MA15.04 Timing of Pre-Biopsy COVID-mRNA Vaccination and PD-L1 Expression in Advanced Non-Small Cell Lung Cancer

The effectiveness of anti-PD-1/PD-L1 therapies in Stage III/IV (advanced) non-small cell lung cancer (NSCLC) is correlated with tumor percentage score (TPS) of PD-L1, such that patients with TPS ≥ 50% may benefit from single agent checkpoint blockade without the need for augmentation with chemotherapy. Preclinical evidence demonstrates that mRNA vaccines stimulate interferon-mediated increases in PD-L1 expression at the tumor site. We therefore hypothesized that COVID-mRNA vaccines would similarly increase PD-L1 expression in biopsy samples from patients with advanced NSCLC.