Cystic-fibrosis-focused Sionna Therapeutics is joining the Nasdaq this morning with an upsized public offering, while obesity biotech Aardvark Therapeutics unveiled plans for a nine-figure IPO of its own.
Waltham, Massachusetts-based Sionna is selling its shares for $18, at the upper end of the range it set out on Monday. The biotech has also increased the number of shares in its offering—from the 8.8 million it had originally planned up to 10.6 million today.
This means that the company is set to bring in gross proceeds of $191 million from the IPO, compared with the net proceeds of $135.3 million it outlined earlier this week. The amount of shares available to underwriters has also risen slightly from 1.3 million to 1.6 million, meaning Sionna still has a chance to bring in a further $28.6 million from the IPO.
The main focus of Sionna, which will list on the Nasdaq Feb. 7 under the ticker “SION,” is advancing 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 related to three CFTR modulators that the biotech picked up last year from the pharma.
Sionna wants to test its lead candidate in combination with Vertex’s Trikafta, but it also plans to study the molecule with its own CFTR modulators.
The company's Nasdaq debut comes a week after fellow obesity biotech Metsera and renal- and metabolic-focused Maze Therapeutics both listed with offerings of $275 million and $140 million, respectively.
Coming up behind Sionna in the IPO queue is Aardvark, which has now given a sense of the size of the listing it’s aiming for. The obesity-focused biotech is hoping to offer 5.9 million shares priced between $16 and $18 apiece, according to a Securities and Exchange Commission filing Feb. 6.
Assuming the final share price falls in the middle of this range, the IPO should bring in net proceeds of $88.9 million—rising to $102.9 million if underwriters fully take up their option to buy an additional 883,200 shares at the same price.
Aardvark’s pipeline is headed up by ARD-101, a bitter taste receptor (TAS2R) pan-agonist designed to stimulate enteroendocrine cells of the digestive tract. The aim is to release gut-peptide hormones such as GLP-1—the function of which is a focus of Novo Nordisk and Eli Lilly’s blockbuster weight loss drugs—and the satiety hormone cholecystokinin, thereby activating gut-brain neurologic signaling to reduce feelings of hunger.
ARD-101 has already shown an ability to suppress appetite when used alone or in combination with Novo and Lilly’s approved drugs, according to previous comments by Aardvark.
The biotech has evaluated ARD-101 in a trio of phase 2 studies, including a trial in 20 patients with general obesity that showed individuals who received ARD-101 experienced a 2.51-fold greater reduction in hunger rating compared to placebo. Meanwhile, a study in 12 patients with a rare genetic condition called Prader-Willi syndrome, which makes them feel constantly hungry, showed that 11 of these patients experienced a reduction in severe hunger in 28 days.
There are also plans to begin a phase 2 study in severe hunger and obesity linked to the treatment of a type of brain tumor called craniopharyngioma.
When it unveiled last month an ambition to go public, Aardvark said it expected to use the proceeds to “advance the clinical development of ARD-101” as well as continue work on another clinical-stage obesity asset called ARD-201, which is a fixed-dose combination of ARD-101 and a DPP-4 inhibitor.
The biotech has raised a total of $129.1 million since being launched in 2021, with the most recent funding infusion being a $85 million series C in May 2024 led by VC firm Decheng Capital.