White Blood Cells May Indicate Response to Lung Cancer Immunotherapy

Immune checkpoint inhibitors have revolutioned cancer treatment, but not all patients respond to immunotherapy.

Immunotherapy has become an increasingly popular treatment for various forms of cancer. Instead of subjecting the whole body to harmful drugs, immunotherapy boosts the efficacy of a person’s immune system and allows it to better target cancer. Like all treatments, some patients may be unresponsive to immunotherapy.

Results from a study presented at the European Lung Cancer Conference suggests that white blood cell count can accurately predict whether a patient with lung cancer will respond to immunotherapy.

"Immune checkpoint inhibitors, such as nivolumab and pembrolizumab, significantly improve overall survival in some -- but not all -- patients with non-small cell lung cancer (NSCLC)," said lead study author Marcello Tiseo, MD, PhD. "Researchers are looking for a predictive biomarker to select patients that will benefit from this treatment to avoid unnecessary toxicity and a waste of resources in patients who will not respond."

A test to determine white blood cell count for immunotherapy response would also likely drive down overall healthcare costs for patients, payers, and providers.

Currently, PD-L1 expression is used to predict which patients may benefit from treatment, according to the study.

"PD-L1 expression in a biopsy of tumour [sic] tissue is used to select patients but it is not completely accurate, possibly because it does not reflect the evolving immune response,” Dr Tiseo said. “Biomarkers in the blood are easier to obtain and may be better indicators of immune response."

In the study, the authors assessed the ability of white blood cell count to predict if a patient would respond to treatment with nivolumab (Opdivo). Included in the study were 54 patients with NSCLC who were administered 3-mg/kg of nivolumab every 14 days.

White blood cell counts were taken at baseline, after 2 treatments, and after 4 treatments to compare the counts for responders and non-responders.

The investigators discovered that baseline white blood cell counts predicted response to nivolumab. A higher concentration and number of natural killer cells at baseline and during treatment was linked to response to treatment, according to the study. Responders also had an increased concentration and number of CD8+ T cells expressing PD-1.

"The number and function of natural killer cells and the frequency of PD-1 expression in CD8 positive T cells could be predictive biomarkers for nivolumab treatment in advanced NSCLC,” Dr Tiseo said. “The identification of a panel of blood predictive biomarkers would enable the early identification of patients most likely to benefit from anti-PD-1 and anti-PD-L1 treatment."

If confirmed in future clinical trials, this biomarker could be used in a clinical setting to inform treatment decisions and improve a patient’s overall course of therapy.

"This study found that baseline levels of certain white blood cells do have a role in predicting response to immunotherapy in patients with lung cancer. These new factors should be investigated in future clinical trials, together with tumour [sic] PD-L1 expression and other markers that constitute the cancer immunogram predict whether or not patients will benefit from treatment,” commented Stefan Zimmermann, MD, senior consultant, Medical Oncology Department, HFR -- Hôpital Cantonal, Fribourg, Switzerland.