Welcome to our dedicated page for GT Biopharma SEC filings (Ticker: GTBP), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
GT Biopharma's SEC filings document the regulatory record of a Delaware clinical-stage immuno-oncology company developing TriKE® natural killer cell engager candidates. Registration statements describe securities offerings, Rule 415 offering status, issuer filer status and capital-structure information tied to common stock and preferred-stock instruments.
Current reports cover financial results, material clinical research agreements for GTB-5550, Nasdaq listing-compliance notices, and accounting conclusions involving Series L 10% Convertible Preferred Stock and related purchase rights. Other disclosures address waivers of preferred-stock redemption rights and non-reliance determinations for previously issued interim financial statements.
GT Biopharma, Inc. reports that all holders of its Series L 10% Convertible Preferred Stock have agreed to waive their contractual rights to redemption under Section 10 of the applicable certificate of designations. This means those preferred holders no longer have the ability to require the company to redeem the Series L shares for cash as previously provided.
The change modifies the rights of the Series L preferred stockholders and reduces a potential future cash obligation for the company, while leaving other terms to be interpreted from the full waiver document attached as an exhibit.
GT Biopharma, Inc. reports that certain holders of its Series L 10% Convertible Preferred Stock have agreed to waive their contractual redemption rights. On September 17, 18 and 23, 2025, these Series L preferred stockholders delivered a waiver to the company’s Certificate of Designation for the Series L 10% Convertible Preferred Stock.
Under this waiver, the participating Series L holders give up the right to require redemption described in Section 10 of the Certificate of Designations. This change reduces the possibility that the company could be required by these holders to redeem their preferred shares for cash or other consideration under that section. The company has filed the form of waiver as an exhibit so investors can review the detailed terms.
GT Biopharma director David C. Mun-Gavin acquired 31,250 shares of common stock by exercising options with a $1.33 exercise price. The reported transaction lists an acquisition of 31,250 option shares that convert to 31,250 common shares, and the filer notes the options are fully vested and exercisable.
The ownership after the reported transaction is 31,250 shares held directly. The filing is a standard Section 16 disclosure by an insider documenting option exercise and resulting beneficial ownership.
Michael Martin Breen, CEO and Director of GT Biopharma, reported three option grants on 09/04/2025 totaling 300,000 options to purchase common stock. Each option covers 100,000 shares with an exercise price of $1.33 and an expiration date of 08/19/2035. Following the reported transactions, Mr. Breen directly beneficially owns 100,000 shares for each grant (total reported underlying shares: 300,000). One grant is fully vested and exercisable; the other two vest in quarterly installments beginning 01/01/2025 and 01/01/2026 respectively. The form was signed on 09/08/2025.
Alan Urban, Chief Financial Officer of GT Biopharma, reported receipt of two stock option awards. Each option allows purchase of 50,000 shares of the company's common stock at an exercise price of $1.33 per share and lists 50,000 shares underlying each option. Both options expire on 08/19/2035. One option vests in four equal quarterly installments beginning on January 1, 2025; the other vests in four equal quarterly installments beginning on January 1, 2026. The filing reports the options as directly held by Mr. Urban and shows the reported post-transaction beneficial ownership as 50,000 shares per option line (totaling 100,000 underlying shares across both awards).
Charles J. Casamento, a director of GT Biopharma, acquired derivative securities tied to the company's common stock on 09/04/2025. The filing reports an acquisition of 62,500 options to purchase common stock with an exercise price of $1.33. The options are reported as fully vested and exercisable and are recorded as direct beneficial ownership of 62,500 underlying shares following the transaction. No cash price for the underlying shares is reported in the filing and no other transactions or dispositions are included.
Hilary Kramer, a director of GT Biopharma, Inc. (GTBP), exercised options to acquire 31,250 shares of common stock on 09/04/2025 at an exercise price of $1.33 per share. The options are reported as fully vested and exercisable, and following the transaction Ms. Kramer directly beneficially owns 31,250 shares. The Form 4 was signed by the reporting person and reflects a single option exercise converting derivative securities into common stock.
GT Biopharma, Inc. reported that it entered into Amendment No. 3 to the employment agreement with Michael Breen, the company’s Executive Chairman and Chief Executive Officer. The amendment is effective as of April 29, 2025 and renews Mr. Breen’s position as Chief Executive Officer for a two-year term starting from that date.
After this two-year period, Mr. Breen’s employment will automatically renew for additional two-year terms unless either GT Biopharma or Mr. Breen provides at least ninety days’ written notice that they do not wish to renew. The company filed the full text of Amendment No. 3 as an exhibit to this report for further details.