Sionna Therapeutics Targets $156 Million in IPO to Advance Cystic Fibrosis Research

Sionna Therapeutics, a biotechnology firm headquartered in Waltham, Massachusetts, is preparing to raise up to $156 million through an initial public offering (IPO) as it aims to propel its leading cystic fibrosis (CF) candidate into the next phase of clinical development.
The company had previously signaled its plans to go public, but a recent filing with the Securities and Exchange Commission on has provided more concrete details. Sionna intends to offer approximately 8.8 million shares, with an anticipated price range of $16 to $18 per share. If the shares are priced at the midpoint of this range, the company expects to generate around $135.3 million in net proceeds. This figure could rise to $156.2 million if underwriters fully exercise their 30-day option to purchase an additional 1.3 million shares at the same price.

Sionna’s IPO comes shortly after other biotech firms, including Metsera and Maze Therapeutics, launched their own Nasdaq offerings, raising $275 million and $140 million, respectively. These recent IPOs reflect a broader trend of biotech companies seeking public funding to support research and development efforts.
The proceeds from Sionna’s IPO will primarily support the advancement of its lead therapeutic candidate, a combination of an NBD1 stabilizer and a complementary modulator. This combination is currently in early-stage clinical trials, with plans to progress through phase 1 and phase 2a trials and eventually into phase 2b. While the specific molecules for the combination have yet to be finalized, the company is evaluating various candidates.
An important aspect of Sionna’s development strategy involves potential collaboration with AbbVie. Under an existing agreement, Sionna may owe AbbVie up to $360 million in milestone payments and has granted the pharmaceutical giant rights to the first negotiation for three CFTR modulators acquired from AbbVie in 2023. These modulators could play a critical role in Sionna’s ongoing research efforts.
Sionna also plans to investigate the efficacy of its lead candidate in combination with Trikafta, a CF treatment developed by Vertex Pharmaceuticals. Additionally, the company aims to explore the potential of its molecule when paired with its own CFTR modulators, broadening the scope of its research.

However, Sionna acknowledges the challenges associated with its clinical trials, particularly those that might require participants to discontinue standard-of-care treatments. In its initial IPO filing, the company noted that AbbVie had previously terminated part of a phase 2 study involving a CFTR potentiator and corrector licensed to Sionna, citing difficulties in enrolling participants due to the widespread availability of Trikafta.