With more than 25 companies debuting on the public markets, 2026 has recorded the highest number of biotech IPOs since 2021. Now, four companies—including Iambic Therapeutics and ADARx Pharmaceuticals—are looking to grow this total even further.
Four drugmakers have announced their plans to go public, adding to this year’s flood of IPOs after a closed window period.
This year has already broken biotech’s 2025 IPO slump and marks the highest number of debuts since the pandemic-driven high of 2021. This uptick has fueled the sentiment that “IPOs are working again,” Jack Bannister, senior managing director of equity capital markets at Leerink Partners, told BioSpace last month. To date, 26 biotechs have IPOed this year.
Over the last few days, four more drugmakers have sought to add to this growing total: AI-centric Iambic Therapeutics, siRNA specialist ADARx Pharmaceuticals, immunology-focused TRex Bio and cardiovascular company Retension Pharmaceuticals.
This flood of IPOs tracks with Bannister’s prediction last month that public debuts are likely to continue picking up in the fall of this year. “The latest group of August IPOs are all above deal price and trading well,” he told BioSpace. “Odds are that means we see an even bigger collection in September, October, and it just builds on itself that way.
With Big Tech backer, Iambic seeks money to advance cancer candidates
NVIDIA-backed Iambic is looking to debut on the Nasdaq in an IPO designed to advance the startup’s pipeline of investigational cancer treatments, according to a Monday SEC filing.
Iambic hasn’t specified how much money it expects to raise yet or when the planned offering will close. The company plans to operate under the ticker IAM once it goes public. Proceeds will primarily be used to support the development of its lead candidate IAM1363, an oral HER2 inhibitor designed to be able to penetrate the brain and target several known disease-causing mutations of the protein. IAM1363 is currently being studied in a Phase 1/1b trial for HER2-altered solid tumors, with registrational studies planned for 2027.
Some of the money will also be put toward moving the KIF18A blocker IAM217 and the dual CDK2/4 inhibitor IAM-C1 into clinical trials. Both molecules are actively undergoing research that could enable regulatory filings to launch in-human trials. Both submissions are planned for the fourth quarter.
Also on Monday, Iambic announced that it has entered into a multi-year discovery pact with AbbVie to use the biotech’s AI platform to advance small-molecule drugs for neurology, oncology and immunology indications. The AI-centered biotech has also signed recent partnerships with Takeda and Bayer.
ADARx seeks $319M for siRNA programs
ADARx is also looking to debut on the Nasdaq and raise funds for a pipeline of siRNA therapies that can address a variety of conditions “at the genetic level,” according to the biotech’s Monday prospectus.
ADARx has set a $318.6 million fundraising target for the planned IPO, assuming a $16 price per share. The financing could increase to $367.4 million if underwriters completely exercise their option to buy additional shares.
The money will help the biotech move its siRNA candidates through clinical development. In particular, the California company has set aside around $180 million to push its complement factor B program agazisiran through Phase 2 studies and beyond in a rare blood disorder called paroxysmal nocturnal hemoglobinuria, an advanced, in a late-stage form of age-related macular degeneration and in various renal diseases.
ADARx believes agazisiran “represents a pipeline-in-a-product opportunity,” with the potential to reduce infection risk across several indications, according to the SEC document.
The proceeds will also help ADARx’s most mature asset onvuzosiran complete Phase 3 testing in hereditary angioedema (HAE), for which the biotech has earmarked $65 million. Topline data from this trial are expected by the end of 2027 and, if positive, could support an approval application in 2028. The FDA has granted onvuzosiran fast track designation for HAE.
ADARx will also channel some of the money toward the Factor XI program ADX-626, the obesity asset ADX-077 and the neuron-targeting ADX-199.
ADARx is also partnered with AbbVie, with a $335 million upfront commitment in May 2025 to collaborate on siRNA-based therapies in the neurology, immunology and oncology arenas. That deal could mean “several billion dollars” in milestones, the companies said at the time.
TRex, Retension eye IPO for immuno, cardiovascular pipelines
TRex Bio and Retension Pharmaceuticals have also lined up to join 2026’s IPO class, looking to raise money for their respective pipelines focusing on immune-mediated and cardiovascular diseases. Neither company has disclosed how much they expect to raise.
TRex plans to use the proceeds for its investigational fusion protein TRB-061, currently in early-stage development for atopic dermatitis, according to a Sept. 18 prospectus. A topline Phase 1b readout is expected in mid-2027. TRex will also put some of the money into the CD30 agonist TRB-071, an investigational monoclonal antibody undergoing research to enable filings to start clinical testing.
Eli Lilly has “indicated an interest” in participating in TRex’s planned IPO, according to the SEC filing. The pharma giant in early 2023 paid $55 million upfront and bet more than $1.1 billion in potential milestones to work with TRex on immune-mediated diseases.
Meanwhile, Retension plans to put its own IPO proceeds behind its sole clinical candidate: RTN-001, a daily oral small-molecule PDE-5 blocker being developed for hypertension. The asset is currently in Phase 2b development. If it comes to pass, the IPO will help see this mid-stage study through to completion and support the advancement of the drug to Phase 3, according to a Sept. 18 prospectus.
RTN-001 is Retension’s only listed pipeline asset.
