The EC50 binding characteristics of novel trispecific protein, RO-104

Abstract

Purpose : This study investigated the binding characteristics of novel trispecific Surrobody, RO-104 that binds Vascular Endothelial Growth Factor A and C (VEGF-A, VEGF-C), and Angiopoietin 2 (Ang-2). The benefits of bispecific inhibition of VEGF-A and Ang-2 have been established clinically with the approved use of faricimab. Recent clinical studies suggest VEGF-C as a third significant contributor to retinal neovascularization. The study was designed to compare binding affinity EC50 analysis of RO-104 to faricimab for both VEGF-A and Ang-2. Additionally, we designed experiments to determine EC50 binding affinity of RO-104 to VEGF-C.

Methods : Individual target-based binding Enzyme-linked Immunoassays (ELISA) were used to determine the EC50 of RO-104 to recombinant human VEGF-A, Ang-2, and VEGF-C. Each target was separately coated onto ELISA plates and specific binding of RO-104 was detected by biotinylated anti-VpreB antibody and HRP-conjugated streptavidin. Faricimab ELISAs were similar except binding was detected by anti-IgG Fc-HRP. In each case dose response analysis was performed in duplicates starting at 10 nM using 3-fold dilutions.

Results : The EC50 of RO-104 binding to VEGF-A was determined to be 5.0 pM, compared to Faricimab that was 22.8 pM. The EC50 of RO-104 binding to Ang-2 was 10.7 pM and compared favorably to the EC50 of faricimab of 676.4 pM. Lastly, the EC50 of RO-104 uniquely binds to VEGF-C with 19.2 pM potency compared to faricimab.

Conclusions : RO-104 binds with higher affinity to VEGF-A and Ang-2 than faricimab providing potential for greater efficacy. Additionally, RO-104 is more versatile than faricimab as it can potently bind VEGF-C that has shown significant implications to neovascular disease. These data suggest that RO-104 has collectively desirable characteristics compared to faricimab warranting further therapeutic development.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Comparison of RO-104 binding to VEGF-A, Ang-2, and VEGF-C to faricimab binding to VEGF-A and Ang-2. <div id="accel-snackbar" style="left: 50%; transform: translate(-50%, 0px); top: 50px;"> </div>