Two RNA biotechs, ADARx Pharmaceuticals and City Therapeutics, are taking advantage of the IPO frenzy, which has led to a total of 27 newly public biotechs so far this year.
ADARx Pharmaceuticals has surpassed its own IPO expectations, raising $446.3 million to go public. Meanwhile, City Therapeutics has filed plans to make its own public debut.
ADARx hit the markets Thursday with an upsized offering at $17 per share, higher than its previously expected $318.6 million target at an estimated $16 per share. In total, the California biotech sold 26.25 million shares of common stock, with underwriters given the option to purchase 3.9 million more shares within 30 days.
Additionally, AbbVie is conducting a simultaneous private placement that will give the pharma about 4.9% of ADARx’s outstanding shares after the IPO closes. The pharma already has ties to ADARx, linking up last year via a licensing deal that included $335 million upfront to find new treatments across neuroscience, immunology and oncology.
ADARx’s financing is the third largest biotech IPO so far this year, coming in after two industry record-breakers: Kailera Therapeutics at $625 million and Parabilis Medicines’ $670 million debut.
ADARx will use the newfound cash to advance its siRNA candidate agazisiran, a complement factor B program, through mid-stage studies and beyond for several complement-mediated diseases. The biotech believes agazisiran represents a pipeline-in-a-product opportunity, with the potential to reduce infection risk across several indications.
The proceeds will also move ADARx’s most mature asset onvuzosiran through Phase 3 testing in hereditary angioedema (HAE), with topline data expected by the end of next year.
ADARx is led by CEO Zhen Li, who started her pharma career at Merck before cofounding the biotech. The company is the most recent industry addition to the public market, becoming the 27th industry IPO after Electra Therapeutics’upsized $350 million last week.
Meanwhile, another RNA biotech also plans to join the IPO frenzy. City Therapeutics, a member of BioSpace’s 2026 NextGen class of startups to watch, intends to go public, according to a Thursday SEC filing. The RNAi biotech did not lay out how much money it planned to raise.
Founded in 2023 by former Alnylam leader John Maraganore, City broke ground with a $135 million series A in the fall of 2024 and raised an additional $99.5 million in series B money this summer, with backing from big name investors such as ARCH Venture Partners, Fidelity and Regeneron Ventures, among others.
The proceeds will go toward the clinical development of CITY-FXI, which is currently being evaluated in a Phase 1 trial for thrombosis, or the abnormal formation of blood clots. The IPO will also fuel trials for other assets and continue to build out City’s RNA platform.
Over the past two weeks, three other biotechs—AI-centric Iambic Therapeutics, immunology-focused TRex Bio and cardiovascular company Retension Pharmaceuticals—have also filed to go public.
