Sionna Therapeutics, Inc.

Sionna Therapeutics, Inc. (Nasdaq: SION) is a clinical-stage biopharmaceutical company focused on developing novel medicines to treat cystic fibrosis by normalizing the function of the cystic fibrosis transmembrane conductance regulator protein. The company's website is www.sionnatherapeutics.com.

The company's mission centers on revolutionizing the treatment paradigm for cystic fibrosis, a progressive and life-threatening genetic disease affecting approximately 40,000 people in the United States and 106,000 globally across 94 countries. Sionna's approach targets the nucleotide binding domain 1 of the CFTR protein, which has historically been considered undruggable despite being identified as critical for proper CFTR function. The company leverages more than a decade of its co-founders' research on NBD1 stabilization, combined with biophysical, cell-based, and virtual screening campaigns and structural biology insights.

Sionna's pipeline includes multiple product candidates at various development stages. SION-719, a highly potent NBD1 stabilizer, is currently in a Phase 2a proof-of-concept trial called PreciSION CF, evaluating its use as an add-on to the standard of care. SION-451, another NBD1 stabilizer, is being evaluated in Phase 1 dual combination trials with complementary modulators SION-2222 and SION-109. The company also maintains a portfolio of additional CFTR modulators including SION-2851 and SION-3067 at earlier development stages.

The company's competitive advantage stems from its focus on NBD1 stabilization, a mechanism not directly targeted by currently approved therapies. Sionna employs a proprietary cystic fibrosis human bronchial epithelial model as a translational roadmap to predict clinical outcomes and prioritize compounds for development. This model has demonstrated high correlation with clinical trial results for approved CFTR modulators.

The global market for approved CFTR modulators reached approximately twelve billion dollars in 2025, with projections exceeding fifteen billion by 2030. Despite advances in treatment, at least two-thirds of patients on current standard-of-care therapies do not achieve normal CFTR function, representing a significant unmet medical need that Sionna aims to address through its differentiated approach.