1. Academic Validation
  2. A potent anti-CD70 antibody-drug conjugate combining a dimeric pyrrolobenzodiazepine drug with site-specific conjugation technology

A potent anti-CD70 antibody-drug conjugate combining a dimeric pyrrolobenzodiazepine drug with site-specific conjugation technology

  • Bioconjug Chem. 2013 Jul 17;24(7):1256-63. doi: 10.1021/bc400217g.
Scott C Jeffrey 1 Patrick J Burke Robert P Lyon David W Meyer Django Sussman Martha Anderson Joshua H Hunter Chris I Leiske Jamie B Miyamoto Nicole D Nicholas Nicole M Okeley Russell J Sanderson Ivan J Stone Weiping Zeng Stephen J Gregson Luke Masterson Arnaud C Tiberghien Philip W Howard David E Thurston Che-Leung Law Peter D Senter
Affiliations

Affiliation

  • 1 Department of Research & Translational Medicine, Seattle Genetics, Inc., Bothell, WA 98021, USA. sjeffrey@seagen.com
Abstract

A highly cytotoxic DNA cross-linking pyrrolobenzodiazepine (PBD) dimer with a valine-alanine dipeptide linker was conjugated to the anti-CD70 h1F6 mAb either through endogenous interchain cysteines or, site-specifically, through engineered cysteines at position 239 of the heavy chains. The h1F6239C-PBD conjugation strategy proved to be superior to interchain cysteine conjugation, affording an antibody-drug conjugate (ADC) with high uniformity in drug-loading and low levels of aggregation. In vitro cytotoxicity experiments demonstrated that the h1F6239C-PBD was potent and immunologically specific on CD70-positive renal cell carcinoma (RCC) and non-Hodgkin lymphoma (NHL) cell lines. The conjugate was resistant to drug loss in plasma and in circulation, and had a pharmacokinetic profile closely matching that of the parental h1F6239C antibody capped with N-ethylmaleimide (NEM). Evaluation in CD70-positive RCC and NHL mouse xenograft models showed pronounced antitumor activities at single or weekly doses as low as 0.1 mg/kg of ADC. The ADC was tolerated at 2.5 mg/kg. These results demonstrate that PBDs can be effectively used for antibody-targeted therapy.

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