Abstract 43: Discovery of ARV-110, a first in class androgen receptor degrading PROTAC for the treatment of men with metastatic castration resistant prostate cancer

Prostate cancer is the second leading cause of cancer death in men in the United States. The androgen receptor (AR) plays critical roles in both early disease and advanced prostate cancer. Current therapeutic approaches targeting the androgen/AR axis are initially effective, but castration resistant prostate cancer (CRPC) inevitably develops. CRPC is tightly linked with increased AR activity via gene overexpression, amplification, and gain-of-function mutations. To address these mechanisms of AR-dependent prostate tumor growth, we have developed a novel therapeutic agent, ARV-110, a proteolysis targeting chimera (PROTAC®) that induces a protein-protein interaction between the AR and E3 ubiquitin ligase complexes, leading to the ubiquitination of AR and its subsequent degradation via the proteasome. In vitro, ARV-110 robustly degrades AR in various prostate cancer cell lines with a half-maximal degradation concentration (DC50) of ~1 nM. Whole cell lysate proteomics and ubiquitin proteomics demonstrated high selectivity for AR in VCaP cells. ARV-110 potently downregulates androgen responsive genes, inhibits proliferation and induces apoptosis in AR dependent prostate cancer cells. In vivo, ARV-110 is orally bioavailable and robustly degrades AR with a >90% observed maximum degradation (Dmax) at efficacious doses. ARV-110 significantly and dose-dependently inhibits tumor growth in murine LNCaP and VCaP xenograft models, including enzalutamide-resistant VCaP and enzalutamide-insensitive patient-derived xenograft models. These preclinical data supported the clinical development of ARV-110 for the treatment of men with metastatic CRPC. The discovery, chemical structure and initial clinical data of ARV-110 will be presented Citation Format: Lawrence B. Snyder, Taavi K. Neklesa, Xin Chen, Hanqing Dong, Caterina Ferraro, Deborah A. Gordon, Jennifer Macaluso, Jennifer Pizzano, Jing Wang, Ryan R. Willard, Nicholas Vitale, Ron Peck, Marcia Dougan Moore, Craig M. Crews, John Houston, Andrew P. Crew, Ian Taylor. Discovery of ARV-110, a first in class androgen receptor degrading PROTAC for the treatment of men with metastatic castration resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 43.