A Non-immunogenic Bivalent d-Protein Potently Inhibits Retinal Vascularization and Tumor Growth.

Area of Science:

• Biotechnology
• Protein Engineering
• Immunology

Background:

• Antibodies are crucial therapeutics but can elicit immunogenic responses.
• Developing alternative biologics with similar efficacy and reduced immunogenicity is essential.
• Vascular Endothelial Growth Factor A (VEGF-A) is a key target in angiogenesis-related diseases.

Purpose of the Study:

• To establish a general method for engineering multivalent d-proteins with antibody-like activities.
• To create a d-protein antagonist targeting VEGF-A for therapeutic applications.
• To evaluate the efficacy and immunogenicity of the d-protein antagonist compared to antibodies.

Main Methods:

• Utilized mirror-image phage display and structure-guided design to create d-proteins.
• Employed phage-displayed libraries against VEGF-A to select high-affinity binders.
• Determined X-ray crystal structures of d-protein/VEGF-A complexes for affinity maturation.
• Constructed a heterodimeric d-protein VEGF-A antagonist.

Main Results:

• Identified two d-proteins binding distinct sites on VEGF-A.
• Achieved picomolar activity with the heterodimeric d-protein VEGF-A antagonist.
• Demonstrated efficacy in preventing vascular leakage in a wet age-related macular degeneration model.
• Showed tumor growth inhibition in a mouse model comparable to antibody drugs.
• Confirmed non-immunogenicity of the d-protein in vivo.

Conclusions:

• A generalizable approach for engineering potent, non-immunogenic d-protein therapeutics was established.
• The d-protein VEGF-A antagonist shows therapeutic potential for angiogenesis-related diseases.
• D-proteins represent a promising alternative to antibodies with reduced immunogenicity concerns.