ADARx Pharmaceuticals files for IPO, plans Nasdaq listing as ADRX

The offering

ADARx Pharmaceuticals, Inc. (ADRX) filed a Form S-1 on September 4, 2026 for an initial public offering of its common stock. The San Diego company has applied to list on The Nasdaq Global Market under the symbol ADRX, and the offering is contingent on that approval. The cover leaves the number of shares and the expected price range blank, so the size of the raise is not yet known. The company has granted the underwriters a 30-day option to buy additional shares.

The underwriters named on the cover are J.P. Morgan, Morgan Stanley, TD Cowen, UBS Investment Bank and LifeSci Capital. The cover does not label a lead or sole bookrunner. At the company's request, the underwriters have reserved up to 2% of the shares for directors, officers, certain employees, business associates, investors and friends and family, with sales made by J.P. Morgan Securities LLC through a directed share program. Cooley LLP and Latham & Watkins LLP appear in the "Copies to" block on the cover, which does not state which firm acts for the company and which for the underwriters. The company is an emerging growth company and a smaller reporting company.

Before the offering, all convertible preferred stock outstanding at June 30, 2026 converts into 76,920,354 shares of common stock. Proceeds are to fund agazisiran, onvuzosiran, ADX-626, ADX-077 and ADX-199, together with existing cash, with the rest for research, working capital and general purposes.

The pipeline

ADARx calls itself a late-clinical stage company developing small interfering RNA (siRNA) drugs. It has three clinical programs and two advanced preclinical programs. It was incorporated in December 2019, and the prospectus warns that it has not completed any clinical program and has no approved product.

Its most advanced program, onvuzosiran, targets prekallikrein to prevent hereditary angioedema attacks. A randomized, double-blind, placebo-controlled phase 3 trial, STOP-HAE, is enrolling 90 adults, with topline data expected by the end of 2027 and a possible NDA submission in 2028 if the data are positive. The FDA granted Fast Track designation in August 2026. The company says a recently approved antisense drug in the same field showed attack-free rates of 35% (Q8W) to 53% (Q4W), which it says leaves room for improvement.

Agazisiran, aimed at complement factor B, is in three phase 2 trials covering kidney diseases, paroxysmal nocturnal hemoglobinuria and geographic atrophy, with initial data expected in mid- to second half of 2027. ADX-626 targets Factor XI for secondary stroke prevention and is in a phase 1 single ascending dose trial in healthy volunteers; the company plans a phase 2a/b trial in 2027. It cites asundexian, a rival oral drug, which reduced recurrent ischemic stroke by 26% against placebo in a phase 3 trial, and names milvexian and abelacimab as other late-stage competitors.

The company says it saw deep, durable protein reduction in each clinical program, but the summary gives no patient numbers or response data. The preclinical obesity program ADX-077 and Alzheimer's program ADX-199 are not yet in humans; phase 1 trials are planned for 2027 and by the end of 2027 or early 2028, with data in 2028.

The money

In May 2025 ADARx signed a discovery collaboration with AbbVie and received an upfront cash payment of $335.0 million. It is eligible for up to $385.0 million in option payments, up to $7.45 billion in contingent milestones and royalties from the high single digits to mid-teens.

The statements show collaboration revenue of $3,449 thousand in 2025 and none in 2024. Research and development expense was $71,512 thousand in 2025, up from $43,357 thousand, and general and administrative expense was $20,302 thousand. The net loss was $73,088 thousand in 2025, against $46,360 thousand in 2024, after interest income of $13,641 thousand. For the six months ended June 30, 2026, the net loss was $48,426 thousand, against $33,644 thousand a year earlier, on revenue of $2,886 thousand.

Zhen Li, Ph.D., the chief executive and co-founder, previously worked at Arrowhead Pharmaceuticals and Merck. Ryan Fisk, the chief financial officer, previously worked at Goldman Sachs.

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