Form SCHEDULE 13D/A Outlook Therapeutics, Filed by: GMS Ventures & Investments

The response to Item 3 in the Schedule 13D is hereby amended to add the following after the last paragraph: The source of funds for the purchases in the May 2026 Offering (as defined below) was the working capital of GMS Ventures and capital contributions made to GMS Ventures.

Item 4 of the Schedule 13D is hereby amended to add the following after the last paragraph: On May 28, 2026, GMS Ventures entered into a securities purchase agreement with the Issuer (the "May 2026 SPA") pursuant to which the Issuer agreed to sell, and GMS Ventures agreed to purchase, 8,539,709 Shares at the price of $0.5855 per Share, for an aggregate purchase price of approximately $5.0 million in a registered direct offering (the "May 2026 Offering"), subject to customary closing conditions. The May 2026 Offering closed on May 29, 2026. In connection with the May 2026 Offering, on May 28, 2026, the Issuer entered into a warrant amendment agreement (the "May 2026 Warrant Amendment") with GMS Ventures pursuant to which the Issuer agreed to amend certain outstanding common stock warrants to purchase up to an aggregate of 15,488,570 shares of Common Stock previously issued to GMS Ventures in January 2025 and May 2025, with a weighted average exercise price of $1.78 per share, effective upon the closing of the May 2026 Offering, such that the amended warrants have a reduced exercise price of $0.5855 per share. Other than as described herein, the terms of the amended warrants remain unchanged.

Item 5 of the Schedule 13D is hereby amended and restated in its entirety to read: The following disclosure is based upon 148,587,119 Shares outstanding immediately following the May 2026 Offering as of May 29, 2026, as set forth in the Issuer's Prospectus Supplement, as filed pursuant to Rule 424(b)(5), filed with the SEC on May 29, 2026, plus 15,488,570 Shares underlying the Warrants. As of the date hereof, GMS Ventures directly owns 22,092,068 Shares and 15,488,570 warrants to purchase Shares, representing a total of 37,580,638 Shares beneficially owned by GMS Ventures. This represents approximately 22.9% of the outstanding Shares, calculated pursuant to Rule 13d-3 under the Act. Sukhtian is the holder of a controlling interest in GMS Holdings, which is the sole owner of GMS Ventures. By virtue of such relationship, Sukhtian may be deemed to beneficially own the securities held by GMS Ventures for purposes of Rule 13d-3 under the Act. This represents approximately 22.9% of the outstanding Shares calculated pursuant to Rule 13d-3 under the Act.

GMS Ventures: 1. Sole power to vote or direct vote: 0 2. Shared power to vote or direct vote: 37,580,638 3. Sole power to dispose or direct the disposition: 0 4. Shared power to dispose or direct the disposition: 37,580,638 Sukhtian: 1. Sole power to vote or direct vote: 0 2. Shared power to vote or direct vote: 37,580,638 3. Sole power to dispose or direct the disposition: 0 4. Shared power to dispose or direct the disposition: 37,580,638

The transactions described in Item 4 are incorporated herein by reference. Except as described in Item 4, the Reporting Persons have not effected any transactions in Shares during the past sixty (60) days.

Not applicable.

Not applicable.

Item 6 of the Schedule 13D is hereby amended to add the following after the last paragraph: May 2026 Securities Purchase Agreement Item 4 above summarizes certain provisions of the May 2026 SPA and is incorporated herein by reference. The description of the May 2026 SPA does not purport to be complete and is qualified in its entirety by reference to the full text of the May 2026 SPA, the form of which is filed as Exhibit 6 to this Schedule 13D, and is incorporated herein by reference. May 2026 Warrant Amendment Item 4 above summarizes certain provisions of the May 2026 Warrant Amendment and is incorporated herein by reference. The description of the May 2026 Warrant Amendment does not purport to be complete and is qualified in its entirety by reference to the full text of the May 2026 Warrant Amendment, the form of which is filed as Exhibit 5 to this Schedule 13D, and is incorporated herein by reference.

Item 7 of the Schedule 13D is hereby supplemented as follows: Exhibit No. Description 1. Joint Filing Agreement, between Ghiath M. Sukhtian and GMS Ventures and Investments, dated June 1, 2026.* 2. Amended & Restated Investor Rights Agreement by and between Outlook Therapeutics, Inc. and GMS Ventures and Investments, dated as of April 21, 2022 (incorporated by reference to Exhibit 10.1 to the Issuer's Form 8-K, filed with the SEC on April 22, 2022). 3. Power of Attorney by Ghiath M. Sukhtian, dated as of December 30, 2019 (incorporated by reference to Exhibit 24.4 to the Form 4 filed by Ghiath M. Sukhtian with the SEC on January 29, 2020). 4. Power of Attorney by GMS Ventures and Investments, dated as of February 25, 2020 (incorporated by reference to Exhibit 24.1 to the Form 3 filed by GMS Ventures and Investments with the SEC on February 27, 2020). 5. Form of Warrant Amendment, dated as of May 28, 2026, by and between the Issuer and GMS Ventures (incorporated by reference to Exhibit 4.1 to the Issuer's Form 8-K, filed with the SEC on May 28, 2026). 6. Form of Securities Purchase Agreement, dated as of May 28, 2026, by and between the Issuer and GMS Ventures (incorporated by reference to Exhibit 10.1 to the Issuer's Form 8-K, filed with the SEC on May 28, 2026). * Filed herewith.