Orally bioavailable


ANITAC™ degraders can eliminate full length, mutant and splice variant forms of AR that are expressed in castration-resistant prostate cancer (CRPC) patients

ANITAC degraders inhibit AR-dependent transcription and reduce viability of AR-dependent prostate cancer cells

Data to be presented at the 2022 American Association for Cancer Research Annual Meeting

SOUTH SAN FRANCISCO, CALIFORNIA

and

VANCOUVER, BC


,


April 8, 2022


/PRNewswire/ – ESSA Pharma Inc. (“ESSA”, or the “Company”) (NASDAQ: EPIX), a clinical-stage pharmaceutical company focused on developing novel therapies for the treatment of prostate cancer, today announced the presentation of preclinical data for its first generation of androgen receptor (AR) ANITen bAsed Chimera (ANITAC™) N-terminal domain (NTD) degraders at the 2022 American Association for Cancer Research (AACR) Annual Meeting.

“We look forward to presenting our first preclinical data demonstrating the potential of ESSA’s ANITAC degraders as a new approach to AR pathway inhibition. The NTD is a promising target for the suppression of AR biology which is responsible for driving most prostate cancers, but due to the intrinsically disordered nature of the NTD region of AR, it has been generally considered undruggable. Through their unique ability to bind to the NTD of AR, ANITACs have the ability to inhibit NTD-mediated AR transcription while also degrading AR protein including resistant forms of AR which are commonly associated with castration-resistant prostate cancer,” said Dr. David. R. Parkinson, Chief Executive Officer, ESSA Pharma Inc. “Our bifunctional degraders leverage ESSA’s deep scientific expertise and success in targeting the AR NTD with a new treatment modality aimed at suppressing AR biology by eliminating the AR protein itself. We look forward to providing further updates this year from this exciting new preclinical program.”

The preclinical results demonstrate that ANITAC degraders utilize the ubiquitin proteasome system and can degrade many forms of AR including full length, mutant and splice variants which are often expressed in CRPC patients. Specifically, the ANITAC degraders show robust potency in inhibiting AR transcriptional activity driven by AR-FL, AR-V7, or AR-V567es. In addition, the orally bioavailable ANITAC degraders exhibit high potency in inhibiting AR-dependent transcription and reducing viability of AR-dependent prostate cancer cells.

Poster presentation details are as follows:

Title:

Androgen receptor (AR) N-Terminal Domain degraders can degrade AR full length and AR splice variants in CRPC preclinical models


Authors:

Nan Hyung Hong,

et al.



Abstract Number:

429


Session Title:

Protein Degraders and Proteasome Inhibitors


Session Date and Time:


Sunday, April 10, 2022

|

1:30 p.m. – 5:00 p.m. ET



Location:

New Orleans Convention Center, Exhibit Halls D-H, Poster Section 26

The poster is available to 2022 AACR Annual Meeting attendees and in the Science section of the Company’s website at

www.essapharma.com

.

ESSA is a clinical-stage pharmaceutical company focused on developing novel and proprietary therapies for the treatment of patients with prostate cancer. For more information, please visit

www.essapharma.com

and follow us on Twitter under

@ESSAPharma

.

Prostate cancer is the second-most commonly diagnosed cancer among men and the fifth most common cause of male cancer death worldwide (Globocan, 2018). Adenocarcinoma of the prostate is dependent on androgen for tumor progression and depleting or blocking androgen action has been a mainstay of hormonal treatment for over six decades. Although tumors are often initially sensitive to medical or surgical therapies that decrease levels of testosterone, disease progression despite castrate levels of testosterone can lead to metastatic CRPC (mCRPC). The treatment of mCRPC patients has evolved rapidly over the past ten years. Despite these advances, many patients with mCRPC fail or develop resistance to existing treatments, leading to continued disease progression and limited survival rates.

This release contains certain information which, as presented, constitutes “forward-looking information” within the meaning of the Private Securities Litigation Reform Act of 1995 and/or applicable Canadian securities laws. Forward-looking information involves statements that relate to future events and often addresses expected future business and financial performance, containing words such as “anticipate”, “believe”, “plan”, “estimate”, “expect”, and “intend”, statements that an action or event “may”, “might”, “could”, “should”, or “will” be taken or occur, or other similar expressions and includes, but is not limited to, statements regarding the potential of ESSA’s ANITAC degraders as a new approach to AR pathway inhibition, NTD being a promising target for the suppression of AR biology, the potential benefits of ANITAC degraders, the anticipated timeline for providing further updates on preclinical programs, the ability of  ANITAC degraders to utilize the ubiquitin proteasome system and degrade many forms of AR, inhibit AR-dependent transcription and reduce viability of AR-dependent prostate cancer cells and other statements surrounding the Company’s clinical evaluation of ANITAC degraders.

Forward-looking statements and information are subject to various known and unknown risks and uncertainties, many of which are beyond the ability of ESSA to control or predict, and which may cause ESSA’s actual results, performance or achievements to be materially different from those expressed or implied thereby. Such statements reflect ESSA’s current views with respect to future events, are subject to risks and uncertainties and are necessarily based upon a number of estimates and assumptions that, while considered reasonable by ESSA as of the date of such statements, are inherently subject to significant medical, scientific, business, economic, competitive, political and social uncertainties and contingencies. In making forward looking statements, ESSA may make various material assumptions, including but not limited to (i) the accuracy of ESSA’s financial projections; (ii) obtaining positive results of clinical trials; (iii) obtaining necessary regulatory approvals; and (iv) general business, market and economic conditions.

Forward-looking information is developed based on assumptions about such risks, uncertainties and other factors set out herein and in ESSA’s Quarterly Report on Form 10-Q dated

February 3

, 2022 under the heading “Risk Factors”, a copy of which is available on ESSA’s profile on EDGAR at


www.sec.gov,


and as otherwise disclosed from time to time on ESSA’s SEDAR profile


www.sedar.com


.Forward-looking statements are made based on management’s beliefs, estimates and opinions on the date that statements are made and ESSA undertakes no obligation to update forward-looking statements if these beliefs, estimates and opinions or other circumstances should change, except as may be required by applicable Canadian and

United States

securities laws. Readers are cautioned against attributing undue certainty to forward-looking statements.

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SOURCE ESSA Pharma Inc