Abstract 1987: Delivery of potent cytotoxic camptothecin derivatives to tumors by OncoFAP-based small molecule-drug conjugates

Abstract Small Molecule-Drug Conjugates (SMDCs) are anti-cancer pro-drugs composed by a tumor-targeting small organic ligand, a linker structure and a potent cytotoxic payload. OncoFAP is an ultra-high affinity ligand of Fibroblast Activation Protein (FAP), a stromal protein overexpressed in multiple types of solid human malignancies. Nuclear medicine studies validated the applicability of the OncoFAP technology for tumor-targeting applications in a wide variety of tumor types. We have recently reported the development of SMDC products in which OncoFAP is used to deliver Monomethyl Auristatin E (MMAE) to tumors, exploiting linkers that are selectively cleaved by FAP. Here we describe the generation and in vivo characterization of novel OncoFAP-based SMDC products bearing potent camptothecin derivatives acting as topoisomerase I inhibitors. Those drug payloads have been already included in approved ADC products (EnhertuTM and TrodelvyTM). The FAP-cleavable linker technology was directly compared against linker strategies used for approved ADCs. Therapy results in preclinical xenograft models of solid tumors revealed that SMDC products activated by FAP show superior anti-cancer activity and deserve industrial development for the treatment of various human solid tumors. Citation Format: Matilde Bocci, Samuele Cazzamalli, Dario Neri, Andrea Galbiati. Delivery of potent cytotoxic camptothecin derivatives to tumors by OncoFAP-based small molecule-drug conjugates [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1987.