RNAi Drug Developer ADARx Raises $446.3 Million in U.S. IPO, First in More Than a Decade

RNA interference (RNAi) drug developer ADARx raised about $446.3 million through an initial public offering (IPO). It is the first traditional IPO by an RNAi company in the United States in more than a decade.

ADARx issued more than 26 million shares at $17 per share on the 24th, local time, according to BioPharma Dive. The price was at the top of the initially proposed range of $15 to $17.

The company also raised about $89 million through a private placement to development partner AbbVie. ADARx will begin trading on Nasdaq on the 25th under the ticker symbol “ADRX.”

RNAi is a method of making drugs that prevent the production of disease-causing proteins. Alnylam and Arrowhead have succeeded in bringing RNAi therapies to market.

However, in its IPO filing, ADARx said the technology’s “broader potential” has been limited by constraints in delivery and efficacy. All RNAi therapies currently on the market target the liver.

ADARx’s lead drug candidate is onvuzosiran, which is in late-stage clinical trials for patients with hereditary angioedema (HAE), a rare swelling disorder.

In early studies, the drug lowered plasma kallikrein protein levels by up to 93%. A reduction in plasma kallikrein is known to reduce swelling attacks in HAE. Initial phase 3 data are expected around the end of 2027.

ADARx is also conducting several midstage clinical trials of agazisiran. The drug targets certain kidney diseases, geographic atrophy and paroxysmal nocturnal hemoglobinuria.

Last year, AbbVie paid ADARx $335 million upfront under a deal to jointly develop treatments for neurological diseases, immune diseases and cancer. Before the IPO, venture investors including OrbiMed and Bain Capital had invested more than $350 million.

ADARx’s listing is the first for an RNA-based biotech company in about two years. Most of the 22 pharmaceutical companies that held IPOs this year were developing small-molecule drugs or biologics.

According to IPO tracker Renaissance Capital, biotech IPOs are moving at their fastest pace since 2021. However, in its quarterly review, Renaissance Capital said “concerns about AI spending, the highest bond yields in 19 years and the resumption of interest rate hikes” could slow the pace of future listings.

Meanwhile, four biotechs, including RNA drug developer City Therapeutics and AI drug developer Iambic Therapeutics, filed plans to go public in the past week.