Dr. Gandara on the Evaluation of Tumor Biomarkers in NSCLC

David R. Gandara, MD, professor of medicine emeritus, Division of Hematology/Oncology, codirector, Center for Experimental Therapeutics in Cancer, senior advisor to the director of the University of California Davis Comprehensive Cancer Center, and chief medical officer of the International Society of Liquid Biopsy, discusses the evaluation of tumor biomarkers in non–small cell lung cancer (NSCLC).

Two biomarkers have agents approved by the FDA in different subpopulations of patients, Gandara says. One approval is immunohistochemistry for PD-L1, which is used in many regimens, and the second is tumor mutational burden (TMB), Gandara adds. Both approaches are FDA approved, and there is controversy about how important they are in each respective population, as well as when they should be used, Gandara explains.

Both approaches are good biomarkers for immunotherapy, though they are incomplete and only tell part of the story, Gandara continues. Moreover, PD-L1 and TMB both measure the inflammatory component of the immune microenvironment, but do not largely overlap and are independent biomarkers, Gandara says.

Gandara adds that newer tests in the space incorporate information on negative signals, providing insight on factors that make a tumor cold instead of hot, as well as what makes it less likely to respond to checkpoint immunotherapy.