Sionna Therapeutics (SION.US) has filed for a US$100 million IPO.

Second-stage biotechnology company Sionna Therapeutics, which is developing new therapies for cystic fibrosis, filed a preliminary prospectus with the U.S. Securities and Exchange Commission on Friday to raise up to $100 million in an initial public offering.

Sionna is developing treatments for CF patients that normalize the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which is dysfunctional in CF patients. The company's goal is to restore CFTR function as much as possible by directly stabilizing the nucleotide binding domain 1 (NBD1) of CFTR, which is different from the current CFTR modulator therapies marketed by Vertex Pharmaceuticals (VRTX.US). Currently, Vertex sells all five approved CFTR modulators, and the drugs are expected to generate about $10 billion in sales in 2023.

Sionna is emphasizing that its chief medical officer previously served as the vice president of cystic fibrosis at Vertex. The company is currently conducting Phase 1 trials of its two main NBD1 stabilizer candidates and expects to start Phase 2a trials in the second half of 2025. The company is also conducting a series of complementary CFTR modulator Phase 1 and 2 trials, some of which are licensed from AbbVie.

Sionna was founded in 2019 and plans to list on the Nasdaq under the ticker symbol SION. Sionna Therapeutics filed confidentially on September 12, 2024. Goldman, TD Cowen, Stifel, and Guggenheim Securities are joint bookrunners on the deal. The company did not disclose pricing terms.