Dr. Sabari Discusses Immunotherapy Biomarkers in NSCLC

Joshua K. Sabari, MD

Joshua K. Sabari, MD, assistant professor of medicine, NYU Langone's Perlmutter Cancer Center, discusses biomarkers of immunotherapy response in patients with non–small cell lung cancer (NSCLC).

The reliability of PD-L1 expression as a biomarker is up for debate in the field, but Sabari says he still orders PD-L1 testing for his patients and uses the 50% cutoff to define if a patient should receive pembrolizumab (Keytruda) alone or in combination with chemotherapy. He adds that he does this for patients presenting with non–small cell adenocarcinoma as well as those with squamous NSCLC.

Sabari notes that if you parse the data, no matter how you look at it, patients with high levels of PD-L1 expression have a greater chance to benefit from immunotherapy. His treatment approach is to weigh the risks of each therapy with the benefits. For example, if a patient has a PD-L1 expression of 100%, who he knows has a high likelihood of responding to immunotherapy, then chemotherapy can be avoided.

Another key biomarker coming down the pike is tumor mutational burden (TMB), he adds. Although this is a controversial topic, there are studies looking at it prospectively as well as retrospectively. For example, the CheckMate-227 trial, which was recently published, showed an improvement in patients who had high TMB. The controversy, he explains, lies in the question of how to define “TMB-high” and if it is possible to establish a unified definition by looking at different assays.
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