Sionna Therapeutics, Inc. (SION)

Sionna Therapeutics, Inc. is a clinical-stage biopharmaceutical company based in the Boston area. It went public on the Nasdaq in 2025 and is developing new medicines for cystic fibrosis.

The company's research centers on the first nucleotide-binding domain (NBD1) of the CFTR protein. In patients with the most common cystic fibrosis mutation, F508del, this domain fails to fold properly. Sionna is developing small-molecule NBD1 stabilizers that it hopes can restore CFTR function to near-normal levels, either alone or combined with other CFTR modulators.

Its pipeline includes several NBD1 stabilizer candidates as well as complementary modulators intended for use in combination regimens.