Odyssey, Sionna join band of biotechs ready to brave thawing IPO waters in 2025

Odyssey Therapeutics and Sionna Therapeutics have filed IPO paperwork, swelling the pack of startups that will provide an early look at how receptive public investors could be to biotech listings in 2025.

Maze Therapeutics and Metsera filed to list their stocks earlier in January. Like those two companies, Odyssey and Sionna have clinical-phase programs, sizable bank balances and investor syndicates stocked with well-known VCs—the sorts of attributes that have enabled biotechs to successfully navigate choppy IPO waters in the recent past.

Sionna is building on the efforts of Sanofi and AbbVie in cystic fibrosis. Greg Hurlbut, Ph.D., and Mark Munson, Ph.D., set up the biotech after working together at Sanofi, and it wasn't long before Sionna had licensed compounds designed to stabilize NBD1 from the French pharma for $1.5 million upfront.

Multiple companies have studied NBD1, reflecting its key role in CFTR function, but are yet to develop a drug against the target. Pfizer called its results “discouraging,” adding that the binding domain “may not contain the features needed to build high‐affinity interactions.” However, Sionna believes it can hit the target, positioning it to advance treatments for the 90% of cystic fibrosis patients with F508del mutations.

Vertex already sells its triple combination therapies Trikafta and Alyftrek for use in patients with F508del mutations. Sionna wants to test its lead NBD1 stabilizer candidate in combination with Trikafta, but it also plans to study the molecule with its own CFTR modulators. The biotech added to its portfolio of CFTR modulators last year by picking up three candidates from AbbVie.

Sionna plans to advance a combination of an NBD1 stabilizer and complementary modulator through phase 1 and phase 2a and into phase 2b using the IPO funds. The biotech is yet to pick which molecules to include in the combination. AbbVie could benefit from the choice, with Sionna agreeing to give the Big Pharma up to $360 million in milestones and rights of first negotiation.

The IPO filing acknowledges some of the challenges Sionna may face if it runs trials that require people to stop taking standard of care. Sionna said AbbVie terminated part of a phase 2 trial that planned to test a CFTR potentiator and corrector after deeming it “not enrollable due to, among other reasons, the increasing availability of Trikafta.” The biotech licensed the CFTR potentiator and corrector from AbbVie.

Meanwhile, Odyssey is seeking funding for autoimmune and inflammatory disease programs, according to its filing. The pipeline is led by a RIPK2 inhibitor that is set to start a phase 2a monotherapy trial for ulcerative colitis this quarter. Odyssey said the IPO funding will enable it to complete the monotherapy trial and generate induction-stage data from a phase 2a trial that will test the candidate in combination with Takeda’s Entyvio.

The biotech has struck deals to add to its assets and capabilities, buying Rahko for its machine learning prowess and acquiring IFM Discovery for MDA5 and NLRP1 discovery programs. IFM was a subsidiary of IFM Therapeutics, a biotech founded by Odyssey CEO Gary Glick, Ph.D. Glick previously set up and ran Scorpion Therapeutics, which Eli Lilly is now buying for up to $2.5 billion.

Johnson & Johnson and Pfizer have partnerships with Odyssey. J&J paid $6.5 million to jointly discover and optimize small molecules using Odyssey’s artificial intelligence and machine learning capabilities. Pfizer paid $1 million as part of a collaboration intended to identify novel hits using Odyssey’s natural product platform.