Rochester Resources Ltd. — Capital/Financing Update 2020

Aug 10, 2020

FORM 51-102F3 MATERIAL CHANGE REPORT

Item 1: Name and Address of Company ESSA Pharma Inc. ("ESSA" or the "Company") Suite 720, 999 West Broadway Vancouver, British Columbia, Canada V5Z 1K5

Item 2: Date of Material Change July 31, 2020

Item 3: News Release A news release announcing the material change referred to in this report was issued on July 31, 2020 through Canada NewsWire and a copy has been filed on SEDAR at www.sedar.com and EDGAR at www.sec.gov.

Item 4: Summary of Material Change On July 31, 2020, ESSA announced that it had closed an underwritten public offering of 7,100,000 common shares of the Company at a public offering price of US$6.00 per share, before underwriting discounts, for an aggregate offering of approximately US$42.6 million (the "Offering"). ESSA granted the underwriters a 30-day option to purchase up to an additional 1,065,000 common shares (the "Option"), and the underwriters exercised the Option on July 29, 2020.

Item 5: Full Description of Material Change 5.1 Full Description of Material Change On July 31, 2020, ESSA closed the Offering. ESSA granted the underwriters the Option, and the underwriters exercised the Option on July 29, 2020. The proceeds to ESSA from the Offering, including the exercise of the Option, were approximately US$45.0 million after deducting underwriting discounts and commissions (such commission being equal to 6% of the aggregate gross proceeds of the Offering) and other estimated offering expenses. Certain existing investors participated in the financing along with new investors Pfizer Inc. (NYSE: PFE), Avidity Partners, CAM Capital, Point72, Ridgeback Capital, Sphera Healthcare and Vivo Capital and others.

ESSA intends to use the net proceeds of the Offering for pre-clinical and clinical activities, chemistry, manufacturing and controls, research and development, as well as working capital and general corporate purposes. Such proceeds will primarily be used to expand the ongoing Phase 1 dose-escalation and extension studies and allow the potential for conducting multiple combination studies with EPI-7386. The proceeds are also expected to cover initial expenses of the following Phase 2 trial and allow further investment in the Company's pipeline programs. Based on current Company estimates, the net proceeds from the Offering combined with the Company's current cash reserves are expected to provide sufficient cash resources through 2023.

---

Jefferies acted as sole book-running manager for the Offering. Oppenheimer & Co. acted as lead manager for the Offering and Bloom Burton Securities Inc. acted as co-manager for the Offering.

The securities described above were offered by ESSA in the United States pursuant to a shelf registration statement on Form F-3 (File No. 333-225969) that was previously filed by ESSA with the Securities and Exchange Commission (the "SEC") and became effective on July 17, 2018 and in Canada pursuant to ESSA's Canadian short form base shelf prospectus (the "Canadian Base Shelf Prospectus") dated July 12, 2018 that was previously filed with the securities regulatory authorities in each of the provinces of British Columbia, Alberta and Ontario.

A preliminary prospectus supplement related to the Offering was filed with the SEC on July 28, 2020, and a final prospectus supplement related to the Offering was filed with the SEC on July 29, 2020, and each are available on the SEC's website at http://www.sec.gov. A preliminary prospectus supplement to ESSA's Canadian Base Shelf Prospectus was also filed with the securities regulatory authorities in each of the provinces of British Columbia, Alberta and Ontario on July 28, 2020 and is available at http://www.sedar.com and a final prospectus related to the Offering was filed with the securities regulatory authorities in each of the provinces of British Columbia, Alberta and Ontario on July 29, 2020 and is available at http://www.sedar.com.

The issuance of an aggregate of 341,666 common shares in the capital of the Company under the Offering, to certain insiders of the Company, for aggregate gross proceeds of US$2,049,996.00 constitutes a related-party transaction pursuant to Multilateral Instrument 61-101 - Protection of Minority Security Holders in Special Transactions, which is adopted in TSX-V Policy 5.9 ("MI 61-101"). Such insiders collectively held 3,942,973 common shares immediately prior to the Offering representing approximately 18.92% of the issued and outstanding common shares. Immediately following the closing of the Offering the insiders collectively held 4,284,639 common shares representing approximately 14.77% of the issued and outstanding common shares. These transactions are exempt from the formal valuation and minority shareholder approval requirements of MI 61-101 pursuant to sections 5.5(a) and 5.7(1)(a) of MI 61-101 as neither the fair market value of any securities issued to nor the consideration paid by such persons exceeds 25% of the Company's market capitalization.

The board of directors of the Company met to consider the Offering, the directors having an interest in the Offering declaring their interest in such Offering, and the board of directors formed a pricing committee (the "Pricing Committee") comprised entirely of directors who did not participate in the Offering, the Pricing Committee approved the Offering, the related party transaction and all ancillary matters. No materially contrary view was expressed nor was there any material disagreement in the approval process adopted by the directors. The insiders participated in the Offering on the same terms as conditions as the other investors in the Offering. The Company did not file this material change report 21 days prior to closing of the Offering, as such insiders participation was not settled until shortly prior to the closing, which the Company deemed reasonable in the circumstances in order to complete the Offering in a timely manner.

2

---

3

5.2 Disclosure of Restructuring Transactions

Not applicable.

Item 6: Reliance on subsection 7.1(2) of National Instrument 51-102

Not applicable.

Item 7: Omitted Information

Not applicable.

Item 8: Executive Officer

For further information, please contact David Wood, Chief Financial Officer of the Company at 778-331-0962.

Item 9: Date of Report

August 7, 2020