion score (TPS), which focuses on identifying PD-L1–expressing tumor cells, is a common method, although some lung cancer immunotherapy biomarkers can also be found using a combined positive score (CPS) that localizes PD-L1 among other biomarkers, Henick explains. Additionally, atezolizumab (Tecentriq) is often administered to patients with lung cancer based on a score combining PD-L1 expression in both tumor cells and immune cells, Henick notes. Although lung cancer has several effective biomarker identification strategies, in tumor types beyond lung cancer, such as esophageal cancer and head and neck cancer, the CPS is the most useful for identifying biomarkers, Henick emphasizes.
A better understanding of the implications of PD-L1 expression in different immune cell subsets may allow for more refined biomarker identification processes across PD-L1–expressing tumor types, Henick says. For example, a study that measured PD-L1 expression through multiple methods found that most PD-L1 expression in patients with non–small cell lung cancer occurred in tumor-associated macrophages. In that cohort of patients, the level of PD-L1 expression in CD68+ macrophages was associated with PD-L1 levels in tumor cells and may be predictive of response, indicating a connection between high PD-L1 levels in the macrophages and patient response to immunotherapy.
In addition, novel biomarkers, such as a PD-L1 tumor infiltrating lymphocyte subset that can predict immunotherapy response independently of PD-L1 status, may be useful for predicting immunotherapy response going forward, Henick notes. As clinicians and researchers gain a clearer understanding of PD-L1 and other biomarkers, they may be able to use them to determine optimal treatments for individual patients, Henick explains. However, this is still an ongoing research field, and many of these biomarkers and detection methods need to be validated with prospective data, Henick concludes.