Bringing the Heavy Chain to Light: Creating a Symmetric, Bivalent IgG-Like Bispecific.

Area of Science:

• Biotechnology
• Immunology
• Protein Engineering

Background:

• Bispecific molecules are valuable but present manufacturing and pharmacokinetic challenges.
• Existing IgG-like bispecifics lack target bivalency and require complex engineering for chain pairing.
• Drug metabolism and pharmacokinetic (DMPK) properties of bispecifics are critical for therapeutic development.

Purpose of the Study:

• To introduce and characterize a novel IgG-like bispecific antibody format, termed 2xVH.
• To demonstrate the 2xVH format's ability to achieve bivalency for each target without requiring specific engineering for chain pairing.
• To assess the expression, binding, and stability of 2xVH molecules compared to traditional monoclonal antibodies (mAbs).

Main Methods:

• Grafting two distinct variable heavy (VH) domains onto the CH1 and CL domains of an IgG scaffold.
• Generating prototype 2xVH IgG and Fragment antigen-binding (Fab) molecules.
• Characterizing expression, binding affinity, and stability of the generated molecules.

Main Results:

• The 2xVH format allows for bivalent binding to each target or epitope.
• Generated 2xVH molecules exhibited properties similar to mAbs.
• These molecules did not require post-expression purification for chain pairing and maintained simultaneous dual binding capacity.

Conclusions:

• The 2xVH format offers a bivalent, bispecific design overcoming manufacturing limitations of current IgG-like bispecifics.
• This format facilitates biologically relevant dual target engagement.
• The 2xVH approach simplifies production while ensuring functional bispecificity.