Abstract 1760: The antibody-drug conjugate GENA-111 conjugated to auristatin F shows therapeutic potency in BCAM positive epithelial cancer

Abstract Antibody-drug conjugates (ADCs) are considered as promising cancer treatment modalities that combine the selectivity of antibodies and the cytotoxic properties of payloads using chemical linkers. However, despite their success, ADCs still suffer from drawbacks, e.g., systemic toxicity, which limit their potential clinical applications. The systemic toxicity of an ADC is mainly related to the stability of its linker, and to the selectivity of its antibody towards the targeted antigen expressed on cancer cells. Lu/BCAM (Lutheran/basal cell adhesion molecule) is a member of the immunoglobulin superfamily and is a receptor for laminin, a protein that facilitates cell adhesion, migration, and invasion. A growing number of studies show that BCAM plays an essential role in tumor progression and is overexpressed on epithelial cancers e.g., skin cancer. Here we describe GENA-111, a human monoclonal anti-BCAM IgG4 (S228P) antibody that binds to human BCAM with high affinity, and that is significantly internalized by BCAM-positive tumor cells. We also describe the GENA-111-auristatin F ADC, wherein the GENA-111 antibody has been armed with an auristatin F derivative using a new linker technology and a stabilized thiol maleimide conjugation. This new linker technology comprises a cleavable peptidic sequence that facilitates multidrug attachment and the production of ADCs with tailored drug-to-antibody ratios (DARs). Cytotoxic drugs are rapidly and selectively released from the linker by the carboxypeptidase activity of Cathepsin B. In vitro cytotoxicity examination showed the potent cytotoxic effects of this GENA-111-auristatin F ADC on BCAM-expressing tumor cells, with a positive correlation between cytotoxicity and BCAM expression. Moreover, this ADC was also shown to significantly reduce the growth of tumor cells, including A431, T47D, and Huh7. The GENA-111-auristatin F ADC was evaluated in a xenograft mouse model established by subcutaneous injection of A431 cells, a BCAM positive human skin cancer cell line. The results of this study will be presented and discussed. Taken together, our data suggest that an ADC targeting BCAM e.g., GENA-111-auristatin F, might be a promising treatment strategy for BCAM positive epithelial cancer patients. Citation Format: Hyunkyung Yu, Nathalie Bellocq, Youngeun Ha, Hyunuk Kim, Yunyeon Kim, Bu-Nam Jeon, Léo Marx, Mathilde Pantin, Hyunjin Yoo, Seungmin Byun, Joo-Yeon Chung, Mi Young Cha, Patrick Garrouste, Frédéric Lévy. The antibody-drug conjugate GENA-111 conjugated to auristatin F shows therapeutic potency in BCAM positive epithelial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1760.