Spatial architecture of complex antibody formats dictates pharmacokinetics via FcRn-recycling
- 1Roche Pharma Research and Early Development, Roche Innovation Center Munich
Abstract
Complex antibody formats are advancing in the biotherapeutic landscape to address the need for multi-specificity, tailored valency, and novel mechanisms of action. However, understanding how non-canonical architectures impact fundamental pharmacokinetic pathways remains a critical challenge. While canonical IgGs experience steric hindrance at the endosomal membrane during FcRn engagement, whether -- and how strongly -- this constraint impacts FcRn-mediated recycling across the expanding diversity of non-canonical antibody architectures has remained unknown. By systematically evaluating a diverse panel of rationally designed antibody geometries utilizing orthogonal in vitro assays we demonstrate that spatial layout profoundly influences FcRn-recycling efficiency; inverting the antibody structure by positioning the Fab-domains to the C-terminus (invertbodies) maximizes recycling, whereas crowding the N-terminus severely impairs it. In contrast, non-specific endocytosis was only modestly and inconsistently affected by Fab number, dependent on the Fv-sequence, but not by the spatial architecture itself. Notably, antibody architecture and affinity-enhancing Fc-FcRn mutations act independently yet cooperatively, ultimately revealing a physiological recycling ceiling. These FcRn-recycling dynamics translate with high fidelity to in vivo clearance (CL) in a humanized FcRn mouse model. Across the antibody panel, architecture drove a near 15-fold variance in CL, an effect that collapsed in FcRn-knockout mice. As proof of concept, we applied the invertbody design to a variant of the marketed antibody golimumab, achieving a three-fold reduction in clearance without compromising potency. These findings reveal the magnitude and predictability with which the antibody architecture governs FcRn-recycling and non-specific CL, establishing a rational, generalizable framework to optimize the pharmacokinetics of biotherapeutics.
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BibTeX
@misc{weise2026spatial,
title = {{Spatial architecture of complex antibody formats dictates pharmacokinetics via FcRn-recycling}},
author = {S. C. Weise and C. Jany and S. Imhof-Jung and C. Simonneau and J. Fraidling and A.-L. Bolender and A. Padamsey and E. Di Lenarda and A. C. Cascais and T. Emrich and T. Schlothauer and A. Indlekofer and H. Kettenberger and V. Haucke and W. F. Richter and T. E. Kraft},
howpublished = {bioRxiv},
year = {2026},
month = nov,
doi = {10.64898/2026.11.02.763654},
url = {https://www.biorxiv.org/content/10.64898/2026.11.02.763654v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Spatial architecture of complex antibody formats dictates pharmacokinetics via FcRn-recycling
AU - S. C. Weise
AU - C. Jany
AU - S. Imhof-Jung
AU - C. Simonneau
AU - J. Fraidling
AU - A.-L. Bolender
AU - A. Padamsey
AU - E. Di Lenarda
AU - A. C. Cascais
AU - T. Emrich
AU - T. Schlothauer
AU - A. Indlekofer
AU - H. Kettenberger
AU - V. Haucke
AU - W. F. Richter
AU - T. E. Kraft
PY - 2026
DA - 2026/11/02
PB - bioRxiv
DO - 10.64898/2026.11.02.763654
UR - https://www.biorxiv.org/content/10.64898/2026.11.02.763654v1
AB - Complex antibody formats are advancing in the biotherapeutic landscape to address the need for multi-specificity, tailored valency, and novel mechanisms of action. However, understanding how non-canonical architectures impact fundamental pharmacokinetic pathways remains a critical challenge. While canonical IgGs experience steric hindrance at the endosomal membrane during FcRn engagement, whether -- and how strongly -- this constraint impacts FcRn-mediated recycling across the expanding diversity of non-canonical antibody architectures has remained unknown. By systematically evaluating a diverse panel of rationally designed antibody geometries utilizing orthogonal in vitro assays we demonstrate that spatial layout profoundly influences FcRn-recycling efficiency; inverting the antibody structure by positioning the Fab-domains to the C-terminus (invertbodies) maximizes recycling, whereas crowding the N-terminus severely impairs it. In contrast, non-specific endocytosis was only modestly and inconsistently affected by Fab number, dependent on the Fv-sequence, but not by the spatial architecture itself. Notably, antibody architecture and affinity-enhancing Fc-FcRn mutations act independently yet cooperatively, ultimately revealing a physiological recycling ceiling. These FcRn-recycling dynamics translate with high fidelity to in vivo clearance (CL) in a humanized FcRn mouse model. Across the antibody panel, architecture drove a near 15-fold variance in CL, an effect that collapsed in FcRn-knockout mice. As proof of concept, we applied the invertbody design to a variant of the marketed antibody golimumab, achieving a three-fold reduction in clearance without compromising potency. These findings reveal the magnitude and predictability with which the antibody architecture governs FcRn-recycling and non-specific CL, establishing a rational, generalizable framework to optimize the pharmacokinetics of biotherapeutics.
ER -