WALTHAM, Mass., April 27, 2026 (GLOBE NEWSWIRE) -- Sionna Therapeutics, Inc. (Nasdaq: SION), a clinical-stage biopharmaceutical company on a mission to revolutionize the current treatment paradigm for cystic fibrosis (CF), today announced the completion of enrollment in the PreciSION CF Phase 2a proof-of-concept (POC) trial. This trial is evaluating SION-719, a first-in-class nucleotide binding domain 1 (NBD1) stabilizer, when added to Trikafta® (elexacaftor/tezacaftor/ivacaftor), the current standard of care (SOC) in CF. Sionna anticipates data from the PreciSION CF trial in the summer of 2026.

“Completion of enrollment in our PreciSION CF proof-of-concept trial represents a significant milestone for both Sionna and the cystic fibrosis community,” said Charlotte McKee, M.D., Chief Medical Officer of Sionna. “This is the first clinical trial evaluating an NBD1 stabilizer in people with CF, marking an important step toward directly addressing the underlying defect of the most common CF-causing mutation. We are thankful to the patients, investigators, and the broader CF community for their strong engagement as we advance this trial. We remain focused on executing and look forward to our first data readout in CF patients this summer.”

The PreciSION CF Phase 2a trial ( NCT07108153 ) is a randomized, double-blind, placebo-controlled, crossover POC study that enrolled adult CF patients homozygous for F508del on a stable dose of physician-prescribed Trikafta. The objectives of the trial are to evaluate the safety, tolerability, and pharmacokinetics of SION-719 when administered with SOC and to assess change in sweat chloride levels, an important measure of CFTR function. The PreciSION CF trial is being conducted at multiple sites, including sites in the CF Foundation-supported Therapeutics Development Network (TDN), the largest CF clinical trials network in the world.

About Sionna Therapeutics
Sionna Therapeutics is a clinical-stage biopharmaceutical company on a mission to revolutionize the current treatment paradigm for cystic fibrosis (CF) by developing novel medicines that normalize the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Sionna’s goal is to deliver differentiated medicines for people living with CF that can restore their CFTR function to as close to normal as possible by directly stabilizing CFTR’s nucleotide binding domain 1 (NBD1), which Sionna believes is central to potentially unlocking dramatic improvements in clinical outcomes and quality of life for people with CF. Leveraging more than a decade of the co-founders’ research on NBD1, Sionna is advancing a pipeline of small molecules engineered to correct the defects caused by the F508del genetic mutation, which resides in NBD1. Sionna is also developing a portfolio of complementary CFTR modulators that are designed to work synergistically with its NBD1 stabilizers to improve CFTR function. For more information about Sionna, visit www.sionnatx.com .

Cautionary Note Regarding Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, implied and express statements about Sionna’s beliefs and expectations regarding: its goal of transforming the treatment paradigm for CF; the timing, progress, objectives and results of the development of its clinical and preclinical pipeline; the therapeutic potential, clinical benefits and safety of Sionna’s product candidates, including with respect to SION-719; the timing of topline data from the PreciSION CF Phase 2a clinical trial; the ability of clinical trials to demonstrate safety and efficacy of Sionna’s product candidates; and other statements that are not historical facts. In some cases, the forward-looking statements can be identified by terms such as “may,” “will,” “should,” “would,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “believe,” “estimate,” “predict,” “potential” or “continue” or the negative of these terms or other similar expressions. Any forward-looking statements in this press release are based on management’s current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by the forward-looking statements contained in this press release, including, without limitation, risks associated with: uncertainties inherent in the development of product candidates, including concerning the initiation, timing, design, progress, and results of current and future clinical trials; the Company’s ability to replicate positive results from earlier preclinical studies or clinical trials in current or future clinical trials; the Company’s ability to demonstrate that its product candidates are safe and effective for their proposed indications; the timing and outcome of interactions with regulatory authorities, and any regulatory developments in the United States and foreign countries; the availability of funding sufficient for the Company’s operating expenses and capital expenditure requirements; and general economic, industry and market conditions. These risks and uncertainties are described in the section entitled “Risk Factors” in Sionna’s most recent Annual Report on Form 10-K as well as any subsequent filings with the Securities and Exchange Commission. The events and circumstances reflected in the forward-looking statements may not be achieved or occur. In addition, any forward-looking statements represent Sionna’s views only as of today and should not be relied upon as representing its views as of any subsequent date. Sionna explicitly disclaims any obligation to update any forward-looking statements except as required by law. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements.

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