Navocaftor

Cystic fibrosis drug developer Sionna Therapeutics hopes to join the IPO wave started by Metsera and Maze Therapeutics last week. Sionna, which snagged some of its programs from AbbVie last year, hopes to garner net proceeds of $135 million from its proposed Nasdaq debut as $SION, according to an updated SEC filing on Monday morning. The biotech had revealed its IPO intentions at the same time as immunology drug developer Odyssey Therapeutics a day after the JP Morgan Healthcare Conference concluded last month. Odyssey has not yet revealed its IPO sizing. Sionna, Odyssey and a handful of other biotech startups seek to follow obesity-focused Metsera and kidney disease drug developer Maze. Metsera and Maze floated last Friday , raising about $275 million and $140 million, respectively. Metsera popped 47% $MTSR in its first day of trading, perhaps a sign of investors’ ongoing enthusiasm for new obesity medications. Maze, meanwhile, struggled to stay at its launch price, ending the first day down 0.31% $MAZE . After the listings from Sionna, Odyssey and other Nasdaq hopefuls Aardvark and Aurion, the IPO market will likely be quiet for a few weeks as companies digest year-end audits, Raymond James bankers wrote in a biotech market check on Sunday evening. Activity will then likely resume in early March. “A growing backlog of 10-15 biotechs are watching the market and could potentially launch in that window,” the Raymond James team wrote. “It is clear that launching an IPO in this market is not an obvious yes and we expect companies to be appropriately cautious.” In its updated IPO planning docs, Sionna outlined an offering of 8.82 million shares. It’s marketing the shares at $16 to $18 apiece. Last week, Metsera priced above its range, but sold fewer shares than initially planned. Maze, on the other hand, sold more shares than initially anticipated but priced at the midpoint of its marketed range. Metsera’s IPO was oversubscribed 14-fold, the Raymond James bankers said. “The majority of this early wave of IPOs this year needs to trade well in the aftermarket to have a functioning and constructive IPO market going forward,” the bankers wrote. Boston-based Sionna disclosed a $182 million Series C last year and shortly after disclosed an in-licensing deal for three experimental cystic fibrosis drugs from AbbVie. While the upfront payments were minimal — $5 million plus $8.6 million worth of common stock — AbbVie stands to receive up to $490 million in development, commercial and sales-based biobucks. Sionna plans for topline Phase 1 data on its NBD1 stabilizers SION-719 and SION-451 in the first half of this year. It will then select one of those for a Phase 2a in the second half of 2025, according to its IPO paperwork. The biotech also has clinically-tested assets galicaftor, a TMD1-directed CFTR corrector, and navocaftor, a CFTR potentiator. Galapagos had originally tested them before handing them to AbbVie . Founded in 2019, Sionna isn’t in dire need of cash. CEO Mike Cloonan, a former Sage and Biogen executive, told Endpoints News last year that the Series C would bankroll Sionna through 2026 . The company still had $180 million in cash, equivalents and marketable securities at the end of September, according to its S-1 filing. In the first nine months of 2024, it devoted $43 million to R&D. Its biggest investors include RA Capital, TPG Growth, Atlas Venture and OrbiMed. Odyssey, meanwhile, hopes to go public with a new chief financial officer announced just last month. Jason Haas joined after a three-year stint in the same post at Syros Pharmaceuticals . Prior to that, he was a longtime investment banker at Barclays, Deutsche Bank and Goldman Sachs.

Sionna Therapeutics has secured exclusive worldwide rights to develop and commercialize multiple clinical-stage compounds through a license agreement with AbbVie. Under the terms of the agreement, Sionna will assume all development responsibilities for galicaftor (ABBV-2222), a transmembrane domain 1 (TMD1)-directed cystic fibrosis transmembrane conductance regulator (CFTR) corrector, and navocaftor (ABBV-3067), a CFTR potentiator, both of which have completed Phase 2 studies, and a Phase 1 TMD1-directed corrector, ABBV-2851. Sionna will prioritize advancing one of the AbbVie compounds and SION-109 as potential dual combination options with a first nucleotide binding domain (NBD1) stabilizer. AbbVie will receive an upfront payment, an equity investment in Sionna and will be eligible to receive late-stage development and commercial milestones and royalties. "Our strategy is to build a CF franchise anchored on our novel correctors that stabilize the NBD1 of the CFTR protein," said Mike Cloonan, President and Chief Executive Officer of Sionna. "Combining NBD1 stabilizers with just one complementary CFTR modulator gives us the potential to deliver superior efficacy over the current standard of care. With this agreement, we are significantly expanding and accelerating our pipeline of complementary modulators to combine with NBD1 and creating multiple options for potentially transformational combinations to fully normalize CFTR function. We are well-positioned to execute our differentiated dual combination development path to provide more efficacious options for people with CF," Cloonan added. In clinical studies conducted by AbbVie, ABBV-2222 and ABBV-3067 have been generally safe and well-tolerated. In Phase 2 studies, ABBV-2222 in combination with ABBV-3067 demonstrated clinical efficacy, including increased percent predicted forced expiratory volume in 1 second (ppFEV1) and reduced sweat chloride (SwCl) levels, comparable to approved dual modulator combinations. In pre-clinical assays, including the Cystic Fibrosis Human Bronchial Epithelial (CFHBE) assay, performed by Sionna, dual combinations of a Sionna NBD1 stabilizer and a licensed complementary AbbVie modulator demonstrated the potential for superior efficacy over the current standard of care and some combinations have the potential to fully correct ΔF508 CFTR and achieve wild type levels of CFTR function. "With the CF therapies available today approximately two-thirds of people still do not achieve normal CFTR function," said Patrick Flume, MD, Professor of Medicine and Pediatrics at the Medical University of South Carolina and clinical advisor to Sionna. "It is exciting to see new potential modulator combinations being developed based on the novel ability to stabilize NBD1 and encouraging to see that NBD1 modulators combined with the three licensed programs from AbbVie have the potential for superior efficacy compared to standard of care. There is more we can do for people with ΔF508 CF, and I look forward to seeing these novel double combinations advanced in clinical development," Flume added. As previously announced, Sionna expects to complete a Phase 1 study of its complementary modulator SION-109, targeting the interface between the intracellular loop 4 (ICL4) region and the NBD1 domain of the CFTR protein, in the second half of 2024. The company also plans to initiate Phase 1 studies of two NBD1 stabilizers, SION-451 and SION-719, this year.