Storage stability and solution binding affinity of an Fc-fusion mimetic.

This study evaluates the storage stability and solution binding affinity of a novel Fc-fusion mimetic, receptor-PEG-receptor (RpR), designed to address limitations of the current therapeutic aflibercept, a gold-standard therapy for age-macular degeneration (AMD). Using di(bis-sulfone) PEG linker as a structural scaffold, the mimetic aims to improve the storage stability and binding efficacy of the Fc fusion protein. Mass photometry and size-exclusion chromatography demonstrated that RpR, even in an unformulated buffer, exhibits superior storage stability exceeding 10 months compared to aflibercept. Furthermore, microscale thermophoresis was employed to determine RpR's binding affinity to VEGF in solution, providing a more physiologically relevant assessment than traditional binding assays. These findings highlight RpR's potential as a therapeutic candidate for the treatment of AMD disease, warranting further investigation.