bc5005747_si_001.pdf (970.92 kB)
Effect of Attachment Site on Stability of Cleavable Antibody Drug Conjugates
journal contribution
posted on 2015-04-15, 00:00 authored by Magdalena Dorywalska, Pavel Strop, Jody A. Melton-Witt, Adela Hasa-Moreno, Santiago
E. Farias, Meritxell Galindo Casas, Kathy Delaria, Victor Lui, Kris Poulsen, Carole Loo, Stellanie Krimm, Gary Bolton, Ludivine Moine, Russell Dushin, Thomas-Toan Tran, Shu-Hui Liu, Mathias Rickert, Davide Foletti, David L. Shelton, Jaume Pons, Arvind RajpalThe
systemic stability of the antibody–drug linker is crucial
for delivery of an intact antibody–drug conjugate (ADC) to
target-expressing tumors. Linkers stable in circulation but readily
processed in the target cell are necessary for both safety and potency
of the delivered conjugate. Here, we report a range of stabilities
for an auristatin-based payload site-specifically attached through a
cleavable valine-citrulline-p-aminobenzylcarbamate
(VC-PABC) linker across various sites on an antibody. We demonstrate
that the conjugation site plays an important role in determining VC-PABC
linker stability in mouse plasma, and that the stability of the linker
positively correlates with ADC cytotoxic potency both in vitro and
in vivo. Furthermore, we show that the VC-PABC cleavage in mouse plasma
is not mediated by Cathepsin B, the protease thought to be primarily
responsible for linker processing in the lysosomal degradation pathway.
Although the VC-PABC cleavage is not detected in primate plasma in
vitro, linker stabilization in the mouse is an essential prerequisite
for designing successful efficacy and safety studies in rodents during
preclinical stages of ADC programs. The divergence of linker metabolism
in mouse plasma and its intracellular cleavage offers an opportunity
for linker optimization in the circulation without compromising its
efficient payload release in the target cell.