Structure-based engineering of a novel CD3ε-targeting antibody for reduced polyreactivity

Area of Science:

• Biotechnology
• Immunology
• Pharmacology

Background:

• Bispecific antibodies, particularly T-cell engagers utilizing an anti-CD3 binding arm, are a rapidly expanding area of therapeutic development.
• CD3 antibodies with cynomolgus monkey cross-reactivity often target a specific N-terminal epitope on CD3 epsilon (CD3ε), leading to high isoelectric points and problematic polyreactivity, which negatively impacts pharmacokinetics.

Purpose of the Study:

• To engineer high-affinity CD3 antibody variants with reduced polyreactivity and enhanced biophysical developability.
• To break the established correlation between CD3 affinity and polyreactivity observed in existing CD3 antibodies.

Main Methods:

• Utilized crystal structure insights of an anti-Hu/Cy CD3 antibody (ADI-26906) complexed with CD3ε.
• Employed antibody engineering with a yeast-based platform to derive novel CD3 antibody variants.

Main Results:

• Developed high-affinity CD3 antibody variants exhibiting very low polyreactivity and significantly improved biophysical properties.
• Demonstrated that engineered CD3 antibodies can achieve a broad affinity range with minimal to no polyreactivity, decoupling affinity from polyreactivity.

Conclusions:

• The engineered CD3 antibodies present a promising solution for developing bispecific therapeutics with enhanced pharmacokinetic and safety profiles.
• These findings offer valuable engineering strategies for the growing field of T-cell engagers.