485 Impact of opioid signaling on the tumor microenvironment and clinical outcomes in patients with non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICIs)

<h3>Background</h3> Increasing evidence indicates that opioid signaling may be linked to immune suppressive effects in patients with cancer, potentially worsening clinical outcomes in those treated with ICIs. Patients with advanced stage NSCLC often present with high symptoms burden/pain, requiring systemic opioids at baseline. Despite these concerns, there is a lack of research investigating the impact of opioid signaling on the tumor immune microenvironment (TIME) and clinical outcomes. <h3>Methods</h3> RNAseq data was retrieved from the Cancer Genomic Atlas lung adenocarcinoma (LUAD, n=566 pts) and squamous cell carcinoma (LUSC, n=487 pts) cohorts to further investigate TIME dynamics in opioid signaling pathway (OSP) using an 11-gene established signature from the gene ontology library (GO:0038003). To clinically validate our findings, we conducted a single institution analysis on patients with advanced-stage NSCLC treated with 1^st line chemotherapy plus pembrolizumab (chemo-ICI) from Dec 2019 to Sep 2023. Systemic opioids taken for at least 7 consecutive days within 30 days prior to chemo-ICI initiation were screened. Data cut-off was March 2024. Clinical endpoints were overall survival (OS) and progression-free survival (PFS). <h3>Results</h3> Using the OSP signature, TCGA-LUAD and LUSC tumor samples were categorized using single-sample gene set enrichment analysis into high (n=498 pts) and low (n=498) expression groups. CIBERSORT deconvolution algorithm showed significant (Wilcoxon p&lt;0.05) higher levels of CD8+ T cells, M1 macrophages, and plasma cells in low OSP samples, while M2 macrophages were higher in high OSP samples (figure 1). The tumor inflammation signature, interferon-gamma signature, and cytotoxic T-cell score were significantly higher in low OSP samples compared to high OSP samples (figure 1). Out of 134 patients, 33 (24.6%) were on opioids at baseline. Treatment with opioids was associated with a higher burden of metastatic sites as expected (p=0.0015, table 1). At a median follow-up of 22.6 months, opioid exposure was associated with worse PFS (HR 1.81, 95%CI: 1.08–3.01, figure 2A) but not OS (HR 1.58, 95%CI: 0.92–2.71, figure 2B) compared to patients not exposed to opioids at baseline. <h3>Conclusions</h3> High OSP levels are associated with a distinct immunosuppressive TIME impeding potential benefit from ICIs while baseline opioid exposure in patients with NSCLC treated with chemo-ICI is specifically associated with worse PFS, suggesting a detrimental link beyond the merely prognostic associative effect between opioid treatment and worse conditions. Considering that opioids are the cornerstone of pain management, these findings highlight the need for further research on potential mitigation strategies in this setting. <h3>Ethics Approval</h3> Ethics approval and consent to participate: The procedures followed were in accordance with the precepts of Good Clinical Practice and the declaration of Helsinki. The study was approved by the local ethical committees on human experimentation (Comitato Etico Fondazione Policlinico Universitario Campus Bio-Medico, IRB ID approval N.PAR 70.23 OSS, 17 May 2023, registry number: SC 2023.068). <h3>Consent</h3> Ethics approval and consent to participate: The procedures followed were in accordance with the precepts of Good Clinical Practice and the declaration of Helsinki. The study was approved by the local ethical committees on human experimentation (Comitato Etico Fondazione Policlinico Universitario Campus Bio-Medico, IRB ID approval N.PAR 70.23 OSS, 17 May 2023, registry number: SC 2023.068).