Sionna Therapeutics, Inc. reported financial results for the third quarter ended September 30, 2026, and provided an update on its clinical development pipeline. The company announced that it is advancing its SION-451 + SION-2222 dual combination into an AscenSION CF Phase 2 proof-of-concept trial, with plans to initiate the study in the first quarter of 2027.
The open-label trial will evaluate participants with cystic fibrosis who are homozygous for the F508del mutation. Participants will receive the dual combination for 28 days after switching from Trikafta. The trial will assess sweat chloride levels, safety, and pharmacokinetics, incorporating design elements based on learnings from the PreciSION CF trial.
The decision to advance the dual combination follows a review of data from the PreciSION CF Phase 2a trial of SION-719, which did not meet its key activity endpoint. Post hoc analyses of that trial suggested a mean placebo-adjusted sweat chloride reduction of up to -8.6 mmol/L when SION-719 was added to Trikafta. Sionna also presented clinical and nonclinical data at the 2026 North American Cystic Fibrosis Conference in October, highlighting the potential of NBD1 stabilizer combinations to benefit a broad population of people with CF.
On the corporate front, Sionna implemented a workforce reduction of approximately 46% in September 2026 to focus resources on the SION-451 + SION-2222 program and extend its operating runway. As of September 30, 2026, the company reported cash, cash equivalents, and marketable securities totaling $249.8 million. Sionna expects this cash position to fund operations into the second half of 2029.
For the third quarter of 2026, the company reported research and development expenses of $22.0 million and general and administrative expenses of $12.8 million. This resulted in a net loss of $32.4 million for the quarter, compared to a net loss of $20.3 million in the prior year period.
