A Boston-area biotech that wants to eliminate the immune cells responsible for autoimmune disease, rather than merely suppress the inflammation they cause, emerged from stealth last week with $48 million in Series A funding. The company, ai3Bio, was formed by merging Corner Therapeutics with Novasenta and reflects a broader industry shift toward permanently altering rather than chronically managing autoimmune conditions.
UPMC Enterprises and Ziff Capital Partners led the round, which also drew backing from Cockrell Interests and Tanis Ventures. The financing supports two experimental platforms designed to selectively kill disease-causing Th17 cells in patients with autoimmune disorders. Management said the capital will fund preclinical work toward investigational new drug applications, with hopes of reaching human trials sometime in the next couple of years.
ai3Bio itself is something of a hybrid. Earlier this year, Watertown, Massachusetts-based Corner Therapeutics—which raised $54 million in April 2024—combined with Novasenta, a Pittsburgh oncology immunology startup backed by UPMC that had raised $40 million in 2022. The new entity now operates from headquarters in Watertown with additional operations in Pittsburgh, though it declined to disclose employee headcount or valuation details.
"We founded ai3Bio to reimagine autoimmune care, shifting the focus from broadly suppressing inflammation to precisely removing the underlying cause of disease," CEO Steven Altschuler said in a statement announcing the funding.
Altschuler brings considerable credibility to the venture. He ran Children's Hospital of Philadelphia from 2000 to 2015 and co-founded Spark Therapeutics, where he served as board chair. That pedigree, combined with a scientific advisory board that includes John Maraganore—founding CEO of Alnylam Pharmaceuticals—and several prominent immunology researchers, suggests the company has attracted serious attention despite its early stage.
The science centers on a target called CD161, a marker associated with pathogenic Th17 cell populations implicated in autoimmune conditions. ai3Bio is pursuing two distinct methods to reach those cells. The first, dubbed STARx, uses lipid nanoparticles to deliver mRNA that triggers targeted cell death by activating the cGAS-STING pathway. The company reported it has demonstrated ex vivo depletion of pathogenic Th17 cells from blood samples of autoimmune patients using this approach, though details remain sparse.
The second platform, T Deplete, takes a more conventional route with a monoclonal antibody that recruits natural killer cells and other immune effectors to eliminate the same Th17 populations. That antibody showed what the company described as "potent efficacy" in a non-human primate model.
Jonathan Kagan, the scientific co-founder leading strategy as distinguished scientist, framed the approach with a memorable analogy. "Immunologically, the cytokine is the bullet, and the cell is the gun," he told Fierce Biotech. "We want to take this gun out of the hands of the immune system when it's misbehaving."
It's a distinction with potential significance. Most current autoimmune therapies block IL-17, the inflammatory cytokine that Th17 cells produce. Drugs like Cosentyx and Taltz have built multi-billion-dollar franchises doing exactly that, but they require continuous dosing because the underlying cells persist. ai3Bio is wagering that eliminating the cells themselves could offer something closer to a reset, perhaps even a one-time intervention.
Whether that ambition proves realistic remains an open question. The company has not disclosed a lead indication or provided timelines beyond a general aspiration for clinical trials in 2027 or 2028. Management confirmed to Fierce Biotech that another fundraising round is already underway, a signal that the $48 million may fund only an initial phase of development.
The broader market context, though, suggests investors see opportunity in cell-targeted autoimmune therapies. AbbVie paid up to $2.1 billion in 2025 to acquire Capstan Therapeutics and its in vivo anti-CD19 CAR-T candidate for autoimmune indications. Bristol Myers Squibb followed with a $1.5 billion upfront deal for Orbital Therapeutics and its circular RNA-encoded CD19 CAR-T. Both transactions centered on repurposing cancer immunotherapy technology for autoimmune disease.
Kyverna Therapeutics is advancing an autologous anti-CD19 CAR-T through multiple autoimmune indications and received an investigational new drug acceptance in January for a faster-manufacturing version. Sana Biotechnology is evaluating its own candidate in B-cell mediated autoimmune diseases. The competition, in other words, is heating up.
ai3Bio is targeting a different cell type—Th17 rather than B cells—which may offer a distinct mechanism or patient population. Kagan emphasized that point in the company's announcement, noting that the approach aims to preserve the function of the broader immune system while selectively removing pathogenic cells. "We believe this unique mechanism will allow for a true, first-of-its-kind T cell immune system reset," he said.
The market certainly seems large enough to accommodate multiple approaches. Autoimmune disease treatment has grown into a sector exceeding $130 billion globally, driven by conditions affecting more than 15 million Americans. A September 2026 report from Research and Markets estimated the market at $132.75 billion in 2025, with a compound annual growth rate of 7.5 percent projected through 2034.
Still, the path from promising preclinical data to approved therapy is notoriously difficult in immunology. The field is littered with candidates that looked compelling in animal models but failed to translate in humans. ai3Bio will need to demonstrate not just that it can deplete Th17 cells, but that doing so provides meaningful clinical benefit without unacceptable side effects. Th17 cells, after all, also play roles in defending against certain infections.
For now, the company is betting that its dual-platform strategy—both a nanoparticle-mRNA system and a more traditional antibody—offers flexibility and perhaps a better shot at finding the right approach for different patient populations or disease settings. The next couple of years will reveal whether that bet, and the $48 million backing it, can deliver on the promise of fundamentally changing how autoimmune diseases are treated.
Fabian Tenenbaum, executive vice president at UPMC Enterprises, chairs the board. Vijay Kuchroo, one of the scientific advisors and a prominent immunology researcher, said in the release that he was selective about time commitments but believed ai3Bio "has the potential to revolutionize autoimmune disease treatment."
Perhaps it does. The industry has certainly shown it believes cell-targeted therapies represent the next frontier in autoimmune care, judging by the acquisition activity and capital flowing into the space. Whether ai3Bio can execute on that vision, and whether its particular approach to Th17 cells proves clinically meaningful, are questions that only data from human trials will answer.
