Abstract 5965
Background
The androgen receptor (AR) pathway drives most metastatic castration-resistant prostate cancers (mCRPC) even in late stages of the disease. Anti-androgen resistance mechanisms include AR gene amplification, C-terminal ligand-binding domain (LBD) mutations and expression of constitutively-active truncated AR splice variants lacking the LBD (eg. AR-V7). Selective inhibition of the N-terminal domain (NTD) of the AR can inhibit its’ transcriptional activity even in the presence of LBD-driven resistance. A Phase I clinical trial of the first-generation AR NTD inhibitor, EPI-506, demonstrated minor PSA declines in mCRPC patients. EPI-7386 is a more potent and stable NTD inhibitor (Anitens) that is advancing to clinical trials. The compounds’ characteristics and the initial clinical study plans including potential biomarkers will be reviewed.
Methods
Chemical structure activity relationships were developed to increase molecule potency using a wide variety of CRPC models in vivo and in vitro. Similarly, the stability and selectivity of the molecule were characterized with screening and functional assays. Biomarkers were also explored.
Results
EPI-7386 demonstrated a 20 fold improvement in AR-driven cellular potency compared to EPI-002, while being highly stable in human and animal hepatocytes. In vitro proliferation assays demonstrated on-target activity across a panel of prostante cancer cell lines, with activity in AR-V7-driven cellular models. EPI-7386 was able to control tumor growth and induce tumor regressions in several CRPC xenografts, including enzalutamide resistant models. In addition, the combination of enzalutamide with EPI-7386 demonstrated a more robust and more homogeneuous antitumor response. Pharmacodynamic markers specific to NTD inhibitors will be presented.
Conclusions
The next generation aniten compound EPI-7386 is more active and more metabolically stable than EPI-002. It demonstrated potential as single agent in overcoming anti-androgen clinical resistance as well as in combination therapy in earlier stages of the disease. The clinical strategy supporting the development of this new generation of Aniten will be discussed.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
ESSA Pharmaceuticals.
Funding
ESSA Pharmaceuticals.
Disclosure
R. Le Moigne: Full / Part-time employment: ESSA pharma. C.A. Banuelos: Shareholder / Stockholder / Stock options: ESSA pharma. N.R. Mawji: Shareholder / Stockholder / Stock options: ESSA pharma. R.J. Andersen: Research grant / Funding (institution), Shareholder / Stockholder / Stock options, Officer / Board of Directors: ESSA pharma. A. Cesano: Advisory / Consultancy: ESSA pharma; Full / Part-time employment: Nanostring. M.D. Sadar: Speaker Bureau / Expert testimony, Leadership role, Research grant / Funding (institution), Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Officer / Board of Directors: ESSA pharma; Speaker Bureau / Expert testimony: Pfizer. H. Zhou: Shareholder / Stockholder / Stock options, Full / Part-time employment: ESSA pharma. P. Virsik: Shareholder / Stockholder / Stock options, Full / Part-time employment: ESSA pharma. All other authors have declared no conflicts of interest.
Resources from the same session
3181 - Effects of Three Products in the Prevention and Treatment of Chemotherapy and Radiation Therapy-Induced Oral Mucositis
Presenter: Francesca Zannier
Session: Poster Display session 1
Resources:
Abstract
2433 - Boiling Histotripsy-induced Mechanical Ablation Modulates Tumour Microenvironment by Promoting Immunogenic Cell Death of Cancers
Presenter: Cheol-Hee Shin
Session: Poster Display session 1
Resources:
Abstract
2663 - The bacterial receptor NOD2 mediates LGR5+ intestinal stem cells protection against irradiation via mitophagy activation
Presenter: Antonin Levy
Session: Poster Display session 1
Resources:
Abstract
3213 - Pulse mode irradiation regimen of PDT results in high progression free and overall survival in mice with model tumor
Presenter: Alexey Bogdanov
Session: Poster Display session 1
Resources:
Abstract
3722 - Proton-sensitizing effect of small molecule inhibitor of P300 histone acetyltransferase C646 in human pancreatic cancer cells.
Presenter: Sungwon Shin
Session: Poster Display session 1
Resources:
Abstract
5805 - Red-Blood-Cell-Membrane-Enveloped Magnetic Nanoclusters as a Biomimetic Theranostic Nanoplatform for Bimodal Imaging Guided Cancer Photothermal Therapy
Presenter: sheng wang
Session: Poster Display session 1
Resources:
Abstract
5251 - Urine cell-free and extracellular vesicle cargo miRNAs as biomarkers for prostate cancer diagnosis
Presenter: Ivan Zaporozhchenko
Session: Poster Display session 1
Resources:
Abstract
3657 - Parkin, APEX1 and BCL2L1 Tissue Expression in Southern Brazilian Patients with Different Breast Cancer Molecular Subtypes
Presenter: Bianca Cabral
Session: Poster Display session 1
Resources:
Abstract
2839 - Obesity and prognosis in breast cancer
Presenter: Noha Ibrahim
Session: Poster Display session 1
Resources:
Abstract
5132 - SIPA1 is a modulator of HGF induced tumor metastasis via the regulation of tight junctions in lung adenocarcinoma cells
Presenter: Chang Liu
Session: Poster Display session 1
Resources:
Abstract