Material Modifications to Rights of Security Holders. To the extent required by

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard. On May 20, 2026, GT Biopharma, Inc., a Delaware corporation (the “Company”), received a letter from the Nasdaq Listing Qualifications Staff (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) notifying the Company that the Staff has granted the Company an additional compliance period of 180 calendar days, or until November 16, 2026, to regain compliance with Nasdaq Listing Rule 5550(a)(2), which requires liste…

Entry into a Material Definitive Agreement. On April 3, 2026, GT Biopharma, Inc., a Delaware corporation (the “Company”), entered into an Investigator Initiated Clinical Trial Agreement (the “Agreement”) with the Regents of the University of Minnesota (the “University”), pursuant to which, the University shall sponsor an Investigational New Drug (“IND”) application for IND 169118 GTB-5550 (the “Research Program”) and shall serve as a sponsor investigator for a phase 1a/1b clinical trial entit…

Non-Reliance on Previously Issued Financial Statements or a Related Audit Report or Completed Interim Review. In connection with the preparation of GT Biopharma, Inc.’s (the “Company”) Annual Report on Form 10-K for the year ended December 31, 2025 (“2025 Form 10-K”), the Company’s management, in consultation with its independent registered public accounting firm Weinberg & Company, P.A. (“Weinberg”), reevaluated the classification of certain stock purchase rights to purchase shares of Series…

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. On November 20, 2025, GT Biopharma, Inc. (the “Company”) received a letter (the “Letter”) from the Nasdaq Listing Qualifications Staff (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) notifying the Company that its common stock, $0.001 par value per share (the “Common Stock”) had closed below $1 per share for 30 consecutive business days and, as a result, the Company was not in complian…

Results of Operations and Financial Condition. On November 14, 2025, GT Biopharma, Inc. issued a press release announcing its financial results for its fiscal quarter ended September 30, 2025. A copy of the press release is furnished as Exhibit 99.1. The information furnished under this Item 2.02, including Exhibit 99.1, is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by refe…

Material Modification to Rights of Security Holders. On each of September 17, 2025, September 18, 2025 and September 23, 2025, certain of the holders of GT Biopharma, Inc.’s Series L 10% Convertible Preferred Stock (the “Series L Preferred Stock”) provided a waiver (the “Waiver”) to the Certificate of Designation of Preferences, Rights and Limitations of Series L 10% Convertible Preferred Stock (the “Certificate of Designations”). Pursuant to the Waiver, such Series L Preferred Stockholders a…

Chief Executive Officer — Michael Breen: The employment agreement was amended to renew Mr. Breen's position as Chief Executive Officer for a period of two years with automatic renewal provisions.

Director — Andrew Ritter: Andrew Ritter resigned as a member of the board of directors.

Entry into a Material Definitive Agreement. Common Shares Purchase Agreement As previously disclosed on May 14, 2025, GT Biopharma, Inc. (the “Company”) entered into a common shares purchase agreement (the “Purchase Agreement”) with investors (each an “Investor,” and collectively, the “Investors”) relating to a committed equity facility (the “Facility”). Pursuant to the Purchase Agreement, the Company has the right from time to time at its option to sell to the Investors up to $20 million of…

Unregistered Sales of Equity Securities. The information set forth in

Material Modification to Rights of Security Holders. The information set forth in

Entry into a Material Definitive Agreement. Private Placement of Preferred Stock and Warrants As previously disclosed on May 12, 2025, GT Biopharma, Inc. (the “Company”) entered into a Securities Purchase Agreement (the “Securities Purchase Agreement”) with the purchasers identified therein (collectively, the “Original Purchasers”) providing for the issuance and sale to the Original Purchasers of (i) up to 6,056 shares of the Company’s Series L 10% Convertible Preferred Stock (the “Preferred…

in its entirety. On May 12, 2025, the Company filed a Certificate of Designation of Preferences, Rights and Limitations of Series L 10% Convertible Preferred Stock with the Secretary of State of the State of Delaware, in the form attached as Exhibit 3.1 to this Current Report on Form 8-K. The Certificate of Designation creates and specifies the rights of Series L 10% Convertible Preferred Stock, including the terms and conditions on which shares of such preferred stock would convert into shar…

Entry into a Material Definitive Agreement. Private Placement of Preferred Stock and Warrants On May 12, 2025, GT Biopharma, Inc. (the “Company”) entered into a Securities Purchase Agreement (the “Securities Purchase Agreement”) with the purchasers identified therein (collectively, the “Purchasers”) providing for the issuance and sale to the Purchasers of (i) up to 6,056 shares of the Company’s Series L 10% Convertible Preferred Stock (the “Preferred Stock”), (ii) warrants to purchase up to a…

Unregistered Sales of Equity Securities. The information set forth in

Director — Bruce Wendel and Rajesh Shrotriya: Two directors resigned from the board.

Chief Executive Officer — Michael Breen: Michael Breen was appointed as the Chief Executive Officer, a significant internal promotion.

Unregistered Sales of Equity Securities. On March 31, 2025, GT Biopharma, Inc. (the “Company”) issued to Cytovance Biologics, Inc. (“Cytovance”) a pre-funded warrant (the “Warrant”) to purchase up to 326,251 shares of Common Stock (the “Warrant Shares”) in partial consideration for services provided to the Company by Cytovance. The Warrant is immediately exercisable, in whole or in part and at any time, subject to limitations on beneficial ownership as set forth therein, until the pre-funded…

The Inducement Warrants are being sold and, upon exercise the Inducement Warrant Shares, will be issued without registration under the Securities Act, in reliance on the exemptions provided by Section 4(a)(2) of the Securities Act as a transaction not involving a public offering and Rule 506 promulgated under the Securities Act as sales to accredited investors, and in reliance on similar exemptions under applicable state laws. The Holders made relevant representations in their respective Indu…

Entry into a Material Definitive Agreement. Warrant Inducement On February 25, 2025, GT Biopharma, Inc. (the “Company”) entered into warrant exercise inducement offer letter agreements (each an “Inducement Letter” and together, the “Inducement Letters”) with certain holders (each a “Holder” and collectively, the “Holders”) of existing warrants to purchase the Company’s common stock, par value $0.001 per share (the “Common Stock”), exercisable for an aggregate of 302,069 shares of Common Stock…

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. On November 21, 2024, GT Biopharma, Inc. (the “Company”) received a letter (the “Letter”) from the Nasdaq Listing Qualifications Staff (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) notifying the Company that its amount of stockholders’ equity has fallen below the $2,500,000 required minimum for continued listing set forth in Nasdaq Listing Rule 5550(b)(1). Nasdaq’s determination was…

Entry into a Material Definitive Agreement. On November 18, 2024, the Registrant entered into an Investigator Initiated Clinical Trial Agreement (the “Agreement”) with the Regents of the University of Minnesota (the “University”), pursuant to which, the University shall sponsor an Investigational New Drug (“IND”) application for IND 165546 GTB-3650 (the “Research Program”) and shall serve as a sponsor investigator for a phase 1 clinical trial entitled, “GTB-3650 (CD16/IL-15/CD33) Tri-Specific…

Consulting Senior Medical Director — Dr. Jeffrey Miller: Dr. Miller's title change is due to aligning with the University of Minnesota’s policies regarding conflicts of interest.

Chief Financial Officer — Manu Ohri: The CFO's employment was terminated and a new CFO was appointed.