ADARx Pharmaceuticals raises $446.3 million in upsized US IPO

Sept 25 (Reuters) - ADARx Pharmaceuticals ADRX.O said on Thursday it had raised $446.3 million in an upsized US initial public offering, reflecting growing investor appetite for biotech listings.

The San Diego-based drug developer sold 26.3 million shares at $17 apiece, the top end of its marketed range, up from its earlier plan to sell 21.9 million shares.

Biotech has emerged as a bright spot in this year's IPO market, with a steady flow of listings continuing into the fall as investors favor the sector's relative insulation from the Iran war and AI-driven disruption.

Drug developers City Therapeutics and Iambic Therapeutics filed for US IPOs this week, while Retension Pharmaceuticals and TRex Bio filed for listings last week.

Electra Therapeutics ETRA.O also raised $350 million in an upsized US IPO before making its market debut last Friday. Its shares have fallen about 21% since.

Founded in 2019, ADARx's experimental drugs target diseases related ​to immunity, kidney, cardiovascular and neurological systems.

The company's most advanced candidate, onvuzosiran, is in late-stage testing for hereditary angioedema, a rare genetic disorder that causes sudden swelling attacks.

Drugmaker AbbVie ABBV.N has agreed to invest up to $100 million in a concurrent private placement, which would give it a roughly 4.9% stake ​post-IPO, ADARx said.

J.P. Morgan, Morgan Stanley, TD ​Cowen, among others, are the underwriters for ADARx's offering. The stock will start trading on Nasdaq on Friday under the symbol "ADRX."

(Reporting by Pragyan Kalita in Bengaluru; Editing by Shreya Biswas)

((Pragyan.Kalita@thomsonreuters.com;))