Molecular Characteristics and Pretreatment Neutrophil-to-Lymphocyte Ratio as Predictors of Durable Clinical Benefit from Immune Checkpoint Inhibition in Non-Small Cell Lung Cancer.

Background: Prior research in non-small cell lung cancer (NSCLC) has shown that tumors with specific driver mutations may be less likely to respond to immune checkpoint inhibitors (ICI). In this analysis, we evaluated the characteristics of patients with durable clinical benefit (DCB) to ICI compared to those with no durable clinical benefit (NDB), with emphasis on the role of molecular alterations in EGFR, ALK, and ROS1 and pretreatment neutrophil-to-lymphocyte ratio (NLR).

Methods: We retrospectively collected clinical characteristics and outcomes for patients who initiated ICI monotherapy for advanced NSCLC at Stanford University between April 2015 and May 2018. Patients were classified as having DCB if time on ICI therapy was greater than or equal to 180 days, or NDB if less than 180 days. Outcomes included best radiographic benefit while on ICI and survival from time of ICI initiation.

Results: Of 123 patients treated with ICI for NSCLC, 28 patients had DCB (23%), while 95 had NDB (77%). Median overall survival from initiation of ICI in the 33 patients with molecular alterations in EGFR (n = 31), ALK, or ROS1 and NLR of 5.9 or higher was 2.0 months, compared to 8.1 months in patients with these genomic alterations and NLR less than 5.9. Median overall survival in patients without alterations in EGFR, ALK, or ROS1 and NLR of 5.9 or higher was 4.3 months, compared to 12.1 months in patients with NLR less than 5.9 (P = .023).

Conclusions: Elevation in pretreatment NLR was associated with significantly lower overall median survival from initiation of ICI, particularly when in combination with NSCLC with alterations in EGFR, ALK, or ROS1. This finding could influence clinical practice as NLR is readily available through routine blood testing.