Abstract LB022: Preclinical anti-tumorigenic evaluation of AXL targeting antibody-drug-conjugate in an adenoid cystic carcinoma cell line xenograft model

Abstract Adenoid cystic carcinoma (ACC) is a rare type of salivary gland cancer. Despite the many advances made in helping understand the disease behavior and characteristics, the prevailing challenge in managing patients with ACC is the lack of clinically approved systemic therapy drugs to successfully treat those with advanced recurrent or metastatic disease. There are multiple promising candidate agents being evaluated preclinically and in early phase clinical trials, yet an effective drug with consistent overall response remains to be identified. AXL is a member of the TAM family of tyrosine kinase receptors, and its overexpression and activation is generally associated with poor prognosis and chemoresistance in many cancer types. Previous reports show AXL is significantly upregulated in a subset of ACC tumors. Here, we evaluate the tumor growth inhibition effects of a newly developed antibody-drug-conjugate targeting AXL (ADCT-601) in a xenograft ACC cell line model. MDA-ACC-01 cells express high levels of cell surface AXL as confirmed by biochemical analysis. The tumor growth inhibition of MDA-ACC-01 cell xenograft was tested in a single-dose drug administration study. Immunodeficient mice bearing ACC tumors were either injected with vehicle (n=7) or with ADCT-601 at 0. 5 (n=9) or 1. 0 mg/kg (n=7). ADCT-601 treatment with either 0. 5 mg/kg or 1. 0 mg/kg resulted in complete response (CR) for all tumor implants. To reaffirm the drug’s efficacy, we challenged the vehicle-treated tumor, prior to exceeding the tumor volume endpoint, with a single-dose of ADCT-601 at 1. 0 mg/kg. Strikingly, by day 6 post-treatment, tumor volume began to shrink and eventually resulted in CR except in all but one case. These results demonstrate ADCT-601 is an effective drug with significant anti-tumor activity in our preclinical models and is worthy of additional investigation to determine its translational potential. Citation Format: Joseph O. Humtsoe, Anita Pothukuchi, Hyunseok Kang, Patrick Ha. Preclinical anti-tumorigenic evaluation of AXL targeting antibody-drug-conjugate in an adenoid cystic carcinoma cell line xenograft model abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (7Suppl): Abstract nr LB022.