title: Effect of attachment site on stability of cleavable antibody drug conjugates.
abstract: The 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.
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Magdalena
authors: M
authors: Dorywalska
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Pavel
authors: P
authors: Strop
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Jody A
authors: JA
authors: Melton-Witt
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Adela
authors: A
authors: Hasa-Moreno
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Santiago E
authors: SE
authors: Farias
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Meritxell
authors: M
authors: Galindo Casas
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Kathy
authors: K
authors: Delaria
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Victor
authors: V
authors: Lui
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Kris
authors: K
authors: Poulsen
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Carole
authors: C
authors: Loo
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Stellanie
authors: S
authors: Krimm
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Gary
authors: G
authors: Bolton
authors: ‡Worldwide Medicinal Chemistry, Pfizer Inc., 445 Eastern Point Road, Groton, Connecticut 06340, United States.
authors: Ludivine
authors: L
authors: Moine
authors: ‡Worldwide Medicinal Chemistry, Pfizer Inc., 445 Eastern Point Road, Groton, Connecticut 06340, United States.
authors: Russell
authors: R
authors: Dushin
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Thomas-Toan
authors: TT
authors: Tran
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Shu-Hui
authors: SH
authors: Liu
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Mathias
authors: M
authors: Rickert
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Davide
authors: D
authors: Foletti
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: David L
authors: DL
authors: Shelton
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Jaume
authors: J
authors: Pons
authors: †Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, United States.
authors: Arvind
authors: A
authors: Rajpal
mesh_terms: D062365:Aminobenzoates / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D000970:Antineoplastic Agents / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology; D002219:Carbamates / Q000737:chemistry; D002401:Cathepsin B / Q000737:chemistry / Q000378:metabolism; D045744:Cell Line, Tumor; D004151:Dipeptides / Q000737:chemistry; D016503:Drug Delivery Systems / Q000379:methods; D004355:Drug Stability; D005260:Female; D006801:Humans; D018796:Immunoconjugates / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology; D051379:Mice; D008819:Mice, Nude; D008958:Models, Molecular; D009842:Oligopeptides / Q000097:blood / Q000737:chemistry* / Q000493:pharmacokinetics / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D013329:Structure-Activity Relationship; D023041:Xenograft Model Antitumor Assays
chemical_list: D062365:Aminobenzoates; D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D002219:Carbamates; D004151:Dipeptides; D018796:Immunoconjugates; D009842:Oligopeptides; C543533:auristatin; D002401:Cathepsin B