As filed with the Securities and Exchange Commission on June 27, 2024 Registration No. 333-280326 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO. 1 TO THE FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 GT BIOPHARMA, INC. (Exact name of registrant as specified in its charter) Delaware 2834 94-1620407 State or other jurisdiction (Primary Standard Industrial (I.R.S. Employer incorporation or organization Classification Code Number) Identification Number) ...