Alopexx has resuscitated its plans for a public listing as the biotech seeks urgently needed funds to advance a pipeline that includes an infectious disease antibody that was once the focus of a $375 million deal with Sanofi.
The Cambridge, Massachusetts-based company is planning to offer 3 million shares priced between $10 and $12 apiece, according to a June 26 filing with the Securities and Exchange Commission. Assuming the final price falls in the middle of this range, Alopexx expects to bring in $30.1 million in net proceeds—rising to $34.7 million if underwriters fully take up their option of buying an additional 450,000 shares at the same price.
The aim is to list the common stock on the NYSE American exchange under the ticker “ALPX.”
The biotech is developing two candidates, both of which target poly N-acetyl glucosamine (PNAG). The target is expressed by more than 75 pathogens, including antimicrobial-resistant microbes, and plays a role in their survival and virulence. Those attributes have led scientists to hail PNAG as an important vaccine target and have fueled years of research.
The company has earmarked $6 million for a proof-of-concept study of a PNAG vaccine dubbed AV0328, which has previously completed a phase 1 trial. The biotech has previously pitched the asset as complementary to the currently approved Streptococcus pneumoniae vaccines Prevnar, Pneumovax and Vaxneuvance.
Alopexx also expects it will need $9 million of the IPO haul to launch a proof-of-concept trial of an antibody called F598. Sanofi had licensed the asset from Alopexx Pharmaceuticals, an ancestor to the current biotech of the same name, in 2009 but faced challenges such as the slow enrollment (PDF) of a phase 2a trial.
The plan now is to test F598 in intensive care patients as a way to provide immediate protection against pathogens for individuals at urgent or near-term risk of developing an infection.
A high-net-worth U.S. family with ties to Alopexx CEO Daniel Vlock, M.D., funded the programs through 2017 but then decided to exit investments including the vaccine and antibody candidates. Should the IPO go through, Vlock will hold 56.3% of Alopexx’s outstanding common stock, making the biotech a “controlled company” under the NYSE American’s listing requirements.
Alopexx has been mulling an IPO since 2022, and as recently as February 2025 the company had updated its paperwork to suggest a $9.9 million offering could be in the works. But with just $40,000 left in the bank, the biotech can’t afford to wait any longer. According to last Friday’s filing, the company doesn’t “intend to have any full-time employees prior to the completion of the IPO.”
The timing couldn’t be better—recent record-breaking listings from the likes of Kailera Therapeutics and Parabilis Medicines have demonstrated a renewed appetite for drug developers on the public markets.