RNA drugmaker ADARx Pharmaceuticals on Thursday priced its $446.3 million initial public offering, and received an additional boost with a separate investment from development partner AbbVie.
The biotechnology firm sold more than 26 million shares at $17 apiece, at the top end of the $15-$17 price point it originally laid out in federal filings. It also secured about $89 million through a private stock sale to AbbVie. ADARx begins trading on Nasdaq on Friday under the ticker symbol “ADRX.”
ADARx is one of a handful of companies specializing in what’s called RNA interference, a form of drugmaking that involves stopping the body from producing problematic proteins. Biotechs like Alnylam Pharmaceuticals and Arrowhead Pharmaceuticals have successfully brought RNAi drugs to market.
Still, in its IPO filing, ADARx referred to the technology as “constrained” by delivery and potency challenges that have blunted its “broader potential.” So far, every marketed RNAi medicine aims at drug targets in the liver. ADARx has a pipeline of therapies directed at targets in the liver and elsewhere. The company is also relying on tools it believes to have created “optimized” RNA interference therapies for chronic conditions.
Its most advanced drug is dubbed onvuzosiran and in late-stage testing for patients with the rare swelling disorder hereditary angioedema. Though a different kind of RNA-based therapy from Ionis Pharmaceuticals is available for HAE, ADARx claimed onvuzosiran could be more potent and be dosed as infrequently as twice yearly.
Early-stage study results showed ADARx’s drug could drive down levels of the protein plasma kallikrein by as much as 93%. Lowering plasma kallikrein is known to reduce swelling episodes in HAE.
Early data from a Phase 3 study are expected by the end of 2027, according to the IPO filing.
ADARx is also conducting multiple mid-stage trials for a drug called agazisiran, which the company referred to as a “pipeline-in-a-product opportunity” for certain kidney diseases, geographic atrophy and the rare blood disorder paroxysmal nocturnal hemoglobinuria. Behind agazisiran is a treatment for stroke prevention and two prospects for obesity and neurological disorders that act on targets outside of the liver.
Last year, AbbVie paid ADARx $335 million up front in a deal to codevelop drugs for neurological conditions, immune disorders and cancer. Prior to its IPO, venture firms such as OrbiMed, Bain Capital, TCGX and Venrock had loaded the biotech with more than $350 million in private funding.
ADARx’s IPO is the first for an RNA-focused biotech in almost two years. It’s also the only maker of RNAi drugs to price a traditional IPO in the U.S. in over a decade. The bulk of the 22 drug companies to price IPOs in 2026 have been small molecule or biologics developers, according to BioPharma Dive data.
New stock sales for the sector are on their fastest pace since 2021. Biotech firms have also dominated recent overall IPO activity, according to Renaissance Capital, a firm tracking new stock offerings. But “more concerns about AI spending, a 19-year high in bond yields and resumed rate hikes” could slow the rate of new offerings in the coming months, according to a quarterly review Renaissance posted Thursday.
Still, four biotechs have filed plans to go public over the past week, including fellow RNA drug developer City Therapeutics, AI drugmaker Iambic Therapeutics and immune disease-focused TRex Bio.
