Post hoc analyses of SION-719 PreciSION CF subset showed a mean placebo-adjusted sweat chloride reduction of up to -8.6 mmol/L consistent with NBD1 biological activity

Dual combination Phase 2a trial expected to initiate in first quarter of 2027

46% workforce reduction and other cost-saving measures prioritize advancing the dual combination program and extend cash runway into the second half of 2029

Sionna to host conference call today at 4:30 p.m. ET

WALTHAM, Mass., Sept. 14, 2026 (GLOBE NEWSWIRE) -- Sionna Therapeutics, Inc. (NASDAQ:SION), a clinical-stage biopharmaceutical company on a mission to develop novel medicines for cystic fibrosis (CF), today announced plans to advance SION-451 + SION-2222, its preferred proprietary dual combination, into the AscenSION CF Phase 2a proof-of-concept (POC) trial, and results from the company’s post hoc analysis of the PreciSION CF Phase 2a trial. The decision to advance SION-451 + SION-2222 follows an extensive review of clinical, pharmacokinetic (PK) and nonclinical data from PreciSION CF. Learnings from that trial and the previous Phase 1 dual combination trial will inform the development strategy for the dual combination.