UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): January 8, 2026 Image_0.jp ARDELYX, INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation) (Commission File Number) Delaware 001-36485 26-1303944 (IRS Employer Identification Number) 400 FIFTH AVE., SUITE 210, WALTHAM, MASSACHUSETTS 02451 (Add ...