Abstract ND02: GDC-2992: A heterobifunctional Androgen Receptor (AR) antagonist and degrader for the treatment of AR wild-type and mutant prostate cancer

Abstract Prostate cancer is the second most commonly diagnosed cancer in men, with 1 in 8 men being diagnosed with prostate cancer in his lifetime. AR is a hormone-activated transcription factor that promotes cell growth and survival in the normal prostate, and AR signaling is a key driver of cell proliferation in prostate cancer. Inhibition of AR signaling is a mainstay of current prostate cancer treatment, however, patients often develop resistance to these therapies through mechanisms that retain dependency on AR signaling. GDC-2992 (also known as RO7656594) is a potent, orally bioavailable, heterobifunctional molecule that inhibits AR signaling by binding to both AR and the E3 ubiquitin ligase cereblon (CRBN), resulting in ubiquitination and subsequent degradation of AR. GDC-2992 inhibits AR signaling in the context of wild-type AR and AR proteins with mutations associated with resistance to standard-of-care AR signaling inhibitors (ARSIs). Unlike ARSIs, GDC-2992 does not display evidence of agonism against any AR variants evaluated. Co-treatment of GDC-2992 with the CRBN ligand pomalidomide prevents AR degradation mediated by GDC-2992 in vitro, supporting the role of CRBN in GDC-2992-mediated AR degradation. Importantly however, anti-proliferative potential of GDC-2992 is maintained even when degradation is attenuated, suggesting that the mechanism of GDC-2992 includes competitive AR antagonism in addition to degradation. In vivo, GDC-2992 decreases circulating PSA and inhibits prostate tumor growth in a dose responsive manner. The totality of in vitro and in vivo preclinical data supports that GDC-2992 represents a compelling advance over standard-of-care ARSIs. An ongoing Phase I dose-escalation and expansion study will assess the safety, tolerability, pharmacokinetics, and preliminary anti-tumor activity of GDC-2992 in patients with advanced or metastatic prostate cancer who have previously received AR-targeted therapy [NCT05800665]. By providing more complete and sustained AR inhibition, GDC-2992 has the potential to reduce the occurrence of treatment-resistance and disease relapse in prostate cancer. Citation Format: Ciara Metcalfe, Wei Zhou, Darlene Dela Cruz, Thomas Hunsaker, Pablo Saenz-Lopez Larrocha, Elizabeth Levy, Bu-Er Wang, Tonia Hafner, Nayan Chaudhary, Marc Hafner, Kalpit Shah, Elisia Villemure, Yuxiang Zheng, Jodie Pang, Udi Segal. GDC-2992: A heterobifunctional Androgen Receptor (AR) antagonist and degrader for the treatment of AR wild-type and mutant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr ND02.