Investigating the impact of CMV on outcomes in pleural mesothelioma

<bold>Background:</bold> Pleural mesothelioma (PM) is a primary pleural malignancy, with poor survival. Response rate of first line treatment with dual immunotherapy is 50%. Cytomegalovirus (CMV), a common viral infection, has been linked with all-cause & cancer-related mortality (Okedele OO, CCC 2020;31:541-7). We hypothesise that chronic CMV immunosurveillance reduces the ability of CD4+ T cells to exert anti-tumour effects within the PM tumour microenvironment, impacting overall survival (OS). We examined the relationship between CMV serostatus & outcomes. <bold>Methods:</bold> 240 patients were recruited from two prospective cohort studies. Baseline bloods were tested for CMV IgG antibodies. Logistic & Cox regression evaluated the relationship between CMV serostatus, OS & treatment response (TR). <bold>Results:</bold> Of 73 patients in the preliminary analysis, 70% were male. Median age was 75 (69-79) & 67% had epithelioid PM. 82.2% were CMV seropositive. With preliminary results, serostatus was not associated with TR or OS (HR 1.66(95% CI:0.78,3.53);adj HR 0.81(0.32,2.05)) but the Kaplan-Meier curve (Fig.1) may indicate an association. <bold>Conclusions:</bold> Although preliminary results did not confirm a relationship between CMV & outcomes, testing of the full cohort is underway to robustly test the hypothesis that quiescent CMV infection impacts immune resources needed to control PM tumours. Final results will be presented at congress. <fig><object-id>erj;66/suppl_69/PA2953/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>