Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K __________________________ (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM____ to Commission file number 001-42504 _________________________________________________ SIONNA THERAPEUTICS, INC. (E ...

Exhibit 99.1 Sionna Therapeutics Reports Fourth Quarter and Full Year 2024 Financial Results Phase 1 MAD dosing completed for SION-451 and final MAD cohort of SION-719 planned; Interim data in healthy volunteers show potential to provide clinically meaningful benefit to CF patients. Topline data anticipated in first half of 2025 On track to initiate NBD1 Phase 2a proof-of-concept trial in combination with SOC in CF patients and combination MAD trials of an NBD1 stabilizer with a complementary modulator in h ...