Nasopharyngeal Microbial Signatures Associated with Anti-VEGF Therapeutic Outcomes in Exudative Age-Related Macular Degeneration: A Pilot Study

Exudative age-related macular degeneration (AMD) is driven by choroidal angiogenesis, and the response to anti-vascular endothelial growth factor (anti-VEGF) therapy varies between patients. In this pilot study, we investigated whether the pretreatment nasopharyngeal microbiota differs between patients with exudative AMD and controls and whether it is associated with treatment response. Nasopharyngeal swabs were analysed by 16S rRNA gene (V3–V4) amplicon sequencing; after removal of host-derived, chloroplast and contaminant sequences and rarefaction, 55 samples (25 patients and 30 controls) were retained. Treatment response was assessed six months after starting therapy. Community composition was compared using permutational multivariate analysis of variance (PERMANOVA) adjusted for age, sex and statin use. Alpha and beta diversity did not differ between patients and controls (Shannon index, p = 0.892; PERMANOVA, p = 0.067). Pretreatment community composition differed between 19 responders and five non-responders (Bray–Curtis R2 = 0.057, p = 0.015; weighted UniFrac R2 = 0.143, p = 0.006), and non-responders had lower diversity (observed ASVs, p = 0.004). Non-responders had a higher relative abundance of Corynebacterium (median 71% vs. 19%; p = 0.009), which did not remain significant after correction for all genera tested. Pretreatment nasopharyngeal microbiota composition was associated with the response to anti-VEGF therapy but not with AMD status. These preliminary findings require confirmation in larger, independent cohorts.