Aldehyde tag coupled with HIPS chemistry enables the production of ADCs conjugated site-specifically to different antibody regions with distinct in vivo efficacy and PK outcomes

Bioconjug Chem. 2014 Jul 16;25(7):1331-41. doi: 10.1021/bc500189z. Epub 2014 Jun 23.


It is becoming increasingly clear that site-specific conjugation offers significant advantages over conventional conjugation chemistries used to make antibody-drug conjugates (ADCs). Site-specific payload placement allows for control over both the drug-to-antibody ratio (DAR) and the conjugation site, both of which play an important role in governing the pharmacokinetics (PK), disposition, and efficacy of the ADC. In addition to the DAR and site of conjugation, linker composition also plays an important role in the properties of an ADC. We have previously reported a novel site-specific conjugation platform comprising linker payloads designed to selectively react with site-specifically engineered aldehyde tags on an antibody backbone. This chemistry results in a stable C-C bond between the antibody and the cytotoxin payload, providing a uniquely stable connection with respect to the other linker chemistries used to generate ADCs. The flexibility and versatility of the aldehyde tag conjugation platform has enabled us to undertake a systematic evaluation of the impact of conjugation site and linker composition on ADC properties. Here, we describe the production and characterization of a panel of ADCs bearing the aldehyde tag at different locations on an IgG1 backbone conjugated using Hydrazino-iso-Pictet-Spengler (HIPS) chemistry. We demonstrate that in a panel of ADCs with aldehyde tags at different locations, the site of conjugation has a dramatic impact on in vivo efficacy and pharmacokinetic behavior in rodents; this advantage translates to an improved safety profile in rats as compared to a conventional lysine conjugate.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aldehydes / chemistry*
  • Animals
  • Antibodies, Monoclonal / chemistry*
  • Antibodies, Monoclonal / immunology
  • Antineoplastic Agents / pharmacology*
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / pathology
  • Cell Proliferation / drug effects*
  • Female
  • Humans
  • Immunoconjugates / chemistry*
  • Immunoconjugates / pharmacokinetics*
  • Immunoconjugates / pharmacology
  • Mice
  • Mice, SCID
  • Molecular Structure
  • Rats
  • Rats, Sprague-Dawley
  • Receptor, ErbB-2 / immunology*
  • Structure-Activity Relationship
  • Tissue Distribution
  • Tumor Cells, Cultured
  • Xenograft Model Antitumor Assays


  • Aldehydes
  • Antibodies, Monoclonal
  • Antineoplastic Agents
  • Immunoconjugates
  • ERBB2 protein, human
  • Receptor, ErbB-2