White Blood Cells in Patients Treated with Programmed Cell Death-1 Inhibitors for Non-small Cell Lung Cancer

Area of Science:

• Oncology
• Immunotherapy
• Hematology

Background:

• Immune checkpoint inhibitors (ICIs) like anti-Programmed Cell Death-1 (PD-1) and anti-PD-Ligand-1 (PD-L1) have revolutionized non-small cell lung cancer (NSCLC) treatment.
• Identifying reliable biomarkers for treatment response and prognosis is crucial for optimizing ICI therapy in NSCLC patients.

Purpose of the Study:

• To evaluate the potential of eosinophils and other white blood cell (WBC) subtypes as response and prognostic markers for anti-PD-1 or anti-PD-L1 therapies in NSCLC.
• To investigate the relationship between WBC counts and treatment outcomes in NSCLC patients receiving ICI monotherapy.

Main Methods:

• Retrospective analysis of 191 advanced NSCLC patients treated with PD-1/PD-L1 inhibitors in monotherapy.
• Evaluation of WBC counts and subtypes at three time-points to assess correlation with tumor response.
• Statistical analysis to determine the significance of WBC subtypes as predictive and prognostic markers, controlling for smoking status, PD-L1 expression, and immune-related toxicity.

Main Results:

• No significant difference in baseline WBC counts was observed based on treatment response.
• A higher relative eosinophil count (REC) was significantly associated with better objective response rates (p=0.019 at t1, p=0.014 at t2) and longer treatment duration (p=0.0096), independent of other factors.
• Baseline absolute neutrophil count, and at t1 relative lymphocytes, absolute and relative neutrophils, and neutrophil-to-lymphocyte ratio demonstrated prognostic value (p<0.05).

Conclusions:

• Anti-PD-1/PD-L1 therapy in NSCLC induces an early increase in blood eosinophils, particularly in responding patients, and is linked to longer treatment duration.
• Eosinophil levels are a promising predictive marker for response to ICI therapy, irrespective of smoking status, PD-L1 status, or immune-related toxicity.
• Neutrophils, lymphocytes, and their ratio serve as important prognostic indicators in advanced NSCLC patients undergoing PD-(L)1 blockade therapy.