posted on 2024-04-02, 07:23authored byJoshua D. Thomas, Aleksandr V. Yurkovetskiy, Mao Yin, Natalya D. Bodyak, Shuyi Tang, Marina Protopopova, Eugene Kelleher, Brian Jones, Liping Yang, Daniel Custar, Kalli C. Catcott, Damon R. Demady, Scott D. Collins, Ling Xu, Charlie Bu, LiuLiang Qin, Elena Ter-Ovanesyan, Marc Damelin, Dorin Toader, Timothy B. Lowinger
Figure shows Efficacy in OVCAR-3 xenograft for A) targeted ADCs X-17 and X-19 and B) their corresponding non-binding control ADCs NB-17 and NB-19
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ARTICLE ABSTRACT
Although microtubule inhibitors (MTI) remain a therapeutically valuable payload option for antibody–drug conjugates (ADC), some cancers do not respond to MTI-based ADCs. Efforts to fill this therapeutic gap have led to a recent expansion of the ADC payload “toolbox” to include payloads with novel mechanisms of action such as topoisomerase inhibition and DNA cross-linking. We present here the development of a novel DNA mono-alkylator ADC platform that exhibits sustained tumor growth suppression at single doses in MTI-resistant tumors and is well tolerated in the rat upon repeat dosing. A phosphoramidate prodrug of the payload enables low ADC aggregation even at drug-to-antibody ratios of 5:1 while still delivering a bystander-capable payload that is effective in multidrug resistant (MDR)-overexpressing cell lines. The platform was comparable in xenograft studies to the clinical benchmark DNA mono-alkylator ADC platform DGN459 but with a significantly better tolerability profile in rats. Thus, the activity and tolerability profile of this new platform make it a viable option for the development of ADCs.