Table of Contents As filed with the Securities and Exchange Commission on December 11, 2023 Registration No. 333-275870 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO.1 To FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 APTOSE BIOSCIENCES INC. (Exact Name of Registrant As Specified In Its Charter) (State or other jurisdiction of incorporation or organization) Canada 2836 98-1136802 (Primary Standard Industrial Classification Code Number) (I.R.S. Employe ...