Dual angiopoietin‐2/VEGF‐A neutralisation prevents vascular leakage, cell death and subretinal macrophage infiltration in mouse models of retinal ischaemia/reperfusion injury and spontaneous CNV

Purpose Explore impact of dual angiopoietin‐2 (Ang‐2)/vascular endothelial growth factor‐A (VEGF‐A) targeting by faricimab on vessel destabilisation and retinal inflammation in 2 mouse models: retinal ischaemia/reperfusion (I/R) injury model to assess vascular permeability, and JR5558 spontaneous choroidal neovascularisation (sCNV) model to investigate inflammation, in the context of phase 2/3 clinical data on faricimab. Methods Antibodies against Ang‐2, VEGF‐A, or both (VA2) and IgG (control) were intravitreally injected 2 days before I/R injury in the I/R model. Vascular permeability and ongoing cell death were assessed by retinal FITC‐BSA accumulation and DNA fragmentation assay, respectively, 48h after injury. JR5558 mice were treated intraperitoneally at postnatal days P45, P52 with mouse cross‐reactive tool antibodies to Ang‐2, VEGF‐A, both (VA2) and IgG. Subretinal inflammatory cell (Iba1+, CD45+, CD11b+) infiltration was evaluated by flat‐mount retinal pigment epithelium (RPE)/choroid histology at 1 (PT1), 3 (PT2), and 5 weeks (PT3) post‐treatment. Results Post‐I/R injury, VA2 significantly prevented retinal vascular permeability by 64%; anti–VEGF‐A by 37%; anti–Ang‐2 produced no significant change. VA2 significantly reduced ongoing cell death by 47%; VEGF‐A, Ang‐2 alone had no significant effect. In JR5558 mice, VA2, not anti–VEGF‐A or anti–Ang‐2 alone, significantly reduced Iba1+ microglia/macrophages on RPE/choroid and around lesions versus IgG at PT1 and PT2. At PT3, anti–Ang‐2, VA2, not anti–VEGF‐A, showed significant reductions in Iba1+ cells versus IgG. CD45+, CD11b+ cells on RPE/choroid and around lesions were significantly reduced only with VA2 versus IgG. Conclusions Dual Ang‐2/VEGF‐A inhibition synergistically prevented retinal vascular leakage, cell death and inflammation in retinal I/R injury and sCNV mouse models, suggesting that vascular leakage, prolonged inflammation are driven by Ang‐2, and supporting recent phase 2/3 clinical data that demonstrated sustained efficacy of faricimab versus intravitreal anti‐VEGF monotarget therapy and extended durability up to every 16 weeks.