Autologous hinge-masked anti-TNFα antibody to mitigate immunogenicity, antigen sink effects, and anti-idiotypic antibody interference

Monoclonal antibody (mAb) therapies are limited by factors affecting their pharmacokinetics (PK), such as anti-idiotypic antibodies (anti-ID Abs) and the antigen sink effect. To address this, we developed six pro-anti-TNFα Abs (pro-Infliximab) incorporating unique hinge regions ("Ab locks") from different immunoglobulin subtypes linked via protease-sensitive peptides. The steric shielding formed by the endogenous hinge's disulfide bonds provides a modular design that can be applied to various Ab drugs with minimal structural modification. Compared to other spatial hindrance strategies, this Ab lock approach is anticipated to offer a favorable immunogenicity profile.

Among the variants, The IgG1 hinge exhibited the most robust masking capability among the evaluated domains, resulting in a 128-fold reduction in Infliximab's antigen binding. IgG1 pro-Infliximab demonstrated low immunogenicity after repeated dosing and maintained stable PK in both naïve and immunized mice, retaining 74.2% serum levels one hour after TNFα challenge. It also reduced anti-ID Ab binding by 87.3-fold, while showing a trend toward decreasing Ab-mediated drug clearance in these treated mice.

This IgG1 Ab lock strategy provides binding-level proof of concept for several pro-Abs, offering the potential to mitigate immunogenicity. It blocked systemic hTNFα in an acute target challenge model and reduced clearance to preserve pro-Infliximab PK, ultimately helping to enhance patient quality of life.