In vivo Drug-Linker Stability of an Anti-CD30 Dipeptide-Linked Auristatin Immunoconjugate

• Published in: Clinical cancer research Vol. 11; no. 2; pp. 843 - 852
• Main Authors: SANDERSON, Russell J, HERING, Michelle A, JAMES, Stephanie F, SUN, Michael M. C, DORONINA, Svetlana O, SIADAK, Anthony W, SENTER, Peter D, WAHL, Alan F
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 15-01-2005
• Subjects: Animals; Antibodies, Anti-Idiotypic - therapeutic use; Antibodies, Monoclonal - chemistry; Antibodies, Monoclonal - metabolism; Antibodies, Monoclonal - pharmacology; antibody; Antineoplastic agents; auristatin; Biological and medical sciences; CD30; conjugate; Disulfides; Drug Stability; drug-linker; Female; Hodgkin Disease - drug therapy; Hodgkin Disease - immunology; Hodgkin Disease - metabolism; Hydrazones; Immunoconjugates - chemistry; Immunoconjugates - metabolism; Immunoconjugates - therapeutic use; Ki-1 Antigen - immunology; Ki-1 Antigen - metabolism; Lymphoma, Large-Cell, Anaplastic - drug therapy; Lymphoma, Large-Cell, Anaplastic - immunology; Lymphoma, Large-Cell, Anaplastic - metabolism; Macaca fascicularis; Medical sciences; Mice; Mice, Inbred BALB C; Mice, SCID; Oligopeptides - chemistry; Oligopeptides - therapeutic use; Pharmacology. Drug treatments; Sensitivity and Specificity; Tumor Cells, Cultured; Xenograft Model Antitumor Assays; Genetic mapping; Drug; In vivo; Stability; Genetic linkage; Dipeptides; Immunoconjugate
• ISSN: 1078-0432; 1557-3265
• DOI: 10.1158/1078-0432.843.11.2

Effective antibody-drug conjugates (ADC) combine high drug-linker stability in circulation and efficient intratumoral release
of drug. Conjugation of monomethyl auristatin E (MMAE) to the anti-CD30 monoclonal antibody (mAb), cAC10, produced a selective
and potent ADC against CD30 + anaplastic large cell lymphoma and Hodgkin's disease models. This ADC, cAC10-valine-citrulline-MMAE, uses a protease-sensitive
dipeptide linker designed to release MMAE by lysosomal cathepsin B in target cells but maintain a stable linkage and attenuate
drug potency in circulation. To evaluate ADC stability in vivo , we developed methods for measuring drug/mAb ratios at progressive times in plasma from ADC-treated mice and nonhuman primates.
Anti-idiotype mAb permitted the capture and quantitation of mAb cAC10, whereas antidrug mAb and MMAE-conjugated horseradish
peroxidase reporter provided quantitative detection of conjugated drug following its in vitro release by cathepsin B. These data were validated by an alternative ELISA using anti-idiotype and anti-MMAE mAbs for capture
and detection, respectively. Both methods differentiated ADC with variable levels of drug loading and were subsequently applied
to stability studies in severe combined immunodeficient mice and cynomolgus monkeys. Evaluation of ADC from mouse circulation
showed the linker half-life to be ∼144 hours (6.0 days), significantly greater than that reported for disulfide- or hydrazone-linked
ADCs in mice or human trials. In cynomolgus monkey, the apparent linker half-life was ∼230 hours (9.6 days), suggesting that
the drug-linker will be highly stable in humans. These data represent the longest reported drug-linker half-life to date and
provide the basis for the pronounced specificity and antitumor activity of cAC10-valine-citrulline-MMAE.