ADARx Pharmaceuticals has made a strong entry into the public markets, raising $535.3 million in its initial public offering (IPO) and concurrent private placement. The company’s research focuses on RNA-targeting drugs, specifically using small-interfering RNA (siRNA) to degrade disease-causing proteins. This approach, known as RNA interference or gene silencing, aims to stop protein production at its source, addressing limitations of traditional therapies like small molecules and monoclonal antibodies.
The IPO, which priced at $17 per share, exceeded initial expectations, with ADARx offering over 26 million shares. This, combined with a private placement from partner AbbVie that raised $89 million, brings the total funding to $535.3 million. Shares began trading on the Nasdaq under the symbol “ADRX.”
A New Approach to Drug Development
The company’s lead program, onvuzosiran, is an experimental treatment for hereditary angioedema (HAE), a rare genetic disorder causing unpredictable and potentially fatal swelling attacks. Onvuzosiran targets the protein pre-kallikrein, which plays a key role in HAE. In Phase 1/2 testing, onvuzosiran led to a “robust reduction” in blood levels of pre-kallikrein and kallikrein, with durability supporting dosing every three or six months. A 90-patient placebo-controlled Phase 3 study is ongoing, with preliminary data expected by the end of 2027. If positive, ADARx plans to file an FDA submission in 2028.
Advancing the Pipeline
In addition to onvuzosiran, ADARx has several other programs in development. Agazisiran, a siRNA targeting factor B, is being tested in rare kidney diseases, paroxysmal nocturnal hemoglobinuria, and geographic atrophy. ADX-626 targets Factor XI for secondary stroke prevention, with a Phase 1 test in healthy volunteers ongoing. ADARx plans to start a Phase 2a/b trial in 2027, expecting preliminary data by year-end.
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The company’s preclinical programs, ADX-077 and ADX-199, aim to demonstrate siRNA delivery beyond the liver, targeting adipose tissue for obesity and neurons for Alzheimer’s disease, respectively. A Phase 1 trial for ADX-077 is planned with a $25 million budget.
Financial Backing and Future Plans
ADARx has secured significant financial backing, including a $200 million Series C round led by Bain Capital Life Sciences and TCGX in 2023. OrbiMed is the largest shareholder, with a 22.7% stake post-IPO. AbbVie, a key partner, will own approximately 4.9% of ADARx’s shares after the private placement, having paid $335 million upfront for a partnership in neuroscience, immunology, and oncology.
With a cash position of $427.3 million as of June and the IPO proceeds, ADARx plans to allocate funds across its pipeline. Approximately $65 million is designated for onvuzosiran’s key trial and pre-commercialization activities. Another $180 million is budgeted for completing the Phase 2 test of agazisiran and advancing that program to Phase 3. ADARx has budgeted $80 million for ADX-626’s Phase 1 test in healthy volunteers and the start of Phase 2 testing in secondary stroke prevention.
