As filed with the Securities and Exchange Commission on September 10, 2025 Registration Statement No. 333-289864 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1/A (Amendment No. 1) REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 ENTERO THERAPEUTICS, INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Delaware 2834 46-4993860 (Primary Standard Industrial Classification Code Number) (I.R.S. Employer ...