title: A New Triglycyl Peptide Linker for Antibody-Drug Conjugates (ADCs) with Improved Targeted Killing of Cancer Cells.
abstract: A triglycyl peptide linker (CX) was designed for use in antibody -: drug conjugates (ADC), aiming to provide efficient release and lysosomal efflux of cytotoxic catabolites within targeted cancer cells. ADCs comprising anti-epithelial cell adhesion molecule (anti-EpCAM) and anti-EGFR antibodies with maytansinoid payloads were prepared using CX or a noncleavable SMCC linker (CX and SMCC ADCs). The in vitro cytotoxic activities of CX and SMCC ADCs were similar for several cancer cell lines; however, the CX ADC was more active (5-100-fold lower IC50) than the SMCC ADC in other cell lines, including a multidrug-resistant line. Both CX and SMCC ADCs showed comparable MTDs and pharmacokinetics in CD-1 mice. In Calu-3 tumor xenografts, antitumor efficacy was observed with the anti-EpCAM CX ADC at a 5-fold lower dose than the corresponding SMCC ADC in vivo Similarly, the anti-EGFR CX ADC showed improved antitumor activity over the respective SMCC conjugate in HSC-2 and H1975 tumor models; however, both exhibited similar activity against FaDu xenografts. Mechanistically, in contrast with the charged lysine-linked catabolite of SMCC ADC, a significant fraction of the carboxylic acid catabolite of CX ADC could be uncharged in the acidic lysosomes, and thus diffuse out readily into the cytosol. Upon release from tumor cells, CX catabolites are charged at extracellular pH and do not penetrate and kill neighboring cells, similar to the SMCC catabolite. Overall, these data suggest that CX represents a promising linker option for the development of ADCs with improved therapeutic properties. Mol Cancer Ther; 15(6); 1311-20. ©2016 AACR.
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts. rajeeva.singh@immunogen.com wayne.widdison@immunogen.com.
authors.forename: Rajeeva
authors.initials: R
authors.lastname: Singh
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Yulius Y
authors.initials: YY
authors.lastname: Setiady
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Jose
authors.initials: J
authors.lastname: Ponte
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Yelena V
authors.initials: YV
authors.lastname: Kovtun
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Katharine C
authors.initials: KC
authors.lastname: Lai
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: E Erica
authors.initials: EE
authors.lastname: Hong
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Nathan
authors.initials: N
authors.lastname: Fishkin
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Ling
authors.initials: L
authors.lastname: Dong
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Jones
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Coccia
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Leanne
authors.initials: L
authors.lastname: Lanieri
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Karen
authors.initials: K
authors.lastname: Veale
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Juliet A
authors.initials: JA
authors.lastname: Costoplus
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Anna
authors.initials: A
authors.lastname: Skaletskaya
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Rabih
authors.initials: R
authors.lastname: Gabriel
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Paulin
authors.initials: P
authors.lastname: Salomon
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Rui
authors.initials: R
authors.lastname: Wu
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Qiu
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Hans K
authors.initials: HK
authors.lastname: Erickson
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: John M
authors.initials: JM
authors.lastname: Lambert
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts.
authors.forename: Ravi V J
authors.initials: RV
authors.lastname: Chari
authors.affiliation: ImmunoGen, Inc., Waltham, Massachusetts. rajeeva.singh@immunogen.com wayne.widdison@immunogen.com.
authors.forename: Wayne C
authors.initials: WC
authors.lastname: Widdison
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000071858:Epithelial Cell Adhesion Molecule / Q000037:antagonists & inhibitors*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D006801:Humans; D018796:Immunoconjugates / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D020714:Maximum Tolerated Dose; D008453:Maytansine / Q000737:chemistry*; D051379:Mice; D016513:Mice, SCID; D009369:Neoplasms / Q000188:drug therapy*; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D000071858:Epithelial Cell Adhesion Molecule; D018796:Immunoconjugates; D010455:Peptides; D008453:Maytansine; C512478:EGFR protein, human; D066246:ErbB Receptors