Sionna Therapeutics launches US $150M IPO for cystic fibrosis drugs

USA – Sionna Therapeutics, a biotech company based in Massachusetts, has announced its plans to raise US $150 million through an initial public offering (IPO).

The funds will be used to advance the company’s cystic fibrosis treatments into mid-stage clinical trials, aiming to compete in a market currently dominated by Vertex Pharmaceuticals.

The company plans to sell 8.8 million shares priced between US $16 and US $18 each. At the midpoint of this range, Sionna would achieve a market capitalization of approximately US $692 million. This announcement follows plans filed earlier in January.

Sionna’s focus is on developing innovative therapies targeting cystic fibrosis transmembrane conductance regulator (CFTR) proteins.

Mutations in these proteins are the primary cause of cystic fibrosis. The company is particularly interested in stabilizing the nucleotide-binding domain 1 (NBD1) of CFTR, which has been considered undruggable until now.

According to Sionna, its approach aims to restore CFTR function “as close to normal as possible.” The company’s two leading candidates, SION-719 and SION-451, are designed to stabilize NBD1. Both drugs are expected to enter Phase IIa trials later this year.

Additionally, Sionna is conducting Phase I/II studies on complementary CFTR modulators, including some acquired through a licensing deal with AbbVie.

Sionna’s development pipeline has caught attention in a market where the global demand for CFTR-targeting drugs reached US $10 billion in 2023 and is projected to grow to US $15 billion by 2029.

The most prominent drug in this space, Vertex’s Trikafta, enhances CFTR function through a different mechanism.

Analysts have noted that Sionna’s work could pose a significant challenge to Vertex’s dominance, suggesting Vertex should “stay vigilant.”

In March 2024, Sionna raised US $182 million in a Series C funding round, which, according to CEO Mike Cloonan, will sustain the company through 2026.

That same year, Sionna entered into a licensing agreement with AbbVie for two additional cystic fibrosis drugs currently in Phase II trials.

While Sionna’s approach has generated excitement, it’s not alone in exploring treatments for CFTR mutations.

Swiss-based Idorsia Pharmaceuticals recently published preclinical research on a drug targeting the same NBD1 mutation as Sionna’s candidates.

The biotech IPO landscape has been active recently. Along with IPOs from Metsera and Maze, the year began with Ascentage Pharma, a Chinese company, successfully obtaining a dual listing on NASDAQ.

Meanwhile, three other biotech firms—Aurion Biotech, Aardvark Therapeutics, and Odyssey Therapeutics—are preparing for their upcoming IPOs.