Sionna plans US $156M IPO to fund cystic fibrosis trials

USA – Sionna Therapeutics, a biotech company focused on cystic fibrosis (CF) treatments, is preparing for a US $156 million initial public offering (IPO) to advance its lead drug candidate into phase 2 trials.

Based in Waltham, Massachusetts, Sionna had already announced its plan to go public but has now revealed details on how much it hopes to raise.

According to a Feb. 3 SEC filing, Sionna plans to sell 8.8 million shares at a price range of US $16 to US $18 per share.

If shares are sold at the mid-point price, the company expects to raise US $135.3 million. This could increase to US $156.2 million if underwriters exercise their 30-day option to buy an additional 1.3 million shares.

Sionna’s move follows recent biotech IPOs, including Metsera, which raised US $275 million, and Maze Therapeutics, which secured US $140 million.

The company’s main goal is to push a combination therapy—including an NBD1 stabilizer and complementary modulator—through early-stage trials and into phase 2b using funds from the IPO.

However, it has not yet finalized which molecules will be included in this treatment.

As part of its research, Sionna plans to test its drug alongside Vertex Pharmaceuticals’ Trikafta, a leading CF therapy. The biotech is also considering studying its own CFTR modulators as alternative options.

Partnership with AbbVie

In 2023, Sionna licensed three CFTR modulators from AbbVie, agreeing to pay up to US $360 million in milestone payments.

AbbVie also retains first negotiation rights for these treatments. If Sionna’s lead candidate performs well, AbbVie could benefit significantly from the deal.

Sionna acknowledged potential recruitment challenges for its trials, as patients may be reluctant to stop taking existing CF treatments.

The company pointed to an earlier phase 2 trial, where AbbVie ended part of the study because it was “not enrollable” due to the widespread use of Trikafta.