Assessment of Contrast and Molecular Ultrasound Parameters to Predict Response to anti-PD-L1 Immune Checkpoint Inhibitor

The objective of this study was to explore the application of quantitative parameters from contrast-enhanced and molecular ultrasound imaging for assessing anti PD-L1 tumor treatment response in a preclinical setting. Tumor ECs are thought to contribute to immune evasion, potentially limiting the effectiveness of ICIs, and the study sought to utilize ultrasound techniques to understand this relationship better. Using CT26 cells in 9-week-old mice, we monitored tumor growth and treatment response, administering anti PD-L1 antibodies to one group. Ultrasound imaging using non-targeted and anti PD-L1 targeted microbubbles was performed, revealing a 3.5-day tumor growth delay in the treated group compared to controls. The treated group was further classified into responsive and non-responsive subgroups, with one-way ANOVA tests demonstrating significant differences in dTE and AUC parameters between these subgroups. The findings highlight the potential of CEUS and molecular US in assessing the response to PD-L1 therapy, suggesting a need for further investigations in this area.