Table of Contents UNDER THE SECURITIES ACT OF 1933 REIN THERAPEUTICS, INC. (Exact name of registrant as specified in its charter) As filed with the Securities and Exchange Commission on September 3, 2025 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1 REGISTRATION STATEMENT (State or other jurisdiction of incorporation or organization) (Primary Standard Industrial Classification Code) Delaware 2834 13-4196017 (I.R.S. Employer Identification No.) 12407 N ...