Tracking the Response to Immunotherapy: Blood microRNA Dynamics in Patients With Advanced Non-Small Cell Lung Cancer.

Purpose: Despite the significant improvement in outcomes for patients with advanced non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICIs), resistance, whether primary or secondary, remains a substantial challenge. Currently, reliable biomarkers to monitor ICI response are lacking, highlighting the need for minimally invasive tools like liquid biopsy to track treatment efficacy. This study aimed to identify circulating microRNAs (miRNAs) as potential biomarkers to track ICI response in patients with NSCLC.

Materials and methods: The Apollo longitudinal study enrolled patients with advanced NSCLC receiving ICI in first or subsequent lines. Plasma samples were collected at baseline and follow-up to prospectively assess miRNA profiles until progressive disease (PD). Using a custom reverse transcription-quantitative polymerase chain reaction platform, 276 ratios among 24 lung cancer-related miRNAs were analyzed. The generalized estimating equation and joint models were applied to select the miRNA ratios most associated with PD over time. To control for multiple testing, the Benjamini-Yekutieli method was applied setting a 10% false discovery rate threshold.

Results: From the 211 patients, a total of 454 plasma samples were analyzed. Clinical and biochemical variables had little effect on miRNAs' profile. The analysis identified nine miRNA ratios, all involving miR-145-5p, as significant biomarkers for monitoring treatment response, even after adjustment for the line of therapy. These ratios exhibited a longitudinal modulation pattern consistent with radiologic response, particularly in patients who initially benefited from ICI treatment. In addition, in an independent set of 32 plasma samples from 10 patients receiving ICI as maintenance therapy, the same trends were observed.

Conclusion: A focused panel of miRNA ratios, driven by miR-145-5p, effectively reflects response to ICI therapy in patients with advanced NSCLC, highlighting their potential as biomarkers for treatment monitoring.