Comparative Pharmacokinetic Analysis of Aflibercept and Brolucizumab in Human Aqueous Humor Using Nano-Surface and Molecular-Orientation Limited Proteolysis

Aflibercept and brolucizumab, two anti-VEGF agents used as intravitreal injections in ophthalmology, differ significantly in molecular weight (aflibercept-115 kDa and brolucizumab-26 kDa). Using aqueous humor samples collected after drug administration, we measured and performed a comparative analysis of pharmacokinetics and half-lives of these drugs in the human eye. Since the quantification of monoclonal antibodies (mAbs) using antigen-antibody reactions, such as ELISA, is influenced by endogenous ligands or anti-drug antibodies, we employed nano-surface and molecular-orientation limited proteolysis (nSMOL), combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS), for accurate measurements. Aqueous humor samples were collected from 59 eyes of 59 patients treated with aflibercept and 52 eyes of 52 patients treated with brolucizumab. Samples were obtained with a median post-injection period of 30 (range, 2-49) days for aflibercept and 28 (range, 4-60) days for brolucizumab. A population pharmacokinetic (PPK) analysis revealed that the half-life of aflibercept in human aqueous humor was significantly shorter than that of brolucizumab, 2.88 days versus 9.00 days, respectively (p = 1.16 × 10^-7). Using the same mass spectrometry conditions, we calculated the half-lives of the two drugs. These results may be useful for optimizing the efficacy of these drugs in clinical practice.