CD24, not CD47, negatively impacts upon response to PD-1/L1 inhibitors in non-small-cell lung cancer with PD-L1 tumor proportion score < 50.

CD24, a heavily glycosylated glycosylphosphatidylinositol-anchored surface protein, inhibits phagocytosis as potently as CD47. The relationship between such anti-phagocytic factors and the immune response with immune-checkpoint inhibitors (ICI) remains unexplored. We evaluated CD24 and CD47 tumor proportion scores (TPS) in 68 of the 106 patients with advanced non-small-cell lung cancer who participated in a prospective observational study of ICI treatment. We also explored the impact of CD24 TPS and CD47 TPS on ICI efficacy and serum cytokine changes. CD24 positivity (TPS ≥ 1) was negatively associated with progression-free survival (PFS) of ICI when PD-L1 TPS was < 50 (median PFS; 37 vs 127 d, P = .033), but there was no association when PD-L1 TPS was ≥ 50 (median PFS; 494 vs 144 d, P = .168). CD24 positivity was also related to significantly higher increase of CCL2 from baseline to 4-6 wk later, and such increase was notably observed only when PD-L1 TPS < 50 (P = .0004). CCL2 increase after ICI initiation was negatively predictive for survival after initiation of ICI (median survival time; not reached vs 233 d; P = .028). CD47 TPS high (≥60) significantly suppressed the increase in vascular endothelial growth factor (VEGF)-A, D and PDGF-AB/BB after ICI initiation. There was no association, however, between CD47 tumor expression and the efficacy of ICI. In conclusion, CD24, not CD47, is a candidate negative predictive marker of ICI in advanced, non-small-cell lung cancer with PD-L1 TPS < 50. Tumor expression of both CD24 and CD47 was associated with changes in factors related to monocytes and angiogenesis after ICI initiation (UMIN000024414).