ESSA Pharma Inc. — Director's Dealing 2025

Oct 14, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ESSA Pharma Inc. (EPIX)
CIK: 0001633932
Period of Report: 2025-10-09

Reporting Person: BVF PARTNERS L P/IL (10% Owner)
Reporting Person: BIOTECHNOLOGY VALUE FUND L P (10% Owner)
Reporting Person: BVF I GP LLC (10% Owner)
Reporting Person: BIOTECHNOLOGY VALUE FUND II LP (See Explanation of Responses)
Reporting Person: BVF II GP LLC (See Explanation of Responses)
Reporting Person: Biotechnology Value Trading Fund OS LP (See Explanation of Responses)
Reporting Person: BVF Partners OS Ltd. (See Explanation of Responses)
Reporting Person: BVF GP HOLDINGS LLC (10% Owner)
Reporting Person: BVF INC/IL (10% Owner)
Reporting Person: LAMPERT MARK N (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-10-09	Common Stock	U	6194145	—	Disposed	0	Direct
2025-10-09	Common Stock	U	4726743	—	Disposed	0	Direct
2025-10-09	Common Stock	U	560797	—	Disposed	0	Direct

Footnotes

F1: This Form 4 is filed jointly by Biotechnology Value Fund, L.P. ("BVF"), Biotechnology Value Fund II, L.P. ("BVF2"), Biotechnology Value Trading Fund OS LP ("Trading Fund OS"), BVF Partners OS Ltd. ("Partners OS"), BVF I GP LLC ("BVF GP"), BVF II GP LLC ("BVF2 GP"), BVF GP Holdings LLC ("BVF GPH"), BVF Partners L.P. ("Partners"), BVF Inc. and Mark N. Lampert (collectively, the "Reporting Persons"). Each of the Reporting Persons is a member of a Section 13(d) group. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein except to the extent of his or its pecuniary interest therein.

F2: This Form 4 reports securities disposed of pursuant to an arrangement under Section 288 of the Business Corporations Act (British Columbia) involving the Issuer, XenoTherapeutics, Inc. (the "Parent"), Xeno Acquisition Corp. (the "Purchaser"), a wholly-owned subsidiary of Parent, and XOMA Royalty Corporation pursuant to a business combination agreement dated July 13, 2025, and the plan of arrangement, pursuant to which, among other things, the Purchaser acquired all of the outstanding shares of common stock of the Issuer, effective October 9, 2025 (the "Merger").

F3: Securities owned directly by BVF. As the general partner of BVF, BVF GP may be deemed to beneficially own the securities owned directly by BVF. As the sole member of BVF GP, BVF GPH may be deemed to beneficially own the securities owned directly by BVF. As the investment manager of BVF, Partners may be deemed to beneficially own the securities owned directly by BVF. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF.

F4: Securities owned directly by BVF2. As the general partner of BVF2, BVF2 GP may be deemed to beneficially own the securities owned directly by BVF2. As the sole member of BVF2 GP, BVF GPH may be deemed to beneficially own the securities owned directly by BVF2. As the investment manager of BVF2, Partners may be deemed to beneficially own the securities owned directly by BVF2. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF2. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF2.

F5: Securities owned directly by Trading Fund OS. As the general partner of Trading Fund OS, Partners OS may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment manager of Trading Fund OS and the sole member of Partners OS, Partners may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment adviser and general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by Trading Fund OS. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by Trading Fund OS.

F6: The Reporting Persons received the following in exchange for each share of the Issuer's common stock disposed of in connection with the Merger: $0.124231 in cash per share of common stock (excluding the approximately $1.69 of cash per share of common stock previously distributed to the Issuer's shareholders) and one contingent value right per share of common stock for potential cash payments of up to approximately $0.14 per share of common stock.