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
5638 - Incidence of Vascular Thromboembolism Events in Cancer Patients Receiving Immunotherapy: A Single Institution Experience.
Presenter: Laura Gutiérrez Sainz
Session: Poster Display session 1
Resources:
Abstract
5182 - High Incidence of Venous Thromboembolic Events (VTE) in Patients with Diffuse Large B-Cell Lymphoma.
Presenter: Alaa Abufara
Session: Poster Display session 1
Resources:
Abstract
1504 - Weight Loss over Time in Non-Small Cell Lung Cancer: Results from a Landmark Analysis of 800+ Prospectively-Treated Patients
Presenter: Jennifer Le-rademacher
Session: Poster Display session 1
Resources:
Abstract
3972 - The prognostic significance of preoperative nutritional status in resected pancreatic ductal adenocarcinoma (PDAC).
Presenter: Salvatore Paiella
Session: Poster Display session 1
Resources:
Abstract
2313 - Impact of Timing and Technique of Gastrostomy Placement on the Outcome of Patients (pts) with Head and Neck Cancer (HNC)
Presenter: M Julia Lostes Bardaji
Session: Poster Display session 1
Resources:
Abstract
5219 - Clinical & nutritional determinants of quality of life in patients with incurable cancer
Presenter: Louise Daly
Session: Poster Display session 1
Resources:
Abstract
4075 - Loss of skeletal muscle mass during palliative chemotherapy is a poor prognostic factor in patients with advanced gastric cancer
Presenter: In Gyu Hwang
Session: Poster Display session 1
Resources:
Abstract
4159 - Impact of nutritional derangement on treatment outcome in advanced non-small-cell lung cancer (A-NSCLC) patients (pts).
Presenter: Ilaria Trestini
Session: Poster Display session 1
Resources:
Abstract
1210 - Sarcopenia and pretreatment anemia as prognostic factors for patients with localized muscle invasive bladder cancer treated by neoadjuvant chemotherapy and radical cystectomy
Presenter: Emilien Billon
Session: Poster Display session 1
Resources:
Abstract
2490 - Gender effect on the pharmacokinetics (PK) and pharmacodynamics (PD) of anamorelin (ANAM) in healthy volunteers and cancer patients with cachexia
Presenter: Stein Kaasa
Session: Poster Display session 1
Resources:
Abstract