Immunogenicity testing of therapeutic antibodies in ocular fluids after intravitreal injection

Aim: High drug concentrations in ocular fluids after intravitreal administration preclude the use of drugsensitive immunoassays. A drug-tolerant immunoassay is therefore desirable for immunogenicity testing in ophthalmology. Experimental: Immune complex (IC) antidrug antibody (ADA) assays were established for two species. The assays were compared with the bridging assay in ocular and plasma samples from two preclinical studies. Results: The IC assays showed high drug tolerance, which enabled a reliable ADA detection in ocular fluids after intravitreal administration. The IC assays were superior to the bridging assay in the analysis of ocular fluids with high drug concentrations. Conclusion: The IC assay allows a reliable ADA detection in matrices with high drug concentrations, such as ocular fluids.